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Sample records for real-time intraocular pressure

  1. Real-time intraocular pressure measurement during phacoemulsification in dogs ex vivo

    PubMed Central

    KANG, Seonmi; PARK, Sangwan; NOH, Hyunwoo; KWAK, Jiyoon; SEO, Kangmoon

    2015-01-01

    This study was performed to evaluate changes in intraocular pressure (IOP) during standard coaxial phacoemulsification using 4 different bottle heights (BHs) and 2 different incision sizes. Coaxial phacoemulsification was performed with a venturi-based machine in 8 enucleated canine eyes through 3.0 and 3.2 mm clear corneal incisions (CCIs). A pressure transducer inserted in the peripheral cornea monitored the IOP in real-time. The surgery was subdivided into 4 stages: sculpt-segment removal, irrigation/aspiration, capsular polishing and viscoelastic removal. The mean IOP and the difference between the maximum and minimum IOPs were calculated at each stage and compared. The ultrasound time and volume of irrigation fluid used were recorded. The mean IOP increased with an elevation in the BH. The mean IOP in the irrigation/aspiration stage was significantly higher than that in the sculpt-segment removal stage at the same BH. The difference between the maximum and minimum IOP at each stage was greater in the 3.2 mm than the 3.0 mm CCIs, although the mean IOP was lower with the 3.2 mm than the 3.0 mm CCIs. The ultrasound time and irrigation fluid volume were greater with the 3.2 mm than the 3.0 mm CCIs. Therefore, fluidic parameters during each stage could be reassessed and adjusted to reduce complications arising from an elevated IOP. Phacoemulsification with 3.0 mm CCIs at a lower BH might lead to less stress on the eye from IOP fluctuations, ultrasound energy and irrigation fluid. PMID:25716691

  2. Atracurium and intraocular pressure.

    PubMed Central

    Murphy, D F; Eustace, P; Unwin, A; Magner, J B

    1985-01-01

    The effect of atracurium on intraocular pressure was studied by comparing it with pancuronium in a randomised controlled trial. The intraocular pressure was measured in patients undergoing cataract surgery before administration of the muscle relaxant, at 1, 3, and 5 minutes after its administration, and at 1 minute after tracheal intubation. Atracurium was found to decrease intraocular pressure to a significantly greater degree than pancuronium. The intraocular pressure after tracheal intubation was found to be significantly higher than that measured immediately after induction of anaesthesia. The authors conclude that atracurium provides an acceptable alternative to pancuronium for ophthalmic surgery but does not overcome the ocular hypertensive effect of tracheal intubation. PMID:3899166

  3. Pseudophakia and intraocular pressure.

    PubMed

    Radius, R L; Schultz, K; Sobocinski, K; Schultz, R O; Easom, H

    1984-06-01

    We studied the change in intraocular pressure in 373 consecutive eyes undergoing cataract extraction with intraocular lens implantation between Jan. 1, 1981, and May 31, 1982. There was a mean increase in intraocular pressure of 0.1 mm Hg following this surgery. This increase, however, was not statistically significant (P greater than .5). There was a mean rise in pressure of 0.8 mm Hg in the eyes undergoing intracapsular surgery and a mean fall in pressure of 0.6 mm Hg in the eyes undergoing extracapsular surgery (P less than .05). The change in pressure was unrelated to age, surgeon, or lens type. The results of a separate analysis of 16 eyes with a preoperative diagnosis of glaucoma and eight eyes with ocular hypertension were similar.

  4. Real-Time Retinal Vessel Mapping and Localization for Intraocular Surgery.

    PubMed

    Becker, Brian C; Riviere, Cameron N

    2013-01-01

    Computer-aided intraocular surgery requires precise, real-time knowledge of the vasculature during retinal procedures such as laser photocoagulation or vessel cannulation. Because vitreoretinal surgeons manipulate retinal structures on the back of the eye through ports in the sclera, voluntary and involuntary tool motion rotates the eye in the socket and causes movement to the microscope view of the retina. The dynamic nature of the surgical workspace during intraocular surgery makes mapping, tracking, and localizing vasculature in real time a challenge. We present an approach that both maps and localizes retinal vessels by temporally fusing and registering individual-frame vessel detections. On video of porcine and human retina, we demonstrate real-time performance, rapid convergence, and robustness to variable illumination and tool occlusion.

  5. Intraocular pressure reduction and regulation system

    NASA Technical Reports Server (NTRS)

    Baehr, E. F.; Burnett, J. E.; Felder, S. F.; Mcgannon, W. J.

    1979-01-01

    An intraocular pressure reduction and regulation system is described and data are presented covering performance in: (1) reducing intraocular pressure to a preselected value, (2) maintaining a set minimum intraocular pressure, and (3) reducing the dynamic increases in intraocular pressure resulting from external loads applied to the eye.

  6. Intraocular pressure reduction and regulation

    NASA Technical Reports Server (NTRS)

    Baehr, E. F.; Mcgannon, W. J.

    1979-01-01

    System designed to reduce intraocular pressure hydraulically to any level desired by physician over set time and in controlled manner has number of uses in ophthalmology. Device may be most immediately useful in treatment of glaucoma.

  7. [Physical exercise and intraocular pressure].

    PubMed

    Liang, Yuan-bo; Wu, Yue; Li, Si-zhen; Sun, Lan-ping; Wang, Ning-li

    2011-09-01

    In the 1960s, it had been observed that physical exercises could reduce the intraocular pressure (IOP) in patients with glaucoma. However, the effect of IOP reduction varied with exercise type and intensity, as well as the duration after exercise. Difference of lowering the IOP in glaucoma patients and healthy people were also observed. The mechanisms of reducing the IOP by exercise were very complicated and believed to be associated with the lower concentration of norepinephrine, the rising of colloid osmotic pressure, the co-action of nitric oxide and endothelin after exercise, and also related to the gene polymorphism of β2-adrenergic receptor. Physical exercise, such as jogging, walking and bicycle riding, could be suggested as a complimentary therapy in addition to the pharmaceutical and surgical therapies available for glaucoma patients, even though the mechanism for lowering IOP is not clear enough.

  8. The genetics of intraocular pressure.

    PubMed

    Ojha, Pallavi; Wiggs, Janey L; Pasquale, Louis R

    2013-01-01

    Glaucoma is a leading cause of irreversible blindness. Intraocular pressure (IOP) is the only modifiable risk factor for glaucoma, yet there is little known about the molecular events that regulate IOP. Genetic and genomic studies have helped identify genes that influence IOP and could lead to the identification of biological pathways that serve as targets for novel pressure-modifying therapies. Genetic linkage studies resulted in the identification of several genes that cause Mendelian (autosomal dominant or autosomal recessive) forms of high-pressure glaucoma, including MYOC. PITX2, FOXC1, and CYP1B1. Classical twin studies suggest that IOP is a heritable trait. More recently, genome-wide association studies (GWAS) have shown that common genetic variants in the GAS7 and TMCO1 genomic regions are associated with elevated IOP. TMCO1 has also been associated with primary open-angle glaucoma in patients with advanced disease. A further study identifying additional genes contributing to IOP will be necessary to fully define the underlying genetic architecture of IOP.

  9. Real-Time Detection of Dust Devils from Pressure Readings

    NASA Technical Reports Server (NTRS)

    Wagstaff, Kiri

    2009-01-01

    A method for real-time detection of dust devils at a given location is based on identifying the abrupt, temporary decreases in atmospheric pressure that are characteristic of dust devils as they travel through that location. The method was conceived for use in a study of dust devils on the Martian surface, where bandwidth limitations encourage the transmission of only those blocks of data that are most likely to contain information about features of interest, such as dust devils. The method, which is a form of intelligent data compression, could readily be adapted to use for the same purpose in scientific investigation of dust devils on Earth. In this method, the readings of an atmospheric- pressure sensor are repeatedly digitized, recorded, and processed by an algorithm that looks for extreme deviations from a continually updated model of the current pressure environment. The question in formulating the algorithm is how to model current normal observations and what minimum magnitude deviation can be considered sufficiently anomalous as to indicate the presence of a dust devil. There is no single, simple answer to this question: any answer necessarily entails a compromise between false detections and misses. For the original Mars application, the answer was sought through analysis of sliding time windows of digitized pressure readings. Windows of 5-, 10-, and 15-minute durations were considered. The windows were advanced in increments of 30 seconds. Increments of other sizes can also be used, but computational cost increases as the increment decreases and analysis is performed more frequently. Pressure models were defined using a polynomial fit to the data within the windows. For example, the figure depicts pressure readings from a 10-minute window wherein the model was defined by a third-degree polynomial fit to the readings and dust devils were identified as negative deviations larger than both 3 standard deviations (from the mean) and 0.05 mbar in magnitude. An

  10. 21 CFR 886.4280 - Intraocular pressure measuring device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Intraocular pressure measuring device. 886.4280... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4280 Intraocular pressure measuring device. (a) Identification. An intraocular pressure measuring device is a manual or AC-powered...

  11. 21 CFR 886.4280 - Intraocular pressure measuring device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Intraocular pressure measuring device. 886.4280... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4280 Intraocular pressure measuring device. (a) Identification. An intraocular pressure measuring device is a manual or AC-powered...

  12. 21 CFR 886.4280 - Intraocular pressure measuring device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Intraocular pressure measuring device. 886.4280... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4280 Intraocular pressure measuring device. (a) Identification. An intraocular pressure measuring device is a manual or AC-powered...

  13. Real-Time Strap Pressure Sensor System for Powered Exoskeletons

    PubMed Central

    Tamez-Duque, Jesús; Cobian-Ugalde, Rebeca; Kilicarslan, Atilla; Venkatakrishnan, Anusha; Soto, Rogelio; Contreras-Vidal, Jose Luis

    2015-01-01

    Assistive and rehabilitative powered exoskeletons for spinal cord injury (SCI) and stroke subjects have recently reached the clinic. Proper tension and joint alignment are critical to ensuring safety. Challenges still exist in adjustment and fitting, with most current systems depending on personnel experience for appropriate individual fastening. Paraplegia and tetraplegia patients using these devices have impaired sensation and cannot signal if straps are uncomfortable or painful. Excessive pressure and blood-flow restriction can lead to skin ulcers, necrotic tissue and infections. Tension must be just enough to prevent slipping and maintain posture. Research in pressure dynamics is extensive for wheelchairs and mattresses, but little research has been done on exoskeleton straps. We present a system to monitor pressure exerted by physical human-machine interfaces and provide data about levels of skin/body pressure in fastening straps. The system consists of sensing arrays, signal processing hardware with wireless transmission, and an interactive GUI. For validation, a lower-body powered exoskeleton carrying the full weight of users was used. Experimental trials were conducted with one SCI and one able-bodied subject. The system can help prevent skin injuries related to excessive pressure in mobility-impaired patients using powered exoskeletons, supporting functionality, independence and better overall quality of life. PMID:25690551

  14. Real-time strap pressure sensor system for powered exoskeletons.

    PubMed

    Tamez-Duque, Jesús; Cobian-Ugalde, Rebeca; Kilicarslan, Atilla; Venkatakrishnan, Anusha; Soto, Rogelio; Contreras-Vidal, Jose Luis

    2015-02-16

    Assistive and rehabilitative powered exoskeletons for spinal cord injury (SCI) and stroke subjects have recently reached the clinic. Proper tension and joint alignment are critical to ensuring safety. Challenges still exist in adjustment and fitting, with most current systems depending on personnel experience for appropriate individual fastening. Paraplegia and tetraplegia patients using these devices have impaired sensation and cannot signal if straps are uncomfortable or painful. Excessive pressure and blood-flow restriction can lead to skin ulcers, necrotic tissue and infections. Tension must be just enough to prevent slipping and maintain posture. Research in pressure dynamics is extensive for wheelchairs and mattresses, but little research has been done on exoskeleton straps. We present a system to monitor pressure exerted by physical human-machine interfaces and provide data about levels of skin/body pressure in fastening straps. The system consists of sensing arrays, signal processing hardware with wireless transmission, and an interactive GUI. For validation, a lower-body powered exoskeleton carrying the full weight of users was used. Experimental trials were conducted with one SCI and one able-bodied subject. The system can help prevent skin injuries related to excessive pressure in mobility-impaired patients using powered exoskeletons, supporting functionality, independence and better overall quality of life.

  15. Primary cilia signaling mediates intraocular pressure sensation.

    PubMed

    Luo, Na; Conwell, Michael D; Chen, Xingjuan; Kettenhofen, Christine Insinna; Westlake, Christopher J; Cantor, Louis B; Wells, Clark D; Weinreb, Robert N; Corson, Timothy W; Spandau, Dan F; Joos, Karen M; Iomini, Carlo; Obukhov, Alexander G; Sun, Yang

    2014-09-02

    Lowe syndrome is a rare X-linked congenital disease that presents with congenital cataracts and glaucoma, as well as renal and cerebral dysfunction. OCRL, an inositol polyphosphate 5-phosphatase, is mutated in Lowe syndrome. We previously showed that OCRL is involved in vesicular trafficking to the primary cilium. Primary cilia are sensory organelles on the surface of eukaryotic cells that mediate mechanotransduction in the kidney, brain, and bone. However, their potential role in the trabecular meshwork (TM) in the eye, which regulates intraocular pressure, is unknown. Here, we show that TM cells, which are defective in glaucoma, have primary cilia that are critical for response to pressure changes. Primary cilia in TM cells shorten in response to fluid flow and elevated hydrostatic pressure, and promote increased transcription of TNF-α, TGF-β, and GLI1 genes. Furthermore, OCRL is found to be required for primary cilia to respond to pressure stimulation. The interaction of OCRL with transient receptor potential vanilloid 4 (TRPV4), a ciliary mechanosensory channel, suggests that OCRL may act through regulation of this channel. A novel disease-causing OCRL allele prevents TRPV4-mediated calcium signaling. In addition, TRPV4 agonist GSK 1016790A treatment reduced intraocular pressure in mice; TRPV4 knockout animals exhibited elevated intraocular pressure and shortened cilia. Thus, mechanotransduction by primary cilia in TM cells is implicated in how the eye senses pressure changes and highlights OCRL and TRPV4 as attractive therapeutic targets for the treatment of glaucoma. Implications of OCRL and TRPV4 in primary cilia function may also shed light on mechanosensation in other organ systems.

  16. Primary cilia signaling mediates intraocular pressure sensation

    PubMed Central

    Luo, Na; Conwell, Michael D.; Chen, Xingjuan; Kettenhofen, Christine Insinna; Westlake, Christopher J.; Cantor, Louis B.; Wells, Clark D.; Weinreb, Robert N.; Corson, Timothy W.; Spandau, Dan F.; Joos, Karen M.; Iomini, Carlo; Obukhov, Alexander G.; Sun, Yang

    2014-01-01

    Lowe syndrome is a rare X-linked congenital disease that presents with congenital cataracts and glaucoma, as well as renal and cerebral dysfunction. OCRL, an inositol polyphosphate 5-phosphatase, is mutated in Lowe syndrome. We previously showed that OCRL is involved in vesicular trafficking to the primary cilium. Primary cilia are sensory organelles on the surface of eukaryotic cells that mediate mechanotransduction in the kidney, brain, and bone. However, their potential role in the trabecular meshwork (TM) in the eye, which regulates intraocular pressure, is unknown. Here, we show that TM cells, which are defective in glaucoma, have primary cilia that are critical for response to pressure changes. Primary cilia in TM cells shorten in response to fluid flow and elevated hydrostatic pressure, and promote increased transcription of TNF-α, TGF-β, and GLI1 genes. Furthermore, OCRL is found to be required for primary cilia to respond to pressure stimulation. The interaction of OCRL with transient receptor potential vanilloid 4 (TRPV4), a ciliary mechanosensory channel, suggests that OCRL may act through regulation of this channel. A novel disease-causing OCRL allele prevents TRPV4-mediated calcium signaling. In addition, TRPV4 agonist GSK 1016790A treatment reduced intraocular pressure in mice; TRPV4 knockout animals exhibited elevated intraocular pressure and shortened cilia. Thus, mechanotransduction by primary cilia in TM cells is implicated in how the eye senses pressure changes and highlights OCRL and TRPV4 as attractive therapeutic targets for the treatment of glaucoma. Implications of OCRL and TRPV4 in primary cilia function may also shed light on mechanosensation in other organ systems. PMID:25143588

  17. Real-time portal imaging devices operating on high-pressure gaseous electronic principles

    NASA Astrophysics Data System (ADS)

    Giakos, George C.; Richardson, Donna B.; Ghotra, P.; Pillai, Bindu; Seetharaman, Lakshmi; Passalaqua, Anthony M.; DiBianca, Frank A.; Endorf, Robert J.; Devidas, Sreenivas

    1995-05-01

    A novel real-time portal imaging scanning detector, based on high-pressure gaseous electronics principles and operating up to 60 atmospheres, is presented and the predicted performance of this detector is analyzed. The idea is to utilize high pressure gaseous electronics imaging detectors operating in the saturation regime, aimed at improving image performance characteristics in real time portal imaging. As a result, beam localization errors are controlled, identified and corrected accurately and the patient radiotherapy treatment becomes more effective.

  18. Factors affecting intraocular pressure in lions.

    PubMed

    Ofri, Ron; Steinmetz, Andrea; Thielebein, Jens; Horowitz, Igal H; Oechtering, Gerhard; Kass, Philip H

    2008-07-01

    The aim of this study was to conduct a detailed analysis of the relationship between age and intraocular pressure (IOP) in lions. Tonometry was conducted in 33 lions aged 5 days to 80 months. Age was significantly associated with IOP (P<0.005). Mean IOP was 12.8+/- and 23.9+/-4.1 mmHg in lions < or =1 year old and >1 year old, respectively. IOP linearly rose with age during the first 20 months of life, plateaued until approximately 40 months, and then gradually declined (r=0.85). Age-related changes in IOP were highly correlated with ultrasonographic measurements of intraocular dimensions (r > or = 0.72), and may be a determinant factor in developmental ocular growth. The dramatic rise in IOP of young lions is similar to that observed in children, but has not been previously demonstrated in animals. Significant IOP differences between lion sub-species were also demonstrated.

  19. Continual monitoring of intraocular pressure: effect of central venous pressure, respiration, and eye movements on continual recordings of intraocular pressure in the rabbit, dog, and man.

    PubMed Central

    Cooper, R. L.; Beale, D. G.; Constable, I. J.; Grose, G. C.

    1979-01-01

    A new method has been devised for continual monitoring of intraocular pressure by radiotelemetry. The use of this instrument for monitoring intraocular pressure by a variety of ophthalmic conditions is described. Images PMID:526459

  20. Circadian rhythm of intraocular pressure in the adult rat.

    PubMed

    Lozano, Diana C; Hartwick, Andrew T E; Twa, Michael D

    2015-05-01

    Ocular hypertension is a risk factor for developing glaucoma, which consists of a group of optic neuropathies characterized by progressive degeneration of retinal ganglion cells and subsequent irreversible vision loss. Our understanding of how intraocular pressure damages the optic nerve is based on clinical measures of intraocular pressure that only gives a partial view of the dynamic pressure load inside the eye. Intraocular pressure varies over the course of the day and the oscillator regulating these daily changes has not yet been conclusively identified. The purpose of this study was to compare and contrast the circadian rhythms of intraocular pressure and body temperature in Brown Norway rats when these animals are housed in standard light-dark and continuous dim light (40-90 lux) conditions. The results from this study show that the temperature rhythm measured in continuous dim light drifted forward relative to external time, indicating that the rhythm was free running and being regulated by an internal biological clock. Also, the results show that there is a persistent, but dampened, circadian rhythm of intraocular pressure in continuous dim light and that the circadian rhythms of temperature and intraocular pressure are not synchronized by the same central oscillator. We conclude that once- or twice-daily clinical measures of intraocular pressure are insufficient to describe intraocular pressure dynamics. Similarly, our results indicate that, in experimental animal models of glaucoma, the common practice of housing animals in constant light does not necessarily eliminate the potential influence of intraocular pressure rhythms on the progression of nerve damage. Future studies should aim to determine whether an oscillator within the eye regulates the rhythm of intraocular pressure and to better characterize the impact of glaucoma on this rhythm.

  1. Loop mediated isothermal amplification assay using hydroxy naphthol blue, conventional polymerase chain reaction and real-time PCR in the diagnosis of intraocular tuberculosis.

    PubMed

    Balne, P K; Basu, S; Rath, S; Barik, M R; Sharma, S

    2015-01-01

    This study is a comparative evaluation (Chi-square test) of a closed tube loop mediated isothermal amplification assay using hydroxy naphthol blue dye (HNB-LAMP), real-time polymerase chain reaction (PCR) and conventional PCR in the diagnosis of intraocular tuberculosis. Considering clinical presentation as the gold standard in 33 patients, the sensitivity of HNB-LAMP assay (75.8%) was higher (not significant, P value 0.2) than conventional PCR (57.6%) and lower than real-time PCR (90.9%). Specificity was 100% by all three methods. No amplification was observed in negative controls (n = 20) by all three methods. The cost of the HNB-LAMP assay was Rs. 500.00 and it does not require thermocycler, therefore, it can be used as an alternative to conventional PCR in resource-poor settings.

  2. A real-time pressure estimation algorithm for closed-loop combustion control

    NASA Astrophysics Data System (ADS)

    Al-Durra, Ahmed; Canova, Marcello; Yurkovich, Stephen

    2013-07-01

    The cylinder pressure is arguably the most important variable characterizing the combustion process in internal combustion engines. In light of the recent advances in combustion technologies and in engine control, the use of cylinder pressure is now frequently considered as a feedback signal for closed-loop combustion control algorithms. In order to generate an accurate pressure trace for real-time combustion control and diagnostics, the output of the in-cylinder pressure transducer must be conditioned with signal processing methods to mitigate the well-known issues of offset and noise. While several techniques have been proposed for processing the cylinder pressure signal with limited computational burden, most of the available methods still require one to apply low-pass filters or moving average windows in order to mitigate the noise. This ultimately limits the opportunity of exploiting the in-cylinder pressure feedback for a cycle-by-cycle control of the combustion process. To this extent, this paper presents an estimation algorithm that extracts the pressure signal from the in-cylinder sensor in real-time, allowing for estimating the 50% burn rate location and IMEP on a cycle-by-cycle basis. The proposed approach relies on a model-based estimation algorithm whose starting point is a crank-angle based engine combustion model that predicts the in-cylinder pressure from the definition of a burn rate function. Linear parameter varying (LPV) techniques are then used to expand the region of estimation to cover the engine operating map, as well as allowing for real-time cylinder estimation during transients. The estimator is tested on the experimental data collected on an engine dynamometer as well as on a high-fidelity engine simulator. The results obtained show the effectiveness of the estimator in reconstructing the cylinder pressure on a crank-angle basis and in rejecting measurement noise and modeling errors, with considerably low computation effort.

  3. Intraocular Pressure Changes With Positioning During Laparoscopy

    PubMed Central

    Onakpoya, Oluwatoyin H.; Adenekan, Anthony T.; Awe, Oluwaseun. O.

    2016-01-01

    Background and Objectives: Pneumoperitoneum during laparoscopy can produce changes in intraocular pressure (IOP) that may be influenced by several factors. In this study, we investigated changes in IOP during laparoscopy with different positioning. Methods: We recruited adult patients without eye disease scheduled to undergo laparoscopic operation requiring a reverse Trendelenburg tilt (rTr; group A; n = 20) or Trendelenburg tilt (Tr; Group B; n = 20). IOP was measured at 7 time points (T1–T7). All procedures were performed with standardized anaesthetic protocol. Mean arterial pressure (MAP), heart rate (HR), peak and plateau airway pressure, and end-tidal carbon dioxide (ETCO2) measurements were taken at each time point. Results: Both groups were similar in age, sex, mean body mass index (BMI), duration of surgery, and preoperative IOP. A decrease in IOP was observed in both groups after induction of anaesthesia (T2), whereas induction of pneumoperitoneum produced a mild increase in IOP (T3) in both groups. The Trendelenburg tilt produced IOP elevations in 80% of patients compared to 45% after the reverse Trendelenburg tilt (P = .012). A significant IOP increase of 5 mm Hg or more was recorded in 3 (15%) patients in the Trendelenburg tilt group and in none in the reverse Trendelenburg group. At T7, IOP had returned to preoperative levels in all but 3 (15%) in the Trendelenburg and 1 (5%) in the reverse Trendelenburg group. Reversible changes were observed in the MAP, HR, ETCO2, and airway pressures in both groups. Conclusions: IOP changes induced by laparoscopy are realigned after evacuation of pneumoperitoneum. A Trendelenburg tilt however produced significant changes that may require careful patient monitoring during laparoscopic procedures. PMID:28028381

  4. Effects of Different Intensities of Exercise on Intraocular Pressure

    ERIC Educational Resources Information Center

    Rowe, Deryl; And Others

    1976-01-01

    The decrease in intraocular pressure during exercise and the first few minutes of recovery is related to a decrease in blood pH and an increase in blood lactate concentration, not to the intensity of the exercise. (MB)

  5. Postprandial Glucose as a Risk Factor for Elevated Intraocular Pressure

    PubMed Central

    Wu, Chen-Jung; Fang, Wen-Hui; Kao, Tung-Wei; Chen, Ying-Jen; Liaw, Fang-Yih; Chang, Yaw-Wen; Wang, Gia-Chi; Peng, Tao-Chun; Chen, Wei-Liang

    2016-01-01

    The aim of this study was to investigate the association between postprandial glucose and intraocular pressure in a relatively healthy population. We examined 1,439 adults getting a health check-up in a health promotion center at Tri-Service General Hospital (TSGH) in Taiwan between 2012 and 2013. All participants underwent examinations to measure metabolic variables and intraocular pressure. Multiple linear regression analyses were performed to assess the relationship between postprandial glucose and intraocular pressure. The levels of postprandial glucose were divided into quartiles with subjects in the lowest quartile being regarded as the reference group to perform quartile-based analysis. Covariate adjustment was designed for three models for further analysis. Subjects with higher quartiles of postprandial glucose level had a higher systolic blood pressure, a greater waist circumference and an elevated fasting glucose level (all p < 0.001). The β coefficient with adjusted covariates showed a significant positive association between postprandial glucose and intraocular pressure. The trends of intraocular pressure across increasing quartiles of postprandial glucose were statistically significant (all p for trend < 0.001). Thus, higher levels of postprandial glucose positively correlated with elevated intraocular pressure. PMID:27977733

  6. Reduced pressure for fewer pressure ulcers: can real-time feedback of interface pressure optimise repositioning in bed?

    PubMed

    Gunningberg, Lena; Carli, Cheryl

    2016-10-01

    The aim of this study was to (i) describe registered nurses' and assistant nurses' repositioning skills with regard to their existing attitudes to and theoretical knowledge of pressure ulcer (PU) prevention, and (ii) evaluate if the continuous bedside pressure mapping (CBPM) system provides staff with a pedagogic tool to optimise repositioning. A quantitative study was performed using a descriptive, comparative design. Registered nurses (n = 19) and assistant nurses (n = 33) worked in pairs, and were instructed to place two volunteers (aged over 70 years) in the best pressure-reducing position (lateral and supine), first without viewing the CBPM monitor and then again after feedback. In total, 240 positionings were conducted. The results show that for the same person with the same available pressure-reducing equipment, the peak pressure varied considerably between nursing pairs. Reducing pressure in the lateral position appeared to be the most challenging. Peak pressures were significantly reduced, based on visual feedback from the CBPM monitor. The number of preventive interventions also increased, as well as patients' comfort. For the nurses as a group, the knowledge score was 59·7% and the attitude score was 88·8%. Real-time visual feedback of pressure points appears to provide another dimension to complement decision making with respect to PU prevention.

  7. Damage dosimetry and embrittlement monitoring of nuclear pressure vessels in real time by magnetic properties measurement

    SciTech Connect

    Stubbins, J.F.; Ougouag, A.M.; Williams, J.G.

    1992-07-01

    The objective of this project is to develop a technique for real-time monitoring of neutron dose and of the onset and progression of embrittlement in operating nuclear pressure vessels. The technique relies on the measurement of magnetic properties of steel and other magnetic materials which are extremely sensitive to radiation-induced properties changes. The approach being developed here is innovative and unique. It promises to be readily applicable to all existing and planned reactor structures. The significance of this program is that it addresses a major concern in the operation of existing nuclear pressure vessels. The development of microscopic defect clusters during irradiation in the nuclear pressure vessel beltline region leads to an increase in material yield strength and a concomitant decrease in ductility, or ability to absorb energy in fracture (i.e. fracture toughness). This decrease in fracture toughness is alarming since it may impair the ability of the pressure vessel to resist fracture during unusual loading situations.

  8. Changes in intraocular pressure after exercise test

    PubMed Central

    Esfahani, Morteza Abdar; Gharipour, Mojgan; Fesharakinia, Hamid

    2017-01-01

    Background: The decrease in intraocular pressure (IOP) within exercise has been recently suggested; however, this change remained ambiguous following exercise test. The present study aimed to assess changes in IOP induced by exercise test in patients who suspected to coronary artery disease (CAD) and indicated for exercise test evaluation. Methods: In a cross-sectional study at the cardiovascular research center of Amin Heart Hospital in Isfahan, 101 eyes from 51 consecutive patients suspected to CAD aged 30–70 years referred for exercise testing were evaluated. IOP was measured at the three time points of before exercise test as well as 5 and 20 min after completing exercise test using Schiotz tonometer. All exercise tests were programmed by the treadmill. Results: The mean IOP in all assessed eyes was 16.12 ± 2.61 mmHg initially that was gradually decreased to 13.79 ± 2.40 mmHg 5 min after the exercise test, but elevated to 15.67 ± 2.26 mmHg 20 min after the test. Assessing IOP following exercise testing showed a significant decrease in IOP in 75 eyes (74.3%), remained unchanged in 19.8% of eyes, and even elevated in 5.9% of eyes. There was a significant direct association between patients' age and IOP changes assessed by the Pearson's correlation test (r = 0.350,P = 0.009). No significant difference was revealed in the trend of the changes in IOP after exercise test between men and women, between left-sided and right-sided eyes as well as between different body mass index subgroups. Conclusion: IOP temporarily reduced after exercise test, but return to baseline value shortly after test. This lowering is more evident in advanced aging. PMID:28298859

  9. Relationship between homocysteine and intraocular pressure in men and women

    PubMed Central

    Leibovitzh, Haim; Cohen, Eytan; levi, Amos; Kramer, Michal; Shochat, Tzippy; Goldberg, Elad; Krause, Ilan

    2016-01-01

    Abstract The relationship between homocysteine levels and glaucoma has been questioned in previous studies without conclusive results. In the current study, we assessed the relationship between homocysteine levels and intraocular pressure which is one of the main factors in the development of glaucoma in men and women. A retrospective cross-sectional analysis of a database from a screening center in Israel which assessed 11,850 subjects, within an age range 20 to 80 years. The relationship between homocysteine and intraocular pressure has been investigated by comparing intraocular pressure in subjects with elevated and normal homocysteine and by comparing homocysteine levels in subjects with elevated and normal intraocular pressure. In addition, we compared the levels of homocysteine in subjects with and without a confirmed diagnosis of glaucoma. The mean IOP (±SD) in subjects with normal homocysteine levels(≤15 μmol/L) was 13.2 ± 2.3 mm Hg and 13.4 ± 2.4 mm Hg in those with high homocysteine levels (>15 μmol/L) (P < 0.008, 95% confidence interval [CI] 0.3–0.09).Nonetheless, after multivariate adjustment for age, gender, vitamin B12, and folic acid statistical significance was no longer demonstrated (P = 0.37). Mean homocysteine levels (±SD) in subjects with normal intraocular pressure of ≤ 21 mm Hg was 11.7 ± 5.5 μmol/L and 12.09 ± 3.43 μmol/L in those with elevated intraocular pressure (P = 0.4, 95%CI 1.1–1.8). Mean homocysteine levels (±SD) in subjects with glaucoma were 11.2 ± 3.5 μmol/L compared to 11.7 ± 5.5 μmol/L in subjects without glaucoma and normal intraocular pressure ≤ 21 mm Hg (P = 0.4, 95% CI 1.2–2.1). The current study displays no clinical correlation between the homocysteine level and the intraocular pressure. Homocysteine may not be used as a predictive parameter to recognize those subjects prone to develop elevated intraocular pressure. PMID:27661027

  10. Intra-ocular pressure normalization technique and equipment

    NASA Technical Reports Server (NTRS)

    Baehr, E. F. (Inventor)

    1979-01-01

    A method and apparatus is described for safely reducing abnormally high intraocular pressure in an eye during a predetermined time interval. This allows maintenance of normal intraocular pressure during glaucoma surgery. A pressure regulator of the spring-biassed diaphragm type is provided with additional bias by a column of liquid. The hypodermic needle can be safely inserted into the anterior chamber of the eye. Liquid is then bled out of the column to reduce the bias on the diaphragm of the pressure regulator and, consequently, the output pressure of the regulator. This lowering pressure of the regulator also occurs in the eye by means of a small second bleed path provided between the pressure regulator and the hypodermic needle.

  11. Trabeculectomy for traumatic hyphema with increased intraocular pressure.

    PubMed

    Graul, T A; Ruttum, M S; Lloyd, M A; Radius, R L; Hyndiuk, R A

    1994-02-15

    We reviewed the medical records of 11 consecutive patients who underwent trabeculectomy with anterior chamber washout and peripheral iridectomy as the primary surgical treatment for traumatic hyphema that was unresponsive to medical management. The mean intraocular pressure before surgery was 48 mm Hg. In ten of the patients the intraocular pressure was lowered to 21 mm Hg or lower after surgery and remained below that level up to the most recent follow-up visit, which ranged from eight to 97 months. One patient required a topical beta-blocker and oral acetazolamide to lower pressure to this level after surgery. Eight patients had visual acuity of 20/60 or better at last follow-up. Corneal blood staining occurred in eight patients. Compared with other techniques for surgical management of traumatic hyphema, trabeculectomy provides a means to keep intraocular pressure lowered while the remaining blood is clearing from the anterior chamber. Trabeculectomy with anterior chamber washout and peripheral iridectomy appears to be a safe and reliable procedure in the management of traumatic hyphemas in which medical management fails to control intraocular pressure.

  12. Use of betaxolol in the reduction of elevated intraocular pressure.

    PubMed

    Radius, R L

    1983-06-01

    Forty eyes in 20 patients with elevated intraocular pressure were treated with either a 0.125% betaxolol ophthalmic solution or a placebo. After 2, 4, and 6 weeks of twice-daily therapy, the eyes receiving the betaxolol had a mean percent reduction in IOP greater than that in the eyes treated only with the drug vehicle (placebo). Both solutions were well tolerated.

  13. An ultralow power wireless intraocular pressure monitoring system

    NASA Astrophysics Data System (ADS)

    Demeng, Liu; Niansong, Mei; Zhaofeng, Zhang

    2014-10-01

    This paper describes an ultralow power wireless intraocular pressure (IOP) monitoring system that is dedicated to sensing and transferring intraocular pressure of glaucoma patients. Our system is comprised of a capacitive pressure sensor, an application-specific integrated circuit, which is designed on the SMIC 180 nm process, and a dipole antenna. The system is wirelessly powered and demonstrates a power consumption of 7.56 μW at 1.24 V during continuous monitoring, a significant reduction in active power dissipation compared to existing work. The input RF sensitivity is -13 dBm. A significant reduction in input RF sensitivity results from the reduction of mismatch time of the ASK modulation caused by FM0 encoding. The system exhibits an average error of ± 1.5 mmHg in measured pressure. Finally, a complete IOP system is demonstrated in the real biological environment, showing a successful reading of the pressure of an eye.

  14. Real-time, whole-brain, temporally resolved pressure responses in translational head impact

    PubMed Central

    Zhao, Wei; Ji, Songbai

    2016-01-01

    Theoretical debate still exists on the role of linear acceleration (alin) on the risk of brain injury. Recent injury metrics only consider head rotational acceleration (arot) but not alin, despite that real-world on-field head impacts suggesting alin significantly improves a concussion risk function. These controversial findings suggest a practical challenge in integrating theory and real-world experiment. Focusing on tissue-level mechanical responses estimated from finite-element (FE) models of the human head, rather than impact kinematics alone, may help address this debate. However, the substantial computational cost incurred (runtime and hardware) poses a significant barrier for their practical use. In this study, we established a real-time technique to estimate whole-brain alin-induced pressures. Three hydrostatic atlas pressures corresponding to translational impacts (referred to as ‘brain print’) along the three major axes were pre-computed. For an arbitrary alin profile at any instance in time, the atlas pressures were linearly scaled and then superimposed to estimate whole-brain responses. Using 12 publically available, independently measured or reconstructed real-world alin profiles representative of a range of impact/injury scenarios, the technique was successfully validated (except for one case with an extremely short impulse of approx. 1 ms). The computational cost to estimate whole-brain pressure responses for an entire alin profile was less than 0.1 s on a laptop versus typically hours on a high-end multicore computer. These findings suggest the potential of the simple, yet effective technique to enable future studies to focus on tissue-level brain responses, rather than solely relying on global head impact kinematics that have plagued early and contemporary brain injury research to date. PMID:26855762

  15. Payload and Components Real-Time Automated Test System (PACRATS), Data Acquisition of Leak Rate and Pressure Data Test Procedure

    NASA Technical Reports Server (NTRS)

    Rinehart, Maegan L.

    2011-01-01

    The purpose of this activity is to provide the Mechanical Components Test Facility (MCTF) with the capability to obtain electronic leak test and proof pressure data, Payload and Components Real-time Automated Test System (PACRATS) data acquisition software will be utilized to display real-time data. It will record leak rates and pressure/vacuum level(s) simultaneously. This added functionality will provide electronic leak test and pressure data at specified sampling frequencies. Electronically stored data will provide ES61 with increased data security, analysis, and accuracy. The tasks performed in this procedure are to verify PACRATS only, and are not intended to provide verifications for MCTF equipment.

  16. [Iritis with destabilization of the intraocular pressure due to dislocation of a posterior chamber intraocular lens].

    PubMed

    Handzel, D M

    2012-04-01

    This report concerns the case of a 67-year-old male patient who underwent uncomplicated phacoemulsification with implantation of a posterior chamber intraocular lens (IOL). After an interval of 2 months the patient developed iritis together with an uncontrollable increase in intraocular pressure. After a detailed examination a dislocated haptic of the IOL was identified as the cause of the symptoms. The dislocation had led to uveitis-glaucoma-hyphema syndrome although no hemorrhage was observed. In addition to this complication the haptic had arroded the zonular complex which made implantation of an anterior chamber lens necessary. Although improvements in operating techniques, lens materials and designs have been made uveitis-glaucoma-hyphema syndrome has to be kept in mind. Surgical intervention is the only therapeutic option.

  17. Effects of angiotensin, vasopressin and atrial natriuretic peptide on intraocular pressure in anesthetized rats

    NASA Technical Reports Server (NTRS)

    Palm, D. E.; Shue, S. G.; Keil, L. C.; Balaban, C. D.; Severs, W. B.

    1995-01-01

    The effects of atrial natriuretic peptide (ANP), vasopressin (AVP) and angiotensin (ANG) on blood and intraocular pressures of pentobarbital anesthetized rats were evaluated following intravenous, intracerebroventricular or anterior chamber routes of administration. Central injections did not affect intraocular pressure. Equipressor intravenous infusions of ANG raised, whereas AVP decreased, intraocular pressure. Direct infusions of a balanced salt solution (0.175 microliter/min) raised intraocular pressure between 30 and 60 min. Adding ANG or ANP slightly reduced this solvent effect but AVP was markedly inhibitory. An AVP-V1 receptor antagonist reversed the blunting of the solvent-induced rise by the peptide, indicating receptor specificity. Acetazolamide pretreatment lowered intraocular pressure, but the solvent-induced rise in intraocular pressure and inhibition by AVP still occurred without altering the temporal pattern. Thus, these effects appear unrelated to aqueous humor synthesis rate. The data support the possibility of intraocular pressure regulation by peptides acting from the blood and aqueous humor.

  18. Intraocular pressure with rebound tonometry and effects of topical intraocular pressure reducing medications in guinea pigs

    PubMed Central

    Di, Yue; Luo, Xiu-Mei; Qiao, Tong; Lu, Na

    2017-01-01

    AIM To investigate the intraocular pressure (IOP) of adult guinea pig eyes with rebound tonometry (RBT), and assess the effects of four distinctive topical IOP reducing medications including Carteolol, Brimonidine, Brinzolamide and Latanoprost. METHODS The IOPs of twenty-four 12-week-old guinea pigs (48 eyes) were measured every two hours in one day with RBT as baselines. All the animals were then divided into four groups (Carteolol, Brimonidine, Brinzolamide and Latanaprost groups, n=6). The IOPs were measured and compared to the baseline 1, 2, 3, 5, 7, 9, 15 and 24h after treatment. RESULTS The mean baseline IOP of 24 guinea pigs (48 eyes) was 10.3±0.36 mm Hg (6-13 mm Hg) and no binocular significant differences of IOPs were observed (t=1.76, P>0.05). No significant difference of IOP in Carteolol group at each time point was observed before and after treatment (t=1.48, P>0.05). In Brimonidine group, IOP was 2.2±1.9 mm Hg lower than the baseline after one hour (t=3.856, P=0.003) and lasted for one hour. In Brinzolamide group, IOP was 1.4±1.1 mm Hg lower than the baseline after one hour (t=4.53, P=0.001) and lasted for 7h and the IOP declined most at 3h. In Latanaprost group, IOP was 2.1±1.3 mm Hg lower than the baseline after one hour (t=6.11, P=0.001) and lasted for one hour. CONCLUSION The IOP of guinea pig eyes is relatively stable compared to human eyes. In four reducing IOP medications, no significant effect of Carteolol is observed. Brinzolamide has the longest duration, while the Brimonidine has the shortest duration and the maximum level of treatment. PMID:28251075

  19. Intra-ocular pressure normalization technique and equipment

    NASA Technical Reports Server (NTRS)

    Mcgannon, W. J. (Inventor)

    1980-01-01

    A method and apparatus for safely reducing abnormally high intraocular pressure in an eye during a predetermined time interval is presented. This allows maintenance of normal intraocular pressure during glaucoma surgery. According to the invention, a pressure regulator of the spring biased diaphragm type is provided with additional bias by a column of liquid. The height of the column of liquid is selected such that the pressure at a hypodermic needle connected to the output of the pressure regulator is equal to the measured pressure of the eye. The hypodermic needle can then be safely inserted into the anterior chamber of the eye. Liquid is then bled out of the column to reduce the bias on the diaphragm of the pressure regulator and, consequently, the output pressure of the regulator. This lowering pressure of the regulator also occurs in the eye by means of a small second bleed path provided between the pressure regulator and the hypodermic needle. Alternately, a second hypodermic needle may be inserted into the eye to provide a controlled leak off path for excessive pressure and clouded fluid from the anterior chamber.

  20. Real-time pressure monitoring for dynamic control during paper mill operation using fiber optic pressure sensors

    NASA Astrophysics Data System (ADS)

    Fielder, Robert S.; Boyd, Clark; Palmer, Matthew; Eriksen, Oddbjørn

    2006-03-01

    Fiber optic pressure sensors were integrated into the grinding plates of an operational paper pulp mill for real-time monitoring of the pulp grinding process. On-line system monitoring will allow smart, active control of the grinding plates thereby improving the quality and consistency of the pulp produced. Sensors were constructed and calibrated for use in the harsh environment of an operating paper pulp grinder. The sensors were 1.65mm in diameter including titanium housing, and were installed directly into the grooves of the grinding plates. The sensing elements were flush-mounted with the wall and exposed to the wood pulp slurry. Nine sensors were calibrated up to 1000psi. During operation, pressure was sampled at 1.0MHz, and pressure spikes up to 175psi were observed. Pressure pulses measured are due to the relative motion between the grooves and channels on two pulp grinding plates. The consistency, size distribution, and quality of paper pulp exiting from the grinder are directly related to the distance between the channels on the two rotating elements. The pressure pulses produced are also proportional to the distance between channels. Therefore, by monitoring pressure fluctuations, grinding elements can be dynamically controlled thereby producing a "smart mill."

  1. A new real time tsunami detection algorithm for bottom pressure measurements in open ocean: characterization and benchmarks

    NASA Astrophysics Data System (ADS)

    Embriaco, D.; Chierici, F.; Pignagnoli, L.

    2009-04-01

    In the last decades the use of the Bottom Pressure Recorder (BPR) in a deep ocean environment for tsunami detection has had a relevant development. A key role for an early warning system based on BPRs is played by the tsunami detection algorithms running in real time on the BPR itself or at installation site. We present a new algorithm for tsunami detection that is based on real time pressure data analysis, consisting in tide removing, spike removing, low pass filtering and linear prediction: the output is then matched against a given pressure threshold allowing the detection of anomalous events. Different configurations of the algorithm, consisting for instance in a real time band pass filtering of the pressure signal in place of linear prediction, are also tested for comparison. The algorithm is designed to be used in an autonomous early warning system, with a finite set of input parameters that can be reconfigured in real time. A realistic benchmark scheme is developed in order to characterize the algorithm features with particular regards to false alarm probability, sensitivity to the amplitude and wavelength of the tsunami and detection earliness. The algorithm behaviour in real operation is numerically estimated performing statistical simulations where a large number of synthetic tsunami waves with various amplitude, period, shape and phase is generated and superimposed to time series of real pressure data recorded in different environmental conditions and locations.

  2. Real-Time Optical Monitoring of Flow Kinetics and Gas Phase Reactions Under High-Pressure OMCVD Conditions

    NASA Technical Reports Server (NTRS)

    Dietz, N.; McCall, S.; Bachmann, K. J.

    2001-01-01

    This contribution addresses the real-time optical characterization of gas flow and gas phase reactions as they play a crucial role for chemical vapor phase depositions utilizing elevated and high pressure chemical vapor deposition (HPCVD) conditions. The objectives of these experiments are to validate on the basis of results on real-time optical diagnostics process models simulation codes, and provide input parameter sets needed for analysis and control of chemical vapor deposition at elevated pressures. Access to microgravity is required to retain high pressure conditions of laminar flow, which is essential for successful acquisition and interpretation of the optical data. In this contribution, we describe the design and construction of the HPCVD system, which include access ports for various optical methods of real-time process monitoring and to analyze the initial stages of heteroepitaxy and steady-state growth in the different pressure ranges. To analyze the onset of turbulence, provisions are made for implementation of experimental methods for in-situ characterization of the nature of flow. This knowledge will be the basis for the design definition of experiments under microgravity, where gas flow conditions, gas phase and surface chemistry, might be analyzed by remote controlled real-time diagnostics tools, developed in this research project.

  3. Intraocular pressure following ECCE, phacoemulsification, and PC-IOL implantation.

    PubMed

    Kooner, K S; Cooksey, J C; Perry, P; Zimmerman, T J

    1988-09-01

    Abnormal intraocular pressure (IOP), either transient or permanent, may follow extracapsular cataract extraction (ECCE) with phacoemulsification (PE) and posterior chamber intraocular lens (PC-IOL) implantation. We retrospectively studied IOP measurements at different intervals post ECCE and PE in 242 eyes of 211 patients: 105 males, 106 females, 198 Caucasians and 13 blacks. Elevated IOP (greater than 23 mm Hg) was observed in 20 eyes (8.2%). Only two patients (0.8%) had persistent (greater than 3 months) IOP elevation and needed antiglaucoma therapy. Six more eyes (2.5%), however, developed glaucoma after 1 year. Hence, the incidence of secondary pseudophakic glaucoma at the conclusion of this study was 3.3%. No patient required laser or other mechanical surgery for IOP control. ECCE and PE with PC-IOL does not appear to adversely affect IOP. Patients, however, must be followed closely, as some may develop glaucoma months after surgery.

  4. Is 24-hour Intraocular Pressure Monitoring Necessary in Glaucoma?

    PubMed Central

    Mansouri, Kaweh; Weinreb, Robert N.; Medeiros, Felipe A.

    2013-01-01

    Although intraocular pressure (IOP) is the only treatable risk factor for glaucoma, its 24-hour behavior is poorly understood. Conflicting information is available in the literature with regard to the importance and predictive value of IOP peaks and fluctuations on the risk of glaucoma development and progression. This may be secondary to lack of prospective studies designed to address this issue. This article critically reviews the current evidence for the importance of 24-h IOP measurements in glaucoma and discusses shortcomings of current methods to assess 24-h IOP data, drawing attention to new developments in this field. PMID:23697618

  5. Hypotonous malignant glaucoma: aqueous misdirection with low intraocular pressure.

    PubMed

    Burgansky-Eliash, Zvia; Ishikawa, Hiroshi; Schuman, Joel S

    2008-01-01

    Two patients who underwent trabeculectomy and postoperatively manifested axially shallow anterior chamber associated with hypotony but without choroidal effusion are described. The first patient was treated conservatively with topical cycloplegics. The second patient was treated with pars plana anterior vitrectomy. The interventions resulted in deepening of the anterior chamber and posterior rotation of the ciliary body to a natural position as observed by ultrasound biomicroscopy. Intraocular pressure remained low in both cases. These cases demonstrate that hypotony and axial shallowing of the anterior chamber after trabeculectomy can result in a malignant glaucoma-like appearance.

  6. Note: A micro-perfusion system for use during real-time physiological studies under high pressure

    NASA Astrophysics Data System (ADS)

    Maltas, Jeff; Long, Zac; Huff, Alison; Maloney, Ryan; Ryan, Jordan; Urayama, Paul

    2014-10-01

    We construct a micro-perfusion system using piston screw pump generators for use during real-time, high-pressure physiological studies. Perfusion is achieved using two generators, with one generator being compressed while the other is retracted, thus maintaining pressurization while producing fluid flow. We demonstrate control over perfusion rates in the 10-μl/s range and the ability to change between fluid reservoirs at up to 50 MPa. We validate the screw-pump approach by monitoring the cyanide-induced response of UV-excited autofluorescence from Saccharomyces cerevisiae under pressurization.

  7. Note: A micro-perfusion system for use during real-time physiological studies under high pressure.

    PubMed

    Maltas, Jeff; Long, Zac; Huff, Alison; Maloney, Ryan; Ryan, Jordan; Urayama, Paul

    2014-10-01

    We construct a micro-perfusion system using piston screw pump generators for use during real-time, high-pressure physiological studies. Perfusion is achieved using two generators, with one generator being compressed while the other is retracted, thus maintaining pressurization while producing fluid flow. We demonstrate control over perfusion rates in the 10-μl/s range and the ability to change between fluid reservoirs at up to 50 MPa. We validate the screw-pump approach by monitoring the cyanide-induced response of UV-excited autofluorescence from Saccharomyces cerevisiae under pressurization.

  8. Biomechanics of Schlemm's canal endothelium and intraocular pressure reduction.

    PubMed

    Stamer, W Daniel; Braakman, Sietse T; Zhou, Enhua H; Ethier, C Ross; Fredberg, Jeffrey J; Overby, Darryl R; Johnson, Mark

    2015-01-01

    Ocular hypertension in glaucoma develops due to age-related cellular dysfunction in the conventional outflow tract, resulting in increased resistance to aqueous humor outflow. Two cell types, trabecular meshwork (TM) and Schlemm's canal (SC) endothelia, interact in the juxtacanalicular tissue (JCT) region of the conventional outflow tract to regulate outflow resistance. Unlike endothelial cells lining the systemic vasculature, endothelial cells lining the inner wall of SC support a transcellular pressure gradient in the basal to apical direction, thus acting to push the cells off their basal lamina. The resulting biomechanical strain in SC cells is quite large and is likely to be an important determinant of endothelial barrier function, outflow resistance and intraocular pressure. This review summarizes recent work demonstrating how biomechanical properties of SC cells impact glaucoma. SC cells are highly contractile, and such contraction greatly increases cell stiffness. Elevated cell stiffness in glaucoma may reduce the strain experienced by SC cells, decrease the propensity of SC cells to form pores, and thus impair the egress of aqueous humor from the eye. Furthermore, SC cells are sensitive to the stiffness of their local mechanical microenvironment, altering their own cell stiffness and modulating gene expression in response. Significantly, glaucomatous SC cells appear to be hyper-responsive to substrate stiffness. Thus, evidence suggests that targeting the material properties of SC cells will have therapeutic benefits for lowering intraocular pressure in glaucoma.

  9. MEASUREMENT OF INTRAOCULAR PRESSURE IN THE DOMESTIC PIGEON (COLUMBIA LIVIA).

    PubMed

    Ansari Mood, Maneli; Rajaei, Seyed Mehdi; Hashemi, Seyed Sohail Ghazanfari; Williams, David L

    2016-09-01

    The purpose of this study was to establish intraocular pressure values in clinically normal pigeons. One hundred (52 male and 48 female) healthy pigeons ( Columbia livia ) of six different breeds, ranging in age from 20 to 51 mo were used in the study. Pigeons were gently physically restrained in a dorsoventral position without any pressure or extension to the head and neck. A rebound tonometer with a disposable probe was held horizontally and 4-5 mm from the central corneal surface. Calibration of the device was set to "P." Overall, the mean ± SD intraocular pressure values of all eyes were 6.1 ± 0.9 mmHg (ranging from 3 to 9 mmHg). Mean ± SD values for left and right eyes were 6.1 ± 1.0 and 6.0 ± 1.2 mmHg, respectively. There was no statistically significant difference in IOP between the left eye and right eye or between males and females (P = 0.49; P = 0.74). Analysis of variance revealed that there were no significant differences in the IOP between the breeds (P = 0.22).

  10. 3D Real-Time Echocardiography Combined with Mini Pressure Wire Generate Reliable Pressure-Volume Loops in Small Hearts

    PubMed Central

    Linden, Katharina; Dewald, Oliver; Gatzweiler, Eva; Seehase, Matthias; Duerr, Georg Daniel; Dörner, Jonas; Kleppe, Stephanie

    2016-01-01

    Background Pressure-volume loops (PVL) provide vital information regarding ventricular performance and pathophysiology in cardiac disease. Unfortunately, acquisition of PVL by conductance technology is not feasible in neonates and small children due to the available human catheter size and resulting invasiveness. The aim of the study was to validate the accuracy of PVL in small hearts using volume data obtained by real-time three-dimensional echocardiography (3DE) and simultaneously acquired pressure data. Methods In 17 piglets (weight range: 3.6–8.0 kg) left ventricular PVL were generated by 3DE and simultaneous recordings of ventricular pressure using a mini pressure wire (PVL3D). PVL3D were compared to conductance catheter measurements (PVLCond) under various hemodynamic conditions (baseline, alpha-adrenergic stimulation with phenylephrine, beta-adrenoreceptor-blockage using esmolol). In order to validate the accuracy of 3D volumetric data, cardiac magnetic resonance imaging (CMR) was performed in another 8 piglets. Results Correlation between CMR- and 3DE-derived volumes was good (enddiastolic volume: mean bias -0.03ml ±1.34ml). Computation of PVL3D in small hearts was feasible and comparable to results obtained by conductance technology. Bland-Altman analysis showed a low bias between PVL3D and PVLCond. Systolic and diastolic parameters were closely associated (Intraclass-Correlation Coefficient for: systolic myocardial elastance 0.95, arterial elastance 0.93, diastolic relaxation constant tau 0.90, indexed end-diastolic volume 0.98). Hemodynamic changes under different conditions were well detected by both methods (ICC 0.82 to 0.98). Inter- and intra-observer coefficients of variation were below 5% for all parameters. Conclusions PVL3D generated from 3DE combined with mini pressure wire represent a novel, feasible and reliable method to assess different hemodynamic conditions of cardiac function in hearts comparable to neonate and infant size. This

  11. Visualization and Measurements of Sound Pressure Distribution of Ultrasonic Wave by Stroboscopic Real-Time Holographic Interferometry

    NASA Astrophysics Data System (ADS)

    Hisada, Shigeyoshi; Suzuki, Takahiro; Nakahara, Sumio; Fujita, Takeyoshi

    2002-05-01

    The sound pressure distribution of underwater ultrasonic waves is measured by real-time stroboscope holographic interferometry using bismuth silicon oxide single crystal. Stroboscopic sub-microsecond irradiation of laser light enables the recording of the stationary holographic interferogram of refractive index changes of water by ultrasonic waves for the frame time of a charge coupled device camera. The fringe order distribution is calculated from the interferogram by Fourier transform fringe analysis. The optical path differences caused by sound field along the optical path are converted into local field values of sound pressure, which is displayed as a gray scale distribution image. In the experiment, the sound pressure distributions of ultrasonic waves through rectangular and circular apertures are observed. They are compared with the theoretical sound pressure distribution. The sound pressure values obtained by a hydrophone show good agreement with the measured values obtained by this method. The converging and diverging sound pressure fields realized by an acoustic lens are measured.

  12. Biomechanics of the sclera and effects on intraocular pressure

    PubMed Central

    Jia, Xu; Yu, Juan; Liao, Sheng-Hui; Duan, Xuan-Chu

    2016-01-01

    Accumulating evidence indicates that glaucoma is a multifactorial neurodegenerative disease characterized by the loss of retinal ganglion cells (RGC), resulting in gradual and progressive permanent loss of vision. Reducing intraocular pressure (IOP) remains the only proven method for preventing and delaying the progression of glaucomatous visual impairment. However, the specific role of IOP in optic nerve injury remains controversial, and little is known about the biomechanical mechanism by which elevated IOP leads to the loss of RGC. Published studies suggest that the biomechanical properties of the sclera and scleral lamina cribrosa determine the biomechanical changes of optic nerve head, and play an important role in the pathologic process of loss of RGC and optic nerve damage. This review focuses on the current understanding of biomechanics of sclera in glaucoma and provides an overview of the possible interactions between the sclera and IOP. Treatments and interventions aimed at the sclera are also discussed. PMID:28003987

  13. [Combination surgery (ECCE+IOL+TE) and intraocular pressure levels].

    PubMed

    Hornová, J

    1997-08-01

    The authors investigated the effect of a combined operation, ECCE + TE + IOL, on reduction of intraocular pressure (IOP), changes in antiglaucomatous treatment and on vision six months after operation. In 1994 36 eyes were operated, 16 eyes with primary open angle glaucoma (POAG), 8 eyes with angular glaucoma (PACG) and 12 eyes with marked exfoliative syndrome (CG). Six months after operation the IOP declined from 26.4 mm Hg to 13.3 mm Hg (P 0.05), antiglaucomatous treatment was reduced from 2.55 to 1.11 (P 0.05), vision improved by 0.39, i.e. by 2-3 lines of optotypes (P 0.05). 89% of the operated patients have a vision better than 0.5. Comparison of values before and after operation revealed a more marked drop of IOP in CG (P 0.05) than in POAG.

  14. Prostaglandin Pathway Gene Therapy for Sustained Reduction of Intraocular Pressure

    PubMed Central

    Barraza, Román A; McLaren, Jay W; Poeschla, Eric M

    2009-01-01

    Cyclooxygenase-2 (COX-2) is a rate-limiting enzyme in prostaglandin (PG) biosynthesis. In the eye, loss of COX-2 expression in aqueous humor–secreting cells has been associated with primary open-angle glaucoma (POAG). Reduction of intraocular pressure (IOP) is the main treatment goal in this disease. We used lentiviral vectors to stably express COX-2 and other PG biosynthesis and response transgenes in the ciliary body epithelium and trabecular meshwork (TM), the ocular suborgans that produce aqueous humor and regulate its outflow, respectively. We show that robust ectopic COX-2 expression and PG production require COX-2 complementary DNA (cDNA) sequence optimization. When COX-2 expression was coupled with a similarly optimized synthetic PGF2α receptor transgene to enable downstream signaling, gene therapy produced substantial and sustained reductions in IOP in a large animal model, the domestic cat. This study provides the first gene therapy for correcting the main cause of glaucoma. PMID:19953083

  15. Method for real-time measurement of nitrogen atom density in atmospheric pressure post-discharge flows

    NASA Astrophysics Data System (ADS)

    Oinuma, Gaku; Inanaga, Yasutaka; Noda, Seiji; Tanimura, Yasuhiro; Kuzumoto, Masaki; Tabata, Yoichiro; Watanabe, Kensuke

    2008-08-01

    A method has been developed for real-time measurement of nitrogen atom density in atmospheric pressure post-discharge flows. In this method, nitric oxide is supplied to the downstream of a nitrogen discharge as a reactant. Our chemical simulation has revealed that the injected nitric oxide is consumed mainly by reductive reaction with nitrogen atoms or oxidative reaction with oxygen atoms. The number density of atomic nitrogen is determined almost instantaneously through the measurement of nitric oxide and nitrogen dioxide densities with a gas analyser. The experimental verification was carried out with a dielectric barrier discharge unit as a nitrogen atom source, and the results showed good agreement with simulation predictions.

  16. A new device to noninvasively estimate the intraocular pressure produced during ocular compression

    PubMed Central

    Korenfeld, Michael S; Dueker, David K

    2016-01-01

    Purpose To describe a noninvasive instrument that estimates intraocular pressure during episodes of external globe compression and to demonstrate the accuracy and reliability of this device by comparing it to the intraocular pressures simultaneously and manometrically measured in cannulated eyes. Methods A thin fluid-filled bladder was constructed from flexible and inelastic plastic sheeting and was connected to a pressure transducer with high pressure tubing. The output of the pressure transducer was sent to an amplifier and recorded. This device was validated by measuring induced pressure in the fluid-filled bladder while digital pressure was applied to one surface, and the other surface was placed directly against a human cadaver eye or in vivo pig eye. The human cadaver and in vivo pig eyes were each cannulated to provide a manometric intraocular pressure control. Results The measurements obtained with the newly described device were within ~5% of simultaneously measured manometric intraocular pressures in both a human cadaver and in vivo pig eye model for a pressure range of ~15–100 mmHg. Conclusion This novel noninvasive device is useful for estimating the intraocular pressure transients induced during any form of external globe compression; this is a clinical setting where no other devices can be used to estimate intraocular pressure. PMID:26955260

  17. Real-time combustion control and diagnostics sensor-pressure oscillation monitor

    DOEpatents

    Chorpening, Benjamin T.; Thornton, Jimmy; Huckaby, E. David; Richards, George A.

    2009-07-14

    An apparatus and method for monitoring and controlling the combustion process in a combustion system to determine the amplitude and/or frequencies of dynamic pressure oscillations during combustion. An electrode in communication with the combustion system senses hydrocarbon ions and/or electrons produced by the combustion process and calibration apparatus calibrates the relationship between the standard deviation of the current in the electrode and the amplitudes of the dynamic pressure oscillations by applying a substantially constant voltage between the electrode and ground resulting in a current in the electrode and by varying one or more of (1) the flow rate of the fuel, (2) the flow rate of the oxidant, (3) the equivalence ratio, (4) the acoustic tuning of the combustion system, and (5) the fuel distribution in the combustion chamber such that the amplitudes of the dynamic pressure oscillations in the combustion chamber are calculated as a function of the standard deviation of the electrode current. Thereafter, the supply of fuel and/or oxidant is varied to modify the dynamic pressure oscillations.

  18. Intraocular pressure in cats is lowered by drops of hornet venom.

    PubMed

    Kam, J; Waron, M; Barishak, Y R; Schachner, E; Ishay, J S

    1989-01-01

    1. Nine cats were given an intravenous injection of the Oriental hornet (Vespa orientalis, Vespinae; Hymenoptera) venom sac extract (VSE) and seven cats had the same VSE administered as eye drops. 2. When injected intravenously, the hornet VSE decreased the intraocular pressure in both eyes sharply during the first 20 min and with a slower rate later on until the end of the 3 hr experiment. The intraocular pressure dropped to zero in some cases. 3. VSE eye drops decreased the intraocular pressure only in the treated eye, while in the second eye (left as a control) the intraocular pressure remained the same throughout the experiment. 4. The decrease in the intraocular pressure was sharp during the first 20 min and slowed down afterwards until the end of the experiment. 5. The intraocular pressure did not reduce to zero. 6. This study shows that the active components of the hornet venom which caused a decrease in the intraocular pressure can cross the cornea and exert a hypotensive effect in the eye.

  19. A new real time tsunami detection algorithm for bottom pressure measurements in open ocean: characterization and benchmarks

    NASA Astrophysics Data System (ADS)

    Pignagnoli, Luca; Chierici, Francesco; Embriaco, Davide

    2010-05-01

    In the last decades the use of the Bottom Pressure Recorder (BPR) in a deep ocean environment for tsunami detection has had a relevant development. A key role for an early warning system based on BPRs is played by the tsunami detection algorithms running in real time on the BPR itself or on land. We present a new algorithm for tsunami detection based on real time pressure data analysis by a filtering cascade. This procedure consists of a tide removing, spike removing, low pass filtering and linear prediction or band pass filtering; the output filtered data is then matched against a given pressure threshold. Once exceeded a parent tsunami signal is detected. The main characteristics of the algorithm is its site specific adaptability and its flexibility that greatly enhance the detection reliability. In particular it was shown that removing the predicted tide strongly reduces the dynamical range of the pressure time series, allowing the detection of small tsunami signal. The algorithm can also be applied to the data acquired by a tide gauge. The algorithm is particularly designed and optimized to be used in an autonomous early warning system. A statistical method for algorithms evaluation has been developed in order to characterize the algorithms features with particular regards to false alarm probability, detection probability and detection earliness. Different configurations of the algorithm are tested for comparison using both synthetic and real pressure data set recorded in different environmental conditions and locations. The algorithm was installed onboard of the GEOSTAR abyssal station, deployed at 3264 m depth in the Gulf of Cadiz and successfully operated for 1 year, from August 2007 to August 2008.

  20. Ocular onchocerciasis in the Yanomami communities from Brazilian Amazon: effects on intraocular pressure.

    PubMed

    Herzog-Neto, Guilherme; Jaegger, Karen; Nascimento, Erika S do; Marchon-Silva, Verônica; Banic, Dalma M; Maia-Herzog, Marilza

    2014-01-01

    To determine the influence of onchocercal eye disease on the intraocular pressure of the Yanomami Tribe Aratha-ú of Roraima State, Brazil, considered endemic for onchocerciasis, a total of 86 patients were submitted to an ophthalmologic exam that included external examination, slit lamp examination, intraocular pressure measurement, and a fundus ophthalmoscope examination. A high prevalence of onchocerciasis-related eye lesions was encountered in 68.6% of the patients. Punctate keratitis and microfilariae in the anterior chamber were found in ∼28%. The mean of intraocular eye pressure found was 10.47 mm of Hg.

  1. An examination of the hypothesis that intraocular pressure elevation episodes can have prognostic significance in glaucoma suspects.

    PubMed

    McMonnies, Charles

    2015-01-01

    The efficacy of intraocular pressure reduction in retarding the progression of glaucoma has been demonstrated. This review examines the potential for prognostic advantage for glaucoma suspects in reducing their optic nerve head exposure to elevated intraocular pressure associated with activities which have been shown to elevate intraocular pressure. In this observational study, patients examined at the Centre for Eye Health (University of New South Wales) with a diagnosis of glaucoma suspect were surveyed to determine their histories for participation in activities which are known to elevate intraocular pressure. The evidence regarding the pathological significance of these sources of elevation in susceptible patients was examined. Apart from the universality of sleep-related intraocular pressure elevations, the histories from 183 confirmed glaucoma suspects indicate a wide range and variation in frequency of participation in other intraocular pressure elevating activities. A reduction in exposure to elevated intraocular pressure may improve the prognosis for glaucoma suspects. Additional patient specific assessment of the results of this screening could provide an indication of the degree (frequency, intensity level and duration) of exposure to elevated intraocular pressure. Such information may provide the basis for improving a patient's prognosis by helping them to identify opportunities to reduce such exposure to elevated intraocular pressure. Any benefit of reduction of such exposure appears likely to be greater if activities which elevate intraocular pressure are of long duration, occur frequently, occur over a long period of time, and/or involve high levels of intraocular pressure elevation.

  2. Dorsomedial/Perifornical Hypothalamic Stimulation Increases Intraocular Pressure, Intracranial Pressure, and the Translaminar Pressure Gradient

    PubMed Central

    Samuels, Brian C.; Hammes, Nathan M.; Johnson, Philip L.; Shekhar, Anantha; McKinnon, Stuart J.; Allingham, R. Rand

    2012-01-01

    Purpose. Intraocular pressure (IOP) fluctuation has recently been identified as a risk factor for glaucoma progression. Further, decreases in intracranial pressure (ICP), with postulated increases in the translaminar pressure gradient across the lamina cribrosa, has been reported in glaucoma patients. We hypothesized that circadian fluctuations in IOP and the translaminar pressure gradient are influenced, at least in part, by central autonomic regulatory neurons within the dorsomedial and perifornical hypothalamus (DMH/PeF). This study examined whether site-directed chemical stimulation of DMH/PeF neurons evoked changes in IOP, ICP, and the translaminar pressure gradient. Methods. The GABAA receptor antagonist bicuculline methiodide (BMI) was stereotaxically microinjected into the DMH/PeF region of isoflurane-anesthetized male Sprague-Dawley rats (n = 19). The resulting peripheral cardiovascular (heart rate [HR] and mean arterial pressure [MAP]), IOP, and ICP effects were recorded and alterations in the translaminar pressure gradient calculated. Results. Chemical stimulation of DMH/PeF neurons evoked significant increases in HR (+69.3 ± 8.5 beats per minute); MAP (+22.9 ± 1.6 mm Hg); IOP (+7.1 ± 1.9 mm Hg); and ICP (+3.6 ± 0.7 mm Hg) compared with baseline values. However, the peak IOP increase was significantly delayed compared with ICP (28 vs. 4 minutes postinjection), resulting in a dramatic translaminar pressure gradient fluctuation. Conclusions. Chemical stimulation of DMH/PeF neurons evokes substantial increases in IOP, ICP, and the translaminar pressure gradient in the rat model. Given that the DMH/PeF neurons may be a key effector pathway for circadian regulation of autonomic tone by the suprachiasmatic nucleus, these findings will help elucidate novel mechanisms modulating circadian fluctuations in IOP and the translaminar pressure gradient. PMID:23033392

  3. "Real-time" core formation experiments using X-ray tomography at high pressure and temperature

    NASA Astrophysics Data System (ADS)

    Watson, H. C.; Anzures, B.; Yu, T.; Wang, Y.

    2015-12-01

    The process of differentiation is a defining moment in a planet's history. Direct observation of this process at work is impossible in our solar system because it was complete within the first few tens of millions of years. Geochemical and geophysical evidence points to magma ocean scenarios to explain differentiation of large planets such as Earth. Smaller planets and planetesimals likely never achieved the high temperatures necessary for wide scale melting. In these smaller bodies, silicates may have only partially melted, or not melted at all. Furthermore, isotopic signatures in meteorites suggest that some planetesimals differentiated within just a few million years. Achieving efficient core segregation on this rapid timescale is difficult, particularly in a solid or semi-solid silicate matrix. Direct measurements of metallic melt migration velocities have been difficult due to experimental limitations and most previous work has relied on geometric models based on 2-D observations in quenched samples. We have employed a relatively new technique of in-situ, high pressure, high temperature, X-ray micro-tomography coupled with 3-D numerical simulations to evaluate the efficiency of melt percolation in metal/silicate systems. From this, we can place constraints on the timing of core formation in early solar system bodies. Mixtures of olivine and KLB-1 peridotite and up to 12 vol% FeS were pre-synthesized to achieve an initial equilibrium microstructure of silicate and sulfide. The samples were then were then pressed again to ~2GPa, and heated to ~1300°C to collect X-ray tomography images as the partially molten samples were undergoing shear deformation. The reconstructed 3-D images of melt distribution were used as the input for lattice Boltzmann simulations of fluid flow through the melt network and calculations of permeability and melt migration velocity. Our in-situ x-ray tomography results are complemented by traditional 2-D image analysis and high

  4. Argon laser trabeculoplasty as a means of decreasing intraocular pressure from ''normal'' levels in glaucomatous eyes

    SciTech Connect

    Sharpe, E.D.; Simmons, R.J.

    1985-06-15

    The authors conducted a retrospective study of 67 patients (85 eyes) with severe glaucoma to determine whether argon laser trabeculoplasty could reduce intraocular pressures below the ''normal'' range. All patients had initial intraocular pressures of less than or equal to 19 mm Hg. Success was defined as a decrease in intraocular pressure of at least 20%, no increase in medications, stable visual field, and no subsequent glaucoma surgery. After an average follow-up period of 30 months, treatment was successful in 31 cases. One half of the failures occurred by six months and 11 failures (30%) occurred after 12 months. Sixteen patients were able to decrease their medications. Two patients achieved intraocular pressures between 6 and 9 mm Hg and 20 between 10 and 12 mm Hg.

  5. Prevalence of increased intraocular pressure in Graves' disease--evidence of frequent subclinical ophthalmopathy.

    PubMed

    Gamblin, G T; Harper, D G; Galentine, P; Buck, D R; Chernow, B; Eil, C

    1983-02-24

    Graves' exophthalmos is frequently associated with elevated intraocular pressure on upgaze. Eighty patients with Graves' disease were evaluated prospectively by applanation tonometry to assess the prevalence of ophthalmopathy in this disorder. Whereas 21 (26 per cent) of the 80 patients had exophthalmos, 61 (76 per cent) had abnormal intraocular pressure (delta greater than or equal to 3 mm Hg). All patients with exophthalmos had elevated intraocular pressure on upgaze; 40 (68 per cent) of 59 patients without proptosis had abnormal pressure readings. The mean interval between the onset of Graves' disease and this study was 6.3 +/- 1.0 years (S.E.M.) for those patients who had exaggerated positional changes in intraocular pressure, as compared with 3.0 +/- 1.0 years for those with normal intraocular pressure (P less than 0.005). All but 1 of 15 patients in whom the diagnosis of Graves' disease had been documented 10 or more years earlier had increased intraocular pressure on upgaze. We conclude that Graves' ophthalmopathy is more common than is recognized clinically and that eye involvement is an inevitable complication of the disease.

  6. Effects of ethacrynic acid on intraocular pressure of anesthetized rats.

    PubMed

    Searles, R V; Johnson, M; Shikher, V; Balaban, C D; Severs, W B

    1999-03-01

    Ethacrynic acid (ECA) lowers intraocular pressure (i.o.p.) by an effect usually ascribed to increased drainage of aqueous humor by the trabecular meshwork. Here, we describe the effects of a continuous 2-hr intracameral infusion of balanced salt solution (BSS), with or without 2 mM ECA (sodium salt), on IOP of pentobarbital anesthetized rats. The infusion was divided into a constant (0.05 microliter/min) and a periodic (0.25 microliter/min) component that cycled 4 min on then 4 min off. This permitted the calculation of dynamic changes in resistive (trabecular and uveoslceral drainage) and nonresistive (aqueous synthesis, episcleral venous pressure) components of IOP by fitting a second-order transfer function to the responses. ECA markedly blunted the BSS-induced rise in IOP (P < 0.01). The rise in resistive mechanisms (ocular impedance) was transiently blunted by ECA (P < 0.05) during the third and fourth 8-min cycles, and nonresistive mechanisms were reduced by ECA from cycles 3-10 (P < 0.05). Then, at the end of the infusion, the control and ECA dynamic values were similar (P < 0.05), although IOP of ECA-treated rats was still slightly reduced (P < 0.05). The most likely explanation is a summation of small changes in both resistive and nonresistive components of IOP dynamics. Systemic blood pressure was unchanged within either group. The well-known effects of ECA on the trabecular meshwork, alone, are insufficient to explain the dynamic changes in IOP observed in this model.

  7. Intraocular pressure is sensitive to cumulative and instantaneous mental workload.

    PubMed

    Vera, Jesús; Jiménez, Raimundo; García, José Antonio; Cárdenas, David

    2017-04-01

    We used a repeated-measures design to assess the impact of mental-task complexity on intraocular pressure (IOP). Fourteen participants performed three continuous 11-min blocks of a mental-workload task (3-back) and an oddball version of this task. Also, heart-rate variability (HRV), cognitive-performance scores, and subjective measure of mental load (NASA-TLX) were determined. IOP was taken before each block and afterwards as well as after recovery from mental tasks. We found that IOP increased during heavy mental workloads (p < 0.01). Consistent with this finding, the autonomic control (HRV) and the cognitive performance were significantly lower (p < 0.045, and p < 0.01, respectively), and the NASA-TLX scores were higher during the 3-back task (p < 0.01). We conclude that IOP is sensitive to mental workload, and it could provide a novel neuroergonomic tool to assess mental workload. Our study highlights a potential association between IOP and the nervous system's state of activation.

  8. Prognostic Factor Analysis of Intraocular Pressure with Neovascular Glaucoma.

    PubMed

    Nakano, Satoko; Nakamuro, Takako; Yokoyama, Katsuhiko; Kiyosaki, Kunihiro; Kubota, Toshiaki

    2016-01-01

    Purpose. To perform multivariate analysis for identifying independent predictors of elevated intraocular pressure (IOP) with neovascular glaucoma (NVG), including antivascular endothelial growth factor (VEGF) intravitreal injections. Methods. We retrospectively reviewed 142 NVG patients (181 eyes) with ischemic retinal diseases [proliferative diabetic retinopathy (PDR) in 134 eyes, retinal vein occlusion (RVO) in 29, and ocular ischemic syndrome in 18]. We analyzed age, gender, initial/final LogMAR VA, initial/final IOP, extent of iris and/or angle neovascularization, treatments, preexisting complications, concurrent medications, and follow-up duration. Results. The mean follow-up duration was 23.8 ± 18.8 months. At the final follow-up, 125 (72.3%) eyes had IOP ≤ 21 mmHg. NVG patients with RVO had a higher degree of angle closure and higher IOP. NVG with PDR had better IOP and LogMAR VA. Angle closure had the greatest impact on final IOP. Greater than 90% of patients treated with trabeculectomy with mitomycin C (LEC) had persistent declines in IOP (≤21 mmHg). Stand-alone and combination anti-VEGF therapies were not associated with improved long-term prognosis of IOP. Conclusions. Angle closure was found to have the greatest effect on NVG-IOP prognosis. When target IOP values are not obtained after adequate PRP with or without anti-VEGF, early LEC may improve the prognosis of IOP.

  9. Intraocular Pressure Induced Retinal Changes Identified Using Synchrotron Infrared Microscopy

    PubMed Central

    Chow, Seong Hoong; Wang, Jiang-Hui; He, Zheng; Nguyen, Christine; Lin, Tsung-Wu; Bui, Bang V.

    2016-01-01

    Infrared (IR) spectroscopy has been used to quantify chemical and structural characteristics of a wide range of materials including biological tissues. In this study, we examined spatial changes in the chemical characteristics of rat retina in response to intraocular pressure (IOP) elevation using synchrotron infrared microscopy (SIRM), a non-destructive imaging approach. IOP elevation was induced by placing a suture around the eye of anaesthetised rats. Retinal sections were collected onto transparent CaF2 slides 10 days following IOP elevation. Using combined SIRM spectra and chemical mapping approaches it was possible to quantify IOP induced changes in protein conformation and chemical distribution in various layers of the rat retina. We showed that 10 days following IOP elevation there was an increase in lipid and protein levels in the inner nuclear layer (INL) and ganglion cell layer (GCL). IOP elevation also resulted in an increase in nucleic acids in the INL. Analysis of SIRM spectra revealed a shift in amide peaks to lower vibrational frequencies with a more prominent second shoulder, which is consistent with the presence of cell death in specific layers of the retina. These changes were more substantial in the INL and GCL layers compared with those occurring in the outer nuclear layer. These outcomes demonstrate the utility of SIRM to quantify the effect of IOP elevation on specific layers of the retina. Thus SIRM may be a useful tool for the study of localised tissue changes in glaucoma and other eye diseases. PMID:27711151

  10. Prognostic Factor Analysis of Intraocular Pressure with Neovascular Glaucoma

    PubMed Central

    Nakamuro, Takako; Yokoyama, Katsuhiko; Kiyosaki, Kunihiro

    2016-01-01

    Purpose. To perform multivariate analysis for identifying independent predictors of elevated intraocular pressure (IOP) with neovascular glaucoma (NVG), including antivascular endothelial growth factor (VEGF) intravitreal injections. Methods. We retrospectively reviewed 142 NVG patients (181 eyes) with ischemic retinal diseases [proliferative diabetic retinopathy (PDR) in 134 eyes, retinal vein occlusion (RVO) in 29, and ocular ischemic syndrome in 18]. We analyzed age, gender, initial/final LogMAR VA, initial/final IOP, extent of iris and/or angle neovascularization, treatments, preexisting complications, concurrent medications, and follow-up duration. Results. The mean follow-up duration was 23.8 ± 18.8 months. At the final follow-up, 125 (72.3%) eyes had IOP ≤ 21 mmHg. NVG patients with RVO had a higher degree of angle closure and higher IOP. NVG with PDR had better IOP and LogMAR VA. Angle closure had the greatest impact on final IOP. Greater than 90% of patients treated with trabeculectomy with mitomycin C (LEC) had persistent declines in IOP (≤21 mmHg). Stand-alone and combination anti-VEGF therapies were not associated with improved long-term prognosis of IOP. Conclusions. Angle closure was found to have the greatest effect on NVG-IOP prognosis. When target IOP values are not obtained after adequate PRP with or without anti-VEGF, early LEC may improve the prognosis of IOP. PMID:27579175

  11. Noncontact measurement of intraocular pressure using a modified Michelson interferometer

    NASA Astrophysics Data System (ADS)

    Drescher, Joerg; Stork, Wilhelm; Hey, Stefan; Gundlach, Arnd; Mueller-Glaser, Klaus-Dieter; Kreiner, Christine F.

    1999-06-01

    This paper describes a new method to examine the intraocular pressure (IOP) without any contact with the eye. In our new approach the IOP is determined indirectly from the acoustic properties of the eye, as the resonance frequencies of the bulbus are shifting with increasing IOP. In a first step simulations were made with the Finite Element Method to explore the correlation between the IOP and the acoustic properties of the bulbus. The results showed a significant rise of the resonance-frequencies with increasing IOP. Simultaneously a in-vitro measurement system was built comprising a modified michelson interferometer to measure the vibrations, a transducer to stimulate the eye and a controlling PC. With this system measurements were made with artificial eyes and enucleated pig eyes to prove the correlation experimentally. The eyes were stimulated both contacting the eye with a transducer by a stick and contactless with sonic waves. Several series of measurements showed a proportional constant of 1,25 Hz/mmHg in average, which can be detected easily. The standard deviation measuring different pig eyes was 4,5 mmHg. Next a in-vivo system was developed to study the acoustic behavior of the human eye in the real environment. The in-vivo system consists of a miniaturized semiconductor-laser interferometer complying laser safety requirements, an automatic positioning unit and an excitation unit to stimulate vibrations of the eye. Sub-micrometer vibrations of the eye can be measured in-vivo with this system.

  12. Mechanisms for vasopressin effects on intraocular pressure in anesthetized rats

    NASA Technical Reports Server (NTRS)

    Balaban, C. D.; Palm, D. E.; Shikher, V.; Searles, R. V.; Keil, L. C.; Severs, W. B.

    1997-01-01

    Continuous intracameral infusions of a balanced salt solution (0.175 microliter min-1) have been reported to raise intraocular pressure (IOP) in anesthetized rats. Palm et al. (1995) previously reported that this effect was attenuated significantly by inclusion of arginine-vasopressin (AVP, 10 ng 0.175 microliter-1) in the infusate. This study used experimental and computer simulation methods to investigate factors underlying these changes in IOP. First, constant intracameral infusions of artificial cerebrospinal fluid (aCSF) at different fixed rates (0.049-0.35 microliter min-1) were used to estimate the outflow resistance. Secondly, IOP responses were measured during an 2 hr intracameral infusion of either aCSF or AVP that was the sum of a small constant component (0.05 microliter min-1) and a larger periodic component (0.25 microliter min-1, cycling for 4 min on, then 4 min off); the mean infusion rate was 0.175 microliter min-1. As shown previously for 0.175 microliter min-1 constant infusions, the periodic aCSF infusion induced a significant rise in IOP that was attenuated by AVP administration. Complex demodulation analysis and the estimated gain parameter of a second order transfer function fit to the periodic responses indicated that outflow resistance increased significantly during the infusions in both aCSF and AVP groups, but that the indices of resistance did not differ significantly between aCSF and AVP infused eyes. This finding implies that changes in outflow resistance do not explain the difference in IOP responses to intracameral aCSF and AVP. The two responses differed significantly, though, in damping factors, such that the aCSF responses were considerably more underdamped than the AVP responses. It is hypothesized that aCSF-induced increase in IOP reflects both (1) a small component reflecting increased outflow resistance and (2) a larger non-resistive component. Since the non-resistive component is insensitive to pretreatment with acetazolamide

  13. The significance of intraocular pressure elevation during sleep-related postures.

    PubMed

    McMonnies, Charles W

    2014-05-01

    Intraocular pressure and its fluctuations are associated with the development and progression of glaucoma. This review examines the potential for sleep-related intraocular pressure elevations to contribute to the onset and progression of glaucoma. Also considered is the potential for patient education and appropriate changes in behaviour as a means of reducing exposure to elevated intraocular pressure. A PubMed search using the combination key words 'glaucoma and sleep' was conducted. Information was taken from representative articles from the 187 yielded from the search. Additional papers were found after accessing references in selected papers. Several studies have indicated an association between the progression of glaucoma and both lateral decubitus (side sleep) and supine sleep positions. Evidence that prone sleep positions could raise intraocular pressure to high levels suggests a similar if not stronger association. Intraocular pressure elevation and progression of glaucoma associated with sleep positions suggest that there are similar risks of progression associated with sleep-related body postures adopted during non-sleep activities, such as reading, watching television and sun-bathing. Posture-related management of patients with glaucoma, which is intended to reduce the risk or degree of progression may include the use of specially designed pillows, bed-head elevation and recommendations to avoid postures which induce higher intraocular pressure.

  14. Multi-index method using offshore ocean-bottom pressure data for real-time tsunami forecast

    NASA Astrophysics Data System (ADS)

    Yamamoto, Naotaka; Aoi, Shin; Hirata, Kenji; Suzuki, Wataru; Kunugi, Takashi; Nakamura, Hiromitsu

    2016-07-01

    We developed a real-time tsunami forecast method using only pressure data collected from the bottom of the ocean via a dense offshore observation network. The key feature of the method is rapid matching between offshore tsunami observations and pre-calculated offshore tsunami spatial distributions. We first calculate the tsunami waveforms at offshore stations and the maximum coastal tsunami heights from any possible tsunami source model and register them in the proposed Tsunami Scenario Bank (TSB). When a tsunami occurs, we use multiple indices to quickly select dozens of appropriate tsunami scenarios that can explain the offshore observations. At the same time, the maximum coastal tsunami heights coupled with the selected tsunami scenarios are forecast. We apply three indices, which are the correlation coefficient and two kinds of variance reductions normalized by the L2-norm of either the observation or calculation, to match the observed spatial distributions with the pre-calculated spatial distributions in the TSB. We examine the ability of our method to select appropriate tsunami scenarios by conducting synthetic tests using a scenario based on "pseudo-observations." For these tests, we construct a tentative TSB, which contains tsunami waveforms at locations in the Seafloor Observation Network for Earthquakes and Tsunamis along the Japan Trench and maximum coastal tsunami heights, using about 2000 tsunami source models along the Japan Trench. Based on the test results, we confirm that the method can select appropriate tsunami scenarios within a certain precision by using the two kinds of variance reductions, which are sensitive to the tsunami size, and the correlation coefficient, which is sensitive to the tsunami source location. In this paper, we present the results and discuss the characteristics and behavior of the multi-index method. The addition of tsunami inundation components to the TSB is expected to enable the application of this method to real-time

  15. Intraocular pressure in very low birth weight preterm infants and its association with postconceptional age

    PubMed Central

    Lindenmeyer, Rodrigo L.; Farias, Lucas; Mendonça, Taís; Filho, João Borges Fortes; Procianoy, Renato S.; Silveira, Rita C.

    2012-01-01

    OBJECTIVE: To evaluate intraocular pressure in very low birth weight preterm infants and correlate it with postconceptional age. METHODS: The intraocular pressure in a prospective cohort of very low birth weight premature infants (defined as a birth weight ≤1,500 g and gestational age ≤32 weeks) admitted to Hospital de Clínicas de Porto Alegre, Brazil was evaluated weekly. The evaluated outcome was the variation in the intraocular pressure following changes in the postconceptional age (defined as the gestational age at birth plus the age in weeks at the time of examination) in the weeks following preterm birth. Mixed-effects models were used for the statistical analysis to determine the intraocular pressure variation according to postconceptional age, and means and 10th and 90th percentiles were calculated for the intraocular pressure values. RESULTS: Fifty preterm infants with a mean gestational age of 29.7±1.6 weeks and a mean birth weight of 1,127.7±222.7 g were evaluated. The mean intraocular pressure for the entire cohort considering both eyes was 14.9±4.5 mmHg, and 13.5% of all recorded intraocular pressure values were greater than 20 mmHg. The analysis revealed a mean reduction in the intraocular pressure of 0.29 mmHg for each increase in postconceptional age (p = 0.047; 95% CI: −0.58 to −0.0035). The mean intraocular pressure (P10–P90) decreased from 16.3 mmHg (10.52–22.16) at 26.3 weeks to 13.1 mmHg (7.28–18.92) at 37.6 weeks of postconceptional age. CONCLUSIONS: The mean intraocular pressure in very low birth weight preterm infants was 14.9±4.5 mmHg. This value decreased 0.29 mmHg per week as the postconceptional age increased. PMID:23184197

  16. Real-time studies of the atomic layer deposition of metal oxides using Ambient pressure x-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Schnadt, Joachim; Head, Ashley R.; Chaudhary, Shilpi; Yngman, Sofie; Johansson, Niclas; Snezhkova, Olesia; Knudsen, Jan; Andersen, Jesper N.; Bluhm, Hendrik; Mikkelsen, Anders; Timm, Rainer

    2014-03-01

    Performing atomic layer deposition (ALD) of metal oxides at pressures around 0.01 mbar slows the half reactions of the process to allow in situ real-time probing of changes in the surface electronic structure using Ambient pressure x-ray photoelectron spectroscopy (APXPS). By monitoring the ALD process as it occurs, new details on the mechanisms of interface formation and thin film growth can be obtained. The deposition of HfO2 on InAs and the deposition of TiO2 on rutile titania from transition metal complexes and water were studied with APXPS. Predictable, cyclic chemical shifts of ligand and substrate ionizations are seen in the growth of the films, but the kinetics of the film growth differs for the two systems. Upon exposure to the titania surface, the titanium precursor reacts straightaway and gradually proceeds to completion. In contrast, the hafnium precursor does not interact with the surface immediately. Once an activation barrier is surpassed, the reaction occurs instantaneously. By understanding the reactivity of different precursors, the ALD process can be more easily optimized in applications that require thin films of metal oxides such as metal-oxide-semiconductor devices and catalytic surfaces. Support by the Swedish Research Council (grant no. 2010-5080) is gratefully acknowledged.

  17. The Real-Time Wall Interference Correction System of the NASA Ames 12-Foot Pressure Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Ulbrich, Norbert

    1998-01-01

    An improved version of the Wall Signature Method was developed to compute wall interference effects in three-dimensional subsonic wind tunnel testing of aircraft models in real-time. The method may be applied to a full-span or a semispan model. A simplified singularity representation of the aircraft model is used. Fuselage, support system, propulsion simulator, and separation wake volume blockage effects are represented by point sources and sinks. Lifting effects are represented by semi-infinite line doublets. The singularity representation of the test article is combined with the measurement of wind tunnel test reference conditions, wall pressure, lift force, thrust force, pitching moment, rolling moment, and pre-computed solutions of the subsonic potential equation to determine first order wall interference corrections. Second order wall interference corrections for pitching and rolling moment coefficient are also determined. A new procedure is presented that estimates a rolling moment coefficient correction for wings with non-symmetric lift distribution. Experimental data obtained during the calibration of the Ames Bipod model support system and during tests of two semispan models mounted on an image plane in the NASA Ames 12 ft. Pressure Wind Tunnel are used to demonstrate the application of the wall interference correction method.

  18. Nanosponge-Mediated Drug Delivery Lowers Intraocular Pressure

    PubMed Central

    Lambert, Wendi S.; Carlson, Brian J.; van der Ende, Alice E.; Shih, Grace; Dobish, Julia N.; Calkins, David J.; Harth, Eva

    2015-01-01

    Purpose We examined the efficacy of an extended-release drug delivery system, nanosponge (NS) encapsulated compounds, administered intravitreally to lower intraocular pressure (IOP) in mice. Methods Bilateral ocular hypertension was induced in mice by injecting microbeads into the anterior chamber. Hypertensive mice received NS loaded with ocular hypotensive drugs via intravitreal injection and IOP was monitored. Retinal deposition and retinal ganglion cell (RGC) uptake of Neuro-DiO were examined following intravitreal injection of Neuro-DiO-NS using confocal microscopy. Results Brimonidine-loaded NS lowered IOP 12% to 30% for up to 6 days (P < 0.02), whereas travoprost-NS lowered IOP 19% to 29% for up to 4 days (P < 0.02) compared to saline injection. Three bimatoprost NS were tested: a 400-nm NS and two 700-nm NS with amorphous (A-NS) or amorphous/crystalline (AC-NS) crosslinkers. A single injection of 400 nm NS lowered IOP 24% to 33% for up to 17 days compared to saline, while A-NS and AC-NS lowered IOP 22% to 32% and 18% to 26%, respectively, for up to 32 days (P < 0.046). Over time retinal deposition of Neuro-DiO increased from 19% to 71%; Neuro-DiO released from NS was internalized by RGCs. Conclusions A single injection of NS can effectively deliver ocular hypotensive drugs in a linear and continuous manner for up to 32 days. Also, NS may be effective at targeting RGCs, the neurons that degenerate in glaucoma. Translational Relevance Patient compliance is a major issue in glaucoma. The use of NS to deliver a controlled, sustained release of therapeutics could drastically reduce the number of patients that progress to vision loss in this disease. PMID:25599009

  19. Apparatus and method for non-contact, acoustic resonance determination of intraocular pressure

    DOEpatents

    Sinha, Dipen N.; Wray, William O.

    1994-01-01

    Apparatus and method for measuring intraocular pressure changes in an eye under investigation by detection of vibrational resonances therein. An ultrasonic transducer operating at its resonant frequency is amplitude modulated and swept over a range of audio frequencies in which human eyes will resonate. The output therefrom is focused onto the eye under investigation, and the resonant vibrations of the eye observed using a fiber-optic reflection vibration sensor. Since the resonant frequency of the eye is dependent on the pressure therein, changes in intraocular pressure may readily be determined after a baseline pressure is established.

  20. Apparatus and method for non-contact, acoustic resonance determination of intraocular pressure

    DOEpatents

    Sinha, D.N.; Wray, W.O.

    1994-12-27

    The apparatus and method for measuring intraocular pressure changes in an eye under investigation by detection of vibrational resonances therein. An ultrasonic transducer operating at its resonant frequency is amplitude modulated and swept over a range of audio frequencies in which human eyes will resonate. The output therefrom is focused onto the eye under investigation, and the resonant vibrations of the eye observed using a fiber-optic reflection vibration sensor. Since the resonant frequency of the eye is dependent on the pressure therein, changes in intraocular pressure may readily be determined after a baseline pressure is established. 3 figures.

  1. Quantitative Assessment of the Impact of Blood Pulsation on Intraocular Pressure Measurement Results in Healthy Subjects

    PubMed Central

    2017-01-01

    Background. Blood pulsation affects the results obtained using various medical devices in many different ways. Method. The paper proves the effect of blood pulsation on intraocular pressure measurements. Six measurements for each of the 10 healthy subjects were performed in various phases of blood pulsation. A total of 8400 corneal deformation images were recorded. The results of intraocular pressure measurements were related to the results of heartbeat phases measured with a pulse oximeter placed on the index finger of the subject's left hand. Results. The correlation between the heartbeat phase measured with a pulse oximeter and intraocular pressure is 0.69 ± 0.26 (p < 0.05). The phase shift calculated for the maximum correlation is equal to 60 ± 40° (p < 0.05). When the moment of measuring intraocular pressure with an air-puff tonometer is not synchronized, the changes in IOP for the analysed group of subjects can vary in the range of ±2.31 mmHg (p < 0.3). Conclusions. Blood pulsation has a statistically significant effect on the results of intraocular pressure measurement. For this reason, in modern ophthalmic devices, the measurement should be synchronized with the heartbeat phases. The paper proposes an additional method for synchronizing the time of pressure measurement with the blood pulsation phase. PMID:28250983

  2. Intraocular pressure and glaucoma: Is physical exercise beneficial or a risk?

    PubMed

    McMonnies, Charles William

    2016-01-01

    Intraocular pressure may become elevated with muscle exertion, changes in body position and increased respiratory volumes, especially when Valsalva manoeuver mechanisms are involved. All of these factors may be present during physical exercise, especially if hydration levels are increased. This review examines the evidence for intraocular pressure changes during and after physical exercise. Intraocular pressure elevation may result in a reduction in ocular perfusion pressure with the associated possibility of mechanical and/or ischaemic damage to the optic nerve head. A key consideration is the possibility that, rather than being beneficial for patients who are susceptible to glaucomatous pathology, any intraocular pressure elevation could be detrimental. Lower intraocular pressure after exercise may result from its elevation causing accelerated aqueous outflow during exercise. Also examined is the possibility that people who have lower frailty are more likely to exercise as well as less likely to have or develop glaucoma. Consequently, lower prevalence of glaucoma would be expected among people who exercise. The evidence base for this topic is deficient and would be greatly improved by the availability of tonometry assessment during dynamic exercise, more studies which control for hydration levels, and methods for assessing the potential general health benefits of exercise against any possibility of exacerbated glaucomatous pathology for individual patients who are susceptible to such changes.

  3. An Effective Approach for Coupling Direct Analysis in Real Time with Atmospheric Pressure Drift Tube Ion Mobility Spectrometry

    NASA Astrophysics Data System (ADS)

    Keelor, Joel D.; Dwivedi, Prabha; Fernández, Facundo M.

    2014-09-01

    Drift tube ion mobility spectrometry (DTIMS) has evolved as a robust analytical platform routinely used for screening small molecules across a broad suite of chemistries ranging from food and pharmaceuticals to explosives and environmental toxins. Most modern atmospheric pressure IM detectors employ corona discharge, photoionization, radioactive, or electrospray ion sources for efficient ion production. Coupling standalone DTIMS with ambient plasma-based techniques, however, has proven to be an exceptional challenge. Device sensitivity with near-ground ambient plasma sources is hindered by poor ion transmission at the source-instrument interface, where ion repulsion is caused by the strong electric field barrier of the high potential ion mobility spectrometry (IMS) inlet. To overcome this shortfall, we introduce a new ion source design incorporating a repeller point electrode used to shape the electric field profile and enable ion transmission from a direct analysis in real time (DART) plasma ion source. Parameter space characterization studies of the DART DTIMS setup were performed to ascertain the optimal configuration for the source assembly favoring ion transport. Preliminary system capabilities for the direct screening of solid pharmaceuticals are briefly demonstrated.

  4. Real-Time, Non-Intrusive Detection of Liquid Nitrogen in Liquid Oxygen at High Pressure and High Flow

    NASA Technical Reports Server (NTRS)

    Singh, Jagdish P.; Yueh, Fang-Yu; Kalluru, Rajamohan R.; Harrison, Louie

    2012-01-01

    An integrated fiber-optic Raman sensor has been designed for real-time, nonintrusive detection of liquid nitrogen in liquid oxygen (LOX) at high pressures and high flow rates in order to monitor the quality of LOX used during rocket engine ground testing. The integrated sensor employs a high-power (3-W) Melles Griot diode-pumped, solid-state (DPSS), frequency-doubled Nd:YAG 532- nm laser; a modified Raman probe that has built-in Raman signal filter optics; two high-resolution spectrometers; and photomultiplier tubes (PMTs) with selected bandpass filters to collect both N2 and O2 Raman signals. The PMT detection units are interfaced with National Instruments Lab- VIEW for fast data acquisition. Studies of sensor performance with different detection systems (i.e., spectrometer and PMT) were carried out. The concentration ratio of N2 and O2 can be inferred by comparing the intensities of the N2 and O2 Raman signals. The final system was fabricated to measure N2 and O2 gas mixtures as well as mixtures of liquid N2 and LOX

  5. [Experimental investigations on the mode of action of alcoholic liquor on the intra-ocular pressure (author's transl)].

    PubMed

    Leydhecker, W; Krieglstein, G K; Uhlich, E

    1978-07-01

    The reasons for the decrease of intraocular pressure after drinking of alcohol were examined. The dose of alcohol was 2 ml 38% Weinbrand per kg body weight, which corresponds to 53 ml pure alcohol for a person of 70 kg body weight. The tonographic data gave no correlation between the blood-alcohol level and the changes of intraocular pressure. The antidiuretic hormon also had no correlation to the intraocular pressure changes. Tonometry with the same frequency as in this study but without alcohol showed no alteration of intraocular pressure. It is suggested that alcohol acts probably by a decrease of secretion of aqueous humour by central actions.

  6. Intraocular pressure in captive American flamingos (Phoenicopterus ruber) as measured by rebound tonometry.

    PubMed

    Molter, Christine M; Hollingsworth, Steven R; Kass, Philip H; Chinnadurai, Sathya K; Wack, Raymund F

    2014-09-01

    Intraocular pressure was measured using rebound tonometry in American flamingos (Phoenicopterus ruber), with the head in an upright standing position and when lowered in a feeding position, to establish a reference range. Mean +/- standard deviation (SD) (range) intraocular pressure for flamingos with the head in an upright position was right eye (OD)= 10.9 +/- 1.8 mm Hg (7-15 mm Hg) and left eye (OS) = 11.1 +/- 2.3 mm Hg (8-21 mm Hg). Median intraocular pressure for flamingos with the head in an upright position was OD and OS = 11 mm Hg. Mean intraocular pressure for flamingos with the head in a feeding position was OD = 14.3 +/- 2.5 mm Hg (10-22 mm Hg) and OS = 14.4 +/- 2.7 mm Hg (11-24 mm Hg), which were significantly higher. Median intraocular pressure for flamingos with the head in a feeding position was OD and OS = 14 mm Hg.

  7. Relationship between homocysteine and intraocular pressure in men and women: A population-based study.

    PubMed

    Leibovitzh, Haim; Cohen, Eytan; Levi, Amos; Kramer, Michal; Shochat, Tzippy; Goldberg, Elad; Krause, Ilan

    2016-09-01

    The relationship between homocysteine levels and glaucoma has been questioned in previous studies without conclusive results. In the current study, we assessed the relationship between homocysteine levels and intraocular pressure which is one of the main factors in the development of glaucoma in men and women.A retrospective cross-sectional analysis of a database from a screening center in Israel which assessed 11,850 subjects, within an age range 20 to 80 years. The relationship between homocysteine and intraocular pressure has been investigated by comparing intraocular pressure in subjects with elevated and normal homocysteine and by comparing homocysteine levels in subjects with elevated and normal intraocular pressure. In addition, we compared the levels of homocysteine in subjects with and without a confirmed diagnosis of glaucoma.The mean IOP (±SD) in subjects with normal homocysteine levels(≤15 μmol/L) was 13.2 ± 2.3 mm Hg and 13.4 ± 2.4 mm Hg in those with high homocysteine levels (>15 μmol/L) (P < 0.008, 95% confidence interval [CI] 0.3-0.09).Nonetheless, after multivariate adjustment for age, gender, vitamin B12, and folic acid statistical significance was no longer demonstrated (P = 0.37). Mean homocysteine levels (±SD) in subjects with normal intraocular pressure of ≤ 21 mm Hg was 11.7 ± 5.5 μmol/L and 12.09 ± 3.43 μmol/L in those with elevated intraocular pressure (P = 0.4, 95%CI 1.1-1.8). Mean homocysteine levels (±SD) in subjects with glaucoma were 11.2 ± 3.5 μmol/L compared to 11.7 ± 5.5 μmol/L in subjects without glaucoma and normal intraocular pressure ≤ 21 mm Hg (P = 0.4, 95% CI 1.2-2.1).The current study displays no clinical correlation between the homocysteine level and the intraocular pressure. Homocysteine may not be used as a predictive parameter to recognize those subjects prone to develop elevated intraocular pressure.

  8. Systemic Medication and Intraocular Pressure in a British Population

    PubMed Central

    Khawaja, Anthony P.; Chan, Michelle P.Y.; Broadway, David C.; Garway-Heath, David F.; Luben, Robert; Yip, Jennifer L.Y.; Hayat, Shabina; Wareham, Nicholas J.; Khaw, Kay-Tee; Foster, Paul J.

    2014-01-01

    Objective To determine the association between systemic medication use and intraocular pressure (IOP) in a population of older British men and women. Design Population-based, cross-sectional study. Participants We included 7093 participants from the European Prospective Investigation into Cancer–Norfolk Eye Study. Exclusion criteria were a history of glaucoma therapy (medical, laser, or surgical), IOP asymmetry between eyes of >5 mmHg, and missing data for any covariables. The mean age of participants was 68 years (range, 48–92) and 56% were women. Methods We measured IOP using the Ocular Response Analyzer. Three readings were taken per eye and the best signal value of the Goldmann-correlated IOP value considered. Participants were asked to bring all their medications and related documentation to the health examination, and these were recorded by the research nurse using an electronic case record form. The medication classes examined were angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, α-blockers, β-blockers, calcium channel blockers, diuretics, nitrates, statins, insulin, biguanides, sulfonylureas, aspirin, and other nonsteroidal anti-inflammatory drugs. We examined associations between medication use and IOP using multivariable linear regression models adjusted for age, sex, and body mass index. Models containing diabetic medication were further adjusted for glycosylated hemoglobin levels. Main Outcome Measures Mean IOP of the right and left eyes. Results Use of systemic β-blockers (−0.92 mmHg; 95% CI, −1.19, −0.65; P<0.001) and nitrates (−0.63 mmHg; 95% CI, −1.12, −0.14; P = 0.011) were independently associated with lower IOP. The observed associations between statin or aspirin use with IOP were no longer significant after adjustment for β-blocker use. Conclusions This is the first population-based study to demonstrate and quantify clinically significant differences in IOP among participants using systemic

  9. Nocturnal blood pressure and intraocular pressure measurement in glaucoma patients and healthy controls.

    PubMed

    Follmann, P; Palotás, C; Süveges, I; Petrovits, A

    Daytime and nocturnal intraocular pressure (IOP) values and systemic blood pressure (BP) values were compared in 60 non-glaucomatous controls, 54 glaucoma patients with normal visual field, and 46 glaucoma patients with visual field loss. The daytime IOP was measured with a Goldmann applanation tonometer and the nocturnal IOP with a Bio-Rad-Tono-Pen 2. The BP was measured with either a mercury manometer or with a Meditech ABPM-02 Ambulatory Blood Pressure Monitor, which took BP readings at 60 minute intervals. A tendency towards increasing IOP and decreasing BP was detected in the non-glaucomatous controls, within normal limits, and pathological changes of IOP and BP were observed with a significantly high occurrence (5% > P > 2%; Pearson's chi 2-test) in the glaucoma group with visual field loss.

  10. Influence of untreated chronic plastic iridocyclitis on intraocular pressure in leprosy patients.

    PubMed

    Karaçorlu, M A; Cakiner, T; Saylan, T

    1991-02-01

    The intraocular pressures of a total of 286 eyes of patients with lepromatous and borderline lepromatous leprosy who never had regular ophthalmological care or local eye treatment were measured. The patients were categorised according to the type of leprosy they had, and the eyes were categorised as without or with chronic plastic iridocyclitis. In patients with lepromatous and borderline lepromatous types of leprosy the intraocular pressure was significantly lower in eyes with chronic plastic iridocylitis 10.1 (3.6) mmHg than in both unaffected eyes 11.0 (3.2) mmHg and control eyes 13.5 (2.5) mmHg. It has been shown that chronic plastic iridocyclitis which remains untreated for years results in a lower intraocular pressure than normal.

  11. Influence of untreated chronic plastic iridocyclitis on intraocular pressure in leprosy patients.

    PubMed Central

    Karaçorlu, M A; Cakiner, T; Saylan, T

    1991-01-01

    The intraocular pressures of a total of 286 eyes of patients with lepromatous and borderline lepromatous leprosy who never had regular ophthalmological care or local eye treatment were measured. The patients were categorised according to the type of leprosy they had, and the eyes were categorised as without or with chronic plastic iridocyclitis. In patients with lepromatous and borderline lepromatous types of leprosy the intraocular pressure was significantly lower in eyes with chronic plastic iridocylitis 10.1 (3.6) mmHg than in both unaffected eyes 11.0 (3.2) mmHg and control eyes 13.5 (2.5) mmHg. It has been shown that chronic plastic iridocyclitis which remains untreated for years results in a lower intraocular pressure than normal. PMID:1995040

  12. Reference intervals for intraocular pressure measured by rebound tonometry in ten raptor species and factors affecting the intraocular pressure.

    PubMed

    Reuter, Anne; Müller, Kerstin; Arndt, Gisela; Eule, Johanna Corinna

    2011-09-01

    Intraocular pressure (IOP) was measured with the TonoVet rebound tonometer in 10 raptor species, and possible factors affecting IOP were investigated. A complete ophthalmic examination was performed, and IOP was assessed in 2 positions, upright and dorsal recumbency, in 237 birds belonging to the families Accipitridae, Falconidae, Strigidae, and Tytonidae. Mean IOP values of healthy eyes were calculated for each species, and differences between families, species, age, sex, left and right eye, as well as the 2 body positions were evaluated. Physiologic fluctuations of IOP were assessed by measuring IOP serially for 5 days at the same time of day in 15 birds of 3 species. Results showed IOP values varied by family and species, with the following mean IOP values (mm Hg +/- SD) determined: white-tailed sea eagle (Haliaeetus albicilla), 26.9 +/- 5.8; red kite (Milvus milvus), 13.0 +/- 5.5; northern goshawk (Accipiter gentilis), 18.3 +/- 3.8; Eurasian sparrowhawk (Accipiter nisus), 15.5 +/- 2.5; common buzzard (Buteo buteo), 26.9 +/- 7.0; common kestrel (Falco tinnunculus), 9.8 +/- 2.5; peregrine falcon, (Falco peregrinus), 12.7 +/- 5.8; tawny owl (Strix aluco), 9.4 +/- 4.1; long-eared owl (Asio otus), 7.8 +/- 3.2; and barn owl (Tyto alba), 10.8 +/- 3.8. No significant differences were found between sexes or between left and right eyes. In goshawks, common buzzards, and common kestrels, mean IOP was significantly lower in juvenile birds than it was in adult birds. Mean IOP differed significantly by body position in tawny owls (P = .01) and common buzzards (P = .04). By measuring IOP over several days, mean physiologic variations of +/- 2 mm Hg were detected. Differences in IOP between species and age groups should be considered when interpreting tonometric results. Physiologic fluctuations of IOP may occur and should not be misinterpreted. These results show that rebound tonometry is a useful diagnostic tool in measuring IOP in birds of prey because it provides rapid

  13. Relationship between Glaucoma Drainage Device Size and Intraocular Pressure Control: Does Size Matter?

    PubMed Central

    Rodgers, Cooper D; Meyer, Alissa M

    2017-01-01

    ABSTRACT There is ambiguity in the literature regarding whether a larger glaucoma drainage device (GDD) achieves a lower long-term intraocular pressure (IOP). There is some evidence on both sides, but overall there seems to be an optimal surface area of approximately 200-250 mm2 beyond which there may be little advantage to increasing the plate size for most patients. How to cite this article Rodgers CD, Meyer AM, Sherwood MB. Relationship between Glaucoma Drainage Device Size and Intraocular Pressure Control: Does Size Matter? J Curr Glaucoma Pract 2017;11(1):1-2. PMID:28138210

  14. Assessment of Intraocular and Systemic Vasculature Pressure Parameters in Simulated Microgravity with Thigh Cuff Countermeasure

    NASA Technical Reports Server (NTRS)

    Huang, Alex S.; Balasubramanian, Siva; Tepelus, Tudor; Sadda, Jaya; Sadda, Srinivas; Stenger, Michael B.; Lee, Stuart M. C.; Laurie, Steve S.; Liu, John; Macias, Brandon R.

    2017-01-01

    Changes in vision have been well documented among astronauts during and after long-duration space flight. One hypothesis is that the space flight induced headward fluid alters posterior ocular pressure and volume and may contribute to visual acuity decrements. Therefore, we evaluated venoconstrictive thigh cuffs as a potential countermeasure to the headward fluid shift-induced effects on intraocular pressure (IOP) and cephalic vascular pressure and volumes.

  15. Intraocular pressure following ECCE and IOL implantation in patients with glaucoma.

    PubMed

    Kooner, K S; Dulaney, D D; Zimmerman, T J

    1988-08-01

    Patients with glaucoma may suffer optic nerve head damage due to elevated intraocular pressure (IOP) after any intraocular procedure. We retrospectively reviewed the IOP data in 82 consecutive patients (103 eyes) with glaucoma after extracapsular cataract extraction (ECCE) and posterior chamber intraocular lens (PC-IOL) implantation. Nine eyes had previous trabeculectomy and three eyes required combined trabeculectomy with ECCE and PC-IOL. The average follow-up period is 1.5 years (range 0.5 to 6 years). The postoperative IOP rise of 8 mm Hg over baseline or above 23 mm Hg was observed in 45 eyes (49.5%). Two eyes needed argon laser trabeculoplasty and one required trabeculectomy to control postoperative IOP elevation. Most of the patients required the same or lesser number of medications for IOP control after surgery. Results suggest that ECCE with PC-IOL may be a relatively safe procedure in cataract patients with preexisting glaucoma.

  16. The intraocular pressure-lowering properties of intravenous paracetamol

    PubMed Central

    van den Heever, Henning; Meyer, David

    2016-01-01

    Aim The aim of this paper was to investigate the intraocular pressure (IOP)-changing properties of a single standard dose of intravenous (IV) paracetamol and compare it to that of topical timolol, oral acetazolamide, and no treatment. Methods A prospective, randomized, investigator-blind, parallel-group study was conducted in 73 eyes of 52 subjects. Subjects received a single dose of IV paracetamol (1 g), oral acetazolamide (250 mg), topical timolol (0.5%, one drop), or no treatment. Baseline IOP was measured, and the measurement was repeated at 1, 2, 4, and 6 hours after treatment. Results Paracetamol reduced IOP from baseline by −10.8% (95% confidence interval [CI]: −4.9% to −16.8%, P=0.146) at 1 hour, −13.3% (95% CI: −8.3% to −18.4%, P=0.045) at 2 hours, −11.8% (95% CI: −5.5% to −18.4%, P=1.000) at 4 hours, and −23.9% (95% CI: −17.8% to −30.1%, P=0.006) at 6 hours after treatment. In the no-treatment group, the change was −2.9% (95% CI: +1.0% to −6.7%, P= referent) at 1 hour, −2.1% (95% CI: +2.9% to −7.2%, P= referent) at 2 hours, −7.6% (95% CI: −3.9% to −11.2%, P= referent) at 4 hours, and −6.9% (95% CI: −3.6% to −10.2%, P= referent) at 6 hours. Acetazolamide reduced IOP by −18.8% (95% CI: −12.7% to −24.8%, P=0.000) at 1 hour, −26.2% (95% CI: −18.2% to −34.2%, P=0.001) at 2 hours, −24.6% (95% CI: −16.9% to −32.3%, P=0.000) after 4 hours, and −26.9% (95% CI: −19.6% to −34.3%, P=0.000) 6 hours after treatment. Timolol reduced IOP by −31.2% (95% CI: −26.7% to −35.7%, P=0.000) at 1 hour, −27.7% (95% CI: −20.7% to −34.8%, P=0.000) at 2 hours, −28.7% (95% CI: −21.1% to −36.2%, P=0.000) at 4 hours, and −21.3% (95% CI: −13.4% to −30.0%, P=0.030) at 6 hours after treatment. The average change in IOP for the no-treatment group was −4.8% (95% CI: −2.6% to −6.9%, P= referent). It was −15.7% (95% CI: −9.3% to −22.1%, P=0.021) for paracetamol, −23.1% (95% CI: −16.4% to

  17. Long-Term Change in Intraocular Pressure after Extracapsular Cataract Extraction with Posterior Chamber Intraocular Lens Implantation Versus Phacoemulsification with Posterior Chamber Intraocular Lens Implantation in Indians

    PubMed Central

    Pal, Virendra K; Agrawal, Ajai; Suman, Suwarna; Pratap, V B

    2013-01-01

    Purpose: The purpose of the study is to evaluate the long-term changes in intraocular pressure (IOP) after extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens (PCIOL) implantation versus phacoemulsification with PCIOL implantation in otherwise normal cataract patients in India. Materials and Methods: The study was conducted in the Department of Ophthalmology, King George's Medical College, Lucknow between August 2000 and August 2001. One hundred and seventeen eyes of 115 patients were included in the study. 84 patients were randomly selected for ECCE with PCIOL implantation (ECCE group) and 31 patients were selected for phacoemulsification with PCIOL implantation (Phaco group). IOP was measured pre-operatively and post-operatively, from the 1st month to the 12th month. Statistical significance was indicated by P > 0.05. Results: There was a mean fall in IOP of 2.70 mm Hg (19.74%) in the ECCE group and 2.74 mm Hg (20.57%) in the phaco group. The decrease in the mean post-operative IOP from baseline was statistically significant (P > 0.01) at the end of 2 months in both groups. There was no statistically significant difference in post-operative IOP at any visit between groups (P < 0.05, all post-operative visits). After 4th monthpost-operatively, the IOP was mostly stable, but it was significantly lower than the pre-operative IOP. Conclusion: Significant IOP reduction may be expected after cataract surgery with either ECCE or phacoemulsification with IOL implantation. The lowering of IOP became statistically significant at about 2 months post-operatively, but became almost stable after the 4th month. PMID:24339684

  18. Evidence for a GPR18 Role in Diurnal Regulation of Intraocular Pressure

    PubMed Central

    Miller, Sally; Leishman, Emma; Oehler, Olivia; Daily, Laura; Murataeva, Natalia; Wager-Miller, Jim; Bradshaw, Heather; Straiker, Alex

    2016-01-01

    Purpose The diurnal cycling of intraocular pressure (IOP) was first described in humans more than a century ago. This cycling is preserved in other species. The physiologic underpinning of this diurnal variation in IOP remains a mystery, even though elevated pressure is indicated in most forms of glaucoma, a common cause of blindness. Once identified, the system that underlies diurnal variation would represent a natural target for therapeutic intervention. Methods Using normotensive mice, we measured the regulation of ocular lipid species by the enzymes fatty acid amide hydrolase (FAAH) and N-arachidonoyl phosphatidylethanolamine phospholipase (NAPE-PLD), mRNA expression of these enzymes, and their functional role in diurnal regulation of IOP. Results We now report that NAPE-PLD and FAAH mice do not exhibit a diurnal cycling of IOP. These enzymes produce and break down acylethanolamines, including the endogenous cannabinoid anandamide. The diurnal lipid profile in mice shows that levels of most N-acyl ethanolamines and, intriguingly, N-arachidonoyl glycine (NAGly), decline at night: NAGly is a metabolite of arachidonoyl ethanolamine and a potent agonist at GPR18 that lowers intraocular pressure. The GPR18 blocker O1918 raises IOP during the day when pressure is low, but not at night. Quantitative PCR analysis shows that FAAH mRNA levels rise with pressure, suggesting that FAAH mediates the changes in pressure. Conclusions Our results support FAAH-dependent NAGly action at GPR18 as the physiologic basis of the diurnal variation of intraocular pressure in mice. PMID:27893106

  19. An integrated instrument for rapidly deforming living cells using rapid pressure pulses and simultaneously monitoring applied strain in near real time

    NASA Astrophysics Data System (ADS)

    Green, M. E.; Goforth, P. B.; Satin, L. S.; Love, B. J.

    2010-12-01

    Because many types of living cells are sensitive to applied strain, different in vitro models have been designed to elucidate the cellular and subcellular processes that respond to mechanical deformation at both the cell and tissue level. Our focus was to improve upon an already established strain system to make it capable of independently monitoring the deflection and applied pressure delivered to specific wells of a commercially available, deformable multiwell culture plate. To accomplish this, we devised a custom frame that was capable of mounting deformable 6 or 24 well plates, a pressurization system that could load wells within the plates, and a camera-based imaging system which was capable of capturing strain responses at a sufficiently high frame rate. The system used a user defined program constructed in Labview® to trigger plate pressurization while simultaneously allowing the deflection of the silicone elastomeric plate bottoms to be imaged in near real time. With this system, up to six wells could be pulsed simultaneously using compressed air or nitrogen. Digital image capture allowed near-real time monitoring of applied strain, strain rate, and the cell loading profiles. Although our ultimate goal is to determine how different strain rates applied to neurons modulates their intrinsic biochemical cascades, the same platform technology could be readily applied to other systems. Combining commercially available, deformable multiwell plates with a simple instrument having the monitoring capabilities described here should permit near real time calculations of stretch-induced membrane strain in multiple wells in real time for a wide variety of applications, including high throughput drug screening.

  20. Placement of a collagen glaucoma drainage device to control intraocular pressure and chronic iritis secondary to juvenile rheumatoid arthritis.

    PubMed

    Price, Francis W; Ziemba, Steven L

    2002-01-01

    A patient with juvenile rheumatoid arthritis and chronic iritis is reported with intraocular pressure near 30 mm Hg and previous episodes of intraocular pressure as high as 50 mm Hg despite maximally tolerated medical therapy. Because of the potential risk involved with a full-thickness filtration procedure, it was decided that a nonpenetrating deep sclerectomy would be appropriate, followed by placement of a collagen glaucoma drainage device to maintain aqueous outflow. Immediately postoperatively, intraocular pressure was stabilized. At 24 months postoperatively, intraocular pressure was well controlled at 15 mm Hg with patient receiving only Lotemax. No significant complications were noted at any point in the postoperative course. Because of the patient's predisposition for serious complications frequently associated with trabeculectomy, nonpenetrating deep sclerectomy with the collagen glaucoma drainage device was an effective alternative for this patient.

  1. [The effect of crystalline lens extraction on intraocular pressure in patients with primary open-angle glaucoma].

    PubMed

    Macarie, S; Macarie, Daniela

    2013-01-01

    This issue presents the results of a study on patients with cataract and primary open angle glaucoma who suffered lens extraction for cataract. We analise the effects of the lens extraction on the level of intraocular pressure at this patients.

  2. Intra-Ocular Pressure Measurement in a Patient with a Thin, Thick or Abnormal Cornea

    PubMed Central

    Clement, Colin I.; Parker, Douglas G.A.; Goldberg, Ivan

    2016-01-01

    Accurate measurement of intra-ocular pressure is a fundamental component of the ocular examination. The most common method of measuring IOP is by Goldmann applanation tonometry, the accuracy of which is influenced by the thickness and biomechanical properties of the cornea. Algorithms devised to correct for corneal thickness to estimate IOP oversimplify the effects of corneal biomechanics. The viscous and elastic properties of the cornea influence IOP measurements in unpredictable ways, a finding borne out in studies of patients with inherently abnormal and surgically altered corneal biomechanics. Dynamic contour tonometry, rebound tonometry and the ocular response analyzer provide useful alternatives to GAT in patients with abnormal corneas, such as those who have undergone laser vision correction or keratoplasty. This article reviews the various methods of intra-ocular pressure measurement available to the clinician and the ways in which their utility is influenced by variations in corneal thickness and biomechanics. PMID:27014386

  3. Damage dosimetry and embrittlement monitoring of nuclear pressure vessels in real time by magnetic properties measurement. Technical progress report for year 2, October 1, 1991--September 30, 1992

    SciTech Connect

    Stubbins, J.F.; Ougouag, A.M.; Williams, J.G.

    1992-07-01

    The objective of this project is to develop a technique for real-time monitoring of neutron dose and of the onset and progression of embrittlement in operating nuclear pressure vessels. The technique relies on the measurement of magnetic properties of steel and other magnetic materials which are extremely sensitive to radiation-induced properties changes. The approach being developed here is innovative and unique. It promises to be readily applicable to all existing and planned reactor structures. The significance of this program is that it addresses a major concern in the operation of existing nuclear pressure vessels. The development of microscopic defect clusters during irradiation in the nuclear pressure vessel beltline region leads to an increase in material yield strength and a concomitant decrease in ductility, or ability to absorb energy in fracture (i.e. fracture toughness). This decrease in fracture toughness is alarming since it may impair the ability of the pressure vessel to resist fracture during unusual loading situations.

  4. Intraocular pressure, retinal vascular, and visual acuity changes during 48 hours of 10-deg head-down tilt

    NASA Technical Reports Server (NTRS)

    Mader, Thomas H.; Taylor, Gerald R.; Hunter, Norwood; Caputo, Michael; Meehan, Richard T.

    1990-01-01

    Intraocular pressures, retinal vascular diameters, and visual acuities of nine men, were repeatedly measured while the subjects were tilted 10 deg head-down for 48 h and while they were seated before (baseline), and after the tilt. An immediate increase in intraocular pressure, measured by pneumatonometer was recorded when subjects assumed the head-down position, and diurnal variations in intraocular pressures were observed for the 48 h. The initial and final head-down intraocular pressures were not significantly different. However, when subjects resumed the sitting position, intraocular pressures fell below the initial sitting values. Computer image analysis of the retinal vasculature detected a 6 percent and 2 percent reduction in the caliber of arteries and veins, respectively, as compared with sitting baseline values. No changes in visual acuity were documented during the 48 h of head-down tilt. The data suggest that the choroidal blood reservoir increases in volume over 48 h at continuous head-down position with a compensatory decrease in aqueous volume. These findings may explain intraocular pressure changes noted in astronauts during previous space missions and in studies associated with change in body position.

  5. Quantitative real-time monitoring of chemical reactions by autosampling flow injection analysis coupled with atmospheric pressure chemical ionization mass spectrometry.

    PubMed

    Zhu, Zhenqian; Bartmess, John E; McNally, Mary Ellen; Hoffman, Ron M; Cook, Kelsey D; Song, Liguo

    2012-09-04

    Although qualitative and/or semiquantitative real-time monitoring of chemical reactions have been reported with a few mass spectrometric approaches, to our knowledge, no quantitative mass spectrometric approach has been reported so far to have a calibration valid up to molar concentrations as required by process control. This is mostly due to the absence of a practical solution that could well address the sample overloading issue. In this study, a novel autosampling flow injection analysis coupled with an atmospheric pressure chemical ionization mass spectrometry (FIA/APCI-MS) system, consisting of a 1 μL automatic internal sample injector, a postinjection splitter with 1:10 splitting ratio, and a detached APCI source connected to the mass spectrometer using a 4.5 in. long, 0.042 in. inner diameter (ID) stainless-steel capillary, was thus introduced. Using this system together with an optional FIA solvent modifier, e.g., 0.05% (v/v) isopropylamine, a linear quantitative calibration up to molar concentration has been achieved with 3.4-7.2% relative standard deviations (RSDs) for 4 replicates. As a result, quantitative real-time monitoring of a model reaction was successfully performed at the 1.63 M level. It is expected that this novel autosampling FIA/APCI-MS system can be used in quantitative real-time monitoring of a wide range of reactions under diverse reaction conditions.

  6. Real-time measurement of the vaginal pressure profile using an optical-fiber-based instrumented speculum

    NASA Astrophysics Data System (ADS)

    Parkinson, Luke A.; Gargett, Caroline E.; Young, Natharnia; Rosamilia, Anna; Vashi, Aditya V.; Werkmeister, Jerome A.; Papageorgiou, Anthony W.; Arkwright, John W.

    2016-12-01

    Pelvic organ prolapse (POP) occurs when changes to the pelvic organ support structures cause descent or herniation of the pelvic organs into the vagina. Clinical evaluation of POP is a series of manual measurements known as the pelvic organ prolapse quantification (POP-Q) score. However, it fails to identify the mechanism causing POP and relies on the skills of the practitioner. We report on a modified vaginal speculum incorporating a double-helix fiber-Bragg grating structure for distributed pressure measurements along the length of the vagina and include preliminary data in an ovine model of prolapse. Vaginal pressure profiles were recorded at 10 Hz as the speculum was dilated incrementally up to 20 mm. At 10-mm dilation, nulliparous sheep showed higher mean pressures (102±46 mmHg) than parous sheep (39±23 mmHg) (P=0.02), attributable largely to the proximal (cervical) end of the vagina. In addition to overall pressure variations, we observed a difference in the distribution of pressure that related to POP-Q measurements adapted for the ovine anatomy, showing increased tissue laxity in the upper anterior vagina for parous ewes. We demonstrate the utility of the fiber-optic instrumented speculum for rapid distributed measurement of vaginal support.

  7. Cluster headache: interictal asymmetric increment in intraocular pressure elicited by Valsalva manoeuvre.

    PubMed

    Barriga, F J; Sánchez-del-Río, M; Barón, M; Dobato, J l; Gili, P; Yangüela, J; Bueno, A; Pareja, J A

    2004-03-01

    Changes in intraocular pressure (IOP) elicited by a Valsalva manoeuvre were studied in 11 male patients (mean age 39.8 years) suffering from episodic cluster headache (CH), and 12 healthy male controls (mean age 39.9 years). The tests were performed at rest and while exhaling hard through a mouthpiece connected to a mercury manometer. In the CH group, during symptomatic periods, between attacks, Valsalva manoeuvre elicited an asymmetric increase in IOP with significantly higher values on the symptomatic side (P = 0011), whereas no asymmetric increments in IOP were found during asymptomatic periods. Outside the cluster period the IOP values both baseline and with Valsalva manoeuvre did not differ from controls. The increment in IOP took place within a few seconds, as in spontaneous CH attacks, thus pointing to a rapid increase in intraocular blood volume or vasodilatation. These findings may reflect a latent increased vascular reactivity of the symptomatic orbit during CH period.

  8. Modeling and Real-Time Process Monitoring of Organometallic Chemical Vapor Deposition of III-V Phosphides and Nitrides at Low and High Pressure

    NASA Technical Reports Server (NTRS)

    Bachmann, K. J.; Cardelino, B. H.; Moore, C. E.; Cardelino, C. A.; Sukidi, N.; McCall, S.

    1999-01-01

    The purpose of this paper is to review modeling and real-time monitoring by robust methods of reflectance spectroscopy of organometallic chemical vapor deposition (OMCVD) processes in extreme regimes of pressure. The merits of p-polarized reflectance spectroscopy under the conditions of chemical beam epitaxy (CBE) and of internal transmission spectroscopy and principal angle spectroscopy at high pressure are assessed. In order to extend OMCVD to materials that exhibit large thermal decomposition pressure at their optimum growth temperature we have designed and built a differentially-pressure-controlled (DCP) OMCVD reactor for use at pressures greater than or equal to 6 atm. We also describe a compact hard-shell (CHS) reactor for extending the pressure range to 100 atm. At such very high pressure the decomposition of source vapors occurs in the vapor phase, and is coupled to flow dynamics and transport. Rate constants for homogeneous gas phase reactions can be predicted based on a combination of first principles and semi-empirical calculations. The pressure dependence of unimolecular rate constants is described by RRKM theory, but requires variational and anharmonicity corrections not included in presently available calculations with the exception of ammonia decomposition. Commercial codes that include chemical reactions and transport exist, but do not adequately cover at present the kinetics of heteroepitaxial crystal growth.

  9. Real-Time Monitoring of Singlet Oxygen and Oxygen Partial Pressure During the Deep Photodynamic Therapy In Vitro.

    PubMed

    Li, Weitao; Huang, Dong; Zhang, Yan; Liu, Yangyang; Gu, Yueqing; Qian, Zhiyu

    2016-09-01

    Photodynamic therapy (PDT) is an effective noninvasive method for the tumor treatment. The major challenge in current PDT research is how to quantitatively evaluate therapy effects. To our best knowledge, this is the first time to combine multi-parameter detection methods in PDT. More specifically, we have developed a set of system, including the high-sensitivity measurement of singlet oxygen, oxygen partial pressure and fluorescence image. In this paper, the detection ability of the system was validated by the different concentrations of carbon quantum dots. Moreover, the correlation between singlet oxygen and oxygen partial pressure with laser irradiation was observed. Then, the system could detect the signal up to 0.5 cm tissue depth with 660 nm irradiation and 1 cm tissue depth with 980 nm irradiation by using up-conversion nanoparticles during PDT in vitro. Furthermore, we obtained the relationship among concentration of singlet oxygen, oxygen partial pressure and tumor cell viability under certain conditions. The results indicate that the multi-parameter detection system is a promising asset to evaluate the deep tumor therapy during PDT. Moreover, the system might be potentially used for the further study in biology and molecular imaging.

  10. Real Time Network Assessment

    DTIC Science & Technology

    2013-07-12

    Demonstrate a simple system Conduct a feasibility assessment of data storage, maintenance, and integration requirements Test a web-based data feed...Real Time Network Assessment Prototype We demonstrated the feasibility of linking near real time network analytics to mashups and web- based...combining similar concepts into single node) Stemmers Thesauri application Network position Statistical common patterns Pronoun identification

  11. Radon surveys and real-time monitoring at Stromboli volcano: Influence of soil temperature, atmospheric pressure and tidal forces on 222Rn degassing

    NASA Astrophysics Data System (ADS)

    Cigolini, C.; Poggi, P.; Ripepe, M.; Laiolo, M.; Ciamberlini, C.; Delle Donne, D.; Ulivieri, G.; Coppola, D.; Lacanna, G.; Marchetti, E.; Piscopo, D.; Genco, R.

    2009-07-01

    We used a network of stations to perform systematic radon surveys at Stromboli volcano. The time series of periodic measurements show that monthly average 222Rn emissions reflect changes in volcanic activity and exhibit increasing trends prior and during the last major eruptive cycles. Maps of radon emissions indicate that diffuse degassing is operative at Stromboli volcano. Concentrated degassing essentially occurs in the summit area and within a sector proximal to the two major NE trending faults. These sites were chosen for deploying the two real-time stations that are currently operating at Stromboli. In these devices, the 222Rn electronic dosimeters are connected to a radiomodem for wireless data transfer to a receiving station at the volcano observatory. Radon activity, soil temperature and atmospheric pressure data are sampled and instantaneously transferred via web so that they can be checked remotely. Collected time series reveal an overall inverse correlation between radon emissions and seasonal temperature variations. Radon emissions in sectors of diffuse degassing are modulated by tidal forces as well. Radon activities recorded at the summit station, located along the fracture zone where the gas flux is concentrated, are positively correlated with changes in atmospheric pressure and confirm the occurrence of the "atmospheric stack effect". We finally emphasize that real-time radon monitoring is an innovative technique that may be systematically applied in volcano surveillance.

  12. Effect of sildenafil citrate on intraocular pressure and blood pressure in human volunteers.

    PubMed

    Gerometta, Rosana; Alvarez, Lawrence J; Candia, Oscar A

    2011-07-01

    Anecdotal reports have suggested that the vasodilator, sildenafil citrate, which evokes its effect via a select inhibition of PDE5, has the potential to increase intraocular pressure (IOP) in some individuals. An ocular hypertensive effect by sildenafil was also recently described in a sheep animal model. In contrast, clinical studies have not found a direct association between sildenafil ingestion (commonly consumed as Viagra) and changes in IOP. However, some such studies also reported no effects of sildenafil on systemic blood pressure (BP) at the time of the IOP determination. Given this surprising result, our purpose was to repeat a study in human volunteers in the city of Corrientes, Argentina to corroborate the effects of sildenafil on human IOP and systemic BP. For the present study, 9 healthy volunteers (male and female, 18-74 years old) were selected as subjects after ophthalmic and cardiovascular evaluation indicated that they exhibited normal parameters for their age. In a masked, placebo-controlled study, the subjects ingested 100 mg sildenafil citrate (provided as Vorst from Laboratorios Bernabo, Argentina) in one session, and a placebo on a second separate occasion. IOP was measured with a Goldman applanation tonometer by an ophthalmologist, and BP by a second physician, neither of whom witnessed the tablet ingestion by the volunteers, nor provided with information on the nature of the test compounds. A third individual administered the tablets. The average baseline IOP of this group of 9 was 13.1 ± 0.6 mm Hg. Subsequent to sildenafil ingestion, IOP increased by 26% to 16.5 ± 0.8 mm Hg 60 min later (P < 0.005, as paired data), and returned to control values within 2 h. Both systolic and diastolic BP were significantly reduced by sildenafil ingestion. At the point of maximal systemic hypotension (90 min), the systolic and diastolic pressures declined by 15% and 13%, respectively. No significant changes in IOP or BP were recorded after

  13. Real-time observation of the dry oxidation of the Si (100) surface with ambient pressure x-ray photoelectron spectroscopy

    SciTech Connect

    Enta, Y.; Mun, B.S.; Rossi, M.; Ross Jr, P.N.; Hussain, Zahid; Fadley, C.S.; Lee, K.-S.; Kim, S.-K.

    2007-09-20

    We have applied ambient-pressure x-ray photoelectron spectroscopy with Si 2p chemical shifts to study the real-time dry oxidation of Si(100), using pressures in the range of 0.01-1 Torr and temperatures of 300-530 oC, and examining the oxide thickness range from 0 to ~;;25 Angstrom. The oxidation rate is initially very high (with rates of up to ~;;225 Angstrom/h) and then, after a certain initial thickness of the oxide in the range of 6-22 Angstrom is formed, decreases to a slow state (with rates of ~;;1.5-4.0 Angstrom/h). Neither the rapid nor the slow regime is explained by the standard Deal-Grove model for Si oxidation.

  14. Study of Variation in Intraocular Pressure Spike (IOP) Following Nd- YAG Laser Capsulotomy

    PubMed Central

    Sridhar, Sriya

    2016-01-01

    Introduction Posterior Capsular Opacifications (PCO) is a frequent complication of cataract surgery following posterior chamber intraocular lens implantation. Nd –Yag laser capsulotomy is the treatment of choice for PCO and is known to be associated with complications like Raised Intraocular Pressure (IOP), Intraocular lens pitting, intraocular lens cracks, cystoid macular oedema, retinal detachment, corneal burns. Raised IOP is the most common complication and prescribing anti-glaucoma drugs post capsulotomy is a common practise. Our study helps us to anticipate the post procedural IOP rise in specific patients and treat only selected group of patients with anti- glaucoma medications. Aim To study and correlate the effect of energy used and number of shots with post procedural IOP spike following Nd-YAG laser capsulotomy cases. Materials and Methods All patients with PCO presenting to Ophthalmology Out Patient Department at Sri Siddhartha Medical College between November 2014 to November 2015 were included. All the patients with glaucoma, uveitis and high myopia were excluded from the study. Data relevant to history, ocular examination and IOP were recorded. Results Significant correlation of IOP spike with the number of Nd- YAG Laser shots delivered was found by One-way ANOVA Post-Hoc Tukeys Test. The p-value was significant for shots more than 40, provided the energy was restricted to 20 mJ and below. Correlation of energy with IOP spike was not significant as found by One-way ANOVA, Post-Hoc Tukey test. Predictability of 2 hours post-procedure IOP regarding persistent IOP rise was significant. Conclusion It was observed that all pseudophakic patients may not require anti-glaucoma medication pre, or post Nd YAG laser capsulotomy. Only patients who required more than 40 shots during the procedure would need a close observation and if persistent rise is documented, ocular hypotensives may be advised. PMID:28208899

  15. Tracking Ocean Gravity Waves in Real-time: Highlights of Bottom Pressure Data Recorded on Ocean Networks Canada's NEPTUNE observatory

    NASA Astrophysics Data System (ADS)

    Heesemann, Martin; Mihaly, Steve; Gemmrich, Johannes; Davis, Earl; Thomson, Richard; Dewey, Richard

    2016-04-01

    Ocean Networks Canada operates two cabled ocean observatories off Vancouver Island on Canada's west coast. The regional NEPTUNE observatory spans the entire Juan de Fuca tectonic plate from the coast across the subduction zone to the hydrothermally active Endeavour Segment of the Juan de Fuca Ridge Segment while the VENUS observatory focuses on coastal processes. Both observatories collect data on physical, chemical, biological, and geological aspects of the ocean over long time periods, supporting research on complex earth processes. High-precision bottom pressure recorders (BPR) deployed on the NEPTUNE observatory are capable of detecting a wide range of phenomena related to sea level variations. The observatory BPRs provide observations of nano-resolution (with respect to full scale of the instrument) pressure variations which correspond to sub-millimeter scale surface water displacements in several kilometers of water. Detected signals include tides, tsunamis, infragravity waves, swell, wave-induced microseisms, storm surge, and seismic signals. Spectral analysis reveals many of these phenomena with periods ranging from a few seconds to many hours. Dispersion patterns from distant swells are prominent in the swell and microseism bands. By comparing the difference of arrival times between longer period waves, which arrive first, and shorter period waves we can estimate the distance the swells travelled since they were generated. Using this information, swell can be tracked back to specific storms across the Pacific. The presentation will high-light some examples of the mentioned phenomena in the continuous time-series that in some instances are more than seven years long.

  16. Effect of prophylactic intraocular pressure-lowering medication (brinzolamide) on intraocular pressure after ranibizumab intravitreal injection: A case–control study

    PubMed Central

    Song, Shuang; Yu, Xiao-bing; Dai, Hong

    2016-01-01

    Purpose: To observe the effect of prophylactic intraocular pressure (IOP)-lowering medication (brinzolamide) on IOP after ranibizumab intravitreal injections (IVIs). Materials and Methods: This prospective case–control study included 352 eyes from 352 patients (1 eye per patient) who were treated with ranibizumab intravitreal injection and divided randomly into two groups. Two hundred and three patients in control group only received the ranibizumab IVI, but 149 patients in case group received one drop of prophylactic intraocular brinzolamide preinjection. The IOP was measured by noncontact tonometer before injection, at 10, 30, 120 min and 1 day after injection in a sitting position. Results: The mean IOP measured before injection, at 10, 30, 120 min and 1 day after injection individually were 15.79 ± 2.21 mmHg, 19.33 ± 4.86 mmHg, 16.64 ± 2.93 mmHg, 16.17 ± 3.13 mmHg, and 15.07 ± 2.55 mmHg in case group and were 15.82 ± 2.57 mmHg, 21.34 ± 5.88 mmHg, 18.17 ± 4.06 mmHg, 17.59 ± 4.42 mmHg, and15.48 ± 2.92 mmHg in control group. Comparing two groups, the mean increase on IOP was statistically significant at 10, 30, 120 min postinjection (P < 0.05). Conclusions: IVI of ranibizumab causes a considerable short-term transient rise on IOP in most patients. The effect of prophylactic IOP-lowering medication on IOP after IVIs can be statistically significant from 10 min to 2 h after IVIs. PMID:27905340

  17. Regulation of intraocular pressure and pupil size by beta-blockers and epinephrine.

    PubMed

    Ohrström, A; Pandolfi, M

    1980-12-01

    The interaction of adrenergic beta-receptor blockers and epinephrine on intraocular pressure and pupil size was investigated in healthy volunteers. Oral (atenolol and propranolol) and local (timolol) beta-blockers were studied. The experiment was carried out under double-blind randomized crossover conditions. The results showed that the combination of oral beta-blockers with topical epinephrine had an additive hypotensive effect on IOP, while timolol and epinephrine eyedrops both reduced the IOP used alone, but combined had an antagonistic effect, resulting in the disappearance of the epinephrine-mediated IOP reduction.

  18. Etiology and Management of Raised Intraocular Pressure following Posterior Chamber Phakic Intraocular Lens Implantation in Myopic Eyes

    PubMed Central

    Senthil, Sirisha; Choudhari, Nikhil S.; Vaddavalli, Pravin K.; Murthy, Somasheila; Reddy, Jagadesh; Garudadri, Chandra S.

    2016-01-01

    Aim To evaluate the etiology and management of elevated intraocular pressure (IOP) following posterior chamber phakic implantable collamer lens (ICL) surgery. Methods Between 2009 and 2015, 638 eyes of 359 subjects with refractive myopia, underwent V4b and V4c (CentraFLOW) model ICL implantation. Ocular hypertension (OHT) was defined as IOP of ≥ 22 mm Hg on two separate occasions and elevated IOP with corresponding optic disc or visual field damage was defined as glaucoma. Results Elevated IOP ≥ 22 mm Hg was noted in 33 eyes of 30 subjects (33/638; 5.17%). Median age of subjects with raised IOP was 26 years (Inter quartile range (IQR):22, 29) and median refarctive error was -16 diopters (-19.5, -13). The median follow up was 7.8 months (IQR:0.3, 17.6) and median time for postoperative IOP rise was 12 days, (IQR:2, 24). The various etiologies for elevated IOP were steroid response in 21 eyes (64%; 10 eyes with V4b, 11 eyes with V4c), retained viscoelastic in 5 eyes (15%) (3 with V4b, 2 with V4c), pupillary block in four eyes (12%; 3 with V4b, 1 with V4c), malignant glaucoma in one eye (3%, V4b), and missed pre-existing Juvenile open angle glaucoma (JOAG) in two eyes (6% with V4b). Elevated IOP in 31 eyes resolved with conservative management. One eye (centraFLOW design) with central aquaport block by viscoelastic, needed AC wash and one eye with malignant glaucoma needed parsplana vitrectomy and hyaloidotomy. Ten eyes required longterm (>2 months) antiglaucoma medications (AGM) for IOP control. Except the two eyes with JOAG, none had disc and field damage. Conclusion In our series, OHT was seen in 4.85% and glaucoma in 0.3% eyes that underwent V4b and V4c model ICL implantation. Multiple etiologies were noted and steroid induced ocular hypertension was the most common cause of elevated IOP followed by retained viscoelastic and pupillary block. One third of these eyes required longterm AGM for IOP control. PMID:27855172

  19. Genome-wide association study of intraocular pressure identifies the GLCCI1/ICA1 region as a glaucoma susceptibility locus

    PubMed Central

    Strange, Amy; Bellenguez, Céline; Sim, Xueling; Luben, Robert; Hysi, Pirro G.; Ramdas, Wishal D.; van Koolwijk, Leonieke M.E.; Freeman, Colin; Pirinen, Matti; Su, Zhan; Band, Gavin; Pearson, Richard; Vukcevic, Damjan; Langford, Cordelia; Deloukas, Panos; Hunt, Sarah; Gray, Emma; Dronov, Serge; Potter, Simon C.; Tashakkori-Ghanbaria, Avazeh; Edkins, Sarah; Bumpstead, Suzannah J.; Blackwell, Jenefer M.; Bramon, Elvira; Brown, Matthew A.; Casas, Juan P.; Corvin, Aiden; Duncanson, Audrey; Jankowski, Janusz A.Z.; Markus, Hugh S.; Mathew, Christopher G.; Palmer, Colin N.A.; Plomin, Robert; Rautanen, Anna; Sawcer, Stephen J.; Trembath, Richard C.; Wood, Nicholas W.; Barroso, Ines; Peltonen, Leena; Healey, Paul; McGuffin, Peter; Topouzis, Fotis; Klaver, Caroline C.W.; van Duijn, Cornelia M.; Mackey, David A.; Young, Terri L.; Hammond, Christopher J.; Khaw, Kay-Tee; Wareham, Nick; Wang, Jie Jin; Wong, Tien Y.; Foster, Paul J.; Mitchell, Paul; Spencer, Chris C.A.; Donnelly, Peter; Viswanathan, Ananth C.

    2013-01-01

    To discover quantitative trait loci for intraocular pressure, a major risk factor for glaucoma and the only modifiable one, we performed a genome-wide association study on a discovery cohort of 2175 individuals from Sydney, Australia. We found a novel association between intraocular pressure and a common variant at 7p21 near to GLCCI1 and ICA1. The findings in this region were confirmed through two UK replication cohorts totalling 4866 individuals (rs59072263, Pcombined = 1.10 × 10−8). A copy of the G allele at this SNP is associated with an increase in mean IOP of 0.45 mmHg (95%CI = 0.30–0.61 mmHg). These results lend support to the implication of vesicle trafficking and glucocorticoid inducibility pathways in the determination of intraocular pressure and in the pathogenesis of primary open-angle glaucoma. PMID:23836780

  20. Long-term effects of mild exercise on intraocular pressure in athletes and sedentary subjects.

    PubMed

    Dane, Senol; Koçer, Ibrahim; Demirel, Havva; Uçok, Kağan; Tan, Uner

    2006-10-01

    The long-term effects of acute submaximal exercise on intraocular pressures (IOPs) of right-and left-eyes and recovery times to basement levels of IOP in postexercise periods in sedentary and physically fit subjects were investigated. Twenty-five sedentary and 24 physically fit subjects, ranging in age 17 to 22 years, participated. Intraocular pressures were measured by a pneumotonometer. Measurements were taken in the morning at about nine (at rest) and immediately, 30 min and 2 h after acute submaximal exercise. In sedentary subjects, IOPs of both right- and left-eyes decreased immediate after exercise, but, these decreases in both eyes continued 30 min and 2 h after exercise. In physically fit subjects, IOPs of both right- and left-eyes increased immediate after exercise, but decreased after 30 min exercise compared to basement levels, and this decrease continued 2 h after exercise. Acute submaximal exercise decreased IOPs of right and left eyes over a period 2 h in sedentary and physically fit subjects. IOP reducing after exercise was different between right- and left-eyes in sedentary subjects. These results suggest that exercise can be used in ocular hypertension treatment.

  1. Incidence of Intraocular Pressure Elevation following Intravitreal Ranibizumab (Lucentis) for Age-related Macular Degeneration

    PubMed Central

    Reis, Gustavo MSM; Grigg, John; Chua, Brian; Lee, Anne; Lim, Ridia; Higgins, Ralph; Martins, Alessandra; Goldberg, Ivan

    2017-01-01

    ABSTRACT Aim The aim of this article is to evaluate the rate of patients developing sustained elevated intraocular pressure (IOP) after ranibizumab (Lucentis) intravitreal (IVT) injections. Design This is a retrospective study. Participants Charts of 192 consecutive patients receiving Lucentis for age-related macular degeneration (AMD) were retrospectively reviewed. Materials and methods We enrolled patients with at least two IOP measurements between injections. Elevated IOP was defined as >21 mm Hg with an increase of at least 20% from baseline. Noninjected contralateral eyes of the same patient cohort were used as control. Main outcome measures Primary outcome was defined as elevated IOP. Secondary outcomes were presence and type of glaucoma, number of injections, and time to IOP elevation. Results Elevated IOP occurred at a significantly higher rate in eyes receiving IVT ranibizumab (7.47%; n = 9) compared with control (0.93%; n = 1). Patients with preexisting glaucoma or ocular hypertension (OHT) were more likely to develop elevated IOP after IVT ranibizumab injection. Conclusion Intravitreal ranibizumab injections are associated with sustained IOP elevation in some eyes. How to cite this article Reis GMSM, Grigg J, Chua B, Lee A, Lim R, Higgins R, Martins A, Goldberg I, Clement CI. The Incidence of Intraocular Pressure Elevation following Intravitreal Ranibizumab (Lucentis) for Age-related Macular Degeneration. J Curr Glaucoma Pract 2017;11(1):3-7. PMID:28138211

  2. Influence of the Hypothalamic Arcuate Nucleus on Intraocular Pressure and the Role of Opioid Peptides

    PubMed Central

    Jin, Ji; Xu, Guo-xu; Yuan, Zhi-lan

    2014-01-01

    Background An opioid peptide neuron/humoral feedback regulation might be involved in changes of intraocular pressure (IOP). The aims of this study are to investigate the effects of arcuate nucleus (ARC) and opioid peptides on intraocular pressure (IOP). Methods Fifty-four healthy purebred New Zealand white rabbits (108eyes) were randomly divided into 4 groups, including control group, electrical stimulation group, [D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin (DAMGO) group, and [D-Pen 2, D-Pen5]- enkephalin (DPDPE) group. Bilateral IOP was measured after unilateral electrical stimulation of the ARC or unilateral microinjection into the ARC of the selective μ-opioid receptor agonist DAMGO or the selective δ opioid receptor agonist DPDPE, both alone and after pre-administration of either the non-selective opioid receptor antagonist naloxone or saline. Results Both electrical stimulation in ARC and micro-injection either or opioid receptor agonists, DAMGO or DPDPE, respectively, caused a significant bilateral reduction in IOP (P<0.05) which was more pronounced in the ipsilateral than in the contralateral eye. Pretreatment with naloxone prevented some, but not all IOP reductions. Conclusion The ARC takes part in the negative regulation of IOP, an action that may involve opioid neurons. PMID:24691128

  3. Real-time radiography

    SciTech Connect

    Bossi, R.H.; Oien, C.T.

    1981-02-26

    Real-time radiography is used for imaging both dynamic events and static objects. Fluorescent screens play an important role in converting radiation to light, which is then observed directly or intensified and detected. The radiographic parameters for real-time radiography are similar to conventional film radiography with special emphasis on statistics and magnification. Direct-viewing fluoroscopy uses the human eye as a detector of fluorescent screen light or the light from an intensifier. Remote-viewing systems replace the human observer with a television camera. The remote-viewing systems have many advantages over the direct-viewing conditions such as safety, image enhancement, and the capability to produce permanent records. This report reviews real-time imaging system parameters and components.

  4. Real time obscuration monitoring

    NASA Astrophysics Data System (ADS)

    Agricola, Koos

    2016-09-01

    Recently a real time particle deposition monitoring system is developed. After discussions with optical system engineers a new feature has been added. This enables the real time monitoring of obscuration of exposed optical components by counting the deposited particles and sizing the obscuration area of each particle. This way the Particle Obscuration Rate (POR) can be determined. The POR can be used to determine the risk of product contamination during exposure. The particle size distribution gives information on the type of potential particle sources. The deposition moments will indicate when these sources were present.

  5. Real-time pulmonary graphics.

    PubMed

    Mammel, Mark C; Donn, Steven M

    2015-06-01

    Real-time pulmonary graphics now enable clinicians to view lung mechanics and patient-ventilator interactions on a breath-to-breath basis. Displays of pressure, volume, and flow waveforms, pressure-volume and flow-volume loops, and trend screens enable clinicians to customize ventilator settings based on the underlying pathophysiology and responses of the individual patient. This article reviews the basic concepts of pulmonary graphics and demonstrates how they contribute to our understanding of respiratory physiology and the management of neonatal respiratory failure.

  6. Influence of Corneal Opacity on Intraocular Pressure Assessment in Patients with Lysosomal Storage Diseases

    PubMed Central

    Politino, Giuseppe; Schmidtmann, Irene; Lorenz, Katrin; Bell, Katharina; Pfeiffer, Norbert; Pitz, Susanne

    2017-01-01

    Aims To investigate an influence of mucopolysaccharidosis (MPS)- and Morbus Fabry-associated corneal opacities on intraocular pressure (IOP) measurements and to evaluate the concordance of the different tonometry methods. Methods 25 MPS patients with or without corneal clouding, 25 Fabry patients with cornea verticillata ≥ grade 2 and 25 healthy age matched controls were prospectively included into this study. Outcome measures: Goldmann applanation tonometry (GAT); palpatory assessment of IOP; Goldmann-correlated intraocular pressure (IOPg), corneal-compensated intraocular pressure (IOPcc), corneal resistance factor (CRF) and corneal hysteresis (CH) assessed by Ocular Response Analyzer (ORA); central corneal thickness (CCT) and density assessed with Pentacam. Statistical analysis was performed using linear mixed effect models and Spearman correlation coefficients. The concordance between tonometry methods was assessed using Bland-Altman analysis. Results There was no relevant difference between study groups regarding median GAT, IOPg, IOPcc and CCT measurements. The limits of agreement between GAT and IOPcc/IOPg/palpatory IOP in MPS were: [-11.7 to 12.1mmHg], [-8.6 to 15.5 mmHg] and [- 5.4 to 10.1 mmHg] respectively. Limits of agreement were less wide in healthy subjects and Fabry patients. Palpatory IOP was higher in MPS than in healthy controls and Fabry patients. Corneal opacity correlated more strongly with GAT, IOPg, CH, CRF, CCT and corneal density in MPS (r = 0.4, 0.5, 0.5, 0.7, 0.6, 0.6 respectively) than in Fabry patients (r = 0.3, 0.2, -0.03, 0.1, 0.3, -0.2 respectively). In contrast, IOPcc revealed less correlation with corneal opacity than GAT in MPS (r = 0.2 vs. 0.4). Conclusions ORA and GAT render less comparable IOP-values in patients suffering from MPS-associated corneal opacity in comparison to Fabry and healthy controls. The IOP seems to be overestimated in opaque MPS-affected corneas. GAT, IOPg and biomechanical parameters of the cornea

  7. Aquaporin deletion in mice reduces intraocular pressure and aqueous fluid production.

    PubMed

    Zhang, Duo; Vetrivel, L; Verkman, A S

    2002-06-01

    Aquaporin (AQP) water channels are expressed in the eye at sites of aqueous fluid production and outflow: AQP1 and AQP4 in nonpigmented ciliary epithelium, and AQP1 in trabecular meshwork endothelium. Novel methods were developed to compare aqueous fluid dynamics in wild-type mice versus mice lacking AQP1 and/or AQP4. Aqueous fluid production was measured by in vivo confocal microscopy after transcorneal iontophoretic introduction of fluorescein. Intraocular pressure (IOP), outflow, and anterior chamber compliance were determined from pressure measurements in response to fluid infusions using micropipettes. Aqueous fluid volume and [Cl(-)] were assayed in samples withdrawn by micropipettes. In wild-type mice (CD1 genetic background, age 4-6 wk), IOP was 16.0 +/- 0.4 mmHg (SE), aqueous fluid volume 7.2 +/- 0.3 microl, fluid production 3.6 +/- 0.2 microl/h, fluid outflow 0.36 +/- 0.06 microl/h/mmHg, and compliance 0.036 +/- 0.006 microl/mmHg. IOP was significantly decreased by up to 1.8 mmHg (P < 0.002) and fluid production by up to 0.9 microl/h in age/litter-matched mice lacking AQP1 and/or AQP4 (outbred CD1 and inbred C57/bl6 genetic backgrounds). However, AQP deletion did not significantly affect outflow, [Cl(-)], volume, or compliance. These results provide evidence for the involvement of AQPs in intraocular pressure regulation by facilitating aqueous fluid secretion across the ciliary epithelium. AQP inhibition may thus provide a novel approach for the treatment of elevated IOP.

  8. Oxygen saturation changes in the optic nerve head during acute intraocular pressure elevation in monkeys

    NASA Astrophysics Data System (ADS)

    Khoobehi, Bahram; Kawano, Hiroyuki; Ning, Jinfeng; Burgoyne, Claude F.; Rice, David A.; Khan, Fareeha; Thompson, Hilary W.; Beach, James M.

    2009-02-01

    Background and Objective: To evaluate the effect of an acute elevated intraocular pressure (IOP) on oxygen saturation of structures of the optic nerve head. Study Design/Materials and Methods: In the cynomolgus monkey eye, IOP was set to 10 mm Hg, and then raised to 30, 45, and 55 mm Hg. The ONH and overlying vessels were imaged using a fundus camera attached to a hyperspectral imaging system (HSI) at 10 and 30 minutes after IOP elevation. Results: Raising IOP from 10 to 30 mm Hg did not significantly (P < 0.0001) change saturation in vessels or ONH tissue structures but at 55 mm Hg, all structures showed significant reduction. Conclusions: Quantitative assay of the blood oxygen saturation in structures on the surface and overlying the optic nerve head is possible using hyperspectral imaging techniques.

  9. Posterior rat eye during acute intraocular pressure elevation studied using polarization sensitive optical coherence tomography

    PubMed Central

    Fialová, Stanislava; Augustin, Marco; Fischak, Corinna; Schmetterer, Leopold; Handschuh, Stephan; Glösmann, Martin; Pircher, Michael; Hitzenberger, Christoph K.; Baumann, Bernhard

    2016-01-01

    Polarization sensitive optical coherence tomography (PS-OCT) operating at 840 nm with axial resolution of 3.8 µm in tissue was used for investigating the posterior rat eye during an acute intraocular pressure (IOP) increase experiment. IOP was elevated in the eyes of anesthetized Sprague Dawley rats by cannulation of the anterior chamber. Three dimensional PS-OCT data sets were acquired at IOP levels between 14 mmHg and 105 mmHg. Maps of scleral birefringence, retinal nerve fiber layer (RNFL) retardation and relative RNFL/retina reflectivity were generated in the peripapillary area and quantitatively analyzed. All investigated parameters showed a substantial correlation with IOP. In the low IOP range of 14-45 mmHg only scleral birefringence showed statistically significant correlation. The polarization changes observed in the PS-OCT imaging study presented in this work suggest that birefringence of the sclera may be a promising IOP-related parameter to investigate. PMID:28101419

  10. Mouse model of sustained elevation in intraocular pressure produced by episcleral vein occlusion.

    PubMed

    Ruiz-Ederra, Javier; Verkman, A S

    2006-05-01

    We have developed an inducible mouse model of glaucoma based on episcleral vein cauterization (EVC). Intraocular pressure (IOP) elevation in adult mice was produced by cauterizing three episcleral veins. Serial IOP measurements were done by induction-impact tonometry. IOP was significantly elevated by 104+/-20% in 20 out of 23 mice (87%) within the first day after EVC, and remained elevated for 4 weeks, with mean IOP 94% higher in EVC-treated vs. contralateral control eyes. Aqueous outflow blockade was verified from the IOP response to pulsed fluid infusions into the anterior chamber. Retinal ganglion cell (RGC) loss, determined by retrograde labelling using Fluoro-Gold applied to the superior colliculous, was approximately 20% at 2 weeks after EVC. We conclude that episcleral vein occlusion in mice produces significant and sustained elevation in IOP associated with increased outflow resistance and RGC loss, and thus may be useful to model glaucoma in genetically modified and drug-treated mice.

  11. Real-time cosmology

    NASA Astrophysics Data System (ADS)

    Quercellini, Claudia; Amendola, Luca; Balbi, Amedeo; Cabella, Paolo; Quartin, Miguel

    2012-12-01

    In recent years, improved astrometric and spectroscopic techniques have opened the possibility of measuring the temporal change of radial and transverse position of sources in the sky over relatively short time intervals. This has made at least conceivable to establish a novel research domain, which we dub “real-time cosmology”. We review for the first time most of the work already done in this field, analysing the theoretical framework as well as some foreseeable observational strategies and their capability to constrain models. We first focus on real-time measurements of the overall redshift drift and angular separation shift in distant sources, which allows the observer to trace the background cosmic expansion and large scale anisotropy, respectively. We then examine the possibility of employing the same kind of observations to probe peculiar and proper accelerations in clustered systems, and therefore their gravitational potential. The last two sections are devoted to the future change of the cosmic microwave background on “short” time scales, as well as to the temporal shift of the temperature anisotropy power spectrum and maps. We conclude revisiting in this context the usefulness of upcoming experiments (like CODEX and Gaia) for real-time observations.

  12. Doping-assisted low-pressure photoionization mass spectrometry for the real-time detection of lung cancer-related volatile organic compounds.

    PubMed

    Li, Zhen; Xu, Ce; Shu, Jinian; Yang, Bo; Zou, Yao

    2017-04-01

    Real-time detection of lung cancer-related volatile organic compounds (VOCs) is a promising, non-intrusive technique for lung cancer (LC) prescreening. In this study, a novel method was designed to enhance the detection selectivity and sensitivity of LC-related polar VOCs by dichloromethane (CH2Cl2) doping-assisted low-pressure photoionization mass spectrometry (LPPI-MS). Compared with conventional LPPI-MS, CH2Cl2 doping-assisted LPPI-MS boosted the peak intensities of n-propanol, n-pentanal, acetone, and butyl acetate in nitrogen specifically by 53, 18, 16, and 43 times, respectively. The signal intensities of their daughter ions were inhibited or reduced. At relative humidity (RH) of 20%, the sensitivities of n-propanol, n-pentanal, acetone, and butyl acetate detection ranged from 116 to 452 counts/ppbv with a detection time of 10s and R(2) >0.99 for the linear calibration curves. The method was also applicable under higher RH levels of 50% and 90%. Breath samples obtained from 10 volunteers and spiked samples were investigated. Eight-fold enhancements in the signal intensities of polar VOCs were observed in the normal and spiked samples. These preliminary results demonstrate the efficacy of the dichloromethane doping-assisted LPPI technique for the detection of LC-related polar VOCs. Further studies are indispensible to illustrating the detailed mechanism and applying the technique to breath diagnosis.

  13. Short-Term Moderately Elevated Intraocular Pressure Is Associated With Elevated Scotopic Electroretinogram Responses

    PubMed Central

    Choh, Vivian; Gurdita, Akshay; Tan, Bingyao; Prasad, Ratna C.; Bizheva, Kostadinka; Joos, Karen M.

    2016-01-01

    Purpose Moderately elevated intraocular pressure (IOP) is a risk factor for open-angle glaucoma. Some patients suffer glaucoma despite clinically measured normal IOPs. Fluctuations in IOP may have a significant role since IOPs are higher during sleep and inversion activities. Controlled transient elevations of IOPs in rats over time lead to optic nerve structural changes that are similar to the early changes observed in constant chronic models of glaucoma. Because early intervention decreases glaucoma progression, this study was done to determine if early physiological changes to the retina could be detected with noninvasive electrophysiological and optical imaging tests during moderately elevated IOP. Methods Intraocular pressures were raised to moderately high levels (35 mm Hg) in one eye of Sprague-Dawley rats while the other (control) eye was untreated. One group of rats underwent scotopic threshold response (STR) and electroretinogram (ERG) testing, while another 3 groups underwent optical coherence tomography (OCT) imaging, Western blot, or histologic evaluation. Results The amplitudes of the STR and ERG responses in eyes with moderately elevated IOPs were enhanced compared to the values before IOP elevation, and compared to untreated contralateral eyes. Structural changes to the optic nerve also occurred during IOP elevation. Conclusions Although ischemic IOP elevations are well-known to globally reduce components of the scotopic ERG, acute elevation in rats to levels often observed in untreated glaucoma patients caused an increase in these parameters. Further exploration of these phenomena may be helpful in better understanding the mechanisms mediating early retinal changes during fluctuating or chronically elevated IOP. PMID:27100161

  14. Intraoperative testing of opening and closing pressure predicts risk of low intraocular pressure after Ahmed glaucoma valve implantation

    PubMed Central

    Bochmann, F; Kipfer, A; Tarantino, J; Kaufmann, C; Bachmann, L; Thiel, M

    2014-01-01

    Purpose The aim of this study was to assess whether intraoperative testing of silicone Ahmed glaucoma valves (AGVs) would identify valves with an increased risk of low postoperative intraocular pressure (IOP). Methods In 30 consecutive cases of glaucoma surgery with AGV implantation, after priming the AGV, we intraoperatively measured the opening pressure A, closing pressure B, and re-opening pressure C using the active infusion pump of a phako-machine. IOP was checked postoperatively on the same day. Low IOP was defined as <5 mm Hg. Intraoperatively measured pressure characteristics of the valve function were analysed for their ability to predict postoperative IOP outcomes. Results Opening A, closing B, and re-opening C pressures (mean, (SD)) were 18.4 (5.1), 8.3 (4.7), and 11.7 (4.8)mm Hg, respectively. Ten patients (33.3%) had low IOP. An opening pressure of ≤18 mm Hg predicted low postoperative IOP with a sensitivity (10/10) of 100% (95% CI, 69.2–100) and a specificity (13/20) of 65.0% (95% CI, 40.8–84.6). Conclusions AGVs have a high variability of opening, closing, and re-opening pressures. An opening pressure of ≤18 mm Hg, a closing pressure of ≤10 mm Hg, or a re-opening pressure of ≤11 mm Hg identified all patients with low postoperative IOP. PMID:25060848

  15. Real time Faraday spectrometer

    DOEpatents

    Smith, Jr., Tommy E.; Struve, Kenneth W.; Colella, Nicholas J.

    1991-01-01

    This invention uses a dipole magnet to bend the path of a charged particle beam. As the deflected particles exit the magnet, they are spatially dispersed in the bend-plane of the magnet according to their respective momenta and pass to a plurality of chambers having Faraday probes positioned therein. Both the current and energy distribution of the particles is then determined by the non-intersecting Faraday probes located along the chambers. The Faraday probes are magnetically isolated from each other by thin metal walls of the chambers, effectively providing real time current-versus-energy particle measurements.

  16. A wireless intraocular pressure monitoring device with a solder-filled microchannel antenna

    NASA Astrophysics Data System (ADS)

    Varel, Çağdaş; Shih, Yi-Chun; Otis, Brian P.; Shen, Tueng S.; Böhringer, Karl F.

    2014-04-01

    This paper presents the prototype of an intraocular pressure sensor as a major step toward building a device that can be permanently implanted during cataract surgery. The implantation will proceed through an incision of 2-3 mm using an injector, during which the complete device must be folded into a cross-section of 2 mm × 1 mm. The device uses radio frequency (RF) for wireless power and data transfer. The prototype includes an antenna, an RF chip and a pressure sensor assembled on a printed circuit board with several circuit components used for testing and calibration. The antenna is fabricated and integrated with the circuit using a fabrication method employing solder-filled microchannels embedded in an elastomer. The monitoring device is powered at 2.716 GHz from a distance of 1-2 cm. The prototype has undergone electrical and mechanical tests for antenna and sensor performance. The flexible antenna can withstand a stress of 33.4 kPa without any electrical disconnection. It did not show a significant increase in electrical resistance after 50 bending cycles with a maximum applied stress of 116 kPa. Transmitted pressure data shows an averaged sensitivity of 16.66 Hz (mm-Hg)-1.

  17. Muscular and intraocular pressure responses among ocular-hypertensive subjects: is there a rationale for biofeedback?

    PubMed

    Raczynski, J M; Mason, D A; Wilson, R P; Silvia, E S; Kleinstein, R N

    1985-12-01

    Several animal and human investigations have indicated that intraocular pressure (IOP) levels may be associated with extreme drug-induced changes in the extraocular muscles. Further, recent data suggest that, among individuals with normal IOP level, moderate increases in facial muscle (EMG) activity around the eye while the eye is open are associated with increases in IOP. To investigate further the relationship between facial EMG activity and IOP levels and to examine a group of individuals with elevated IOP levels, subjects were recruited from outpatients at an optometry clinic. Three groups of subjects were selected: a group of ocular hypertensive subjects who showed elevated pressures at the optometry clinic and upon the day of testing, a group of labile ocular hypertensive subjects who evinced elevated pressures during their visit to the optometry clinic but lower pressures on the day of testing, and a group of normal IOP subjects who showed normal pressures both during their optometry clinic visit and on the day of testing. To investigate anxiety differences, subjects were administered the State-Trait Anxiety Inventory, but subsequent analysis revealed no group differences. To evaluate the role of stress upon muscle (EMG) functioning around the eye, subjects were subjected to imagery and standardized mental arithmetic stressors; analyses of these results also revealed no significant group differences. Finally, subjects were given EMG biofeedback for muscle activity around the eye while IOP was assessed during five alternating periods in which they made decreases and increases in EMG activity. Results revealed significant group, period, and group by period interaction effects. The pattern of results is interpreted as implicating EMG activity in IOP fluctuations; the implications of these data for potential biofeedback and stress management treatments are discussed.

  18. Elevated Intraocular Pressure Induces Rho GTPase Mediated Contractile Signaling in the Trabecular Meshwork

    PubMed Central

    Pattabiraman, Padmanabhan P; Inoue, Toshihiro; Rao, P. Vasantha

    2015-01-01

    Rho GTPase regulated contractile signaling in the trabecular meshwork (TM) has been shown to modulate aqueous humor (AH) outflow and intraocular pressure (IOP). To explore whether elevated IOP, a major risk factor for primary open angle glaucoma (POAG) influences Rho GTPase signaling in the TM, we recorded AH outflow in enucleated contralateral porcine eyes perfused for 4–5 hours at either 15 mm or 50 mm Hg pressure. After perfusion, TM tissue extracted from perfused eyes was evaluated for the activation status of Rho GTPase, myosin light chain (MLC), myosin phosphatase target substrate 1 (MYPT1), myristoylated alanine-rich C-kinase substrate (MARCKS) and paxillin. Eyes perfused at 50 mm Hg exhibited a significant decrease in AH outflow facility compared with those perfused at 15 mm Hg. Additionally, TM tissue from eyes perfused at 50 mm Hg revealed significantly increased levels of activated RhoA and phosphorylated MLC, MYPT1, MARCKS and paxillin compared to TM tissue derived from eyes perfused at 15 mm Hg. Taken together, these observations indicate that elevated IOP-induced activation of Rho GTPase-dependent contractile signaling in the TM is associated with increased resistance to AH outflow through the trabecular pathway, and demonstrate the sensitivity of Rho GTPase signaling to mechanical force in the AH outflow pathway. PMID:25956210

  19. Caveolin-1 modulates intraocular pressure: implications for caveolae mechanoprotection in glaucoma

    PubMed Central

    Elliott, Michael H.; Ashpole, Nicole E.; Gu, Xiaowu; Herrnberger, Leonie; McClellan, Mark E.; Griffith, Gina L.; Reagan, Alaina M.; Boyce, Timothy M.; Tanito, Masaki; Tamm, Ernst R.; Stamer, W. Daniel

    2016-01-01

    Polymorphisms in the CAV1/2 genes that encode signature proteins of caveolae are associated with glaucoma, the second leading cause of blindness worldwide, and with its major risk factor, intraocular pressure (IOP). We hypothesized that caveolin-1 (Cav-1) participates in IOP maintenance via modulation of aqueous humor drainage from the eye. We localize caveolae proteins to human and murine conventional drainage tissues and show that caveolae respond to mechanical stimulation. We show that Cav-1-deficient (Cav-1−/−) mice display ocular hypertension explained by reduced pressure-dependent drainage of aqueous humor. Cav-1 deficiency results in loss of caveolae in the Schlemm’s canal (SC) and trabecular meshwork. However, their absence did not appear to impact development nor adult form of the conventional outflow tissues according to rigorous quantitative ultrastructural analyses, but did affect cell and tissue behavior. Thus, when IOP is experimentally elevated, cells of the Cav-1−/− outflow tissues are more susceptible to plasma membrane rupture indicating that caveolae play a role in mechanoprotection. Additionally, aqueous drainage from Cav-1−/− eyes was more sensitive to nitric oxide (NO) synthase inhibition than controls, suggesting that excess NO partially compensates for outflow pathway dysfunction. These results provide a functional link between a glaucoma risk gene and glaucoma-relevant pathophysiology. PMID:27841369

  20. A Miniature-Implantable RF-Wireless Active Glaucoma Intraocular Pressure Monitor.

    PubMed

    Chow, Eric Y; Chlebowski, Arthur L; Irazoqui, Pedro P

    2010-12-01

    Glaucoma is a detrimental disease that causes blindness in millions of people worldwide. There are numerous treatments to slow the condition but none are totally effective and all have significant side effects. Currently, a continuous monitoring device is not available, but its development may open up new avenues for treatment. This work focuses on the design and fabrication of an active glaucoma intraocular pressure (IOP) monitor that is fully wireless and implantable. Major benefits of an active IOP monitoring device include the potential to operate independently from an external device for extended periods of time and the possibility of developing a closed-loop monitoring and treatment system. The fully wireless operation is based off using gigahertz-frequency electromagnetic wave propagation, which allows for an orientation independent transfer of power and data over reasonable distances. Our system is comprised of a micro-electromechanical systems (MEMS) pressure sensor, a capacitive power storage array, an application-specific integrated circuit designed on the Texas Instruments (TI) 130 nm process, and a monopole antenna all assembled into a biocompatible liquid-crystal polymer-based tadpole-shaped package.

  1. Effects of exercise on intraocular pressure and ocular blood flow: a review.

    PubMed

    Risner, David; Ehrlich, Rita; Kheradiya, Nisha S; Siesky, Brent; McCranor, Lynne; Harris, Alon

    2009-08-01

    Glaucoma is a disease characterized by progressive optic neuropathy resulting in retinal ganglion cell death, which affects approximately 68 million people worldwide. Risk factors include intraocular pressure (IOP), genetics, race, age, and vascular factors. Exercise is known to affect IOP and systemic cardiovascular factors and, therefore, may affect glaucoma pathophysiology. This review discusses the results of articles relevant to glaucoma, IOP, ocular blood flow (OBF), and exercise. Isometric and dynamic exercises have been studied with respect to effects on IOP and OBF. Isometric exercise results in an acute decrease in IOP, which correlates with hypocapnia. Dynamic exercise results in a more pronounced but also short duration decrease in IOP. Physical fitness is associated with lower baseline IOP but diminished acute IOP-lowering response to exercise. Upon cessation of exercise, values return to pretrained levels within 1 month. In glaucoma patients, these IOP-lowering effects are greater than in healthy subjects. In healthy subjects, OBF is unchanged during exercise due to vascular autoregulation. This autoregulation fails at ocular perfusion pressures greater than 70% above baseline. In conclusion exercise in glaucoma patients results in acutely lowered IOP and lower baseline IOP. The effects of exercise on the prevention of glaucoma and glaucomatous progression remain unknown. The role of exercise in glaucoma management should be investigated.

  2. The effect of intraocular and intracranial pressure on retinal structure and function in rats

    PubMed Central

    Zhao, Da; He, Zheng; Vingrys, Algis J; Bui, Bang V; Nguyen, Christine T O

    2015-01-01

    An increasing number of studies indicate that the optic nerve head of the eye is sensitive not only to changes in intraocular pressure (IOP), but also to intracranial pressure (ICP). This study examines changes to optic nerve and retinal structure in a rat model in response to a range of IOP and ICP levels using optical coherence tomography. Furthermore, we examine the functional sequelae of these structural changes by quantifying the effect of pressure changes on the electroretinogram. IOP elevation (10–90 mmHg) induces progressive deformation of the optic nerve head and retinal surface (P < 0.05), compression of the retina (P < 0.05) and bipolar cell (b-wave), and retinal ganglion cell (scotopic threshold response) dysfunction (P < 0.05). Simultaneously altering ICP (−5 to 30 mmHg) modifies these IOP-induced responses, with lower ICP (−5 mmHg) exacerbating and higher ICP (15–30 mmHg) ameliorating structural and functional deficits. Thus, the balance between IOP and ICP (optic nerve pressure gradient, ONPG = IOP − ICP) plays an important role in optic nerve integrity. Structural and functional parameters exhibit a two-phase relationship to ONPG, with structural changes being more sensitive to ONPG modification (threshold = −0.6 to 11.3 mmHg) compared with functional changes (threshold = 49.7–54.6 mmHg). These findings have implications for diseases including glaucoma, intracranial hypertension, and long-term exposure to microgravity. PMID:26290528

  3. Longitudinal analysis of age-related changes in intraocular pressure in South Korea

    PubMed Central

    Baek, S U; Kee, C; Suh, W

    2015-01-01

    Purpose To assess the changes in intraocular pressure (IOP) with age in South Korea Methods Subjects aged 20–79 who had been receiving health examinations at a university hospital were enrolled. They completed physical and ophthalmic examinations. Subjects with ocular disease that could possibly affect their IOP were excluded. The relationships between IOP and age, blood pressure, heart rate, body mass index, blood chemistry, and electrolyte were analyzed using a linear mixed model. Results Of the 33 712 subjects, 31 857 participants were enrolled. In a cross-sectional analysis, IOP also showed a negative correlation in all age groups (respectively, P<0.001). In particular, patients in their 60s~80s had a less steep decreasing slope of IOP with age than patients in their 20s~30s (correlation coefficient −0.260 and −0.168, respectively). In longitudinal analysis, negative trend was shown in the slope of tendency in total subjects. When analyzing the effect of gender on the relationship between age and IOP, females had a less steep decreasing slope of IOP with age than males by 0.05 mm Hg. With regard to systemic parameters, systolic blood pressure and heart rate were positively correlated with IOP (P<0.001). Conclusion IOP was significantly decreased with age, although the amount of change was small. In women and older age groups, IOP was less decreased than that of men and young age groups. In addition, IOP was positively associated with systolic blood pressure and heart rate. PMID:25697455

  4. Effects of inner materials on the sensitivity and phase depth of wireless inductive pressure sensors for monitoring intraocular pressure

    NASA Astrophysics Data System (ADS)

    Jang, Cheol-In; Shin, Kyeong-Sik; Kim, Mi Jeung; Yun, Kwang-Seok; Park, Ki Ho; Kang, Ji Yoon; Lee, Soo Hyun

    2016-03-01

    In this research, we developed wireless, inductive, pressure sensors with high sensitivity and investigated the effects of the inner materials (copper or ferrite) on the performance of the sensors. The proposed sensor is comprised of two parts, i.e., the top and the bottom parts. The top part includes a micro coil and a capacitor for the wireless transfer of data, and the bottom part includes the inner materials and a thick or thin flexible membrane to induce changes in the inductance. An anchor is used to assemble the top and bottom parts. The behavior of the sensor with copper was based on the eddy current effect, and, as the pressure increased, its resonance frequency increased, while its phase depth decreased exponentially. The principle of the sensor with ferrite was related to the effective permeability between a ferrite and a coil, and its response was the opposite of that with copper, i.e., as the pressure increased, the resonance frequency decreased linearly, and the phase depth increased linearly. These different operational mechanisms can be explained by the changes in the equations of inductance presented in this paper. After characterizing four different types of inductive pressure sensors in ambient air, one type of inductive pressure sensor was used to monitor the intraocular pressure (IOP) of a rabbit's eye as a biomedical application. The results showed that, in the animal tests, the measured responsivity and sensitivity were 16.7 kHz/mmHg and 1340 ppm/mmHg, respectively. These data indicate that the proposed sensor is a good candidate for monitoring IOP.

  5. Intraocular Pressure Control after Trabeculectomy, Phacotrabeculectomy and Phacoemulsification in a Hispanic Population

    PubMed Central

    L Jung, Jennifer; Isida-Llerandi, Cristina G; Lazcano-Gomez, Gabriel; SooHoo, Jeffrey R

    2014-01-01

    ABSTRACT Purpose: To compare the efficacy of different surgical strategies for intraocular pressure (IOP) control in Hispanic glaucoma patients with and without visually significant cataracts. Design: Comparative retrospective consecutive case series. Methods: The charts of 153 consecutive patients with primary open angle glaucoma who underwent either trabeculectomy alone (n = 51), phacotrabeculectomy (n = 51), or phacoemulsification alone (n = 51) were reviewed to compare IOP control, the number of glaucoma medications required postoperatively, and the inci dence of surgical complications. Results: Preoperative IOP was 17.5 ± 5.2 mm Hg in the trabe-culectomy group, 15.4 ± 4.5 mm Hg in the phacotrabeculectomy group and 13.9 ± 2.9 mm Hg in the phacoemulsification group (p < 0.001 for all comparisons). Mean IOP reduction from baseline was 4.2 ± 6.9 (24.6%) for the trabeculectomy group, 2.9 ± 5.0 (20.8%) for the phacotrabeculectomy group, and 0.9 ± 3.4 (6.5%) for the phacoemulsification group (p = 0.009). The number of IOP-lowering medications required postoperatively decreased significantly in all three groups (p = 0.001). The rate of early and late postoperative complications was similar between the trabeculectomy and phacotrabeculectomy groups and less for the phacoemulsification group. Conclusion: Trabeculectomy and phacotrabeculectomy are both viable surgical options for managing open angle glau coma. Both resulted in similar rates of success, IOP reduction, decrease in use of IOP-lowering medications and post operative complication rates. Phacoemulsification alone had a lower success rate and greater need for postoperative IOP-lowering medications compared to trabeculectomy alone or phacotrabeculectomy. Phacoemulsification alone may be a reasonable option for patients with visually significant cataract and lower baseline IOP. How to cite this article: Jung JL, Isida-Llerandi CG, Lazcano-Gomez G, SooHoo JR, Kahook MY. Intraocular Pressure Control after

  6. Intraocular Pressure Control after Implantation of an Ahmed Glaucoma Valve in Eyes with a Failed Trabeculectomy

    PubMed Central

    Schimiti, Rui B; Abe, Ricardo Y; Tavares, Carla M; Vasconcellos, Jose PC; Costa, Vital P

    2016-01-01

    Aim To evaluate the results of Ahmed glaucoma valve (AGV) in eyes with a failed trabeculectomy. Materials and methods This retrospective study evaluated 61 eyes with a failed trabeculectomy that underwent implantation of an AGV due to uncontrolled intraocular pressure (IOP) on maximal medical therapy. Success was defined as IOP ≤ 21 mm Hg (criterion 1) or 20% reduction in IOP (criterion 2) with or without antiglaucoma medications. Persistent hypotony, loss of light perception, and reoperation for IOP control were defined as failure. Results Mean preoperative IOP and mean lOPs at 6, 12, and 24 months were 21.93 ± 6.32 mm Hg (n = 61), 14.15 ± 4.33 mm Hg (n = 59), 13.21 ± 4.44 mm Hg (n = 56), and 13.60 ± 3.27 mm Hg (n = 25) respectively. Mean number of antiglaucoma medications preoperatively and at 6, 12, and 24 months was 3.95 ± 0.85, 2.19 ± 1.38, 2.48 ± 1.44, and 2.40 ± 1.32 respectively. The reductions in the number of medications and IOP measurements were statistically significant at all time intervals (p < 0.001, Wilcoxon signed rank test). According to criterion 1, the Kaplan-Meier survival curve disclosed success rates of 75% at 12 and 24 months. According to criterion 2, the success rates were 57% at 12 months and 55% at 24 months. The most frequent complications were hypertensive phase (18%) and shallow anterior chamber (16.4%). Conclusion The AGV may effectively reduce IOP in eyes that had a failed trabeculectomy. Clinical significance The AGV is an alternative in eyes with a failed trabeculectomy. How to cite this article Schimiti RB, Abe RY, Tavares CM, Vasconcellos JPC, Costa VP. Intraocular Pressure Control after Implantation of an Ahmed Glaucoma Valve in Eyes with a Failed Trabeculectomy. J Curr Glaucoma Pract 2016;10(3):97-103. PMID:27857489

  7. Influence of intraocular pressure on geometrical properties of a linear model of the eyeball: Effect of optical self-adjustment

    NASA Astrophysics Data System (ADS)

    Asejczyk-Widlicka, M.; Srodka, D. W.; Kasprzak, H.; Iskander, D. R.

    In general, visual acuity does not change with variations in intraocular pressure. Experiments in vitro as well as our clinical findings lead us to hypothesise that the eyeball could possess certain mechanical properties enabling it to automatically produce a sharp image on the retina despite variations in intraocular pressure. Previously reported simple biomechanical models of the eye did not confirm this hypothesis. Here, we propose a generalised mechanical model of the eyeball in which we include an appropriate limbus ring that mimics the ciliary body and the iris. The Finite Element Method is used to model the eyeball and to test its behaviour. A set of geometrical and material parameters has been determined for the model so that the postulated function of the eye is preserved. Numerical simulations have confirmed the hypothesis. The anatomically justified inclusion of the limbus ring in the proposed model of the eyeball makes it more realistic than those previously reported.

  8. Towards depth profiling of organic aerosols in real time using aerosol flowing atmospheric-pressure afterglow mass spectrometry (AeroFAPA-MS)

    NASA Astrophysics Data System (ADS)

    Brüggemann, Martin; Hoffmann, Thorsten

    2014-05-01

    Organic aerosol accounts for a substantial fraction of tropospheric aerosol and has implications on the earth's climate and human health. However, the characterization of its chemical composition and transformations remain a major challenge and is still connected to large uncertainties (IPCC, 2013). Recent measurements revealed that organic aerosol particles may reside in an amorphous or semi-solid phase state which impedes the diffusion within the particles (Virtanen et al., 2010; Shiraiwa et al., 2011). This means that reaction products which are formed on the surface of a particle, e.g. by OH, NO3 or ozone chemistry, cannot diffuse into the particle's core and remain at the surface. Eventually, this leads to particles with a core/shell structure. In the particles' cores the initial compounds are preserved whereas the shells contain mainly the oxidation products. By analyzing the particles' cores and shells separately, thus, it is possible to obtain valuable information on the formation and evolution of the aerosols' particle and gas phase. Here we present the development of the aerosol flowing atmospheric-pressure afterglow (AeroFAPA) technique which allows the mass spectrometric analysis of organic aerosols in real time. The AeroFAPA is an ion source based on a helium glow discharge at atmospheric pressure. The plasma produces excited helium species and primary reagent ions which are transferred into the afterglow region where the ionization of the analytes takes place. Due to temperatures of only 80 ° C to 150 ° C and ambient pressure in the afterglow region, the ionization is very soft and almost no fragmentation of organic molecules is observed. Thus, the obtained mass spectra are easy to interpret and no extensive data analysis procedure is necessary. Additionally, first results of a combination of the AeroFAPA-MS with a scanning mobility particle sizer (SMPS) suggest that it is not only possible to analyze the entire particle phase but rather that a

  9. Real-time analysis of ambient organic aerosols using aerosol flowing atmospheric-pressure afterglow mass spectrometry (AeroFAPA-MS)

    NASA Astrophysics Data System (ADS)

    Brüggemann, Martin; Karu, Einar; Stelzer, Torsten; Hoffmann, Thorsten

    2015-04-01

    Organic aerosol accounts for a major fraction of atmospheric aerosols and has implications on the earth's climate and human health. However, due to the chemical complexity its measurement remains a major challenge for analytical instrumentation.1 Here, we present the development, characterization and application of a new soft ionization technique that allows mass spectrometric real-time detection of organic compounds in ambient aerosols. The aerosol flowing atmospheric-pressure afterglow (AeroFAPA) ion source utilizes a helium glow discharge plasma to produce excited helium species and primary reagent ions. Ionization of the analytes occurs in the afterglow region after thermal desorption and results mainly in intact molecular ions, facilitating the interpretation of the acquired mass spectra. In the past, similar approaches were used to detect pesticides, explosives or illicit drugs on a variety of surfaces.2,3 In contrast, the AeroFAPA source operates 'online' and allows the detection of organic compounds in aerosols without a prior precipitation or sampling step. To our knowledge, this is the first application of an atmospheric-pressure glow discharge ionization technique to ambient aerosol samples. We illustrate that changes in aerosol composition and concentration are detected on the time scale of seconds and in the ng-m-3 range. Additionally, the successful application of AeroFAPA-MS during a field study in a mixed forest region in Central Europe is presented. Several oxidation products of monoterpenes were clearly identified using the possibility to perform tandem MS experiments. The acquired data are in agreement with previous studies and demonstrate that AeroFAPA-MS is a suitable tool for organic aerosol analysis. Furthermore, these results reveal the potential of this technique to enable new insights into aerosol formation, growth and transformation in the atmosphere. References: 1) IPCC, 2013: Summary for Policymakers. In: Climate Change 2013: The

  10. Ocular Decompression with Cotton Swabs Lowers Intraocular Pressure Elevation Following Intravitreal Injection

    PubMed Central

    Gregori, Ninel Z.; Weiss, Matthew J.; Goldhardt, Raquel; Schiffman, Joyce C.; Vega, Edgardo; Mattis, Cherrie-Ann; Shi, Wei; Kelley, Linda; Hernandez, Vilma; Feuer, William J.

    2013-01-01

    Objective To determine the effect of pre-injection ocular decompression by cotton swabs on the immediate rise in intraocular pressure (IOP) after intravitreal injections. Methods Forty-eight patients receiving 0.05-ml ranibizumab injections in a retina clinic were randomized to two anesthetic methods in each eye on the same day (if bilateral disease) or on consecutive visits (if unilateral disease). One method utilized cotton swabs soaked in 4% lidocaine applied to the globe with moderate pressure and the other 3.5% lidocaine gel applied without pressure. IOPs were recorded at baseline (before injection) and at 0, 5, 10, and 15 minutes after the injection until the IOP was ≤30 mmHg. The IOP elevations from baseline were compared after the two anesthetic methods. Results The pre-injection mean IOP (SD, mmHg) was 15.5 (3.3) before the cotton swabs and 15.9 (3.0) before the gel (p=0.28). Mean IOP (SD, mmHg) change immediately after injection was 25.7 (9.2) after the cotton swabs and 30.9 (9.9) after the gel (P=0.001). Thirty-five percent of gel eyes had IOP ≥50 mmHg compared to only 10% of cotton swab eyes immediately after the injection (P<0.001). Conclusion Decompressing the eye with cotton swabs during anesthetic preparation prior to an intravitreal injection produces a significantly lower IOP spike after the injection. PMID:23632408

  11. Distribution of intraocular pressure and its determinants in an Iranian adult population

    PubMed Central

    Hashemi, Hassan; Khabazkhoob, Mehdi; Emamian, Mohammad Hassan; Shariati, Mohammad; Yekta, Abbasali; Fotouhi, Akbar

    2016-01-01

    AIM To determine the distribution of intraocular pressure (IOP) and its determinants in an Iranian population. METHODS In a cross-sectional survey, random cluster sampling was conducted from the 40-64 years old population of Shahroud, in the north of Iran. All participants had optometry and ophthalmic exams. IOP was determined using the Goldmann tonometry method and biometric components were measured. RESULTS Of the 6311 people selected for the study, 5190 (82.2%) participated. The mean age of the participants was 50.9±6.2y and 58.7% of them were female. Mean IOP was 12.87±2.27 mm Hg. In this study 0.3% of the participants had an IOP higher than 21 mm Hg. The multiple linear regression model revealed that sex (Coef=-0.30; 95% CI: -0.43 to -0.17), diabetes (Coef=0.43; 95% CI: 0.19 to 0.67), high systolic blood pressure (Coef=0.02; 95% CI: 0.01 to 0.02), high body mass index (BMI) (Coef=0.03; 95% CI: 0.01 to 0.04), higher education (Coef=0.02, 95% CI: 0.01 to 0.04), thicker central corneal thickness (Coef=0.01; 95% CI: 0.01 to 0.02), and myopic shift in spherical equivalent (Coef=-0.14; 95% CI: -0.18 to -0.10) significantly correlated with high IOP. CONCLUSION The IOP in this 40-64 years old population is low overall. In the north of Iran, average IOP is statistically significantly correlated with female sex, diabetes, higher BMI, systolic blood pressure, higher education, thicker cornea, and myopic refractive error. PMID:27588277

  12. Real time polarimetric dehazing.

    PubMed

    Mudge, Jason; Virgen, Miguel

    2013-03-20

    Remote sensing is a rich topic due to its utility in gathering detailed accurate information from locations that are not economically feasible traveling destinations or are physically inaccessible. However, poor visibility over long path lengths is problematic for a variety of reasons. Haze induced by light scatter is one cause for poor visibility and is the focus of this article. Image haze comes about as a result of light scattering off particles and into the imaging path causing a haziness to appear on the image. Image processing using polarimetric information of light scatter can be used to mitigate image haze. An imaging polarimeter which provides the Stokes values in real time combined with a "dehazing" algorithm can automate image haze removal for instant applications. Example uses are to improve visual display providing on-the-spot detection or imbedding in an active control loop to improve viewing and tracking while on a moving platform. In addition, removing haze in this manner allows the trade space for a system operational waveband to be opened up to bands which are object matched and not necessarily restricted by scatter effects.

  13. Real time analysis under EDS

    NASA Astrophysics Data System (ADS)

    Schneberk, D.

    1985-07-01

    The analysis component of the Enrichment Diagnostic System (EDS) developed for the Atomic Vapor Laser Isotope Separation Program (AVLIS) at Lawrence Livermore National Laboratory (LLNL) is described. Four different types of analysis are performed on data acquired through EDS: (1) absorption spectroscopy on laser-generated spectral lines, (2) mass spectrometer analysis, (3) general purpose waveform analysis, and (4) separation performance calculations. The information produced from this data includes: measures of particle density and velocity, partial pressures of residual gases, and overall measures of isotope enrichment. The analysis component supports a variety of real-time modeling tasks, a means for broadcasting data to other nodes, and a great degree of flexibility for tailoring computations to the exact needs of the process. A particular data base structure and program flow is common to all types of analysis. Key elements of the analysis component are: (1) a fast access data base which can configure all types of analysis, (2) a selected set of analysis routines, (3) a general purpose data manipulation and graphics package for the results of real time analysis.

  14. Real time analysis under EDS

    SciTech Connect

    Schneberk, D.

    1985-07-01

    This paper describes the analysis component of the Enrichment Diagnostic System (EDS) developed for the Atomic Vapor Laser Isotope Separation Program (AVLIS) at Lawrence Livermore National Laboratory (LLNL). Four different types of analysis are performed on data acquired through EDS: (1) absorption spectroscopy on laser-generated spectral lines, (2) mass spectrometer analysis, (3) general purpose waveform analysis, and (4) separation performance calculations. The information produced from this data includes: measures of particle density and velocity, partial pressures of residual gases, and overall measures of isotope enrichment. The analysis component supports a variety of real-time modeling tasks, a means for broadcasting data to other nodes, and a great degree of flexibility for tailoring computations to the exact needs of the process. A particular data base structure and program flow is common to all types of analysis. Key elements of the analysis component are: (1) a fast access data base which can configure all types of analysis, (2) a selected set of analysis routines, (3) a general purpose data manipulation and graphics package for the results of real time analysis. Each of these components are described with an emphasis upon how each contributes to overall system capability. 3 figs.

  15. Ocular bacterial flora, tear production, and intraocular pressure in a captive flock of Humboldt penguins (Spheniscus humboldti).

    PubMed

    Swinger, Robert L; Langan, Jennifer N; Hamor, Ralph

    2009-09-01

    The purpose of this study was to determine normal ocular surface bacterial flora, tear production, and intraocular pressure in a captive flock of Humboldt penguins, Spheniscus humboldti. Twenty-eight healthy penguins were studied and equally divided between fresh- and saltwater habitats. The population consisted of 15 female and 13 male penguins, ranging from 3-20 years of age. Following complete ophthalmic exam, 4 penguins with cataracts were removed from the study. Eight penguins from each habitat were randomly selected for ocular surface aerobic bacterial culture. Corynebacterium spp. and Staphylococcus spp. were the most common isolates. Twenty-five organisms consisting of 17 species, and 15 organisms consisting of 9 species, were identified in fresh- and saltwater groups, respectively. Tear production and intraocular pressures were evaluated on 24 penguins with normal ocular exams. The range and mean (+/- standard deviation) tear production, measured with the Schirmer tear test, was 1-12 mm/min and 6.45 mm/min +/- 2.9, respectively. The mean tear production for penguins housed in the freshwater habitat was greater (8.5 mm/min) than those in saltwater (4.8 mm/min). The range and mean (+/- standard deviation) intraocular pressure, measured by applanation tonometry using a Tono-Pen XL tonometer, was 10-27 mmHg and 20.36 mmHg +/- 4.1, respectively. This data should be utilized as a reliable resource for those involved in avian and zoo medicine.

  16. Lowered intraocular pressure in a glaucoma patient after intravitreal injection of ocriplasmin

    PubMed Central

    McClintock, Michael; MacCumber, Mathew W

    2015-01-01

    We report the case of a glaucoma patient who received a single intravitreal injection of 125 µg ocriplasmin for vitreomacular traction in the right eye. The patient had bilateral advanced glaucoma and had previously undergone an implantation of an Ahmed glaucoma valve in the right eye and trabeculectomy in both eyes. The patient was using three topical ophthalmic intraocular pressure (IOP)-lowering medications on the day of injection. Baseline uncorrected Snellen visual acuity was 20/80-1 and IOP was 19 mmHg. Resolution of vitreomacular traction was achieved 1 week after injection. IOP was transiently decreased, reaching a maximum reduction of 12 mmHg below baseline at 1 month after injection, when serous choroidal effusion was also present. IOP returned to baseline levels and choroidal effusion resolved at 2 months after injection of IOP-lowering medication. Vitrectomy with epiretinal membrane and internal limiting membrane peeling, endolaser photocoagulation, and fluid–gas exchange were performed in the right eye ~3.5 months after injection to treat persistent epiretinal membrane, and presumed tractional retinal detachment. Final visual acuity was 20/50+ and IOP was 18 mmHg at 16 weeks after surgery. To our knowledge, this is the first report of IOP reduction and serous choroidal effusion after ocriplasmin injection. PMID:26604668

  17. Regulation of intraocular pressure by soluble and membrane guanylate cyclases and their role in glaucoma

    PubMed Central

    Buys, Emmanuel S.; Potter, Lincoln R.; Pasquale, Louis R.; Ksander, Bruce R.

    2014-01-01

    Glaucoma is a progressive optic neuropathy characterized by visual field defects that ultimately lead to irreversible blindness (Alward, 2000; Anderson et al., 2006). By the year 2020, an estimated 80 million people will have glaucoma, 11 million of which will be bilaterally blind. Primary open-angle glaucoma (POAG) is the most common type of glaucoma. Elevated intraocular pressure (IOP) is currently the only risk factor amenable to treatment. How IOP is regulated and can be modulated remains a topic of active investigation. Available therapies, mostly geared toward lowering IOP, offer incomplete protection, and POAG often goes undetected until irreparable damage has been done, highlighting the need for novel therapeutic approaches, drug targets, and biomarkers (Heijl et al., 2002; Quigley, 2011). In this review, the role of soluble (nitric oxide (NO)-activated) and membrane-bound, natriuretic peptide (NP)-activated guanylate cyclases that generate the secondary signaling molecule cyclic guanosine monophosphate (cGMP) in the regulation of IOP and in the pathophysiology of POAG will be discussed. PMID:24904270

  18. Intraocular Pressure, Tear Production, and Ocular Echobiometry in Guinea Pigs (Cavia porcellus).

    PubMed

    Rajaei, Seyed Mehdi; Mood, Maneli Ansari; Sadjadi, Reza; Azizi, Farzaneh

    2016-01-01

    The purpose of this study was to evaluate intraocular pressure (IOP) by means of rebound tonometry, to assess tear production by using the endodontic absorbent paper point tear test (EAPTT) and phenol red thread test (PRTT), and to determine the effects of time of day on IOP and tear production in guinea pigs. The study population comprised 24 healthy adult guinea pigs (12 male, 12 female; 48 eyes) of different breeds and ranging in age from 12 to 15 mo. IOP and tear production were measured at 3 time points (0700, 1500, and 2300) during a 24-h period. Overall values (mean ± 1 SD) were: IOP, 6.81 ± 1.41 mm Hg (range, 4.83 to 8.50); PRTT, 14.33 ± 1.35 mm (range, 12.50 to 16.83); and EAPTT, 8.54 ± 1.08 mm (range, 7.17 to 10.0 mm). In addition, ultrasound biometry was performed by using a B-mode system with linear 8-MHz transducer. This study reports reference values for IOP and tear production in guinea pigs.

  19. Intraocular pressure (IOP) in relation to four levels of daily geomagnetic and extreme yearly solar activity

    NASA Astrophysics Data System (ADS)

    Stoupel, E.; Goldenfeld, M.; Shimshoni, M.; Siegel, R.

    1993-03-01

    The link between geomagnetic field activity (GMA), solar activity and intraocular pressure (IOP) in healthy individuals was investigated. The IOP of 485 patients (970 eyes) was recorded over three nonconsecutive years (1979, 1986, 1989) which were characterized by maximal solar activity (1979, 1989) or minimal solar activity (1986). The measurements were also correlated with four categories of GMA activity: quiet (level I0), unsettled (II0), active (III0), and stormy (IV0). Participants were also differentiated by age and sex. We found that IOP was lowest on days of level IV0 (stormy) GMA. The drop in IOP concomitant with a decrease in GMA level was more significant during periods of low solar activity and in persons over 65 years of age. There was a trend towards higher IOP values on days of levels II0 and IV0 GMA in years of high solar activity. Differences between the sexes and among individuals younger than 65 years were not significant. Our results show an interesting aspect of environmental influence on the healthy population.

  20. Safety and efficacy of travoprost solution for the treatment of elevated intraocular pressure

    PubMed Central

    Quaranta, Luciano; Riva, Ivano; Katsanos, Andreas; Floriani, Irene; Centofanti, Marco; Konstas, Anastasios G P

    2015-01-01

    Travoprost is a prostaglandin analogue widely used for reducing intraocular pressure (IOP) in patients affected with glaucoma and ocular hypertension. It exerts its ocular hypotensive effect through the prostaglandin FP receptors, located in the ciliary muscle and the trabecular meshwork. Several studies have shown that topical administration of travoprost induces a mean IOP reduction ranging from 25% to 32%, and sustained throughout the 24-hour cycle. When compared with timolol, travoprost is more effective at reducing IOP, while generally no difference has been found in the head-to-head comparison with other prostaglandin analogues. The fixed combination of travoprost and timolol has demonstrated a hypotensive efficacy comparable to the concomitant administration of the two drugs. Recently, a new preservative-free formulation of travoprost 0.004% has been marketed for reducing tolerability-related problems in subjects affected with ocular surface disease. Low rates of topical and systemic adverse reactions, strong ocular hypotensive efficacy, and once-a-day dosing make travoprost a first-line treatment for patients affected with elevated IOP. PMID:25914522

  1. Intraocular pressure, ocular toxicity and neurotoxicity after administration of delta 9-tetrahydrocannabinol or cannabichromene.

    PubMed

    Colasanti, B K; Powell, S R; Craig, C R

    1984-01-01

    delta-9-Tetrahydrocannabinol (delta 9-THC) or cannabichromene, a structurally diverse naturally occurring cannabinoid, was delivered unilaterally to the corneas of cats either acutely by application of single drops or chronically via osmotic minipumps over a period of nine days. While delta 9-THC only reduced intraocular pressure (IOP) minimally after acute administration, this cannabinoid produced substantial reductions in ocular tension during the entire period of chronic administration. Ocular toxicity during chronic treatment, however, was pronounced; conjunctival chemosis, erythema, and hyperemia were sustained, and corneal opacities approximating the site of drug delivery became evident within three to five days. In contrast, cannabichromene did not significantly alter IOP either acutely or during the nine days of chronic administration, and ocular toxicity was not apparent. After systemic administration of delta 9-THC to rats, a dose-related increase in the appearance of 8-13 Hz polyspike discharges became evident in the electrocorticogram during wakefulness and behavioral depression. These polyspikes subsequently reappeared during rapid eye movement (REM) sleep episodes. Cannabichromene was devoid of this effect. These results indicate that, in contrast with acute administration, chronic delivery of delta 9-THC to cat eyes produces substantial reductions in IOP. The tension lowering effect, however, is accompanied by considerable ocular toxicity and neurotoxicity. As cannabichromene lacked these activities, the terpenoid portion of the cannabinoid structure appears to be important for their mediation.

  2. Effects of high-intensity interval vs. continuous moderate exercise on intraocular pressure.

    PubMed

    Conte, M; Baldin, A D; Russo, M R R R; Storti, L R; Caldara, A A; Cozza, H F P; Ciolac, E G

    2014-09-01

    Our purpose was to compare the acute effects of high-intensity interval training (HIT) vs. continuous moderate exercise (CME) on intraocular pressure (IOP) in healthy subjects. Fifteen young men (age=22.1±6 years) underwent 30 min of HIT (2 min of walking at 50% of reserve heart rate (HR) alternated with 1 min of running at 80% of reserve HR) and CME sessions (30 min of jogging/running at 60% of reserve HR) in random order (2-5 days between sessions). IOP was measured before (baseline), immediately after (post--exercise), 5 min after (Rec5) and 10 min after (Rec10) each exercise session. IOP was reduced post-exercise and remained reduced at Rec5 during both HIT and CME session, with no significant difference between interventions (~16% between 23%). However, IOP remained reduced at Rec10 only after HIT intervention (~19%), whereas IOP at Rec10 returned to levels similar to the observed at baseline during CME intervention. In summary, both HIT and CME equally reduced IOP immediately and 5 min after exercise session. However, only HIT was able to remain IOP reduced 10 min after exercise. These results suggest that HIT may be more effective than CME for reducing IOP in young healthy men.

  3. Elevation of intraocular pressure in rodents using viral vectors targeting the trabecular meshwork.

    PubMed

    Pang, Iok-Hou; Millar, J Cameron; Clark, Abbot F

    2015-12-01

    Rodents are increasingly being used as glaucoma models to study ocular hypertension, optic neuropathy, and retinopathy. A number of different techniques are used to elevate intraocular pressure in rodent eyes by artificially obstructing the aqueous outflow pathway. Another successful technique to induce ocular hypertension is to transduce the trabecular meshwork of rodent eyes with viral vectors expressing glaucoma associated transgenes to provide more relevant models of glaucomatous damage to the trabecular meshwork. This technique has been used to validate newly discovered glaucoma pathogenesis pathways as well as to develop rodent models of primary open angle glaucoma. Ocular hypertension has successfully been induced by adenovirus 5 mediated delivery of mutant MYOC, bioactivated TGFβ2, SFRP1, DKK1, GREM1, and CD44. Advantages of this approach are: selective tropism for the trabecular meshwork, the ability to use numerous mouse strains, and the relatively rapid onset of IOP elevation. Disadvantages include mild-to-moderate ocular inflammation induced by the Ad5 vector and sometimes transient transgene expression. Current efforts are focused at discovering less immunogenic viral vectors that have tropism for the trabecular meshwork and drive sufficient transgene expression to induce ocular hypertension. This viral vector approach allows rapid proof of concept studies to study glaucomatous damage to the trabecular meshwork without the expensive and time-consuming generation of transgenic mouse lines.

  4. TRPV4 regulates calcium homeostasis, cytoskeletal remodeling, conventional outflow and intraocular pressure in the mammalian eye

    PubMed Central

    Ryskamp, Daniel A.; Frye, Amber M.; Phuong, Tam T. T.; Yarishkin, Oleg; Jo, Andrew O.; Xu, Yong; Lakk, Monika; Iuso, Anthony; Redmon, Sarah N.; Ambati, Balamurali; Hageman, Gregory; Prestwich, Glenn D.; Torrejon, Karen Y.; Križaj, David

    2016-01-01

    An intractable challenge in glaucoma treatment has been to identify druggable targets within the conventional aqueous humor outflow pathway, which is thought to be regulated/dysregulated by elusive mechanosensitive protein(s). Here, biochemical and functional analyses localized the putative mechanosensitive cation channel TRPV4 to the plasma membrane of primary and immortalized human TM (hTM) cells, and to human and mouse TM tissue. Selective TRPV4 agonists and substrate stretch evoked TRPV4-dependent cation/Ca2+ influx, thickening of F-actin stress fibers and reinforcement of focal adhesion contacts. TRPV4 inhibition enhanced the outflow facility and lowered perfusate pressure in biomimetic TM scaffolds populated with primary hTM cells. Systemic delivery, intraocular injection or topical application of putative TRPV4 antagonist prodrug analogs lowered IOP in glaucomatous mouse eyes and protected retinal neurons from IOP-induced death. Together, these findings indicate that TRPV4 channels function as a critical component of mechanosensitive, Ca2+-signaling machinery within the TM, and that TRPV4-dependent cytoskeletal remodeling regulates TM stiffness and outflow. Thus, TRPV4 is a potential IOP sensor within the conventional outflow pathway and a novel target for treating ocular hypertension. PMID:27510430

  5. INTRAOCULAR PRESSURE IN SOUTHERN ROCKHOPPER (EUDYPTES CHRYSOCOME) AND MACARONI PENGUINS (EUDYPTES CHRYSOLOPHUS): EVALUATION OF INFLUENCING FACTORS.

    PubMed

    Woodhouse, Sarah J; Peterson, Edward L; Schmitt, Todd; Aquino, Susette

    2016-03-01

    Ophthalmic examinations were performed on 160 macaroni penguins (Eudyptes chrysolophus) and 90 southern rockhopper penguins (Eudyptes chrysocome) at eight North American zoos and aquaria. Intraocular pressure (IOP) was measured using rebound tonometry while penguins were held in two different body positions. Correlations between IOP and factors including age, body position, eye pathology, and housing parameters were evaluated. Normal macaroni penguins had a mean IOP of 42.0 ± 9.7 mm Hg. Normal rockhopper penguins had a mean IOP of 32.9 ± 6.2 mm Hg. Neither species had significantly different IOP between sexes or between left and right eyes of the same penguin. In both species, there was a negative linear correlation between age and IOP. In the macaroni population, IOP was significantly higher when IOP measurement was performed before ophthalmic exam; this was not true in rockhoppers. In both species, IOP measured in a horizontal body position was significantly higher than IOP measured in a vertical body position. In both species, eyes with corneal lesions had significantly lower IOP than normal eyes. In the macaroni penguin, eyes with rubeosis iridis had significantly lower IOP than normal eyes. In macaroni penguins, eyes with cataracts had significantly lower mean IOP than normal eyes; this was not true for rockhoppers.

  6. Intraocular Pressure, Tear Production, and Ocular Echobiometry in Guinea Pigs (Cavia porcellus)

    PubMed Central

    Rajaei, Seyed Mehdi; Mood, Maneli Ansari; Sadjadi, Reza; Azizi, Farzaneh

    2016-01-01

    The purpose of this study was to evaluate intraocular pressure (IOP) by means of rebound tonometry, to assess tear production by using the endodontic absorbent paper point tear test (EAPTT) and phenol red thread test (PRTT), and to determine the effects of time of day on IOP and tear production in guinea pigs. The study population comprised 24 healthy adult guinea pigs (12 male, 12 female; 48 eyes) of different breeds and ranging in age from 12 to 15 mo. IOP and tear production were measured at 3 time points (0700, 1500, and 2300) during a 24-h period. Overall values (mean ± 1 SD) were: IOP, 6.81 ± 1.41 mm Hg (range, 4.83 to 8.50); PRTT, 14.33 ± 1.35 mm (range, 12.50 to 16.83); and EAPTT, 8.54 ± 1.08 mm (range, 7.17 to 10.0 mm). In addition, ultrasound biometry was performed by using a B-mode system with linear 8-MHz transducer. This study reports reference values for IOP and tear production in guinea pigs. PMID:27423156

  7. Long-term Reliability of Diurnal Intraocular Pressure Patterns in Healthy Asians

    PubMed Central

    Chun, Yeoun Sook; Park, In Ki; Shin, Ko Un

    2017-01-01

    Purpose To determine the long-term repeatability of diurnal intraocular pressure (IOP) patterns in healthy Asian subjects without glaucoma. Methods Twenty-three eyes in 23 healthy Asian subjects without glaucoma underwent diurnal IOP measurements using Goldmann applanation tonometry every 2 hours from 9 AM to 11 PM during two visits that were 8 weeks apart. To validate repeatability between visits, we calculated intra-class correlation coefficients (ICCs) mean IOP, peak IOP, minimum IOP, and IOP fluctuation at each time point and expressed the results as the difference between peak IOP and minimum IOP or as the standard deviation of all diurnal IOP values in the diurnal IOP curve. Results IOP repeatability was excellent at all time points, with ICCs ranging from 0.812 to 0.946 (p < 0.001). The 9 AM IOP showed the best repeatability between visits (ICCs, 0.946). Repeatability of mean IOP, peak IOP, and minimum IOP was also excellent (ICCs ranging from 0.899 to 0.929). However, IOP fluctuations showed poor repeatability, with an ICC lower than 0.15. Conclusions Long-term repeatability of diurnal IOP patterns in healthy Asian subjects was excellent. These findings suggest that IOP measurements at standardized times of the day will be useful for assessing the effectiveness of glaucoma therapy. PMID:28367041

  8. Modeling glaucoma in rats by sclerosing aqueous outflow pathways to elevate intraocular pressure

    PubMed Central

    Morrison, John C.; Cepurna, William O.; Johnson, Elaine C.

    2015-01-01

    Injection of hypertonic saline via episcleral veins toward the limbus in laboratory rats can produce elevated intraocular pressure (IOP) by sclerosis of aqueous humor outflow pathways. This article describes important anatomic characteristics of the rat optic nerve head (ONH) that make it an attractive animal model for human glaucoma, along with the anatomy of rat aqueous humor outflow on which this technique is based. The injection technique itself is also described, with the aid of a supplemental movie, including necessary equipment and specific tips to acquire this skill. Outcomes of a successful injection are presented, including IOP elevation and patterns of optic nerve injury. These concepts are then specifically considered in light of the use of this model to assess potential neuroprotective therapies. Advantages of the hypertonic saline model include a delayed and relatively gradual IOP elevation, likely reproduction of scleral and ONH stresses and strains that may be important in producing axonal injury, and its ability to be applied to any rat (and potentially mouse) strain, leaving the unmanipulated fellow eye as an internal control. Challenges include the demanding surgical skill required by the technique itself, a wide range of IOP response, and mild corneal clouding in some animals. However, meticulous application of the principles detailed in this article and practice will allow most researchers to attain this useful skill for studying cellular events of glaucomatous optic nerve damage. PMID:26003399

  9. The Application of a Contact Lens Sensor in Detecting 24-Hour Intraocular Pressure-Related Patterns

    PubMed Central

    2016-01-01

    Glaucoma is one of the leading causes of blindness worldwide. Recent studies suggest that intraocular pressure (IOP) fluctuations, peaks, and rhythm are important factors in disease advancement. Yet, current glaucoma management remains hinged on single IOP measurements during clinic hours. To overcome this limitation, 24-hour IOP monitoring devices have been employed and include self-tonometry, permanent IOP, and temporary IOP monitoring. This review discusses each IOP measuring strategy and focuses on the recently FDA-approved contact lens sensor (CLS). The CLS records IOP-related ocular patterns for 24 hours continuously. Using the CLS, IOP-related parameters have been found to be associated with the rate of visual field progression in primary open-angle glaucoma, disease progression in primary angle-closure glaucoma, and various clinical variables in ocular hypertension. The CLS has been used to quantify blink rate and limbal strain and measure the circadian rhythm in a variety of disease states including normal-tension glaucoma and thyroid eye disease. The effects of various IOP-lowering interventions were also characterized using the CLS. CLS provides a unique, safe, and well-tolerated way to study IOP-related patterns in a wide range of disease states. IOP-related patterns may help identify patients most at risk for disease progression and assist with the development of tailored treatments. PMID:27525110

  10. Revealing anisotropic properties of cornea at different intraocular pressures using optical coherence elastography

    NASA Astrophysics Data System (ADS)

    Li, Jiasong; Singh, Manmohan; Han, Zhaolong; Wu, Chen; Nair, Achuth; Aglyamov, Salavat R.; Twa, Michael D.; Larin, Kirill V.

    2016-03-01

    In this study we have evaluated the elastic anisotropy of porcine corneas with increasing intraocular pressures (IOPs) using a noncontact optical coherence elastography (OCE) technique. A focused air-pulse induced low amplitude (<=10 μm) elastic waves in fresh porcine corneas (n=9) in situ in the whole eye-globe configuration. A phase-stabilized swept source optical coherence elastography (PhS-SSOCE) system imaged the propagation of the elastic wave in different stepped radial directions. A closed-loop feedback system was utilized to artificially manipulate the IOP, and OCE measurements were repeated while the IOP was increased in 5 mmHg increments from 15 to 30 mmHg. The OCE measurements demonstrated that the elastic anisotropy of the cornea became more pronounced at higher IOPs, and that there were distinct radial angles of higher and lower stiffness. The presented noncontact OCE method was capable of detecting and assessing the corneal elastic anisotropy as a function of IOP. Due to the noninvasive nature and small amplitude of the elastic wave, this method may be able to provide additional information about corneal health and integrity in vivo.

  11. Determination of Tear Production and Intraocular Pressure With Rebound Tonometry in Wild Humboldt Penguins ( Spheniscus humboldti ).

    PubMed

    Sheldon, Julie D; Adkesson, Michael J; Allender, Matthew C; Jankowski, Gwen; Langan, Jennifer; Cardeña, Marco; Cárdenas-Alayza, Susana

    2017-03-01

    Tear production and intraocular pressures (IOPs) were determined in 38 and 102 wild Humboldt penguins (Spheniscus humboldti), respectively, from the Punta San Juan Marine Protected Area in Ica, Peru. Tear production was measured by Schirmer tear test, and IOP was measured with a TonoVet rebound tonometer. Adult (n = 90) and chick (n = 12) penguins were sampled from 2 different beaches (north and south facing) during 2 sampling years (2010 and 2011). Results showed a mean ± SD (range) of 9 ± 4 (2-20) mm/min for tear production and 28 ± 9 (3-49) mm Hg for IOP. Tear production in penguins differed between beach and sex, whereas IOP differed between age, year, and beach. The IOPs were negatively correlated with packed cell volume. Tear production and IOP values had greater variation in this population than it has in other avian species. Previous investigations of IOP and tear production in Spheniscus species were conducted with birds housed under professional care in artificial marine and freshwater environments. This is the first study, to our knowledge, investigating tear production and IOP in wild penguins and establishes valuable reference intervals for this species.

  12. Effects of the new ethacrynic acid derivative SA9000 on intraocular pressure in cats and monkeys.

    PubMed

    Shimazaki, Atsushi; Ichikawa, Masaki; Rao, Ponugoti Vasantha; Kirihara, Tomoko; Konomi, Kouji; Epstein, David Lee; Hara, Hideaki

    2004-07-01

    To evaluate the pharmacological characteristics of the new ethacrynic acid (ECA) derivative SA9000, we examined its ocular hypotensive effects in cats and cynomolgus monkeys, its corneal toxicity in rabbits, and its binding affinities for forty-three receptors, ion channels, and second messenger systems. A 20 microl injection into the anterior chamber of eye (intracameral injection) of 0.1 mM SA9000 significantly reduced intraocular pressure (IOP) 3.8 mmHg in cats. A 10 microl intracameral injection of 1 mM SA9000 significantly reduced IOP 7 mmHg in living monkeys without evidence of in vivo (or in vitro) toxicity. The ocular hypotensive effect of SA9000 in monkeys was greater than that of ECA. The morphology of corneal endothelial and epithelial cells in rabbit eyes after intracameral injection of SA9000 was observed using electron microphotography. SA9000 at 2 mM did not induce any abnormalities, indicating that it has no corneal toxicity at a concentration higher than the minimum needed for an ocular hypotensive effect (1 mM). SA9000 at 0.01 mM showed negligible binding affinity for, or inhibition of, forty-three different receptors, ion channel proteins, and second messenger systems. These findings indicate that SA9000 has the potential to be both effective and safe as an ocular hypotensive drug, although the mechanism of action remains unclear.

  13. The Effect of Altitude on Intraocular Pressure in Vitrectomized Eyes with Sulfur Hexafluoride Tamponade by the Friedenwald Method: Rabbit Animal Model.

    PubMed

    Fromow-Guerra, Jans; Solís-Vivanco, Adriana; Velez-Montoya, Raul; Perez-Reguera, Adriana; Quiroz-Mercado, Hugo; Meza-de Regil, Armando; Papa-Oliva, Gabriela; Morales-Cantón, Virgilio

    2016-01-01

    The aim of this study is to assess the change in intraocular pressure after a road trip, in eyes with different levels of filling with gas tamponade. Five rabbit eyes were subject to pars plana vitrectomy and gas tamponade (filling percentage: 25%, 50%, and 100% of nonexpansile SF6, 100% saline solution, and 100% room air). A sixth eye was injected with 0.35 cc of undiluted SF6 without vitrectomy. Guided by global positioning system, they were driven to the highest point of the highway connecting Mexico City with Puebla city and back, stopping every 300 m to assess intraocular pressure. The rabbit's scleral rigidity and estimation for human eyes were done by using the Friedenwald nomogram. Maximum altitude was 3209 m (Δ949 m). There were significant differences in intraocular pressure on the rabbit eyes filled with SF6 at 100%, 50%, 25%, and 100% room air. Per every 100 m of altitude rise, the intraocular pressure increased by 1.53, 1.0046, 0.971, and 0.97 mmHg, respectively. Using the human Friedenwald rigidity coefficient, the human eye estimate for intraocular pressure change was 2.1, 1.8, 1.4, and 1.1 mmHg per every 100 m of attitude rise. Altitude changes have a significant impact on intraocular pressure. The final effect depends on the percentage of vitreous cavity fill and scleral rigidity.

  14. The Effect of Altitude on Intraocular Pressure in Vitrectomized Eyes with Sulfur Hexafluoride Tamponade by the Friedenwald Method: Rabbit Animal Model

    PubMed Central

    Fromow-Guerra, Jans; Solís-Vivanco, Adriana; Perez-Reguera, Adriana; Quiroz-Mercado, Hugo; Meza-de Regil, Armando; Papa-Oliva, Gabriela; Morales-Cantón, Virgilio

    2016-01-01

    The aim of this study is to assess the change in intraocular pressure after a road trip, in eyes with different levels of filling with gas tamponade. Five rabbit eyes were subject to pars plana vitrectomy and gas tamponade (filling percentage: 25%, 50%, and 100% of nonexpansile SF6, 100% saline solution, and 100% room air). A sixth eye was injected with 0.35 cc of undiluted SF6 without vitrectomy. Guided by global positioning system, they were driven to the highest point of the highway connecting Mexico City with Puebla city and back, stopping every 300 m to assess intraocular pressure. The rabbit's scleral rigidity and estimation for human eyes were done by using the Friedenwald nomogram. Maximum altitude was 3209 m (Δ949 m). There were significant differences in intraocular pressure on the rabbit eyes filled with SF6 at 100%, 50%, 25%, and 100% room air. Per every 100 m of altitude rise, the intraocular pressure increased by 1.53, 1.0046, 0.971, and 0.97 mmHg, respectively. Using the human Friedenwald rigidity coefficient, the human eye estimate for intraocular pressure change was 2.1, 1.8, 1.4, and 1.1 mmHg per every 100 m of attitude rise. Altitude changes have a significant impact on intraocular pressure. The final effect depends on the percentage of vitreous cavity fill and scleral rigidity. PMID:27957500

  15. Allometry and Scaling of the Intraocular Pressure and Aqueous Humour Flow Rate in Vertebrate Eyes

    PubMed Central

    Zouache, Moussa A.; Eames, Ian; Samsudin, Amir

    2016-01-01

    In vertebrates, intraocular pressure (IOP) is required to maintain the eye into a shape allowing it to function as an optical instrument. It is sustained by the balance between the production of aqueous humour by the ciliary body and the resistance to its outflow from the eye. Dysregulation of the IOP is often pathological to vision. High IOP may lead to glaucoma, which is in man the second most prevalent cause of blindness. Here, we examine the importance of the IOP and rate of formation of aqueous humour in the development of vertebrate eyes by performing allometric and scaling analyses of the forces acting on the eye during head movement and the energy demands of the cornea, and testing the predictions of the models against a list of measurements in vertebrates collated through a systematic review. We show that the IOP has a weak dependence on body mass, and that in order to maintain the focal length of the eye, it needs to be an order of magnitude greater than the pressure drop across the eye resulting from gravity or head movement. This constitutes an evolutionary constraint that is common to all vertebrates. In animals with cornea-based optics, this constraint also represents a condition to maintain visual acuity. Estimated IOPs were found to increase with the evolution of terrestrial animals. The rate of formation of aqueous humour was found to be adjusted to the metabolic requirements of the cornea, scaling as Vac0.67, where Vac is the volume of the anterior chamber. The present work highlights an interdependence between IOP and aqueous flow rate crucial to ocular function that must be considered to understand the evolution of the dioptric apparatus. It should also be taken into consideration in the prevention and treatment of glaucoma. PMID:26990431

  16. The relation between intraocular pressure change and plasma natriuretic peptide under simulated hypobaric conditions

    PubMed Central

    Karadag, Remzi; Sen, Ahmet; Yildirim, Nilgun; Basmak, Hikmet; Golemez, Haydar; Cakir, Erdinc; Akin, Ahmet

    2010-01-01

    Purpose: To ascertain whether the changes in intraocular pressure (IOP) that occur during hypobaric hypoxic exposure are related to plasma N-terminal pro-brain natriuretic peptide (BNP) levels. Materials and Methods: The study group comprised 26 healthy participants (all male, mean age 23.1 years). IOP was measured at local ground level, (792 m above sea level), then while in a chamber providing hypobaric hypoxic conditions (the subjects were exposed to a pressure equivalent to 9144 m for 1-3 min), and again after exit from the chamber. In each condition, the mean of three consecutive measurements of IOP was calculated for each eye. For BNP measurements, blood samples were drawn before the participants entered the chamber and just after they left the chamber. Results: IOP during hypobaric hypoxic exposure (18.00 ± 3.70 mmHg) was significantly greater than that before (15.66 ± 2.10 mmHg, P < 0.001) or after (16.10 ± 2.63 mmHg, P = 0.001) the exposure. IOP levels before and after the exposure were not significantly different (P = 0.136). Plasma BNP levels measured before and after exposure to hypobaric hypoxic conditions were not significantly different (P = 0.462). Conclusion: Plasma BNP levels did not change after short-term hypobaric hypoxic exposure, while the IOP increased. This increase may have been caused by some other systemic factors. As the hypobaric hypoxic conditions were reversed, IOP decreased to normal levels. PMID:20413920

  17. Allometry and Scaling of the Intraocular Pressure and Aqueous Humour Flow Rate in Vertebrate Eyes.

    PubMed

    Zouache, Moussa A; Eames, Ian; Samsudin, Amir

    2016-01-01

    In vertebrates, intraocular pressure (IOP) is required to maintain the eye into a shape allowing it to function as an optical instrument. It is sustained by the balance between the production of aqueous humour by the ciliary body and the resistance to its outflow from the eye. Dysregulation of the IOP is often pathological to vision. High IOP may lead to glaucoma, which is in man the second most prevalent cause of blindness. Here, we examine the importance of the IOP and rate of formation of aqueous humour in the development of vertebrate eyes by performing allometric and scaling analyses of the forces acting on the eye during head movement and the energy demands of the cornea, and testing the predictions of the models against a list of measurements in vertebrates collated through a systematic review. We show that the IOP has a weak dependence on body mass, and that in order to maintain the focal length of the eye, it needs to be an order of magnitude greater than the pressure drop across the eye resulting from gravity or head movement. This constitutes an evolutionary constraint that is common to all vertebrates. In animals with cornea-based optics, this constraint also represents a condition to maintain visual acuity. Estimated IOPs were found to increase with the evolution of terrestrial animals. The rate of formation of aqueous humour was found to be adjusted to the metabolic requirements of the cornea, scaling as Vac(0.67), where Vac is the volume of the anterior chamber. The present work highlights an interdependence between IOP and aqueous flow rate crucial to ocular function that must be considered to understand the evolution of the dioptric apparatus. It should also be taken into consideration in the prevention and treatment of glaucoma.

  18. Seasonal changes of 24-hour intraocular pressure rhythm in healthy Shanghai population

    PubMed Central

    Cheng, Jingyi; Xiao, Ming; Xu, Huan; Fang, Shaobin; Chen, Xu; Kong, Xiangmei; Sun, Xinghuai

    2016-01-01

    Abstract The aim of the present study was to investigate and compare the 24-hour intraocular pressure (IOP) rhythms in winter and summer in the healthy population of Shanghai, China. This is a cross-sectional study in which 24-hour IOP measurements were taken for all eligible healthy volunteers in winter and summer, respectively, and the temperature, hours of sunlight (sunlight time), and circulatory parameters, including heart rate, systolic blood pressure, and diastolic blood pressure, were also recorded. The 24-hour IOP curves and IOP parameters (mean, peak, trough, and fluctuation of IOP together with the diurnal-to-nocturnal IOP change) in winter and summer were obtained and compared. The magnitude of IOP changes from summer to winter was also calculated. A total of 29 participants (58 eyes), 14 (48.28%) male and 15 (51.72%) female, aged 43.66 ± 12.20 (19–61) years, were considered eligible for this study. Generally, IOP decreased progressively before noon, increased notably in the nocturnal period, and peaked at 12:00 am in winter and at 2:00 am in summer. The pattern of 24-hour IOP in winter and summer was significantly different (P = 0.002). The average IOPs from 4:00 pm to 8:00 am, except for 6:00 am, were significantly higher in winter (P < 0.05). However, no significant differences were shown after adjusting for temperature and/or sunlight time. From summer to winter, the extent of IOP increase was mostly around 0 to 3 mm Hg, and the IOPs increased more significantly in the nocturnal period than in the diurnal period (P = 0.05). The 24-hour IOP rhythms were different in winter and summer, with higher IOP level in winter. Temperature and sunlight time, which are independent of heart rate and blood pressure, affected the 24-hour IOP rhythms in healthy people in Shanghai, China. Further investigations are expected for the rhythm of some endogenous substance secretion and the inner mechanism of regulation of IOP. PMID:27495076

  19. Intraocular pressure variation associated with body length in young American alligators (Alligator mississippiensis).

    PubMed

    Whittaker, C J; Heaton-Jones, T G; Kubilis, P S; Smith, P J; Brooks, D E; Kosarek, C; Mackay, E O; Gelatt, K N

    1995-10-01

    Using an applanation tonometer, 5 replicate intraocular pressure (IOP) measurements were obtained from each eye of 12 young clinically normal, American alligators. Alligator length ranged from 46 to 117 cm, measured from snout to tail tip. All IOP were recorded by a single observer at an ambient temperature of approximately 25 C, and ranged from 5 to 35 mm of Hg. Observer reliability was excellent (intraclass r = 0.93), and IOP did not change over the ordered sequence of 5 replicate measurements/eye. Replicate IOP) measurements were, therefore, averaged in each eye for comparison between eyes of the same alligator. Left and right eve IOP were highly correlated within individual alligators (r = 0.92), whereas the mean within animal difference between left and right eye IOP was not statistically significant (95% confidence interval [CI] for the left eye-right eye mean difference, - 1.9 to 1.3 min of Hg). Mean IOP determined for 5 confirmed females and 3 confirmed males did not differ significantly between the sexes (95% CI for the male-female difference in means, -2.1 to 3.7 mm of Hg). Mean +/- SEM IOP of 23.7 + 2.1 mm of Hg determined for 4 alligators < -50 cm long was significantly (P = 0.009) greater than mean IOP of 11.6 + 0.5 mm of Hg determined for 8 alligators > 50 cm long (95% CI for the difference in means, 8.5 to 15.7 mm of Hg). In young alligators, the relation between body length and IOP appears to be nonlinear, possibly with a negative exponent.

  20. Silencing of P2Y2 receptors reduces intraocular pressure in New Zealand rabbits

    PubMed Central

    Martin-Gil, Alba; de Lara, María Jesús Perez; Crooke, Almudena; Santano, Concepción; Peral, Assumpta; Pintor, Jesus

    2012-01-01

    BACKGROUND AND PURPOSE P2 receptors are involved in the regulation of ocular physiological processes like intraocular pressure (IOP). In the present study, the involvement of P2Y2 receptors in the hypertensive effect of nucleotides was investigated by use of antagonists and of a siRNA designed for the P2Y2 receptor. EXPERIMENTAL APPROACH Agonists of the P2Y2 receptor a as well as P2 antagonists were applied to eyes of New Zealand rabbits, and the changes in IOP were followed for up to 6 h. Cloning of the P2Y2 receptor cDNA was done using a combination of degenerate reverse transcription PCR (RT-PCR) and rapid amplification of cDNA ends (RACE). siRNA was synthesized and tested by immunohistochemistry. KEY RESULTS Single doses of 2-thioUTP, UTP-γ-S and UTP increased IOP. This behaviour was concentration-dependent and partially antagonized by reactive blue 2. Silencing the P2Y2 receptor was observed in the ciliary body by immunohistochemistry labelling, where a reduction in the immunofluorescence was observed. This reduction in the expression of the P2Y2 receptor was concomitant with a reduction in IOP, which was measurable 24 h after treatment with the siRNA, maximal after 2 days, followed by a slow increase towards control values for the following 5 days. Application of the P2Y2 agonists after pretreatment of the animals with this siRNA did not produce any change in IOP. CONCLUSIONS AND IMPLICATIONS P2Y2 receptors increase IOP in New Zealand rabbits. The application of a siRNA for this receptor significantly reduced IOP, suggesting that this technology might be used for the treatment of glaucoma. PMID:21740413

  1. Recurrent symptomatic intraocular pressure spikes during hemodialysis in a patient with unilateral anterior uveitis

    PubMed Central

    2013-01-01

    Background The relationship between intraocular pressure (IOP) changes and hemodialysis has been evaluated for several decades. However, no report on an IOP rise in uveitis patients during hemodialysis has been previously documented. This report describes the case of an uveitis patient with repetitive IOP spikes associated with severe ocular pain during hemodialysis sessions, which resolved after glaucoma filtering surgery. Case presentation A 47-year-old male with diabetes and hypertension had complained of recurrent ocular pain in the left eye during hemodialysis sessions. A slit-lamp examination showed diffuse corneal epithelial edema with several white keratic precipitates and inflammatory cells (Grade 3+) in the anterior chamber of the left eye. No visible neovascularization or synechiae were visible on the iris or angle. Topical glaucoma eye-drops and intravenous mannitol before hemodialysis did not prevent subsequent painful IOP spikes in the left eye. At the end of hemodialysis, IOP averaged ~40 mmHg. After trabeculectomy with mitomycin C in the left eye, his IOP stabilized in the low-teens (range, 10–14 mmHg) and no painful IOP spikes occurred during hemodialysis over the first postoperative year. Conclusion We present a case of recurrent painful IOP spikes during hemodialysis in a patient with unilateral anterior uveitis unresponsive to conventional medical treatment prior to hemodialysis. To our knowledge, this is the first case report of repetitive symptomatic IOP rise during hemodialysis in an uveitic glaucoma patient. This case highlights the importance of the awareness of the possibility that IOP may rise intolerably during hemodialysis in uveitis patients with a compromised outflow facility. PMID:23384186

  2. Extracellular matrix in the trabecular meshwork: Intraocular pressure regulation and dysregulation in glaucoma

    PubMed Central

    Vranka, Janice A.; Kelley, Mary J.; Acott, Ted S.; Keller, Kate E.

    2014-01-01

    The trabecular meshwork (TM) is located in the anterior segment of the eye and is responsible for regulating the outflow of aqueous humor. Increased resistance to aqueous outflow causes intraocular pressure to increase, which is the primary risk factor for glaucoma. TM cells reside on a series of fenestrated beams and sheets through which the aqueous humor flows to exit the anterior chamber via Schlemm’s canal. The outer trabecular cells are phagocytic and are thought to function as a pre-filter. However, most of the outflow resistance is thought to be from the extracellular matrix (ECM) of the juxtacanalicular region, the deepest portion of the TM, and from the inner wall basement membrane of Schlemm’s canal. It is becoming increasingly evident that the extracellular milieu is important in maintaining the integrity of the TM. Not only have ultrastructural changes been observed in the ECM of the TM in glaucoma, and a significant number of mutations in ECM genes are known to be associated with glaucoma, but the stiffness of glaucomatous TM appears to be greater than that of normal tissue. Additionally, TGFβ2 has been found to be elevated in the aqueous humor of glaucoma patients and is assumed to be involved in ECM changes deep with the juxtacanalicular region of the TM. This review summarizes the current literature on trabecular ECM as well as the development and function of the TM. Animal models and organ culture models targeting specific ECM molecules to investigate the mechanisms of glaucoma are described. Finally, the growing number of mutations that have been identified in ECM genes and genes that modulate ECM in humans with glaucoma are documented. PMID:25819459

  3. Clinical factors affecting intraocular pressure change after orbital decompression surgery in thyroid-associated ophthalmopathy

    PubMed Central

    Jeong, Jae Hoon; Lee, Jeong Kyu; Lee, Dong Ik; Chun, Yeoun Sook; Cho, Bo Youn

    2016-01-01

    Objective To report the physiological monitoring of intraocular pressure (IOP) during the postoperative periods after orbital decompression surgery and ascertain the correlation between the clinical factors and IOP changes. Methods The medical records of 113 orbits from 60 patients who underwent orbital decompression surgery were reviewed retrospectively. IOP measurement during the postoperative periods was classified based on the postoperative day: week 1 (1–7 days), month 1 (8–41 days), month 2 (42–70 days), month 3 (71–97 days), month 4 (98–126 days), and final (after 127 days). The mean postoperative follow-up was 286.5 days for orbits with at least 6 months of follow-up. Univariate and multivariate linear regression analyses were performed to assess the correlation between the IOP reduction percentage and clinical factors. Results The mean IOP increased from 16.9 to 18.6 mmHg (10.1%) at postoperative week 1 and decreased to 14.4 mmHg (14.5%) after 2 months. Minimal little changes were observed postoperatively in the IOP after 2 months. Preoperative IOP had a significant positive effect on the reduction percentage both at postoperative week 1 (β=2.51, P=0.001) and after 2 months (β=1.07, P=0.029), and the spherical equivalent showed a positive correlation with the reduction level at postoperative week 1 (β=1.71, P=0.021). Conclusion Surgical decompression caused a significant reduction in the IOP in thyroid-associated orbitopathy, and the amount of reduction was closely related to preoperative IOP; however, it may also cause a transient elevation in the IOP during the early postoperative phase in highly myopic eyes. PMID:26848257

  4. Effects of diurnal variation and anesthetic agents on intraocular pressure in Syrian hamsters (Mesocricetus auratus).

    PubMed

    Rajaei, Seyed Mehdi; Mood, Maneli Ansari; Paryani, Mohammad Reza; Williams, David L

    2017-01-01

    OBJECTIVE To determine effects of diurnal variation and anesthetic agents on intraocular pressure (IOP) in Syrian hamsters (Mesocricetus auratus). ANIMALS 90 healthy adult Syrian hamsters (45 males and 45 females). PROCEDURES IOP was measured with a rebound tonometer. In phase 1, IOP was measured in all hamsters 3 times during a 24-hour period (7 am, 3 pm, and 11 pm). In phase 2, hamsters were assigned to 5 groups (18 animals [9 males and 9 females]/group). Each group received an anesthetic agent or combination of anesthetic agents (ketamine hydrochloride, xylazine hydrochloride, diazepam, ketamine-diazepam [KD], or ketamine-xylazine [KX] groups) administered via the IP route. The IOP was measured before (time 0 [baseline]) and 10, 30, 60, 90, 120, and 150 minutes after administration of drugs. RESULTS Mean ± SD IOP values were 2.58 ± 0.87 mm Hg, 4.46 ± 1.58 mm Hg, and 5.96 ± 1.23 mm Hg at 7 am, 3 pm, and 11 pm, respectively. Mean baseline IOP was 6.25 ± 0.28 mm Hg, 6.12 ± 0.23 mm Hg, 5.75 ± 0.64 mm Hg, 5.12 ± 1.40 mm Hg, and 4.50 ± 1.30 mm Hg for the ketamine, xylazine, diazepam, KD, and KX groups, respectively. A significant decrease in IOP, compared with baseline IOP, was detected in only the KX group at 30, 60, and 90 minutes after drug administration. CONCLUSIONS AND CLINICAL RELEVANCE Maximum IOP in Syrian hamsters was detected at night. The ketamine-xylazine anesthetic combination significantly decreased IOP in Syrian hamsters.

  5. The effect of orbital decompression surgery on refraction and intraocular pressure in patients with thyroid orbitopathy

    PubMed Central

    Norris, J H; Ross, J J; Kazim, M; Selva, D; Malhotra, R

    2012-01-01

    Purpose To investigate the effect of orbital decompression surgery in thyroid orbitopathy (TO) on both refractive status and intraocular pressure (IOP). Patients and methods A prospective, multicentre, consecutive audit of patients undergoing thyroid decompression surgery. Indications for surgery included cosmetically unacceptable proptosis or corneal exposure. Exclusion criteria included the following: previous orbital surgery, glaucoma, corneal disease, steroid use in the preceding 12 months, or an acute optic neuropathy. Automated refraction, keratometry, pachymetry, Hertel exophthalmometry, and IOP were recorded at 1 month pre- and 3 months postoperatively. IOP using the Tono-Pen (mean of three readings) was measured in the primary, upgaze, and downgaze positions. Results Data were collected from 52 orbits of 33 patients (East Grinstead, New York, and Adelaide). There was no significant difference between pre- and postoperative data for sphere, cylinder, or central corneal thickness (CCT). The mean spherical equivalent was −0.43±1.49 D pre-operatively and −0.28±1.52 D postoperatively. The steepest meridian of corneal curvature was 93.1 degrees pre- and 94.2 degrees postoperatively, with no significant difference. Mean IOP significantly decreased when measuring by Goldmann applanation tonometry (GAT) (2.28 mm Hg, * P=0.001) and Tono-Pen (3.06 mm Hg, * P=<0.0001). IOP measured in upgaze was significantly greater than that in the primary position. Regression analysis between change in IOP and either Hertel exophthalmometry or the number of orbital walls decompressed was non-significant (*Student's t-test). Conclusion Patients with TO undergoing orbital decompression had, on average, with-the-rule astigmatism not affected by orbital decompression surgery. IOP was significantly reduced by decompression surgery although no relationship between IOP and the degree of decompression was observed. PMID:22261739

  6. 28-day intraocular pressure reduction with a single dose of brimonidine tartrate-loaded microspheres.

    PubMed

    Fedorchak, Morgan V; Conner, Ian P; Medina, Carlos A; Wingard, Jeremy B; Schuman, Joel S; Little, Steven R

    2014-08-01

    Treatment of glaucoma by intraocular pressure (IOP) reduction is typically accomplished through the administration of eye drops, the difficult and frequent nature of which contributes to extremely low adherence rates. Poor adherence to topical treatment regimens in glaucoma patients can lead to irreversible vision loss and increased treatment costs. Currently there are no approved treatments for glaucoma that address the inherent inefficiencies in drug delivery and patient adherence. Brimonidine tartrate (BT), a common glaucoma medication, requires dosing every 8-12 h, with up to 97% of patients not taking it as prescribed. This study provides proof-of-principle testing of a controlled release BT formulation. BT was encapsulated in poly(lactic-co-glycolic) acid microspheres and drug release was quantified using UV-Vis spectroscopy. For in vivo studies, rabbits were randomized to receive a single subconjunctival injection of blank (no drug) or BT-loaded microspheres or twice daily topical 0.2% BT drops. The microspheres released an average of 2.1 ± 0.37 μg BT/mg microspheres/day in vitro. In vivo, the percent decrease in IOP from baseline was significantly greater in the treated eye for both topical drug and drug-loaded microspheres versus blank microspheres throughout the 4-week study, with no evidence of migration or foreign body response. IOP measurements in the contralateral, untreated eyes also suggested a highly localized effect from the experimental treatment. A treatment designed using the release systems described in this study would represent a vast improvement over the current clinical standard of 56-84 topical doses over 28 days.

  7. Intraocular Pressure Is a Poor Predictor of Hydration Status following Intermittent Exercise in the Heat

    PubMed Central

    Stewart, Ian B.; Dias, Brittany; Borg, David N.; Bach, Aaron J. E.; Feigl, Beatrix; Costello, Joseph T.

    2017-01-01

    Current hydration assessments involve biological fluids that are either compromised in dehydrated individuals or require laboratory equipment, making timely results unfeasible. The eye has been proposed as a potential site to provide a field-based hydration measure. The present study evaluated the efficacy and sensitivity of intraocular pressure (IOP) to assess hydration status. Twelve healthy males undertook two 150 min walking trials in 40°C 20% relative humidity. One trial matched fluid intake to body mass loss (control, CON) and the other had fluid restricted (dehydrated, DEH). IOP (rebound tonometry) and hydration status (nude body mass and serum osmolality) were determined every 30 min. Body mass and serum osmolality were significantly (p < 0.05) different between trials at all-time points following baseline. Body mass losses reached 2.5 ± 0.2% and serum osmolality 299 ± 5 mOsmol.kg−1 in DEH. A significant trial by time interaction was observed for IOP (p = 0.042), indicating that over the duration of the trials IOP declined to a greater extent in the DEH compared with the CON trial. Compared with baseline measurements IOP was reduced during DEH (150 min: −2.7 ± 1.9 mm Hg; p < 0.05) but remained stable in CON (150 min: −0.3 ± 2.4 mm Hg). However, using an IOP value of 13.2 mm Hg to predict a 2% body mass loss resulted in only 57% of the data being correctly classified (sensitivity 55% and specificity 57%). The use of ΔIOP (−2.4 mm Hg) marginally improved the predictive ability with 77% of the data correctly classified (sensitivity: 55%; specificity: 81%). The present study provides evidence that the large inter-individual variability in baseline IOP and in the IOP response to progressive dehydration, prevents the use of IOP as an acute single assessment marker of hydration status. PMID:28203205

  8. Early and Delayed Effect of Functional Endoscopic Sinus Surgery on Intraocular Pressure

    PubMed Central

    El-Anwar, Mohammad Waheed; Abdelhady, Mohammad; Amer, Hazem Saeed; Ghali, Manar A.

    2016-01-01

    Introduction Due to the close anatomical relationship between the paranasal sinuses and the orbit, involvement or injury of the orbit from paranasal sinuses procedures may occur. Objectives We aimed to study the early and delayed effect of endoscopic sinus surgery on intraocular pressure (IOP). Methods We included in the study 38 patients with chronic rhinosinusitis (CRS), undergoing FESS. We performed FESS with the standard anterior to posterior approach. We measured IOP at the same time one day before surgery as well as day 1 and 6 weeks after surgery. Results One day after surgery, mean IOP in the right eye was 14.176 ± 1.91 mm Hg and in the left eye was 13.79 ± 2.42 mm Hg with statistically non-significant difference from preoperative values. Six weeks postoperative, the mean IOP in the right eye was 15.14 ± 2.28 mm Hg. The difference between the mean preoperative and postoperative IOP values was found to be statistically significant (p = 0.0012). While in the left eye, mean postoperative IOP was 15.14 + 2.23mm Hg. The difference between the mean preoperative and postoperative IOP values was also found to be highly statistically significant (p = 0.0005). Conclusion Delayed significant increase in IOP can occur after FESS, Thus, special measures must be taken to reduce IOP to protect the patient́s eye from the risk of increased IOP, especially in patients with glaucoma. PMID:27746840

  9. Relationship between corneal hysteresis and lamina cribrosa displacement after medical reduction of intraocular pressure

    PubMed Central

    Perez-Lopez, Marta; Palacios-Pozo, Elena; Davo-Cabrera, Juan

    2017-01-01

    Purpose To evaluate the relationship between the displacement of the lamina cribrosa (LC) and prelaminar tissue with corneal hysteresis (CH) using spectral-domain coherence tomography (SD-OCT) after reducing intraocular pressure (IOP) with medical treatment. Methods Sixty-one eyes of 61 patients with ocular hypertension or primary open-angle glaucoma who were going to start with treatment were imaged by means of 12 cross-sectional scans of the optic nerve using enhanced depth imaging SD-OCT before and after 1 week of treatment. We used the ‘follow-up’ mode to make sure that all the measurements were performed in the same location. We also measured the CH using an Ocular Response Analyzer, and we related it to the magnitude of displacement of LC and prelaminar tissue and the thickness of both structures. Results There was a significant variation of LC thickness from 132.66±37.40 to 160.09±41.13 µm (p<0001). LC distance was significantly reduced from 258.53±145 µm before treatment to 239.86±135 µm after it. No significant changes were found in the thickness and movement of prelaminar tissue before and after treatment. The only factors related with LC displacement were CH (R2=0.48) and age (R2=0.42). Conclusions A significant increase in LC thickness and a reduction in the posterior displacement of LC but not in the prelaminar tissue were demonstrated after IOP reduction with medical treatment. The factors most related with LC displacement were age and CH. PMID:27474156

  10. Relationship between Corneal Temperature and Intraocular Pressure in Healthy Individuals: A Clinical Thermographic Analysis

    PubMed Central

    Fabiani, Claudia; Li Voti, Roberto; Rusciano, Dario; Mutolo, Maria Giulia; Pescosolido, Nicola

    2016-01-01

    Purpose. To study the geographical distribution of corneal temperature (CT) and its influence on the intraocular pressure (IOP) of healthy human volunteers. Materials and Methods. Fifteen subjects (7 M, 8 F), 33.8 ± 17.4 years old, were enrolled in this pilot, cross-sectional study. Measurements of CT were taken after one hour with closed eyelids (CET) or closed eyelids with a cooling mask (cm-CET) and compared to baseline. Results. If compared to baseline, after CET, average CT significantly increased by 0.56°C in the RE and by 0.48°C in the LE (p < 0.001) and IOP concomitantly significantly increased by 1.13 mmHg and 1.46 mmHg, respectively, in each eye (p < 0.001). After cm-CET, average CT significantly decreased by 0.11°C and 0.20°C, respectively, in the RE and LE (RE p = 0.04; LE p = 0.024), followed by a significant IOP decrease of 2.19 mmHg and 1.54 mmHg, respectively, in each eye (RE p < 0.001; LE p = 0.0019). Conclusion. Significant variations of CT occurred after CET and cm-CET and were directly correlated with significant differences of IOP. It can be speculated that both oxidative stress and sympathetic nerve fiber stimulation by temperature oscillations may affect the regulation of AH vortex flow and turnover, thus influencing IOP values. PMID:26904273

  11. Elevated intraocular pressure decreases response sensitivity of inner retinal neurons in experimental glaucoma mice

    PubMed Central

    Pang, Ji-Jie; Frankfort, Benjamin J.; Gross, Ronald L.; Wu, Samuel M.

    2015-01-01

    Glaucoma is the second leading cause of blindness in the United States and the world, characterized by progressive degeneration of the optic nerve and retinal ganglion cells (RGCs). Glaucoma patients exhibit an early diffuse loss of retinal sensitivity followed by focal loss of RGCs in sectored patterns. Recent evidence has suggested that this early sensitivity loss may be associated with dysfunctions in the inner retina, but detailed cellular and synaptic mechanisms underlying such sensitivity changes are largely unknown. In this study, we use whole-cell voltage-clamp techniques to analyze light responses of individual bipolar cells (BCs), AII amacrine cells (AIIACs), and ON and sustained OFF alpha-ganglion cells (ONαGCs and sOFFαGCs) in dark-adapted mouse retinas with elevated intraocular pressure (IOP). We present evidence showing that elevated IOP suppresses the rod ON BC inputs to AIIACs, resulting in less sensitive AIIACs, which alter AIIAC inputs to ONαGCs via the AIIAC→cone ON BC→ONαGC pathway, resulting in lower ONαGC sensitivity. The altered AIIAC response also reduces sOFFαGC sensitivity via the AIIAC→sOFFαGC chemical synapses. These sensitivity decreases in αGCs and AIIACs were found in mice with elevated IOP for 3–7 wk, a stage when little RGC or optic nerve degeneration was observed. Our finding that elevated IOP alters neuronal function in the inner retina before irreversible structural damage occurs provides useful information for developing new diagnostic tools and treatments for glaucoma in human patients. PMID:25675503

  12. System for Rapid, Precise Modulation of Intraocular Pressure, toward Minimally-Invasive In Vivo Measurement of Intracranial Pressure

    PubMed Central

    Stockslager, Max A.; Samuels, Brian C.; Allingham, R. Rand; Klesmith, Zoe A.; Schwaner, Stephen A.; Forest, Craig R.; Ethier, C. Ross

    2016-01-01

    Pathologic changes in intracranial pressure (ICP) are commonly observed in a variety of medical conditions, including traumatic brain injury, stroke, brain tumors, and glaucoma. However, current ICP measurement techniques are invasive, requiring a lumbar puncture or surgical insertion of a cannula into the cerebrospinal fluid (CSF)-filled ventricles of the brain. A potential alternative approach to ICP measurement leverages the unique anatomy of the central retinal vein, which is exposed to both intraocular pressure (IOP) and ICP as it travels inside the eye and through the optic nerve; manipulating IOP while observing changes in the natural pulsations of the central retinal vein could potentially provide an accurate, indirect measure of ICP. As a step toward implementing this technique, we describe the design, fabrication, and characterization of a system that is capable of manipulating IOP in vivo with <0.1 mmHg resolution and settling times less than 2 seconds. In vitro tests were carried out to characterize system performance. Then, as a proof of concept, we used the system to manipulate IOP in tree shrews (Tupaia belangeri) while video of the retinal vessels was recorded and the caliber of a selected vein was quantified. Modulating IOP using our system elicited a rapid change in the appearance of the retinal vein of interest: IOP was lowered from 10 to 3 mmHg, and retinal vein caliber sharply increased as IOP decreased from 7 to 5 mmHg. Another important feature of this technology is its capability to measure ocular compliance and outflow facility in vivo, as demonstrated in tree shrews. Collectively, these proof-of-concept demonstrations support the utility of this system to manipulate IOP for a variety of useful applications in ocular biomechanics, and provide a framework for further study of the mechanisms of retinal venous pulsation. PMID:26771837

  13. Real-time temperature determination during retinal photocoagulation on patients

    NASA Astrophysics Data System (ADS)

    Brinkmann, Ralf; Koinzer, Stefan; Schlott, Kerstin; Ptaszynski, Lars; Bever, Marco; Baade, Alexander; Luft, Susanne; Miura, Yoko; Roider, Johann; Birngruber, Reginald

    2012-06-01

    The induced thermal damage in retinal photocoagulation depends on the temperature increase and the time of irradiation. The temperature rise is unknown due to intraocular variations in light transmission, scattering and grade of absorption in the retinal pigment epithelium (RPE) and the choroid. Thus, in clinical practice, often stronger and deeper coagulations are applied than therapeutically needed, which can lead to extended neuroretinal damage and strong pain perception. This work focuses on an optoacoustic (OA) method to determine the temperature rise in real-time during photocoagulation by repetitively exciting thermoelastic pressure transients with nanosecond probe laser pulses, which are simultaneously applied to the treatment radiation. The temperature-dependent pressure amplitudes are non-invasively detected at the cornea with an ultrasonic transducer embedded in the contact lens. During clinical treatment, temperature courses as predicted by heat diffusion theory are observed in most cases. For laser spot diameters of 100 and 300 μm, and irradiation times of 100 and 200 ms, respectively, peak temperatures range between 70°C and 85°C for mild coagulations. The obtained data look very promising for the realization of a feedback-controlled treatment, which automatically generates preselected and reproducible coagulation strengths, unburdens the ophthalmologist from manual laser dosage, and minimizes adverse effects and pain for the patient.

  14. Real-time temperature determination during retinal photocoagulation on patients.

    PubMed

    Brinkmann, Ralf; Koinzer, Stefan; Schlott, Kerstin; Ptaszynski, Lars; Bever, Marco; Baade, Alexander; Luft, Susanne; Miura, Yoko; Roider, Johann; Birngruber, Reginald

    2012-06-01

    The induced thermal damage in retinal photocoagulation depends on the temperature increase and the time of irradiation. The temperature rise is unknown due to intraocular variations in light transmission, scattering and grade of absorption in the retinal pigment epithelium (RPE) and the choroid. Thus, in clinical practice, often stronger and deeper coagulations are applied than therapeutically needed, which can lead to extended neuroretinal damage and strong pain perception. This work focuses on an optoacoustic (OA) method to determine the temperature rise in real-time during photocoagulation by repetitively exciting thermoelastic pressure transients with nanosecond probe laser pulses, which are simultaneously applied to the treatment radiation. The temperature-dependent pressure amplitudes are non-invasively detected at the cornea with an ultrasonic transducer embedded in the contact lens. During clinical treatment, temperature courses as predicted by heat diffusion theory are observed in most cases. For laser spot diameters of 100 and 300 μm, and irradiation times of 100 and 200 ms, respectively, peak temperatures range between 70°C and 85°C for mild coagulations. The obtained data look very promising for the realization of a feedback-controlled treatment, which automatically generates preselected and reproducible coagulation strengths, unburdens the ophthalmologist from manual laser dosage, and minimizes adverse effects and pain for the patient.

  15. Regulation of intraocular pressure in mice: structural analysis of dopaminergic and serotonergic systems in response to cabergoline.

    PubMed

    Platania, Chiara Bianca Maria; Leggio, Gian Marco; Drago, Filippo; Salomone, Salvatore; Bucolo, Claudio

    2013-11-01

    Elevated intraocular pressure (IOP) is the main recognized risk factor of glaucoma. To investigate the contribution of dopaminergic and serotonergic systems in IOP regulation, we used cabergoline, a mixed dopamine and serotonin agonist, in C57BL/6J WT and dopamine D₃ receptor knock-out (D₃R⁻/⁻) mice with normal eye pressure or steroid-induced ocular hypertension. Furthermore, we studied the structural basis of the cabergoline-mediated activation of the dopaminergic and serotonergic systems by molecular modeling. Topical application of cabergoline, significantly decreased, in a dose-dependent manner, the intraocular pressure in WT mice, both in an ocular normotensive group (-9, -5 and -2 mmHg with 5%, 1%, and 0.1%, respectively) and an ocular hypertensive group, with a prolonged effect in this latter group. No change of intraocular pressure was observed after topical application of cabergoline in D₃R⁻/⁻ mice. We modeled and optimized, with molecular dynamics, structures of hD₃, h5HT(1A) and h5HT(2A-C) receptors; thereafter we carried out molecular docking of cabergoline. Docking revealed that binding of cabergoline into D₃ and 5HT(1A) receptors is associated with a better desolvation energy in comparison to 5HT(2A-C) binding. In conclusion, the present study support the hypothesis that dopaminergic system is pivotal to regulate IOP and that D₃R represents an intriguing target in the treatment of glaucoma. Furthermore, the structure-based computational approach adopted in this study is able to build and refine structure models of homologous dopaminergic and serotonergic receptors that may be of interest for structure-based drug discovery of ligands, with dopaminergic selectivity or with multi-pharmacological profile, potentially useful to treat optic neuropathies.

  16. The Risk of Intraocular Pressure Elevation in Pediatric Non-infectious Uveitis

    PubMed Central

    Kothari, Srishti; Foster, C. Stephen; Pistilli, Maxwell; Liesegang, Teresa L.; Daniel, Ebenezer; Sen, H. Nida; Suhler, Eric B.; Thorne, Jennifer E.; Jabs, Douglas A.; Levy-Clarke, Grace A.; Nussenblatt, Robert B.; Rosenbaum, James T.; Lawrence, Scott D.; Kempen, John H.

    2015-01-01

    Purpose To characterize the risk and risk factors for intraocular pressure (IOP) elevation in pediatric non-infectious uveitis. Design Multi-center retrospective cohort study. Participants Nine hundred sixteen children (1593 eyes) <18 years old at presentation with non-infectious uveitis followed between January 1978 through December 2007 at five academic uveitis centers in United States. Methods Medical records review by trained, certified experts. Main outcome measures Prevalence and incidence of IOP≥21 and ≥30mmHg and incidence of a rise in IOP by ≥10mmHg. To avoid under ascertainment, outcomes were counted as present when IOP-lowering therapies were in use. Results Initially 251 (15.8%) and 46 eyes (2.9%) had IOP≥21 and ≥30mmHg, respectively. Factors associated with presenting IOP elevation included age 6–12 years (versus other pediatric ages), prior cataract surgery (adjusted odds ratio≥21mmHg [aOR21]=2.42, P=0.01), pars plana vitrectomy (adjusted odds ratio≥30mmHg[aOR30]=11.1, P=0.03), duration of uveitis ≥6 months (aORs30 up to 11.8, P<0.001), contralateral IOP elevation (aOR21=16.9, aOR30=8.29; each P<0.001), visual acuity worse than 20/40 (aORs21 up to 1.73, P=0.02; aORs30 up to 2.81 P=0.03), and topical corticosteroid use (aORs up to 8.92, P<0.001 in a dose-response relationship). The median follow-up was 1.25 years (interquartile range 0.4–3.66). The estimated risk of any observed IOP elevation to ≥21 mmHg, ≥30 mmHg and of a rise in IOP by ≥10mmHg was 33.4%, 14.8% and 24.4% respectively within 2 years. Factors associated with IOP elevation included pars plana vitrectomy (adjusted hazard ratio≥21mmHg[aHR21]=3.36, P<0.001), contralateral IOP elevation (aHRs up to 9.54, P<0.001), the use of topical (aHRs up to 8.77 that followed a dose-response relationship, P<0.001), periocular (aHRs up to 7.96, P<0.001) and intraocular (aHRs up to 19.7, P<0.001) corticosteroids. Conclusions IOP elevation affects a large minority of children

  17. Associations with intraocular pressure across Europe: The European Eye Epidemiology (E(3)) Consortium.

    PubMed

    Khawaja, Anthony P; Springelkamp, Henriët; Creuzot-Garcher, Catherine; Delcourt, Cécile; Hofman, Albert; Höhn, René; Iglesias, Adriana I; Wolfs, Roger C W; Korobelnik, Jean-François; Silva, Rufino; Topouzis, Fotis; Williams, Katie M; Bron, Alain M; Buitendijk, Gabriëlle H S; Cachulo, Maria da Luz; Cougnard-Grégoire, Audrey; Dartigues, Jean-François; Hammond, Christopher J; Pfeiffer, Norbert; Salonikiou, Angeliki; van Duijn, Cornelia M; Vingerling, Johannes R; Luben, Robert N; Mirshahi, Alireza; Lamparter, Julia; Klaver, Caroline C W; Jansonius, Nomdo M; Foster, Paul J

    2016-11-01

    Raised intraocular pressure (IOP) is the most important risk factor for developing glaucoma, the second commonest cause of blindness globally. Understanding associations with IOP and variations in IOP between countries may teach us about mechanisms underlying glaucoma. We examined cross-sectional associations with IOP in 43,500 European adults from 12 cohort studies belonging to the European Eye Epidemiology (E(3)) consortium. Each study conducted multivariable linear regression with IOP as the outcome variable and results were pooled using random effects meta-analysis. The association of standardized study IOP with latitude was tested using meta-regression. Higher IOP was observed in men (0.18 mmHg; 95 % CI 0.06, 0.31; P = 0.004) and with higher body mass index (0.21 mmHg per 5 kg/m(2); 95 % CI 0.14, 0.28; P < 0.001), shorter height (-0.17 mmHg per 10 cm; 95 % CI -0.25, -0.08; P < 0.001), higher systolic blood pressure (0.17 mmHg per 10 mmHg; 95 % CI 0.12, 0.22; P < 0.001) and more myopic refraction (0.06 mmHg per Dioptre; 95 % CI 0.03, 0.09; P < 0.001). An inverted U-shaped trend was observed between age and IOP, with IOP increasing up to the age of 60 and decreasing in participants older than 70 years. We found no significant association between standardized IOP and study location latitude (P = 0.76). Novel findings of our study include the association of lower IOP in taller people and an inverted-U shaped association of IOP with age. We found no evidence of significant variation in IOP across Europe. Despite the limited range of latitude amongst included studies, this finding is in favour of collaborative pooling of data from studies examining environmental and genetic determinants of IOP in Europeans.

  18. Effect of persistent high intraocular pressure on microstructure and hydraulic permeability of trabecular meshwork

    NASA Astrophysics Data System (ADS)

    Mei, Xi; Ren, Lin; Xu, Qiang; Zheng, Wei; Liu, Zhi-Cheng

    2015-05-01

    As the aqueous humor leaves the eye, it first passes through the trabecular meshwork (TM). Increased flow resistance in this region causes elevation of intraocular pressure (IOP), which leads to the occurrence of glaucoma. To quantitatively evaluate the effect of high IOP on the configuration and hydraulic permeability of the TM, second harmonic generation (SHG) microscopy was used to image the microstructures of the TM and adjacent tissues in control (normal) and high IOP conditions. Enucleated rabbit eyes were perfused at a pressure of 60 mmHg to achieve the high IOP. Through the anterior chamber of the eye, in situ images were obtained from different depths beneath the surface of the TM. Porosity and specific surface area of the TM in control and high IOP conditions were then calculated to estimate the effect of the high pressure on the permeability of tissue in different depths. We further photographed the histological sections of the TM and compared the in situ images. The following results were obtained in the control condition, where the region of depth was less than 55 μm with crossed branching beams and large pores in the superficial TM. The deeper meshwork is a silk-like tissue with abundant fluorescence separating the small size of pores. The total thickness of pathway tissues composed of TM and juxtacanalicular (JCT) is more than 100 μm. After putting a high pressure on the inner wall of the eye, the TM region progressively collapses and decreases to be less than 40 μm. Fibers of the TM became dense, and the porosity at 34 μm in the high IOP condition is comparable to that at 105 μm in the control condition. As a consequent result, the permeability of the superficial TM decreases rapidly from 120 μm2 to 49.6 μm2 and that of deeper TM decreases from 1.66 μm2 to 0.57 μm2. Heterogeneity reflected by descent in permeability reduces from 12.4 μm of the control condition to 3.74 μm of the high IOP condition. The persistently high IOP makes the TM

  19. Digoxin derivatives with selectivity for the α2β3 isoform of Na,K-ATPase potently reduce intraocular pressure

    PubMed Central

    Katz, Adriana; Tal, Daniel M.; Heller, Dan; Habeck, Michael; Ben Zeev, Efrat; Rabah, Bilal; Bar Kana, Yaniv; Marcovich, Arie L.; Karlish, Steven J. D.

    2015-01-01

    The ciliary epithelium in the eye consists of pigmented epithelial cells that express the α1β1 isoform of Na,K-ATPase and nonpigmented epithelial cells that express mainly the α2β3 isoform. In principle, a Na,K-ATPase inhibitor with selectivity for α2β3 that penetrates the cornea could effectively reduce intraocular pressure, with minimal systemic or local toxicity. We have recently synthesized perhydro-1,4-oxazepine derivatives of digoxin by NaIO4 oxidation of the third digitoxose and reductive amination with various R-NH2 substituents and identified derivatives with significant selectivity for human α2β1 over α1β1 (up to 7.5-fold). When applied topically, the most α2-selective derivatives effectively prevented or reversed pharmacologically raised intraocular pressure in rabbits. A recent structure of Na,K-ATPase, with bound digoxin, shows the third digitoxose approaching one residue in the β1 subunit, Gln84, suggesting a role for β in digoxin binding. Gln84 in β1 is replaced by Val88 in β3. Assuming that alkyl substituents might interact with β3Val88, we synthesized perhydro-1,4-oxazepine derivatives of digoxin with diverse alkyl substituents. The methylcyclopropyl and cyclobutyl derivatives are strongly selective for α2β3 over α1β1 (22–33-fold respectively), as determined either with purified human isoform proteins or intact bovine nonpigmented epithelium cells. When applied topically on rabbit eyes, these derivatives potently reduce both pharmacologically raised and basal intraocular pressure. The cyclobutyl derivative is more efficient than Latanoprost, the most widely used glaucoma drug. Thus, the conclusion is that α2β3-selective digoxin derivatives effectively penetrate the cornea and inhibit the Na,K-ATPase, hence reducing aqueous humor production. The new digoxin derivatives may have potential for glaucoma drug therapy. PMID:26483500

  20. Digoxin derivatives with selectivity for the α2β3 isoform of Na,K-ATPase potently reduce intraocular pressure.

    PubMed

    Katz, Adriana; Tal, Daniel M; Heller, Dan; Habeck, Michael; Ben Zeev, Efrat; Rabah, Bilal; Bar Kana, Yaniv; Marcovich, Arie L; Karlish, Steven J D

    2015-11-03

    The ciliary epithelium in the eye consists of pigmented epithelial cells that express the α1β1 isoform of Na,K-ATPase and nonpigmented epithelial cells that express mainly the α2β3 isoform. In principle, a Na,K-ATPase inhibitor with selectivity for α2β3 that penetrates the cornea could effectively reduce intraocular pressure, with minimal systemic or local toxicity. We have recently synthesized perhydro-1,4-oxazepine derivatives of digoxin by NaIO4 oxidation of the third digitoxose and reductive amination with various R-NH2 substituents and identified derivatives with significant selectivity for human α2β1 over α1β1 (up to 7.5-fold). When applied topically, the most α2-selective derivatives effectively prevented or reversed pharmacologically raised intraocular pressure in rabbits. A recent structure of Na,K-ATPase, with bound digoxin, shows the third digitoxose approaching one residue in the β1 subunit, Gln84, suggesting a role for β in digoxin binding. Gln84 in β1 is replaced by Val88 in β3. Assuming that alkyl substituents might interact with β3Val88, we synthesized perhydro-1,4-oxazepine derivatives of digoxin with diverse alkyl substituents. The methylcyclopropyl and cyclobutyl derivatives are strongly selective for α2β3 over α1β1 (22-33-fold respectively), as determined either with purified human isoform proteins or intact bovine nonpigmented epithelium cells. When applied topically on rabbit eyes, these derivatives potently reduce both pharmacologically raised and basal intraocular pressure. The cyclobutyl derivative is more efficient than Latanoprost, the most widely used glaucoma drug. Thus, the conclusion is that α2β3-selective digoxin derivatives effectively penetrate the cornea and inhibit the Na,K-ATPase, hence reducing aqueous humor production. The new digoxin derivatives may have potential for glaucoma drug therapy.

  1. Refraction changes during elevation of intraocular pressure by suction cup, their reflection in the pattern visual evoked cortical potential and their compensation.

    PubMed

    Bernd, A; Ulrich, W D; Teubel, H; Rohrwacher, F; Barth, T

    1993-01-01

    Visual evoked cortical potential studies using pattern stimuli with the intraocular pressure raised artificially by the suction cup method have been reported. Possible changes in the refraction of the eye due to the method employed and their influence on the pattern visual evoked cortical potential have not been considered. Changes in the refraction of the eye during artificial intraocular pressure elevation and the influence of such changes on pattern visual evoked cortical potentials were studied. The refraction changes were found to depend on the shape of the suction cup. They could be compensated for by employing properly shaped suction cups and contact lenses. The behavior of amplitude and latency of the pattern visual evoked cortical potential at artificially elevated intraocular pressure with compensation for refraction changes has been studied and found to depend in a characteristic manner on ocular perfusion pressure.

  2. Clinical evaluation of clobetasone butyrate: a comparative study of its effects in postoperative inflammation and on intraocular pressure.

    PubMed Central

    Ramsell, T G; Bartholomew, R S; Walker, S R

    1980-01-01

    Clobetasone butyrate, a new corticosteroid with a high topical activity, has been compared with prednisolone phosphate and a placebo in the treatment of inflammation following cataract extraction. These 2 steroids were more effective in relieving postoperative inflammation than placebo (P less than 0.05), though no obvious clinical differences between the 2 compounds emerged from this investigation. However, a single-blind comparative study against betamethasone phosphate in patients suspected of having steroid-induced glaucoma showed that, while betamethasone phosphate significantly raised intraocular pressure, clobetasone butyrate had only a minimal effect, and this difference was statistically significant (P less than 0.02). PMID:6986899

  3. Monothiocarbamates Strongly Inhibit Carbonic Anhydrases in Vitro and Possess Intraocular Pressure Lowering Activity in an Animal Model of Glaucoma.

    PubMed

    Vullo, Daniela; Durante, Mariaconcetta; Di Leva, Francesco Saverio; Cosconati, Sandro; Masini, Emanuela; Scozzafava, Andrea; Novellino, Ettore; Supuran, Claudiu T; Carta, Fabrizio

    2016-06-23

    A series of monothiocarbamates (MTCs) were prepared from primary/secondary amines and COS as potential carbonic anhydrase (CA, EC 4.2.1.1) inhibitors, using the dithiocarbamates, the xanthates, and the trithiocarbonates as lead compounds. The MTCs effectively inhibited the pharmacologically relevant human (h) hCAs isoforms I, II, IX, and XII in vitro and showed KIs spanning between the low and medium nanomolar range. By means of a computational study, the MTC moiety binding mode on the CAs was explained. Furthermore, a selection of MTCs were evaluated in a normotensive glaucoma rabbit model for their intraocular pressure (IOP) lowering effects and showed interesting activity.

  4. The impact of intraocular pressure on elastic wave velocity estimates in the crystalline lens.

    PubMed

    Park, Suhyun; Yoon, Heechul; Larin, Kirill V; Emelianov, Stanislav Y; Aglyamov, Salavat R

    2016-12-20

    Intraocular pressure (IOP) is believed to influence the mechanical properties of ocular tissues including cornea and sclera. The elastic properties of the crystalline lens have been mainly investigated with regard to presbyopia, the age-related loss of accommodation power of the eye. However, the relationship between the elastic properties of the lens and IOP remains to be established. The objective of this study is to measure the elastic wave velocity, which represents the mechanical properties of tissue, in the crystalline lens ex vivo in response to changes in IOP. The elastic wave velocities in the cornea and lens from seven enucleated bovine globe samples were estimated using ultrasound shear wave elasticity imaging. To generate and then image the elastic wave propagation, an ultrasound imaging system was used to transmit a 600 µs pushing pulse at 4.5 MHz center frequency and to acquire ultrasound tracking frames at 6 kHz frame rate. The pushing beams were separately applied to the cornea and lens. IOP in the eyeballs was varied from 5 to 50 mmHg. The results indicate that while the elastic wave velocity in the cornea increased from 0.96  ±  0.30 m s(-1) to 6.27  ±  0.75 m s(-1) as IOP was elevated from 5 to 50 mmHg, there were insignificant changes in the elastic wave velocity in the crystalline lens with the minimum and the maximum speeds of 1.44  ±  0.27 m s(-1) and 2.03  ±  0.46 m s(-1), respectively. This study shows that ultrasound shear wave elasticity imaging can be used to assess the biomechanical properties of the crystalline lens noninvasively. Also, it was observed that the dependency of the crystalline lens stiffness on the IOP was significantly lower in comparison with that of cornea.

  5. Increased intraocular pressure on the first postoperative day following resident-performed cataract surgery

    PubMed Central

    Kim, J Y; Jo, M-W; Brauner, S C; Ferrufino-Ponce, Z; Ali, R; Cremers, S L; An Henderson, B

    2011-01-01

    Purpose The aim of this study was to investigate the incidence of intraocular pressure (IOP) elevation after resident-performed cataract surgery and to determine variables, which influence postoperative day 1 (POD1) IOP. Methods In all, 1111 consecutive cataract surgeries performed only by training residents between 1 July 2001 and 30 June 2006 were included. Elevated IOP was defined as ≥23 mm Hg. Surgeries were classified according to the presence of POD1-IOP elevation. Fisher's exact test and Student t-test were used to compare both groups. Multivariate analyses using generalized estimating equations were performed to investigate predictor variables associated with POD1-IOP elevation. Results The average preoperative IOP was 16.0±3.2 mm Hg and the average POD1-IOP was 19.3±7.1 mm Hg, reflecting a significant increase in IOP (P<0.001, paired t-test). The incidence of POD1-IOP elevation ≥23 mm Hg was 22.0% (244/1111). Presence of glaucoma and ocular hypertension, higher preoperative IOP, and longer axial length were frequently encountered variables in the POD1-IOP elevation group (all P<0.05). Using a multivariate analysis, presence of glaucoma (P=0.004, OR=2.38; 95% confidence interval (95% CI)=1.31–4.30), presence of ocular hypertension (P=0.003, OR=6.09; 95% CI=1.81–20.47), higher preoperative IOP (P<0.001, OR=3.73; 95% CI=1.92–7.25), and longer axial length (P=0.01, OR=1.15; 95% CI=1.03–1.29) were significant predictive factors for POD1-IOP elevation. Conclusions IOP elevation on the first postoperative day following resident-performed cataract surgery occurred frequently (22.0%). Increased early postoperative IOP was associated with presence of glaucoma and ocular hypertension, higher preoperative IOP, and longer axial length. PMID:21527959

  6. Comparison of Intraocular Pressure Measurements in Healthy Pediatric Patients using Three Types of Tonometers

    PubMed Central

    Eraslan, Muhsin; Çerman, Eren; Sümmen, Sena

    2017-01-01

    Objectives: This study aimed to compare intraocular pressure (IOP) measurements in healthy pediatric patients using three types of tonometers. Materials and Methods: Seventy-eight eyes of 78 patients under the age of 18 who underwent a routine ophthalmologic examination were included in the study. IOP was measured using Tono-Pen (TP) tonometry, Goldmann applanation tonometry (GAT), and non-contact tonometry (NCT), consecutively. IOP was adjusted based on central corneal thickness (CCT). Patients with any ocular disorders other than a limited refractive error were excluded from the study. Results: The study consisted of 46 girls and 32 boys. The mean age was 12.6±2.7 (range: 5-17) years. The mean CCT was 559.3±35.3 µm. The mean refractive error was -0.50±1.70. The mean level of visual acuity was 0.98±0.1 (range: 0.3-1.0) using the Snellen chart. Significant differences were found between the measurement results of each of the three tonometric methods. Mean IOP was 12.1±2.2 mmHg for TP, 15.7±2.5 mmHg for GAT, and 17.1±3.1 mmHg for NCT. The correlations between measurement methods revealed that the highest correlation was between NCT and GAT (p<0.001, r=0.670). The second highest correlation was between NCT and TP (p<0.001, r=0.477). The lowest correlation was between GAT and TP (p<0.001, r=0.403). A positive correlation was found between CCT and each IOP measurement method. Conclusion: In pediatric patients, TP and NCT measurements were found to be positively correlated with GAT measurements. Because TP measurements were lower than GAT measurements and NCT measurements were higher than GAT measurements, patient follow-ups, treatment strategies, and surgery plans must be organized taking these differences into consideration. PMID:28182167

  7. Circadian Patterns of Intraocular Pressure Fluctuation among Normal-Tension Glaucoma Optic Disc Phenotypes

    PubMed Central

    2016-01-01

    Objective To characterize the 24-h habitual-position intraocular pressure (IOP) patterns of optic disc phenotypes (ODPs) in untreated normal-tension glaucoma (NTG) and the relationships between nocturnal IOP elevation and various clinical factors. Design Prospective, cross-sectional, observational study. Methods Eighty-two NTG patients with focal ischemic (FI) ODP and 82 age- and disease severity-matched NTG patients with myopic glaucomatous (MG) ODP were recruited prospectively over 3 years. The IOP was recorded 11 times over a 24-hour (h) period by a single ophthalmologist using a hand-held tonometer (TonoPen®XL). A cosinor model was used to describe the 24-h IOP rhythm. Associations between nocturnal IOP elevation and both ocular and demographic variables were evaluated using the generalized estimating equation (GEE). Results Mean habitual-position IOP was significantly higher during nighttime than daytime in the FI group (16.44 vs. 14.23 mmHg, P < 0.001), but not in the MG group (15.91 vs. 15.70 mmHg, P = 0.82). The FI group also exhibited a significantly higher peak IOP during sleeping hours (P = 0.01) and lower trough IOP during the 24-h period than the MG group (P < 0.01). The MG group showed a significantly higher peak IOP during waking hours than the FI group (P < 0.01). Therefore, 24-h IOP fluctuation range was significantly higher in the FI group than the MG group (P = 0.013). In the FI group, peak habitual-position IOP and the highest frequency of IOP peaks occurred during sleeping hours (12 AM–6 AM). By contrast, IOP peaks in the MG group occurred during morning hours (8 AM–12 PM). The FI group showed an overall nocturnal acrophase in habitual-position IOP, with 45 patients (54.9%) having a nocturnal acrophase; 10 (12.2%), a diurnal acrophase; and 27 (32.9%), no evident acrophase. By contrast, the MG group showed no evident peak in habitual-position IOP, with 9 patients (10.9%) having a nocturnal acrophase; 43 (52.4%), a diurnal acrophase; and 30

  8. The Relationship between Intraocular Pressure and Progressive Retinal Nerve Fiber Layer Loss in Glaucoma

    PubMed Central

    Medeiros, Felipe A.; Alencar, Luciana M.; Zangwill, Linda M.; Sample, Pamela A.; Weinreb, Robert N.

    2010-01-01

    Purpose To evaluate the relationship between intraocular pressure (IOP) and progressive retinal nerve fiber layer (RNFL) loss, as measured by scanning laser polarimetry with enhanced corneal compensation (GDx ECC), in a cohort of glaucoma patients and individuals suspected of having the disease followed over time. Design Observational cohort study. Participants The study included 344 eyes of 204 patients recruited from the Diagnostic Innovations in Glaucoma Study (DIGS). There were 98 eyes (28%) with a diagnosis of glaucoma and 246 (72%) were considered glaucoma suspects at baseline. Methods Images were obtained annually with the GDx ECC scanning laser polarimeter, along with stereophotographs and SAP. The study included a total of 1211 GDx ECC visits with an average of 3.5 visits per eye. Progression was determined by the Guided Progression Analysis software for SAP and by masked assessment of stereophotographs performed by expert graders. Main Outcome Measures Random coefficient models were used to evaluate the relationship between IOP and RNFL thickness measurements over time in progressors and nonprogressors. Models were adjusted for baseline diagnosis and central corneal thickness. Results For all 344 eyes, the overall rate of change for the GDx ECC average thickness at an average IOP of 17 mmHg was −0.25 μm per year (P = 0.002). Each 1-mmHg higher IOP was associated with an additional loss of 0.05 μm per year of RNFL (P = 0.001). Twenty-nine eyes (8%) showed progression on SAP and/or optic disc stereophotographs. These eyes had a significantly higher rate of RNFL change (−0.95μm/year) than nonprogressors (−0.17 μm/year; P = 0.001). For progressors, each 1-mmHg higher IOP was associated with an additional loss of 0.13 μm per year of RNFL. Conclusions Higher levels of IOP during follow-up were significantly related to higher rates of progressive RNFL loss detected by the GDx ECC. These findings suggest that the GDx ECC may be helpful in monitoring

  9. Design of novel melatonin analogs for the reduction of intraocular pressure in normotensive rabbits.

    PubMed

    Alarma-Estrany, Pilar; Guzman-Aranguez, Ana; Huete, Fernando; Peral, Assumpta; Plourde, Robert; Pelaez, Teresa; Yerxa, Benjamin; Pintor, Jesús

    2011-06-01

    Melatonin, the MT(2) melatonin receptor agonist IIK7 [N-butanoyl-2-(2-methoxy-6H-isoindolo[2,1-a]indol-11-yl)ethanamine], and the putative MT(3) melatonin receptor agonist 5-MCA-NAT [5-methoxycarbonylamino-N-acetyltryptamine] have previously been shown to reduce intraocular pressure (IOP) in ocular normotensive rabbits. To gain a better understanding of the structure-activity relationship of compounds that activate MT(2) and MT(3) receptors mediating reductions in IOP, novel melatonin analogs with rationally varied substitutions were synthesized and tested for their effects on IOP in ocular normotensive rabbits (n = 160). All synthesized melatonin analogs reduced IOP. The best-effect lowering IOP was obtained with the analogs INS48848 [methyl-1-methylene-2,3,4,9-tetrahydro-1H-carbazol-6-ylcarbamate], INS48862 [methyl-2-bromo-3-(2-ethanamidoethyl)-1H-indol-5-ylcarbamate], and INS48852 [(E)-N-(2-(5-methoxy-1H-indol-3-yl)ethyl)-3-phenylprop-2-enamide]. These compounds produced dose-dependent decreases in IOP that were maximal at 0.1 mM (total dose of 0.259 μg for INS48848, 0.354 μg for INS48862, and 0.320 μg for INS48852) and 1 mM (total dose of 2.59 μg for INS48848, 3.54 μg for INS48862, and 3.20 μg for INS48852), with maximal reductions of 36.0 ± 4.0, 24.0 ± 1.5, and 30.0 ± 1.5% for INS48848, INS48862, and INS48852, respectively. Studies using melatonin receptor antagonists (luzindole, prazosin, and DH97 [N-pentanoyl-2-benzyltryptamine]) indicated that INS48862 and INS48852 activate preferentially a MT(2) melatonin receptor and suggest that INS48848 may act mainly via a MT(3) receptor. The most effective compounds were also well tolerated in a battery of standard ocular surface irritation studies. The implication of these findings to the design of novel drugs to treat ocular hypertension is discussed.

  10. Optic nerve head and intraocular pressure in the guinea pig eye.

    PubMed

    Ostrin, Lisa A; Wildsoet, Christine F

    2016-05-01

    The guinea pig is becoming an increasingly popular model for studying human myopia, which carries an increased risk of glaucoma. As a step towards understanding this association, this study sought to characterize the normal, developmental intraocular pressure (IOP) profiles, as well as the anatomy of the optic nerve head (ONH) and adjacent sclera of young guinea pigs. IOP was tracked in pigmented guinea pigs up to 3 months of age. One guinea pig was imaged in vivo with OCT and one with a fundus camera. The eyes of pigmented and albino guinea pigs (ages 2 months) were enucleated and sections from the posterior segment, including the ONH and surrounding sclera, processed for histological analyses - either hematoxylin and eosin (H&E) staining of paraffin embedded, sectioned tissue (n = 1), or cryostat sectioned tissue, processed for immunohistochemistry (n = 3), using primary antibodies against collagen types I-V, elastin, fibronectin and glial fibrillary acidic protein (GFAP). Transmission and scanning electron microscopy (TEM, SEM) studies of ONHs were also undertaken (n = 2 & 5 respectively). Mean IOPs ranged from 17.33 to 22.7 mmHg, increasing slightly across the age range studied, and the IOPs of individual animals also exhibited diurnal variations, peaking in the early morning (mean of 25.8, mmHg, ∼9 am), and decreasing across the day. H&E-stained sections showed retinal ganglion cell axons organized into fascicles in the prelaminar and laminar region of the ONHs, with immunostained sections revealing collagen types I, III, IV and V, as well as elastin, GFAP and fibronectin in the ONHs. SEM revealed a well-defined lamina cribrosa (LC), with radially-oriented collagen beams. TEM revealed collagen fibrils surrounding non-myelinated nerve fiber bundles in the LC region, with myelination and decreased collagen posterior to the LC. The adjacent sclera comprised mainly crimped collagen fibers in a crisscross arrangement. Both the sclera and LC were

  11. The impact of intraocular pressure on elastic wave velocity estimates in the crystalline lens

    NASA Astrophysics Data System (ADS)

    Park, Suhyun; Yoon, Heechul; Larin, Kirill V.; Emelianov, Stanislav Y.; Aglyamov, Salavat R.

    2017-02-01

    Intraocular pressure (IOP) is believed to influence the mechanical properties of ocular tissues including cornea and sclera. The elastic properties of the crystalline lens have been mainly investigated with regard to presbyopia, the age-related loss of accommodation power of the eye. However, the relationship between the elastic properties of the lens and IOP remains to be established. The objective of this study is to measure the elastic wave velocity, which represents the mechanical properties of tissue, in the crystalline lens ex vivo in response to changes in IOP. The elastic wave velocities in the cornea and lens from seven enucleated bovine globe samples were estimated using ultrasound shear wave elasticity imaging. To generate and then image the elastic wave propagation, an ultrasound imaging system was used to transmit a 600 µs pushing pulse at 4.5 MHz center frequency and to acquire ultrasound tracking frames at 6 kHz frame rate. The pushing beams were separately applied to the cornea and lens. IOP in the eyeballs was varied from 5 to 50 mmHg. The results indicate that while the elastic wave velocity in the cornea increased from 0.96  ±  0.30 m s-1 to 6.27  ±  0.75 m s-1 as IOP was elevated from 5 to 50 mmHg, there were insignificant changes in the elastic wave velocity in the crystalline lens with the minimum and the maximum speeds of 1.44  ±  0.27 m s-1 and 2.03  ±  0.46 m s-1, respectively. This study shows that ultrasound shear wave elasticity imaging can be used to assess the biomechanical properties of the crystalline lens noninvasively. Also, it was observed that the dependency of the crystalline lens stiffness on the IOP was significantly lower in comparison with that of cornea.

  12. Intraocular Pressure-Lowering Effect of Latanoprost Is Hampered by Defective Cervical Lymphatic Drainage

    PubMed Central

    Kim, Young Kook; Na, Kyeong Ik; Jeoung, Jin Wook; Park, Ki Ho

    2017-01-01

    Purpose To evaluate whether defects in cervical lymphatic drainage influence the intraocular pressure (IOP)-lowering effect of latanoprost in patients with primary open-angle glaucoma (POAG) who have undergone unilateral radical neck dissection (uRND). Methods We enrolled (1) bilateral POAG patients who had started (bilateral) latanoprost (0.005%) monotherapy prior to their uRND and (2) treatment-naïve, bilateral glaucoma suspects (GSs) who had undergone the same surgery. We compared the eyes ipsilateral to the uRND with their fellow eyes in terms of the changes in IOP between the baseline (prior to the uRND) and the follow-up visits (1, 3, and 6 months after the uRND). Results The study involved 22 eyes of 11 POAG patients and 14 eyes of 7 GSs. In the POAG patients, IOP had increased significantly after surgery in the eyes ipsilateral to the uRND (from 14.7±1.4mmHg to 17.1±2.2mmHg; P = 0.007). Interestingly, in the eyes contralateral to the uRND, IOP had not changed significantly after surgery (from 14.2±1.8mmHg to 14.4±2.0mmHg; P = 0.826). In GSs, the eyes ipsilateral to the uRND did not differ significantly from their fellow eyes in terms of post-operative IOP change (ipsilateral value: 0.3±0.5mmHg, fellow eyes: -0.1±0.7mmHg; P = 0.242). Conclusion In the POAG patients, IOP had increased significantly in the eyes ipsilateral to the uRND. However, it had not changed significantly in the eyes contralateral to the surgery or in the eyes of the GSs. These findings suggest that, latanoprost works, at least in part, by enhancing outflow from the aqueous humor via the uveolymphatic pathway. PMID:28081184

  13. Assessment of corneal biomechanical properties and intraocular pressure in myopic spanish healthy population.

    PubMed

    Del Buey, María A; Lavilla, Laura; Ascaso, Francisco J; Lanchares, Elena; Huerva, Valentín; Cristóbal, José A

    2014-01-01

    Purpose. To examine biomechanical parameters of the cornea in myopic eyes and their relationship with the degree of myopia in a western healthy population. Methods. Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann correlated intraocular pressure (IOP), and corneal compensated IOP (IOPcc) were measured using the ocular response analyzer (ORA) in 312 eyes of 177 Spanish subjects aged between 20 and 56 years. Refraction was expressed as spherical equivalent (SE), which ranged from 0 to -16.50 diopters (D) (mean: -3.88 ± 2.90 D). Subjects were divided into four groups according to their refractive status: group 1 or control group: emmetropia (-0.50 ≤ SE < 0.50); group 2: low myopia (-0.75 ≤ SE < 3.00 D); group 3: moderate myopia (-3.00 ≤ SE ≤ -6.00 D); and group 3: high myopia (SE greater than -6.00 D). We analyzed the relationship between corneal biomechanics measured with ORA and SE. Results. CH in the emmetropia, low myopia, moderate myopia, and high myopia groups was 11.13 ± 0.98, 11.49 ± 1.25, 10.52 ± 1.54, and 10.35 ± 1.33 mmHg, respectively. CH in the highly myopic group was significantly lower than that in the emmetropic group (P = 0.07) and low myopic group (P = 0.035); however, there were no differences with the moderate myopic group (P = 0.872). There were no statistically significant differences regarding IOP among the four groups (P > 0.05); nevertheless, IOPcc was significantly higher in the moderately myopic (15.47 ± 2.47 mmHg) and highly myopic (16.14 ± 2.59 mmHg) groups than in the emmetropia (15.15 ± 2.06 mmHg) and low myopia groups (14.53 ± 2.37 mmHg). No correlation between age and the measured parameters was found. CH and IOPcc were weakly but significantly correlated with SE (r = 0.171, P = 0.002 and r = -0.131, P = 0.021, resp.). Conclusions. Present study showed only a very weak, but significant, correlation between CH and refractive error, with CH being lower in both moderately and highly

  14. Sodium Orthovanadate Effect on Outflow Facility and Intraocular Pressure in Live Monkeys

    PubMed Central

    Tan, James C.H.; Kiland, Julie A.; Gonzalez, Jose M.; Gabelt, B’Ann T.; Peters, Donna M.; Kaufman, Paul L.

    2010-01-01

    Sodium orthovanadate (Na3VO4) is reported to reduce IOP by affecting aqueous formation, but whether it also affects outflow facility (OF) is unclear. We tested the effect of Na3VO4 on OF and intraocular pressure (IOP) in live cynomolgus monkeys, and on actin and cell adhesion organization in cultured human trabecular meshwork (HTM) cells. Total OF (n = 12) was measured by 2-level constant pressure perfusion of the monkey anterior chamber (AC) before and after exchange with 1 mM Na3VO4 or vehicle in opposite eyes. Topical 1% Na3VO4 or vehicle only was given twice daily (each 2×20 μL drops) for 4 days to opposite eyes (n = 8), and Goldmann IOP was measured before and hourly after treatment for 6 hours on Days 1 and 4. Filamentous actin and vinculin-containing cell adhesions were examined by epifluorescence microscopy after the cells had been incubated with 1 mM Na3VO4 for 24 hours. A) In monkeys, Na3VO4 increased OF by 29.3 ± 8.8% (mean ± s.e.m.) over the perfusion interval when adjusted for baseline and contralateral eye washout (p = 0.01; n = 12). B) Day 1 baseline IOP was 16.2 ± 1.5 mmHg in treated eyes and 15.9 ± 1.3 mmHg in the contralateral control eyes. Following treatment on Day 1, IOP was no different (p>0.05) between treated eyes and control eyes at any time-point or compared to baseline. Day 4 mean IOP averaged over hours 2–6 was 13.5 ± 0.8 mmHg in treated eyes and 16.1 ± 0.2 mmHg in control eyes. Treated eye IOP was lower than its Day 4 baseline (p<0.005), lower than control eyes for the same Day 4 interval (p = 0.009), and lower than the Day 1 baseline (p = 0.0000). Control eye IOP on Day 4 was not significantly different from baseline on Day 1. C) Incubation of HTM cells with 1 mM Na3VO4 for 24 hours caused a loss of actin stress fibers and vinculin-containing adhesions. Cell retraction and separation was also observed in vanadate-treated cultures. Reformation of actin stress fibers, vinculin-containing adhesions and confluent monolayers

  15. Efficacy of combined cataract extraction and endoscopic cyclophotocoagulation for the reduction of intraocular pressure and medication burden

    PubMed Central

    Roberts, Sammie J.; Mulvahill, Matthew; SooHoo, Jeffrey R.; Pantcheva, Mina B.; Kahook, Malik Y.; Seibold, Leonard K.

    2016-01-01

    AIM To report on the efficacy of combined endoscopic cyclophotocoagulation (ECP) and phacoemulsification cataract extraction (PCE) with intraocular lens placement for reduction of intraocular pressure (IOP) and medication burden in glaucoma. METHODS A retrospective case review of 91 eyes (73 patients) with glaucoma and cataract that underwent combined PCE/ECP surgery was performed. Baseline demographic and ocular characteristics were recorded, as well as intraocular pressure, number of glaucoma medications, and visual acuity postoperatively with 12-month follow-up. Treatment failure was defined as less than 20% reduction in IOP from baseline on two consecutive visits (at 1, 3, 6, or 12mo postoperatively), IOP ≥21 mm Hg or ≤5 mm Hg on two consecutive visits, or additional glaucoma surgery performed within 12mo after PCE/ECP. RESULTS Overall, mean medicated IOP was reduced from 16.65 mm Hg at baseline to 13.38 mm Hg at 12mo (P<0.0001). Mean number of glaucoma medications was reduced from 1.88 medications at baseline to 1.48 medications at 12mo (P=0.0003). At 3mo postoperatively, the success rate was 73.6% (95%CI: 63.3, 81.5), 57.1% at 6mo (95% CI: 46.3, 66.6), and 49.7% at 12mo (95%CI: 38.9, 59.6). Patient demographic characteristics were not associated with treatment success. The only ocular characteristic associated with treatment success was a higher baseline IOP. CONCLUSION Combined PCE/ECP surgery is an effective surgical option for the reduction of IOP and medication burden in glaucoma patients. Patients with higher baseline IOP levels are most likely to benefit from this procedure. PMID:27275423

  16. Real-time flutter identification

    NASA Technical Reports Server (NTRS)

    Roy, R.; Walker, R.

    1985-01-01

    The techniques and a FORTRAN 77 MOdal Parameter IDentification (MOPID) computer program developed for identification of the frequencies and damping ratios of multiple flutter modes in real time are documented. Physically meaningful model parameterization was combined with state of the art recursive identification techniques and applied to the problem of real time flutter mode monitoring. The performance of the algorithm in terms of convergence speed and parameter estimation error is demonstrated for several simulated data cases, and the results of actual flight data analysis from two different vehicles are presented. It is indicated that the algorithm is capable of real time monitoring of aircraft flutter characteristics with a high degree of reliability.

  17. Combined ab interno trabeculotomy and lens extraction: a novel management option for combined uveitic and chronic narrow angle raised intraocular pressure.

    PubMed

    Lin, Siying; Gupta, Bhaskar; Rossiter, Jonathan

    2016-02-01

    Minimally invasive glaucoma surgery is a developing area that has the potential to replace traditional glaucoma surgery, with its known risk profile, but at present there are no randomised controlled data to validate its use. We report on a case where sequential bilateral combined ab interno trabeculotomy and lens extraction surgery was performed on a 45-year-old woman with combined uveitic and chronic narrow angle raised intraocular pressure. Maximal medical management alone could not control the intraocular pressure. At 12-month follow-up, the patient had achieved stable intraocular pressure in both eyes on a combination of topical ocular antiglaucomatous and steroid therapies. This case demonstrates the effectiveness of trabecular meshwork ablation via ab interno trabeculotomy in a case of complex mixed mechanism glaucoma.

  18. Effectiveness of real-time quantitative PCR compare to repeat PCR for the diagnosis of Charcot-Marie-Tooth Type 1A and hereditary neuropathy with liability to pressure palsies.

    PubMed

    Choi, Jong Rak; Lee, Woon Hyoung; Sunwoo, Il Nam; Lee, Eun Kyung; Lee, Chang Hoon; Lim, Jong Baeck

    2005-06-30

    The majority of cases of Charcot-Marie-Tooth type 1A (CMT1A) and of hereditary neuropathy with a liability to pressure palsies (HNPP) are the result of heterozygosity for the duplication or deletion of peripheral myelin protein 22 gene (PMP22) on 17p11.2. Southern blots, pulsed-field gel electrophoresis (PFGE), fluorescence in situ hybridization (FISH) and polymorphic marker analysis are currently used diagnostic methods. But they are time-consuming, labor-intensive and have some significant limitations. We describe a rapid real- time quantitative PCR method for determining gene copy number for the identification of DNA duplication or deletion occurring in CMT1A or HNPP and compare the results obtained with REP-PCR. Six patients with CMT1A and 14 patients with HNPP [confirmed by Repeat (REP)-PCR], and 16 patients with suspicious CMT1A and 13 patients with suspicious HNPP [negative REP-PCR], and 15 normal controls were studied. We performed REP-PCR, which amplified a 3.6 Kb region (including a 1.7Kb recombination hotspot), using specific CMT1A-REP and real-time quantitative PCR on the LightCycler system. Using a comparative threshold cycle (Ct) method and beta -globin as a reference gene, the gene copy number of the PMP22 gene was quantified. The PMP22 duplication ratio ranged from 1.35 to 1.74, and the PMP22 deletion ratio from 0.41 to 0.53. The PMP22 ratio in normal controls ranged from 0.81 to 1.12. All 6 patients with CMT1A and 14 patients with HNPP confirmed by REP-PCR were positive by real-time quantitative PCR. Among the 16 suspicious CMT1A and 13 suspicious HNPP with negative REP-PCR, 2 and 4 samples, respectively, were positive by real-time quantitative PCR. Real-time quantitative PCR is a more sensitive and more accurate method than REP-PCR for the detection of PMP22 duplications or deletions, and it is also faster and easier than currently available methods. Therefore, we believe that the real-time quantitative method is useful for diagnosing CMT1A and

  19. Study of the effect of distance and misalignment between magnetically coupled coils for wireless power transfer in intraocular pressure measurement.

    PubMed

    Rendon-Nava, Adrian E; Díaz-Méndez, J Alejandro; Nino-de-Rivera, Luis; Calleja-Arriaga, Wilfrido; Gil-Carrasco, Felix; Díaz-Alonso, Daniela

    2014-01-01

    An analysis of the effect of distance and alignment between two magnetically coupled coils for wireless power transfer in intraocular pressure measurement is presented. For measurement purposes, a system was fabricated consisting of an external device, which is a Maxwell-Wien bridge circuit variation, in charge of transferring energy to a biomedical implant and reading data from it. The biomedical implant is an RLC tank circuit, encapsulated by a polyimide coating. Power transfer was done by magnetic induction coupling method, by placing one of the inductors of the Maxwell-Wien bridge circuit and the inductor of the implant in close proximity. The Maxwell-Wien bridge circuit was biased with a 10 MHz sinusoidal signal. The analysis presented in this paper proves that wireless transmission of power for intraocular pressure measurement is feasible with the measurement system proposed. In order to have a proper inductive coupling link, special care must be taken when placing the two coils in proximity to avoid misalignment between them.

  20. Real-time software receiver

    NASA Technical Reports Server (NTRS)

    Ledvina, Brent M. (Inventor); Psiaki, Mark L. (Inventor); Powell, Steven P. (Inventor); Kintner, Jr., Paul M. (Inventor)

    2006-01-01

    A real-time software receiver that executes on a general purpose processor. The software receiver includes data acquisition and correlator modules that perform, in place of hardware correlation, baseband mixing and PRN code correlation using bit-wise parallelism.

  1. Real-time software receiver

    NASA Technical Reports Server (NTRS)

    Ledvina, Brent M. (Inventor); Psiaki, Mark L. (Inventor); Powell, Steven P. (Inventor); Kintner, Jr., Paul M. (Inventor)

    2007-01-01

    A real-time software receiver that executes on a general purpose processor. The software receiver includes data acquisition and correlator modules that perform, in place of hardware correlation, baseband mixing and PRN code correlation using bit-wise parallelism.

  2. Real Time Data System (RTDS)

    NASA Technical Reports Server (NTRS)

    Muratore, John F.

    1991-01-01

    Lessons learned from operational real time expert systems are examined. The basic system architecture is discussed. An expert system is any software that performs tasks to a standard that would normally require a human expert. An expert system implies knowledge contained in data rather than code. And an expert system implies the use of heuristics as well as algorithms. The 15 top lessons learned by the operation of a real time data system are presented.

  3. Real-time vision systems

    SciTech Connect

    Johnson, R.; Hernandez, J.E.; Lu, Shin-yee

    1994-11-15

    Many industrial and defence applications require an ability to make instantaneous decisions based on sensor input of a time varying process. Such systems are referred to as `real-time systems` because they process and act on data as it occurs in time. When a vision sensor is used in a real-time system, the processing demands can be quite substantial, with typical data rates of 10-20 million samples per second. A real-time Machine Vision Laboratory (MVL) was established in FY94 to extend our years of experience in developing computer vision algorithms to include the development and implementation of real-time vision systems. The laboratory is equipped with a variety of hardware components, including Datacube image acquisition and processing boards, a Sun workstation, and several different types of CCD cameras, including monochrome and color area cameras and analog and digital line-scan cameras. The equipment is reconfigurable for prototyping different applications. This facility has been used to support several programs at LLNL, including O Division`s Peacemaker and Deadeye Projects as well as the CRADA with the U.S. Textile Industry, CAFE (Computer Aided Fabric Inspection). To date, we have successfully demonstrated several real-time applications: bullet tracking, stereo tracking and ranging, and web inspection. This work has been documented in the ongoing development of a real-time software library.

  4. Effects of morphine-alfaxalone-midazolam premedication, alfaxalone induction and sevoflurane maintenance on intraocular pressure and tear production in dogs.

    PubMed

    Mayordomo-Febrer, A; Rubio, M; Martínez-Gassent, M; López-Murcia, M M

    2017-01-06

    Intraocular pressure (IOP) and tear production are commonly affected by general anaesthesia. It is necessary to have a good control of both to guarantee successful ophthalmic surgery. The purpose of this research was to evaluate if the protocol based on the administration of morphine-alfaxalone-midazolam as premedication, alfaxalone as induction and sevoflurane as maintenance, can induce changes on IOP and Schirmer's tear test (STT-1) in healthy dogs. Twenty-two adult mixed-breed dogs scheduled for an ovariohysterectomy were enrolled for the study. IOP and STT-1 were registered at baseline (T0), 5 minutes (T1), 10 minutes (T2) and 15 minutes (T3) after premedication with a morphine-alfaxalone-midazolam combination; 5 minutes (T4) after induction with alfaxalone and 15 minutes (T5) and 25 minutes (T6) after maintenance with sevoflurane. A one-way analysis of variance was performed to analyse the difference between IOP and STT-1 over time, respectively. The present study shows a slightly statistically significant increase in IOP (P<0.05) after premedication, induction and maintenance that can be associated with this anaesthetic protocol. STT-1 showed a statistically significant reduction during all the procedures (P<0.001). These results should be taken into consideration, especially in dogs with damaged corneas, in those predisposed to glaucoma and in those due to undergo intraocular surgery. Ocular lubrication is necessary if this protocol is used.

  5. Real-Time Optical Monitoring and Simulations of Gas Phase Kinetics in InN Vapor Phase Epitaxy at High Pressure

    NASA Technical Reports Server (NTRS)

    Dietz, Nikolaus; Woods, Vincent; McCall, Sonya D.; Bachmann, Klaus J.

    2003-01-01

    Understanding the kinetics of nucleation and coalescence of heteroepitaxial thin films is a crucial step in controlling a chemical vapor deposition process, since it defines the perfection of the heteroepitaxial film both in terms of extended defect formation and chemical integrity of the interface. The initial nucleation process also defines the film quality during the later stages of film growth. The growth of emerging new materials heterostructures such as InN or In-rich Ga(x)In(1-x)N require deposition methods operating at higher vapor densities due to the high thermal decomposition pressure in these materials. High nitrogen pressure has been demonstrated to suppress thermal decomposition of InN, but has not been applied yet in chemical vapor deposition or etching experiments. Because of the difficulty with maintaining stochiometry at elevated temperature, current knowledge regarding thermodynamic data for InN, e.g., its melting point, temperature-dependent heat capacity, heat and entropy of formation are known with far less accuracy than for InP, InAs and InSb. Also, no information exists regarding the partial pressures of nitrogen and phosphorus along the liquidus surfaces of mixed-anion alloys of InN, of which the InN(x)P(1-x) system is the most interesting option. A miscibility gap is expected for InN(x)P(1-x) pseudobinary solidus compositions, but its extent is not established at this point by experimental studies under near equilibrium conditions. The extension of chemical vapor deposition to elevated pressure is also necessary for retaining stoichiometric single phase surface composition for materials that are characterized by large thermal decomposition pressures at optimum processing temperatures.

  6. Real-time measurements of temperature, pressure and moisture profiles in High-Performance Concrete exposed to high temperatures during neutron radiography imaging

    SciTech Connect

    Toropovs, N.; Lo Monte, F.; Wyrzykowski, M.; Weber, B.; Sahmenko, G.; Vontobel, P.; Felicetti, R.; Lura, P.

    2015-02-15

    High-Performance Concrete (HPC) is particularly prone to explosive spalling when exposed to high temperature. Although the exact causes that lead to spalling are still being debated, moisture transport during heating plays an important role in all proposed mechanisms. In this study, slabs made of high-performance, low water-to-binder ratio mortars with addition of superabsorbent polymers (SAP) and polypropylene fibers (PP) were heated from one side on a temperature-controlled plate up to 550 °C. A combination of measurements was performed simultaneously on the same sample: moisture profiles via neutron radiography, temperature profiles with embedded thermocouples and pore pressure evolution with embedded pressure sensors. Spalling occurred in the sample with SAP, where sharp profiles of moisture and temperature were observed. No spalling occurred when PP-fibers were introduced in addition to SAP. The experimental procedure described here is essential for developing and verifying numerical models and studying measures against fire spalling risk in HPC.

  7. HEVC real-time decoding

    NASA Astrophysics Data System (ADS)

    Bross, Benjamin; Alvarez-Mesa, Mauricio; George, Valeri; Chi, Chi Ching; Mayer, Tobias; Juurlink, Ben; Schierl, Thomas

    2013-09-01

    The new High Efficiency Video Coding Standard (HEVC) was finalized in January 2013. Compared to its predecessor H.264 / MPEG4-AVC, this new international standard is able to reduce the bitrate by 50% for the same subjective video quality. This paper investigates decoder optimizations that are needed to achieve HEVC real-time software decoding on a mobile processor. It is shown that HEVC real-time decoding up to high definition video is feasible using instruction extensions of the processor while decoding 4K ultra high definition video in real-time requires additional parallel processing. For parallel processing, a picture-level parallel approach has been chosen because it is generic and does not require bitstreams with special indication.

  8. Real-time optoacoustic monitoring during thermotherapy

    NASA Astrophysics Data System (ADS)

    Esenaliev, Rinat O.; Larina, Irina V.; Larin, Kirill V.; Motamedi, Massoud

    2000-05-01

    Optoacoustic monitoring of tissue optical properties and speed of sound in real time can provide fast and accurate feedback information during thermotherapy performed with various heating or cooling agents. Amplitude and temporal characteristics of optoacoustic pressure waves are dependent on tissue properties. Detection and measurement of the optoacoustic waves may be used to monitor the extent of tissue hyperthermia, coagulation, or freezing with high resolution and contrast. We studied real-time optoacoustic monitoring of thermal coagulation induced by conductive heating and laser radiation and cryoablation with liquid nitrogen. Q-switched Nd:YAG laser pulses were used as probing radiation to induce optoacoustic waves in tissues. Dramatic changes in optoacoustic signal parameters were detected during tissue freezing and coagulation due to sharp changes in tissue properties. The dimensions of thermally- induced lesions were measured in real time with the optoacoustic technique. Our studies demonstrated that the laser optoacoustic technique is capable of real-time monitoring of tissue coagulation and freezing front with submillimeter spatial resolution. This may allow accurate thermal ablation or cryotherapy of malignant and benign lesions with minimal damage to normal tissues.

  9. Dependable Real-Time Systems

    DTIC Science & Technology

    1991-09-30

    and F. Wang, "On thle Competitiveness of On-Line Real-Time Task Sc~eduling," to appear. Proc. Icai - Time Systemns Symposium, Dec 1991. 6. Biyabaiii, S...Stankovic, and K. Ramrnamritham, "System Support for lRal-’Vi111C Al: A Spring Project Perspective," Workshop on Real-Time .A1, ICAI ., August 198!). 29...Informatics, Computer S,,iety ,f India , t,, aptpear. 41 . Shilh, C. and J. A. Stankovic, "Distributed Deadlock Detection in Ada IRuntinv En vi- ronments," TRI

  10. 5-MCA-NAT does not act through NQO2 to reduce intraocular pressure in New-Zealand white rabbit.

    PubMed

    Alarma-Estrany, Pilar; Crooke, Almudena; Pintor, Jesús

    2009-09-01

    Solid data support the idea that the MT(3) melatonin binding site is an enzyme, quinone reductase 2 (NQO2), rather than a membrane melatonin receptor. However, the melatonin analogue, 5-methoxycarbonylamino-N-acetyltryptamine (5-MCA-NAT), reduces intraocular pressure (IOP) via MT(3) melatonin receptors. Therefore, the aim of this work was to test whether the melatonin binding site, MT(3), is indeed the enzyme NQO2 in New Zealand rabbit eyes. To investigate this, the action of several substrates and inhibitors for NQO2 was compared to 5-MCA-NAT in their ability to modify IOP. Also, the effect of 5-MCA-NAT on IOP produced after NQO2 silencing by means of a siRNA was determinated. Altogether, the results led us to conclude that the in vivo effect of the MT(3) ligand 5-MCA-NAT on IOP is not mediated by the enzyme NQO2, suggesting the existence of another melatonin receptor.

  11. Applanation optical coherence elastography: noncontact measurement of intraocular pressure, corneal biomechanical properties, and corneal geometry with a single instrument

    NASA Astrophysics Data System (ADS)

    Singh, Manmohan; Han, Zhaolong; Nair, Achuth; Schill, Alexander; Twa, Michael D.; Larin, Kirill V.

    2017-02-01

    Current clinical tools provide critical information about ocular health such as intraocular pressure (IOP). However, they lack the ability to quantify tissue material properties, which are potent markers for ocular tissue health and integrity. We describe a single instrument to measure the eye-globe IOP, quantify corneal biomechanical properties, and measure corneal geometry with a technique termed applanation optical coherence elastography (Appl-OCE). An ultrafast OCT system enabled visualization of corneal dynamics during noncontact applanation tonometry and direct measurement of micro air-pulse induced elastic wave propagation. Our preliminary results show that the proposed Appl-OCE system can be used to quantify IOP, corneal biomechanical properties, and corneal geometry, which builds a solid foundation for a unique device that can provide a more complete picture of ocular health.

  12. Real Time Sonic Boom Display

    NASA Technical Reports Server (NTRS)

    Haering, Ed

    2014-01-01

    This presentation will provide general information about sonic boom mitigation technology to the public in order to supply information to potential partners and licensees. The technology is a combination of flight data, atmospheric data and terrain information implemented into a control room real time display for flight planning. This research is currently being performed and as such, any results and conclusions are ongoing.

  13. Lens Position Parameters as Predictors of Intraocular Pressure Reduction After Cataract Surgery in Glaucomatous Versus Nonglaucomatous Eyes

    PubMed Central

    Coh, Paul; Moghimi, Sasan; Chen, Rebecca I.; Hsu, Chi-Hsin; Masís Solano, Marissé; Porco, Travis; Lin, Shan C.

    2016-01-01

    Purpose To evaluate the relationship between lens position parameters and intraocular pressure (IOP) reduction after cataract surgery in patients with primary open-angle glaucoma (POAG) and in nonglaucomatous patients. Methods The main outcomes of this prospective study were percent and absolute IOP change, which were calculated using the preoperative IOP and the IOP 4 months after cataract surgery in POAG and nonglaucomatous eyes. Lens position (LP), defined as anterior chamber depth (ACD) + one-half lens thickness (LT), was assessed preoperatively using parameters from optical biometry. Preoperative IOP, axial length (AL), ACD, LT, relative lens position (RLP), and the ratio of preoperative IOP to ACD (PD ratio) were also evaluated as potential predictors of IOP change. Results Four months postoperatively, the average IOP reduction was 2.80 ± 3.83 mm Hg (15.79%) from the preoperative mean of 14.73 ± 2.89 mm Hg for nonglaucomatous eyes. The average IOP reduction was 2.66 ± 2.07 mm Hg (16.98%) from the preoperative mean of 14.86 ± 2.97 mm Hg for POAG eyes. Preoperative IOP, sex, AL, ACD, PD ratio, and LP predicted IOP change in nonglaucomatous eyes. Preoperative IOP and PD ratio predicted IOP change in POAG eyes. Conclusions Intraocular pressure reduction after phacoemulsification cataract surgery in nonglaucomatous eyes is significantly greater in more anteriorly positioned lenses. Though it did not reach statistical significance in patients with glaucoma, the association of LP with IOP reduction is in the same direction as in nonglaucomatous patients where smaller LP appears to predict greater IOP reduction. Lens position is a simple, easily calculable, accurate, and widely available parameter, which clinicians can potentially utilize in managing glaucoma. PMID:27163773

  14. Mirtogenol® potentiates latanoprost in lowering intraocular pressure and improves ocular blood flow in asymptomatic subjects

    PubMed Central

    Steigerwalt, Robert D; Belcaro, Gianni; Morazzoni, Paolo; Bombardelli, Ezio; Burki, Carolina; Schönlau, Frank

    2010-01-01

    Purpose: The dietary supplement Mirtogenol® was previously shown to lower elevated intraocular pressure (IOP). We here present the effects of this supplement on IOP in comparison as well as in combination with latanoprost eye drops. Methods: Seventy-nine patients with asymptomatic ocular hypertension were randomly assigned to three groups receiving either the supplement, or latanoprost eye drops, or both in combination. Intraocular pressure and retinal blood flow were investigated in monthly intervals over 24 weeks. Results: Mirtogenol alone lowered IOP from baseline 38.1 to 29.0 mmHg after 16 weeks, with little further improvement during the following eight weeks. Latanoprost rapidly lowered IOP from baseline 37.7 to 27.2 mmHg within four weeks, without further effects thereafter. The combination of the supplement and latanoprost lowered IOP from 38.0 to 27.3 mmHg after four weeks, and further decreased IOP to 24.2 mmHg after six weeks. After 24 weeks IOP with the combination treatment (23.0 mmHg) was significantly lower than with latanoprost alone (27.2 mmHg). Mirtogenol and latanoprost individually showed comparable effects for gradually increasing central artery blood flow with treatment duration. Combination treatment showed higher systolic blood flow velocity throughout the trial period. The diastolic blood flow velocity gradually increased with treatment duration in all three groups. From twelve weeks onwards, the diastolic component with combination treatment was higher than with individual treatments. Conclusions: Mirtogenol lowered elevated IOP in patients almost as effectively as latanoprost, however, it takes much longer (24 vs 4 weeks). The combination of both was more effective for lowering IOP and the combination yielded better retinal blood flow. No serious side effects occurred during the study, apart from standard side effects in patients related to Latanoprost. These promising results warrant further research of Mirtogenol with a larger patient

  15. Utility of the Tono-Pen in Measuring Intraocular Pressure in Trinidad: A Cross-sectional Study

    PubMed Central

    Billy, A; David, PE; Mahabir, AK; Seerattan, CP; Street, JM; Walcott, VD; Yarna, RJ; Murray, DC; Maharaj, RG

    2015-01-01

    ABSTRACT Aim: To determine the sensitivity and specificity of the Reichert™ Tono-Pen AVIA® when used by novice medical students in an ethnically diverse population in Trinidad. Subject and Methods: Participants were residents of Trinidad between the ages of 20 and 90 years attending the Ophthalmology Clinic at the Eric Williams Medical Sciences Complex (EWMSC). Intraocular pressure (IOP) was measured using the Goldmann applanation tonometer (the gold standard) for ophthalmology clinic patients as part of their routine care. Intraocular pressure measurements were then taken using the Tono-Pen. Results: One hundred persons participated, consisting of Indo-Trinidadians (55%), Afro-Trinidadians (36%), Mixed (8%) and 1% of Caucasian descent. Fourteen per cent reported a diagnosis of glaucoma with 70.6% of these being of African descent. One hundred and ninety-eight readings of IOP were taken. At a cut-off point of 21 mmHg, there were nine true positives, four false positives, seven false negatives and 178 true negatives. The sensitivity and specificity were found to be 56.3% (95% CI 33.2, 76.9) and 97.8% (95% CI 94.5, 99.1), respectively. The positive predictive value was calculated as 69.2% (95% CI 42.4, 87.3) while the negative predictive value was 96.2% (95% CI 92.4, 98.2). The prevalence of elevated IOP in this population was 8.1% (95% CI 4.8, 13.0). The likelihood ratio of a positive result was calculated to be 25.6 (95% CI 8.6, 73.9). Conclusion: The high specificity and negative predictive value suggests that the Tono-Pen can be used with minimal training, and can prove beneficial at the primary care level in the exclusion of increased IOP in an ethnically diverse high-risk Caribbean population. PMID:26624589

  16. Comparison of intra-ocular pressure changes with liquid or flat applanation interfaces in a femtosecond laser platform

    PubMed Central

    Williams, G. P.; Ang, H. P.; George, B. L.; Liu, Y. C.; Peh, G.; Izquierdo, L.; Tan, D. T.; Mehta, J. S.

    2015-01-01

    Cataract surgery is the most common surgical procedure and femtosecond laser assisted cataract surgery (FLACS) has gained increased popularity. FLACS requires the application of a suction device to stabilize the laser head and focus the laser beam accurately. This may cause a significant escalation in intra-ocular pressure (IOP), which poses potential risks for patients undergoing cataract surgery. In this study we aimed to assess the effect of the Ziemer LDV Z8 femtosecond cataract machine on IOP. We demonstrated through a porcine model that IOP was significantly higher with a flat interface but could be abrogated by reducing surgical compression and vacuum. Pressure was lower with a liquid interface, and further altering angulation of the laser arm could reduce the IOP to 36 mmHg. A pilot series in patients showed comparable pressure rises with the porcine model (30 mmHg). These strategies may improve the safety profile in patients vulnerable to high pressure when employing FLACS with the Ziemer LDV Z8. PMID:26439499

  17. Radiation damping in real time.

    PubMed

    Mendes, A C; Takakura, F I

    2001-11-01

    We study the nonequilibrium dynamics of a charge interacting with its own radiation, which originates the radiation damping. The real-time equation of motion for the charge and the associated Langevin equation is found in classical limit. The equation of motion for the charge allows one to obtain the frequency-dependent coefficient of friction. In the lowest order we find that although the coefficient of static friction vanishes, there is dynamical dissipation represented by a non-Markovian dissipative kernel.

  18. [Real time 3D echocardiography

    NASA Technical Reports Server (NTRS)

    Bauer, F.; Shiota, T.; Thomas, J. D.

    2001-01-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

  19. Real Time Data Analysis Techniques

    NASA Astrophysics Data System (ADS)

    Silberberg, George G.

    1983-03-01

    By the early 1970s, classical photo-optical range instrumentation technology (as a means of gathering weapons' system performance data) had become a costly and inefficient process. Film costs were increasing due to soaring silver prices. Time required to process, read, and produce optical data was becoming unacceptable as a means of supporting weapon system development programs. NWC investigated the feasibility of utilizing Closed Circuit Television (CCTV) technology as an alternative solution for providing optical data. In 1978 a program entitled Metric Video (measurements from video images) was formulated at the Naval Weapons Center, China Lake, California. The purpose of this program was to provide timely data, to reduce the number of operating personnel, and to lower data acquisition costs. Some of the task elements for this program included a near real-time vector miss-distance system, a weapons scoring system, a velocity measuring system, a time-space position system, and a system to replace film cameras for gathering real-time engineering sequential data. These task elements and the development of special hardware and techniques to achieve real-time data will be discussed briefly in this paper.

  20. Effect of elevated intraocular pressure on the thickness changes of cat laminar and prelaminar tissue using optical coherence tomography.

    PubMed

    Zhao, Qiuyun; Qian, Xiuqing; Li, Lin; Sun, Weijian; Huang, Shan; Liu, Zhicheng

    2014-01-01

    The aim of this study was to examine shape the changes of the lamina cribrosa (LC) under different intraocular pressures (IOPs) with different periods. Images of the optic nerve head were obtained using enhanced depth imaging spectral domain optical coherence tomography (EDI SD-OCT). After an initial scan of the IOP at native pressure, subsequent scanning was taken when the IOP values reached 40, 60, 80 and 100 mm Hg. Then scans continued with the IOP maintained at 100 mm Hg for 1 hour, 2 hours, 3 hours and 4 hours. The thicknesses of the LC and prelaminar tissue were measured and the curvature of the LC was calculated. Our study found that as IOP increased, the thicknesses of both LC and prelaminar tissue decreased and the thickness variation of the LC correlated significantly with the increases of IOP when IOP was higher than 60 mm Hg. An exponential function was proposed to express the relationship between IOP and the thickness variations of LC and prelaminar tissue. Creep curves of the LC and prelaminar tissue was also obtained using the Prony model. In conclusion, both the thickness of the prelaminar tissue and LC thinned as the IOP elevated. The thickness of the LC also decreased after 4 hours of constant 100 mm Hg pressure.

  1. Sigma1 recognition sites in rabbit iris-ciliary body: topical sigma1-site agonists lower intraocular pressure.

    PubMed

    Bucolo, C; Campana, G; Di Toro, R; Cacciaguerra, S; Spampinato, S

    1999-06-01

    In this study, we examined the presence of sigma1 and sigma2 sites in the rabbit iris-ciliary body by receptor binding and investigated their effects on intraocular pressure (IOP) in albino rabbits. The iris-ciliary body has binding sites for the sigma1-site agonist [3H](+)-pentazocine (Kd = 4.6 nM; Bmax = 212 fmol/mg protein) and sigma2 sites labeled with [3H]1,3-di-o-tolylguanidine (DTG) (Kd = 8. 2 nM; Bmax = 1120 fmol/mg protein). In competition binding studies, (+)-pentazocine and the sigma antagonist NE-100 displayed high affinity for sigma1 sites (Ki = 2.1 and 2.4 nM, respectively), whereas (+)-N-allylnormetazocine (NANM) was less potent (Ki = 178 nM). Unilateral topical (+)-pentazocine (0.01-0.1%) caused a significant dose-related reduction of IOP in ocular normotensive rabbits and in the alpha-chymotrypsin model of ocular hypertension. (+)-NANM was less potent than (+)-pentazocine. Neither compound altered the IOP of the contralateral eye, and their hypotensive activity was blocked by NE-100 that, by itself, had no effect on IOP. (-)-Pentazocine, (-)-NANM, and DTG had no effect on IOP. DTG prevented the hypotensive effect of (+)-pentazocine, suggesting that it acts as a sigma1-site antagonist. sigma-Site ligands did not affect pupil diameter or cause ocular inflammation. Topical [3H](+)-pentazocine reaches the intraocular tissues within 30 min, and its uptake in the iris-ciliary body and retina was significantly reduced by topical pretreatment with NE-100, as expected for a receptor-specific agent. Reverse-phase HPLC confirmed the presence of intact (+)-pentazocine in iris-ciliary body homogenates. sigma1-Site agonists may offer a novel class of agents potentially effective in the control of ocular hypertension.

  2. Changes in blood pressure and sleep duration in patients with blue light-blocking/yellow-tinted intraocular lens (CHUKYO study).

    PubMed

    Ichikawa, Kazuo

    2014-07-01

    Blood pressure and sleep duration may be influenced by retinal light exposure. Cataracts may exert such an influence by decreasing the transparency of the crystalline lens. A large-scale clinical study was conducted to examine changes in blood pressure and sleep duration after intraocular lens (IOL) implantation during cataract surgery and to investigate how different types of IOL influence the degree of these effects. Using a questionnaire, we collected information, including blood pressure measurement and sleep duration, from 1367 patients (1367 eyes) before IOL implantation, 1 week after IOL implantation and 1 month after IOL implantation. Systolic and diastolic blood pressures were significantly decreased in the total patient group after implantation. The decrease in systolic blood pressure 1 month after implantation was significantly more in patients who received a yellow-tinted IOL than it was in those who received an ultraviolet (UV) light-filtering IOL. The post-implantation sleep duration, including naps, became shorter in patients who had slept too much and became longer in those who had slept too little before IOL implantation. Our observations suggest that a yellow-tinted IOL is better for patients with high blood pressure than a UV light-filtering IOL. Furthermore, the yellow-tinted IOL is as good as the UV light-filtering IOL for improving sleep duration. A pale yellow-tinted IOL is likely to be superior to a moderate yellow-tinted IOL in terms of allowing patients to discriminate different colors. Thus, the pale yellow-tinted IOL appears to be better for patients than the UV light-filtering IOL and the moderate yellow-tinted IOL.

  3. A resonator sensor for measurement of intraocular pressure--evaluation in an in vitro pig-eye model.

    PubMed

    Eklund, A; Bäcklund, T; Lindahl, O A

    2000-08-01

    Intraocular pressure (IOP) measurement is performed routinely at every eye clinic. High IOP, which can be a sign of glaucoma, can lead to degeneration of the retina and can cause blindness. In this study we developed a resonator sensor for IOP measurement based on an oscillator consisting of a piezoelectric element made of lead zirconate titanate, a flat contact piece of nylon and a feedback circuit. The aim of this study was to evaluate the new sensor's ability to determine lOP in an in vitro pig-eye model. Six eyes from four pigs were removed and fixed in agar. They were then pressurized by a saline column (10-35 cm H2O) through a cannula inserted into the vitreous chamber. The IOP was measured with the resonator sensor applied to cornea. An Alcon applanation pneumatonometer and a standard Viggo-Spectramed pressure sensor connected to the saline column were used as references. The IOP as measured with the resonator sensor correlated well with the pressure elicited by the saline column for individual eyes (r = 0.96-0.99, n = 60) and for all eyes (r = 0.92, n = 360). The correlation between the resonance sensor and the pneumatonometer was r = 0.92 (n = 360). The pneumatonometer also showed a good correlation with the saline column (r = 0.98, n = 360). We conclude that our in vitro pig-eye model made it possible to induce reproducible variation in IOP, and measurement of that pressure with the newly developed resonator sensor gave very promising results for development of a clinically applicable IOP tonometer with unique properties.

  4. Pregnenolone sulfate decreases intraocular pressure and changes expression of sigma receptor in a model of chronic ocular hypertension.

    PubMed

    Sun, Xian; Cheng, Fang; Meng, Bo; Yang, Binbin; Song, Wulian; Yuan, Huiping

    2012-06-01

    Sigma receptors are Ca(2+)-sensitive, ligand-operated receptor chaperones at the mitochondrion-associated endoplasmic reticulum membrane. This study describes the effect of the sigma receptor 1 agonist pregnenolone sulfate on intraocular pressure (IOP) and sigma receptor 1 expression in rat retinas after chronic ocular hypertension. Chronic ocular hypertension was induced by occlusion of episcleral veins. Retinal histological sections were obtained to determine inner plexiform layer thickness and the number of cell bodies in the ganglion cell layer. Sigma receptor expression in rat retinas was analyzed by RT-PCR and Western blotting. Cauterization caused IOP to increase >73%, and the pressure was maintained for 2 months. A time-dependent loss of ganglion cells and retinal thickness occurred at elevated IOP. High IOP decreased sigma receptor 1 expression during the first week, but expression was increased at 8 weeks. Injected pregnenolone significantly decreased IOP, prevented ganglion cell loss, protected inner plexiform layer thickness, and increased sigma receptor 1 expression in episcleral vein-cauterized rats. Sigma receptors appear to be neuroprotective and potential targets for glaucoma therapeutics.

  5. A new design and application of bioelastomers for better control of intraocular pressure in a glaucoma drainage device.

    PubMed

    Luong, Quang Minh; Shang, Lei; Ang, Marcus; Kong, Jen Fong; Peng, Yan; Wong, Tina T; Venkatraman, Subbu S

    2014-02-01

    Glaucoma drainage device (GDD) implantation is an effective method of lowering the intraocular pressure (IOP). Commonly used GDDs can be classified into nonvalved and valved. Although a stable IOP is critical, currently available devices often cause extreme IOP fluctuations: nonvalved GDDs suffer from a risk of hypotony (IOP<5 mmHg), whereas valved GDDs have a higher risk ocular hypertensive (IOP>22 mmHg). It is hypothesized that a GDD with a valve designed to open around the time of onset of the hypertensive phase, would minimize IOP fluctuation. Accordingly, a valve fabricated from a biodegradable polymer poly(L-lactide-co-ϵ-caprolactone) (PLC 70/30) is evaluated in vitro and in vivo. The pressure response is compared with its non-degradable counterpart in in vitro studies of IOP. It is also established that in vitro, the biodegradability of the valve is programmed to occur over 12 weeks. In vivo, a steady and low IOP is achieved with the biodegradable valve and the hypertensive phase is significantly attenuated compared with the commercial device. Fibrotic encapsulation of the device is also minimized with the biodegradable valve in vivo.

  6. Real-time flutter analysis

    NASA Technical Reports Server (NTRS)

    Walker, R.; Gupta, N.

    1984-01-01

    The important algorithm issues necessary to achieve a real time flutter monitoring system; namely, the guidelines for choosing appropriate model forms, reduction of the parameter convergence transient, handling multiple modes, the effect of over parameterization, and estimate accuracy predictions, both online and for experiment design are addressed. An approach for efficiently computing continuous-time flutter parameter Cramer-Rao estimate error bounds were developed. This enables a convincing comparison of theoretical and simulation results, as well as offline studies in preparation for a flight test. Theoretical predictions, simulation and flight test results from the NASA Drones for Aerodynamic and Structural Test (DAST) Program are compared.

  7. Real-time streamflow conditions

    USGS Publications Warehouse

    Graczyk, David J.; Gebert, Warren A.

    1996-01-01

    Would you like to know streamflow conditions before you go fishing in Wisconsin or in more distant locations? Real-time streamflow data throughout Wisconsin and the United States are available on the Internet from the U.S. Geological Survey. You can see if the stream you are interested in fishing is high due to recent rain or low because of an extended dry spell. Flow conditions at more than 100 stream-gaging stations located throughout Wisconsin can be viewed by accessing the Wisconsin District Home Page at: http://wwwdwimdn.er.usgs.gov

  8. Real time infrared aerosol analyzer

    DOEpatents

    Johnson, Stanley A.; Reedy, Gerald T.; Kumar, Romesh

    1990-01-01

    Apparatus for analyzing aerosols in essentially real time includes a virtual impactor which separates coarse particles from fine and ultrafine particles in an aerosol sample. The coarse and ultrafine particles are captured in PTFE filters, and the fine particles impact onto an internal light reflection element. The composition and quantity of the particles on the PTFE filter and on the internal reflection element are measured by alternately passing infrared light through the filter and the internal light reflection element, and analyzing the light through infrared spectrophotometry to identify the particles in the sample.

  9. Interactive real time flow simulations

    NASA Technical Reports Server (NTRS)

    Sadrehaghighi, I.; Tiwari, S. N.

    1990-01-01

    An interactive real time flow simulation technique is developed for an unsteady channel flow. A finite-volume algorithm in conjunction with a Runge-Kutta time stepping scheme was developed for two-dimensional Euler equations. A global time step was used to accelerate convergence of steady-state calculations. A raster image generation routine was developed for high speed image transmission which allows the user to have direct interaction with the solution development. In addition to theory and results, the hardware and software requirements are discussed.

  10. Real-time analysis keratometer

    NASA Technical Reports Server (NTRS)

    Adachi, Iwao P. (Inventor); Adachi, Yoshifumi (Inventor); Frazer, Robert E. (Inventor)

    1987-01-01

    A computer assisted keratometer in which a fiducial line pattern reticle illuminated by CW or pulsed laser light is projected on a corneal surface through lenses, a prismoidal beamsplitter quarterwave plate, and objective optics. The reticle surface is curved as a conjugate of an ideal corneal curvature. The fiducial image reflected from the cornea undergoes a polarization shift through the quarterwave plate and beamsplitter whereby the projected and reflected beams are separated and directed orthogonally. The reflected beam fiducial pattern forms a moire pattern with a replica of the first recticle. This moire pattern contains transverse aberration due to differences in curvature between the cornea and the ideal corneal curvature. The moire pattern is analyzed in real time by computer which displays either the CW moire pattern or a pulsed mode analysis of the transverse aberration of the cornea under observation, in real time. With the eye focused on a plurality of fixation points in succession, a survey of the entire corneal topography is made and a contour map or three dimensional plot of the cornea can be made as a computer readout in addition to corneal radius and refractive power analysis.

  11. Autonomous Real Time Requirements Tracing

    NASA Technical Reports Server (NTRS)

    Plattsmier, George I.; Stetson, Howard K.

    2014-01-01

    One of the more challenging aspects of software development is the ability to verify and validate the functional software requirements dictated by the Software Requirements Specification (SRS) and the Software Detail Design (SDD). Insuring the software has achieved the intended requirements is the responsibility of the Software Quality team and the Software Test team. The utilization of Timeliner-TLX(sup TM) Auto-Procedures for relocating ground operations positions to ISS automated on-board operations has begun the transition that would be required for manned deep space missions with minimal crew requirements. This transition also moves the auto-procedures from the procedure realm into the flight software arena and as such the operational requirements and testing will be more structured and rigorous. The autoprocedures would be required to meet NASA software standards as specified in the Software Safety Standard (NASASTD- 8719), the Software Engineering Requirements (NPR 7150), the Software Assurance Standard (NASA-STD-8739) and also the Human Rating Requirements (NPR-8705). The Autonomous Fluid Transfer System (AFTS) test-bed utilizes the Timeliner-TLX(sup TM) Language for development of autonomous command and control software. The Timeliner- TLX(sup TM) system has the unique feature of providing the current line of the statement in execution during real-time execution of the software. The feature of execution line number internal reporting unlocks the capability of monitoring the execution autonomously by use of a companion Timeliner-TLX(sup TM) sequence as the line number reporting is embedded inside the Timeliner-TLX(sup TM) execution engine. This negates I/O processing of this type data as the line number status of executing sequences is built-in as a function reference. This paper will outline the design and capabilities of the AFTS Autonomous Requirements Tracker, which traces and logs SRS requirements as they are being met during real-time execution of the

  12. Autonomous Real Time Requirements Tracing

    NASA Technical Reports Server (NTRS)

    Plattsmier, George; Stetson, Howard

    2014-01-01

    One of the more challenging aspects of software development is the ability to verify and validate the functional software requirements dictated by the Software Requirements Specification (SRS) and the Software Detail Design (SDD). Insuring the software has achieved the intended requirements is the responsibility of the Software Quality team and the Software Test team. The utilization of Timeliner-TLX(sup TM) Auto- Procedures for relocating ground operations positions to ISS automated on-board operations has begun the transition that would be required for manned deep space missions with minimal crew requirements. This transition also moves the auto-procedures from the procedure realm into the flight software arena and as such the operational requirements and testing will be more structured and rigorous. The autoprocedures would be required to meet NASA software standards as specified in the Software Safety Standard (NASASTD- 8719), the Software Engineering Requirements (NPR 7150), the Software Assurance Standard (NASA-STD-8739) and also the Human Rating Requirements (NPR-8705). The Autonomous Fluid Transfer System (AFTS) test-bed utilizes the Timeliner-TLX(sup TM) Language for development of autonomous command and control software. The Timeliner-TLX(sup TM) system has the unique feature of providing the current line of the statement in execution during real-time execution of the software. The feature of execution line number internal reporting unlocks the capability of monitoring the execution autonomously by use of a companion Timeliner-TLX(sup TM) sequence as the line number reporting is embedded inside the Timeliner-TLX(sup TM) execution engine. This negates I/O processing of this type data as the line number status of executing sequences is built-in as a function reference. This paper will outline the design and capabilities of the AFTS Autonomous Requirements Tracker, which traces and logs SRS requirements as they are being met during real-time execution of the

  13. Digoxin derivatives with enhanced selectivity for the α2 isoform of Na,K-ATPase: effects on intraocular pressure in rabbits.

    PubMed

    Katz, Adriana; Tal, Daniel M; Heller, Dan; Haviv, Haim; Rabah, Bilal; Barkana, Yaniv; Marcovich, Arie L; Karlish, Steven J D

    2014-07-25

    In the ciliary epithelium of the eye, the pigmented cells express the α1β1 isoform of Na,K-ATPase, whereas the non-pigmented cells express mainly the α2β3 isoform of Na,K-ATPase. In principle, a Na,K-ATPase inhibitor with selectivity for α2 could effectively reduce intraocular pressure with only minimal local and systemic toxicity. Such an inhibitor could be applied topically provided it was sufficiently permeable via the cornea. Previous experiments with recombinant human α1β1, α2β1, and α3β1 isoforms showed that the classical cardiac glycoside, digoxin, is partially α2-selective and also that the trisdigitoxose moiety is responsible for isoform selectivity. This led to a prediction that modification of the third digitoxose might increase α2 selectivity. A series of perhydro-1,4-oxazepine derivatives of digoxin have been synthesized by periodate oxidation and reductive amination using a variety of R-NH2 substituents. Several derivatives show enhanced selectivity for α2 over α1, close to 8-fold in the best case. Effects of topically applied cardiac glycosides on intraocular pressure in rabbits have been assessed by their ability to either prevent or reverse acute intraocular pressure increases induced by 4-aminopyridine or a selective agonist of the A3 adenosine receptor. Two relatively α2-selective digoxin derivatives efficiently normalize the ocular hypertension, by comparison with digoxin, digoxigenin, or ouabain. This observation is consistent with a major role of α2 in aqueous humor production and suggests that, potentially, α2-selective digoxin derivatives could be of interest as novel drugs for control of intraocular pressure.

  14. Exercise training prevents increased intraocular pressure and sympathetic vascular modulation in an experimental model of metabolic syndrome.

    PubMed

    Castro, E F S; Mostarda, C T; Rodrigues, B; Moraes-Silva, I C; Feriani, D J; De Angelis, K; Irigoyen, M C

    2015-04-01

    The present study aimed to study the effects of exercise training (ET) performed by rats on a 10-week high-fructose diet on metabolic, hemodynamic, and autonomic changes, as well as intraocular pressure (IOP). Male Wistar rats receiving fructose overload in drinking water (100 g/L) were concomitantly trained on a treadmill for 10 weeks (FT group) or kept sedentary (F group), and a control group (C) was kept in normal laboratory conditions. The metabolic evaluation comprised the Lee index, glycemia, and insulin tolerance test (KITT). Arterial pressure (AP) was measured directly, and systolic AP variability was performed to determine peripheral autonomic modulation. ET attenuated impaired metabolic parameters, AP, IOP, and ocular perfusion pressure (OPP) induced by fructose overload (FT vs F). The increase in peripheral sympathetic modulation in F rats, demonstrated by systolic AP variance and low frequency (LF) band (F: 37±2, 6.6±0.3 vs C: 26±3, 3.6±0.5 mmHg2), was prevented by ET (FT: 29±3, 3.4±0.7 mmHg2). Positive correlations were found between the LF band and right IOP (r=0.57, P=0.01) and left IOP (r=0.64, P=0.003). Negative correlations were noted between KITT values and right IOP (r=-0.55, P=0.01) and left IOP (r=-0.62, P=0.005). ET in rats effectively prevented metabolic abnormalities and AP and IOP increases promoted by a high-fructose diet. In addition, ocular benefits triggered by exercise training were associated with peripheral autonomic improvement.

  15. Real-time flood forecasting

    USGS Publications Warehouse

    Lai, C.; Tsay, T.-K.; Chien, C.-H.; Wu, I.-L.

    2009-01-01

    Researchers at the Hydroinformatic Research and Development Team (HIRDT) of the National Taiwan University undertook a project to create a real time flood forecasting model, with an aim to predict the current in the Tamsui River Basin. The model was designed based on deterministic approach with mathematic modeling of complex phenomenon, and specific parameter values operated to produce a discrete result. The project also devised a rainfall-stage model that relates the rate of rainfall upland directly to the change of the state of river, and is further related to another typhoon-rainfall model. The geographic information system (GIS) data, based on precise contour model of the terrain, estimate the regions that were perilous to flooding. The HIRDT, in response to the project's progress, also devoted their application of a deterministic model to unsteady flow of thermodynamics to help predict river authorities issue timely warnings and take other emergency measures.

  16. Intraocular cyclophotocoagulation.

    PubMed

    Shields, M B

    1986-01-01

    Laser energy, as a cyclodestructive source for the treatment of glaucoma, can be delivered by several routes. The transscleral approach has the advantages of being noninvasive and relatively quick and easy, but the disadvantages of unpredictable results and a high complication rate. Transpupillary cyclophotocoagulation has fewer complications, but is only possible in a small number of eyes. The intraocular intraocular route is a newer technique, which utilises endophotocoagulation through a pars plana incision to treat ciliary processes in aphakic eyes. Visualisation for intraocular cyclophotocoagulation can be either transpupillary with scleral depression to expose the processes or by the use of an endoscope.

  17. Effect on intraocular pressure of switching from latanoprost and travoprost monotherapy to timolol fixed combinations in patients with normal-tension glaucoma.

    PubMed

    Igarashi, Ryoko; Togano, Tetsuya; Sakaue, Yuta; Yoshino, Takaiko; Ueda, Jun; Fukuchi, Takeo

    2014-01-01

    Purpose. To evaluate the effect on intraocular pressure (IOP) of switching from latanoprost and travoprost monotherapy to timolol fixed combinations in Japanese patients with normal-tension glaucoma (NTG). Methods. 27 NTG patients (54 eyes) were compared IOP, superficial punctuate keratitis (SPK) scores, and conjunctival injection scores in eyes treated with prostaglandin (PG) or PG analog/beta-blocker (PG/b) fixed-combination 6 months after the change in therapy. Results. The mean baseline intraocular pressure was 17.4 ± 1.59 mmHg in eyes receiving PG therapy only and 17.4 ± 1.69 mmHg in eyes switched to PG/b. Switching to fixed combination therapy from PG monotherapy, the mean IOP was 13.1 ± 1.79 mmHg (P < 0.001)  (-24.71% reduction from baseline) at 6 months. The mean conjunctival injection score was 0.69 for eyes on PG monotherapy and 0.56 for eyes on fixed combination therapy (P = 0.028). The mean SPK scores were 0.46 and 0.53. This difference was not statistically significant (P = 0.463). Conclusions. Switching from PG monotherapy to PG/b fixed combination therapy for NTG resulted in a greater intraocular pressure reduction than PG alone without increasing the number of instillations.

  18. Pharmacology of novel intraocular pressure-lowering targets that enhance conventional outflow facility: Pitfalls, promises and what lies ahead?

    PubMed

    Prasanna, Ganesh; Li, Byron; Mogi, Muneto; Rice, Dennis S

    2016-09-15

    Intraocular pressure (IOP) lowering drugs that are approved for the treatment of glaucoma and ocular hypertension have limited activity on increasing aqueous humor movement through the trabecular meshwork and Schlemm's canal (TM/SC). The TM/SC complex is considered the conventional outflow pathway and is a primary site of increased resistance to aqueous humor outflow in glaucoma. Novel mechanisms that enhance conventional outflow have shown promise in IOP reduction via modulation of several pathways including Rho kinase, nitric oxide/soluble guanylate cyclase/cGMP, adenosine A1, prostaglandin EP4/cAMP, and potassium channels. The clinical translatability of these pharmacological modulators based on pre-clinical efficacy models is currently being explored. In addition, identification of pathways from GWAS and other studies involving transgenic rodent models with elevated/reduced IOP phenotypes have begun to yield additional insights into IOP regulation and serve as a source for the next generation of IOP lowering targets. Lastly, improvements in drug delivery technologies to enable sustained IOP reduction are also discussed.

  19. Genome-wide analysis of multiethnic cohorts identifies new loci influencing intraocular pressure and susceptibility to glaucoma

    PubMed Central

    Vitart, Veronique; Nag, Abhishek; Hewitt, Alex W; Höhn, René; Venturini, Cristina; Mirshahi, Alireza; Ramdas, Wishal D.; Thorleifsson, Gudmar; Vithana, Eranga; Khor, Chiea-Chuen; Stefansson, Arni B; Liao, Jiemin; Haines, Jonathan L; Amin, Najaf; Wang, Ya Xing; Wild, Philipp S; Ozel, Ayse B; Li, Jun Z; Fleck, Brian W; Zeller, Tanja; Staffieri, Sandra E; Teo, Yik-Ying; Cuellar-Partida, Gabriel; Luo, Xiaoyan; Allingham, R Rand; Richards, Julia E; Senft, Andrea; Karssen, Lennart C; Zheng, Yingfeng; Bellenguez, Céline; Xu, Liang; Iglesias, Adriana I; Wilson, James F; Kang, Jae H; van Leeuwen, Elisabeth M; Jonsson, Vesteinn; Thorsteinsdottir, Unnur; Despriet, Dominiek D.G.; Ennis, Sarah; Moroi, Sayoko E; Martin, Nicholas G; Jansonius, Nomdo M; Yazar, Seyhan; Tai, E-Shyong; Amouyel, Philippe; Kirwan, James; van Koolwijk, Leonieke M.E.; Hauser, Michael A; Jonasson, Fridbert; Leo, Paul; Loomis, Stephanie J; Fogarty, Rhys; Rivadeneira, Fernando; Kearns, Lisa; Lackner, Karl J; de Jong, Paulus T.V.M.; Simpson, Claire L; Pennell, Craig E; Oostra, Ben A; Uitterlinden, André G; Saw, Seang-Mei; Lotery, Andrew J; Bailey-Wilson, Joan E; Hofman, Albert; Vingerling, Johannes R; Maubaret, Cécilia; Pfeiffer, Norbert; Wolfs, Roger C.W.; Lemij, Hans G; Young, Terri L; Pasquale, Louis R; Delcourt, Cécile; Spector, Timothy D; Klaver, Caroline C.W.; Small, Kerrin S; Burdon, Kathryn P; Stefansson, Kari; Wong, Tien-Yin; Viswanathan, Ananth; Mackey, David A; Craig, Jamie E; Wiggs, Janey L; van Duijn, Cornelia M; Hammond, Christopher J; Aung, Tin

    2014-01-01

    Elevated intraocular pressure (IOP) is an important risk factor in developing glaucoma and IOP variability may herald glaucomatous development or progression. We report the results of a genome-wide association study meta-analysis of 18 population cohorts from the International Glaucoma Genetics Consortium (IGGC), comprising 35,296 multiethnic participants for IOP. We confirm genetic association of known loci for IOP and primary open angle glaucoma (POAG) and identify four new IOP loci located on chromosome 3q25.31 within the FNDC3B gene (p=4.19×10−08 for rs6445055), two on chromosome 9 (p=2.80×10−11 for rs2472493 near ABCA1 and p=6.39×10−11 for rs8176693 within ABO) and one on chromosome 11p11.2 (best p=1.04×10−11 for rs747782). Separate meta-analyses of four independent POAG cohorts, totaling 4,284 cases and 95,560 controls, show that three of these IOP loci are also associated with POAG. PMID:25173106

  20. Modification of hydrophobic acrylic intraocular lens with poly(ethylene glycol) by atmospheric pressure glow discharge: A facile approach

    NASA Astrophysics Data System (ADS)

    Lin, Lin; Wang, Yao; Huang, Xiao-Dan; Xu, Zhi-Kang; Yao, Ke

    2010-10-01

    To improve the anterior surface biocompatibility of hydrophobic acrylic intraocular lens (IOL) in a convenient and continuous way, poly(ethylene glycol)s (PEGs) were immobilized by atmospheric pressure glow discharge (APGD) treatment using argon as the discharge gas. The hydrophilicity and chemical changes on the IOL surface were characterized by static water contact angle and X-ray photoelectron spectroscopy to confirm the covalent binding of PEG. The morphology of the IOL surface was observed under field emission scanning electron microscopy and atomic force microscopy. The surface biocompatibility was evaluated by adhesion experiments with platelets, macrophages, and lens epithelial cells (LECs) in vitro. The results revealed that the anterior surface of the PEG-grafted IOL displayed significantly and permanently improved hydrophilicity. Cell repellency was observed, especially in the PEG-modified IOL group, which resisted the attachment of platelets, macrophages and LECs. Moreover, the spread and growth of cells were suppressed, which may be attributed to the steric stabilization force and chain mobility effect of the modified PEG. All of these results indicated that hydrophobic acrylic IOLs can be hydrophilic modified by PEG through APGD treatment in a convenient and continuous manner which will provide advantages for further industrial applications.

  1. Agreement of patient-measured intraocular pressure using rebound tonometry with Goldmann applanation tonometry (GAT) in glaucoma patients

    PubMed Central

    Tan, Shaoying; Yu, Marco; Baig, Nafees; Hansapinyo, Linda; Tham, Clement C.

    2017-01-01

    This study aims to determine the agreement of patient-measured intraocular pressure (IOP) using rebound tonometry with ophthalmologist-measured IOP using Goldmann applanation tonometry (GAT). Fifty-three glaucoma patients used rebound tonometry (Icare ONE, Icare Finland Oy., Finland) to measure their own IOP in ambient environments for 1 week, 5 times per day. Clinic IOP measurements were performed by ophthalmologists using GAT and by patients using rebound tonometry on examination days 1, 4 and 7 of the same week. The agreement between the two tonometries was evaluated by modified Bland-Altman plots and intra-class correlation coefficient (ICC) was determined. Differences in ICCs of them among the three examination days were evaluated by bootstrap resampling analysis. Respective within-measurement ICC of GAT and rebound tonometry were 0.98 and 0.94 on Day 1, 0.98 and 0.93 on Day 4, and 0.96 and 0.92 on Day 7. In a modified Bland-Altman plot, the mean difference ±1 standard deviation (SD) between the two tonometries was 0.15 ± 0.65 mmHg (p = 0.682). Between-measurement ICC were 0.66, 0.76 and 0.73 on the 3 examination days. There was no significant difference among ICCs. In conclusion, patient-measured IOP using rebound tonometry and ophthalmologist-measured IOP using GAT demonstrate good agreement. PMID:28165028

  2. Breakdown of the normal optic nerve head blood-brain barrier following acute elevation of intraocular pressure in experimental animals.

    PubMed

    Radius, R L; Anderson, D R

    1980-03-01

    Five hours of elevated intraocular pressure produced evidence of an altered blood-brain barrier at the optic nerve head in 27 of 29 monkey eyes. The change in vascular permeability was documented by fluorescein angiography (18 of 21 eyes), by Evans blue fluorescence microscopy (21 of 23 eyes), or by both methods. Leakage occurred from major blood vessels as well as from microvasculature of the nerve head. In 22 eyes, rapid axonal transport was studied after intravitreal injection of tritiated leucine. In 18 of these 22 eyes, autoradiography demonstrated a local interruption of axonal transport. In 15 eyes examined by all three methods, leakage from microvasculature (as opposed to leakage from the major vessels) was loosely associated with severe and widespread blockade of axonal transport at the lamina cribrosa. Although cause-and-effect relationships are not proved, ischemia may be responsible both for the focal endothelial damage with breakdown of the normal blood-brain barrier and for the local abnormalities of axonal transport.

  3. Intraocular Pressure, Central Corneal Thickness, and Prevalence of Open-Angle Glaucoma: The Los Angeles Latino Eye Study

    PubMed Central

    Francis, Brian A.; Varma, Rohit; Chopra, Vikas; Lai, Mei-Ying; Shtir, Corina; Azen, Stanley P.

    2008-01-01

    Purpose To examine the relationship between the prevalence of open-angle glaucoma (OAG) and intraocular pressure (IOP) and the impact of central corneal thickness (CCT) on this relationship. Design Population based cross-sectional study. Methods The study cohort consisted of 5970 participants from the Los Angeles Latino Eye Study (LALES) with no history of glaucoma treatment and with complete ophthalmic examination data. The relationship between the prevalence of OAG and IOP was contrasted across persons with CCT designated as thin, normal or thick. Results Prevalence of OAG was exponentially related to IOP. When stratified by CCT, persons with thin CCT had a significantly higher prevalence of OAG than did those with normal or thick CCT’s at all levels of IOP. Adjusting each IOP individually for CCT did not impact significantly the relationship between the prevalence of OAG and IOP. Conclusions These findings suggest that adjusting for the impact of CCT on IOP by correction algorithms is not necessary in a population analysis of glaucoma prevalence; CCT and other associated corneal properties, however, are important independent risk factors for the prevalence of OAG. PMID:18672218

  4. Intraoperative measurement of intraocular pressure in vitrectomized aphakic air-filled eyes using the Tono-Pen XL.

    PubMed

    Badrinath, S S; Vasudevan, R; Murugesan, R; Basti, S; Nicholson, A D; Singh, P; Gopal, L; Sharma, T; Rao, S B; Abraham, C

    1993-01-01

    The Tono-Pen XL (Bio-Rad, Santa Ana, CA) was compared with manometer readings for intraoperative measurement of intraocular pressure (IOP) in 40 eyes of 40 consecutive patients after vitrectomy, lensectomy, and fluid-air exchange. Tono-Pen readings corresponding to manometer readings of 10, 20, 30, 40, and 50 mmHg were obtained in a masked fashion with a randomized sequence of manometer readings. A correlation was obtained between the manometer and Tono-Pen readings (r = 0.96 in emmetropic eyes and r = 0.93 in myopic eyes). The regression curve that represents the calibration curve of Tono-Pen in terms of the manometer readings for air-filled vitrectomized eyes was obtained. Any Tono-Pen reading can be easily translated into the corresponding manometer reading by referring to the curve. The Tono-Pen can therefore be effectively used to accurately determine intraoperative IOP in eyes undergoing vitrectomy, lensectomy, and fluid-air exchange.

  5. Effects of the new ethacrynic acid oxime derivative SA12590 on intraocular pressure in cats and monkeys.

    PubMed

    Shimazaki, Atsushi; Kirihara, Tomoko; Rao, Ponugoti Vasantha; Tajima, Hisashi; Matsugi, Takeshi; Epstein, David Lee

    2007-08-01

    To evaluate the pharmacological characteristics of SA12590, a new oxime-derivative of the ethacrynic acid (ECA) derivative SA9000, we examined both its ocular hypotensive effects (in ocular normotensive cats and cynomolgus monkeys) and its potential corneal toxicity (in rats). A 50 microl topical administration of 3% SA12590 significantly reduced intraocular pressure (IOP) (by 3.5 mmHg) in anesthetized cats (p<0.05). Twenty-four hours after 3 drops (5-min intervals) of 20 microl 3% SA12590, IOP was reduced by 8 mmHg (p<0.05, n=4) in conscious monkeys without evidence of corneal toxicity. Three days' daily single 20 microl dosing with 3% SA12590 reduced IOP by 4 mmHg (p<0.01, n=3) at 72 h after the first administration in conscious monkeys. The toxicity of topically administered 20 microl 3% SA9000 or SA12590 (3 drops with 5-min intervals) on rat corneal epithelium was assessed using a photo-slit lamp. In this study, 3% SA12590, unlike 3% SA9000, exhibited no corneal toxicity. In a glutathione assay for sulfhydryl (SH) reactivity, SA12590, unlike SA9000, displayed no in vitro SH reactivity. Thus, oxime-modification may both improve efficacy towards IOP upon topical administration and improve the safety profile, probably by enhancing corneal penetration and minimizing SH reactivity-related toxicity. These findings indicate that SA12590 has potential as a new ocular hypotensive drug.

  6. Fixed combination of topical brimonidine 0.2% and timolol 0.5% for glaucoma and uncontrolled intraocular pressure

    PubMed Central

    Lee, Anne J; McCluskey, Peter

    2008-01-01

    Lowering IOP is the most readily modifiable risk factor to delay the development and progression of glaucoma (POAG). The fixed combination of brimonidine tartrate 0.2% and timolol maleate 0.5% (FCBT) combines a highly selective α2-adrenergic agonist (brimonidine) with a non-selective β-blocker (timolol). FCBT reduces aqueous production and enhances uveoscleral outflow. Concomitant brimonidine and timolol have additive effects on reducing intraocular pressure (IOP). Multi-center randomized control trials have documented superiority of FCBT twice daily on IOP control compared with monotherapy with the individual components, and equal efficacy compared with concomitant therapy. IOP reduction with FCBT versus fixed combination dorzolamide 2% and timolol 0.5% (FCDT) was similar in a small study. Other studies (n > 293) evaluating concomitant brimonidine and timolol have shown that it is not inferior to FCDT. However, concomitant brimonidine and timolol administered twice daily was significantly less efficacious in IOP reduction than fixed combination latanoprost 0.005% and timolol 0.5% (FCLT). There are no published studies comparing FCBT with FCLT. The side effect profile for FCBT reflects that of its individual components. FCBT was generally well tolerated, with less ocular side effects than brimondine alone, but more than timolol alone. Documented systemic effects were few, although this could be confounded by selection bias. FCBT is a safe and effective IOP lowering agent for POAG and ocular hypertension. PMID:19668752

  7. Phase-Contrast Micro-Computed Tomography Measurements of the Intraocular Pressure-Induced Deformation of the Porcine Lamina Cribrosa.

    PubMed

    Coudrillier, Baptiste; Geraldes, Diogo M; Vo, Nghia T; Atwood, Robert; Reinhard, Christina; Campbell, Ian C; Raji, Yazdan; Albon, Julie; Abel, Richard L; Ethier, C Ross

    2016-04-01

    The lamina cribrosa (LC) is a complex mesh-like tissue in the posterior eye. Its biomechanical environment is thought to play a major role in glaucoma, the second most common cause of blindness. Due to its small size and relative inaccessibility, high-resolution measurements of LC deformation, important in characterizing LC biomechanics, are challenging. Here we present a novel noninvasive imaging method, which enables measurement of the three-dimensional deformation of the LC caused by acute elevation of intraocular pressure (IOP). Posterior segments of porcine eyes were imaged using synchrotron radiation phase contrast micro-computed tomography (PC μCT) at IOPs between 6 and 37 mmHg. The complex trabecular architecture of the LC was reconstructed with an isotropic spatial resolution of 3.2 μm. Scans acquired at different IOPs were analyzed with digital volume correlation (DVC) to compute full-field deformation within the LC. IOP elevation caused substantial tensile, shearing and compressive devformation within the LC, with maximum tensile strains at 30 mmHg averaging 5.5%, and compressive strains reaching 20%. We conclude that PC μCT provides a novel high-resolution method for imaging the LC, and when combined with DVC, allows for full-field 3D measurement of ex vivo LC biomechanics at high spatial resolution.

  8. Phase-contrast Micro-computed Tomography Measurements of the Intraocular Pressure-induced Deformation of the Porcine Lamina Cribrosa.

    PubMed

    Coudrillier, Baptiste; Geraldes, Diogo; Vo, Nghia; Atwood, Robert; Reinhard, Christina; Campbell, Ian; Raji, Yazdan; Albon, Julie; Abel, Richard; Ethier, Ross

    2015-11-30

    The lamina cribrosa (LC) is a complex mesh-like tissue in the posterior eye. Its biomechanical environment is thought to play a major role in glaucoma, the second most common cause of blindness. Due to its small size and relative inaccessibility, highresolution measurements of LC deformation, important in characterizing LC biomechanics, are challenging. Here we present a novel noninvasive imaging method, which enables measurement of the three-dimensional deformation of the LC caused by acute elevation of intraocular pressure (IOP). Posterior segments of porcine eyes were imaged using synchrotron radiation phase contrast micro-computed tomography (PC CT) at IOPs between 6 and 37mmHg. The complex trabecular architecture of the LC was reconstructed with an isotropic spatial resolution of 3.2 m. Scans acquired at different IOPs were analyzed with digital volume correlation (DVC) to compute full-field deformation within the LC. IOP elevation caused substantial tensile, shearing and compressive deformation within the LC, with maximum tensile strains at 30mmHg averaging 5.5%, and compressive strains reaching 20%. We conclude that PC CT provides a novel high-resolution method for imaging the LC, and when combined with DVC, allows for full-field 3D measurement of ex vivo LC biomechanics at high spatial resolution.

  9. Genome-wide analysis of multi-ancestry cohorts identifies new loci influencing intraocular pressure and susceptibility to glaucoma.

    PubMed

    Hysi, Pirro G; Cheng, Ching-Yu; Springelkamp, Henriët; Macgregor, Stuart; Bailey, Jessica N Cooke; Wojciechowski, Robert; Vitart, Veronique; Nag, Abhishek; Hewitt, Alex W; Höhn, René; Venturini, Cristina; Mirshahi, Alireza; Ramdas, Wishal D; Thorleifsson, Gudmar; Vithana, Eranga; Khor, Chiea-Chuen; Stefansson, Arni B; Liao, Jiemin; Haines, Jonathan L; Amin, Najaf; Wang, Ya Xing; Wild, Philipp S; Ozel, Ayse B; Li, Jun Z; Fleck, Brian W; Zeller, Tanja; Staffieri, Sandra E; Teo, Yik-Ying; Cuellar-Partida, Gabriel; Luo, Xiaoyan; Allingham, R Rand; Richards, Julia E; Senft, Andrea; Karssen, Lennart C; Zheng, Yingfeng; Bellenguez, Céline; Xu, Liang; Iglesias, Adriana I; Wilson, James F; Kang, Jae H; van Leeuwen, Elisabeth M; Jonsson, Vesteinn; Thorsteinsdottir, Unnur; Despriet, Dominiek D G; Ennis, Sarah; Moroi, Sayoko E; Martin, Nicholas G; Jansonius, Nomdo M; Yazar, Seyhan; Tai, E-Shyong; Amouyel, Philippe; Kirwan, James; van Koolwijk, Leonieke M E; Hauser, Michael A; Jonasson, Fridbert; Leo, Paul; Loomis, Stephanie J; Fogarty, Rhys; Rivadeneira, Fernando; Kearns, Lisa; Lackner, Karl J; de Jong, Paulus T V M; Simpson, Claire L; Pennell, Craig E; Oostra, Ben A; Uitterlinden, André G; Saw, Seang-Mei; Lotery, Andrew J; Bailey-Wilson, Joan E; Hofman, Albert; Vingerling, Johannes R; Maubaret, Cécilia; Pfeiffer, Norbert; Wolfs, Roger C W; Lemij, Hans G; Young, Terri L; Pasquale, Louis R; Delcourt, Cécile; Spector, Timothy D; Klaver, Caroline C W; Small, Kerrin S; Burdon, Kathryn P; Stefansson, Kari; Wong, Tien-Yin; Viswanathan, Ananth; Mackey, David A; Craig, Jamie E; Wiggs, Janey L; van Duijn, Cornelia M; Hammond, Christopher J; Aung, Tin

    2014-10-01

    Elevated intraocular pressure (IOP) is an important risk factor in developing glaucoma, and variability in IOP might herald glaucomatous development or progression. We report the results of a genome-wide association study meta-analysis of 18 population cohorts from the International Glaucoma Genetics Consortium (IGGC), comprising 35,296 multi-ancestry participants for IOP. We confirm genetic association of known loci for IOP and primary open-angle glaucoma (POAG) and identify four new IOP-associated loci located on chromosome 3q25.31 within the FNDC3B gene (P = 4.19 × 10(-8) for rs6445055), two on chromosome 9 (P = 2.80 × 10(-11) for rs2472493 near ABCA1 and P = 6.39 × 10(-11) for rs8176693 within ABO) and one on chromosome 11p11.2 (best P = 1.04 × 10(-11) for rs747782). Separate meta-analyses of 4 independent POAG cohorts, totaling 4,284 cases and 95,560 controls, showed that 3 of these loci for IOP were also associated with POAG.

  10. Effect of prophylactic timolol 0.1% gel on intraocular pressure after an intravitreal injection of ranibizumab: a randomized study

    PubMed Central

    Pece, Alfredo; Allegrini, Davide; Montesano, Giovanni; Dimastrogiovanni, Andrea Fabio

    2016-01-01

    Purpose The purpose of this study is to make a prospective evaluation of the effect of timolol 0.1% eye gel on short-term intraocular pressure (IOP) after an intravitreal injection (IVI) of ranibizumab. Participants and methods One hundred and fifty eyes of 150 IVI-naïve patients with macular edema caused by various pathological conditions (age-related macular degeneration, central or branch retinal vein occlusion, and diabetic retinopathy) were scheduled to undergo an IVI of ranibizumab (0.5 mg/0.05 cc). The patients were randomly divided into three groups: 50 were not treated with timolol before the IVI (group 1); 50 received an instillation of timolol 0.1% eye gel the evening before the IVI (group 2); and 50 received an instillation of timolol 0.1% eye gel 2 hours before the IVI (group 3). The incidence of clinically significant intraocular hypertensive spikes (>25 mmHg and >40 mmHg) was then assessed. Results Our findings showed that mean IOP at baseline was significantly higher than at both 5 and 60 minutes after IVI (P<0.01). Spikes of >25 mmHg were recorded at either time in 27 patients (54%) in group 1, 23 patients (44%) in group 2, and 24 patients (48%) in group 3. None of the between-group differences were significant. Spikes of >40 mmHg (which were only detected 5 minutes after IVI) were recorded in nine (18%), eight (16%), and one patient (2%) in groups 1, 2, and 3, respectively. The only significant difference was between the control and group 3 (P=0.012). Conclusion An increase in IOP after antivascular endothelial growth factor IVI is a frequent complication. The prophylactic use of timolol 0.1% gel effectively reduced the mean IOP when administered 2 hours before IVI and was also effective in preventing dangerous IOP spikes of >40 mmHg. It is therefore recommended before IVIs as a means of preventing emergency procedures and preserving the health of the optic nerve. PMID:27382246

  11. Cerebral Autoregulation Real-Time Monitoring

    PubMed Central

    Tsalach, Adi; Ratner, Eliahu; Lokshin, Stas; Silman, Zmira; Breskin, Ilan; Budin, Nahum; Kamar, Moshe

    2016-01-01

    Cerebral autoregulation is a mechanism which maintains constant cerebral blood flow (CBF) despite changes in mean arterial pressure (MAP). Assessing whether this mechanism is intact or impaired and determining its boundaries is important in many clinical settings, where primary or secondary injuries to the brain may occur. Herein we describe the development of a new ultrasound tagged near infra red light monitor which tracks CBF trends, in parallel, it continuously measures blood pressure and correlates them to produce a real time autoregulation index. Its performance is validated in both in-vitro experiment and a pre-clinical case study. Results suggest that using such a tool, autoregulation boundaries as well as its impairment or functioning can be identified and assessed. It may therefore assist in individualized MAP management to ensure adequate organ perfusion and reduce the risk of postoperative complications, and might play an important role in patient care. PMID:27571474

  12. Effect of intraocular pressure (IOP) and choroidal circulation on controlled episcleral drug delivery to retina/vitreous.

    PubMed

    Li, Jie; Lan, Bifei; Li, Xiaoli; Sun, Shumao; Lu, Ping; Cheng, Lingyun

    2016-12-10

    Transscleral drug delivery may become a safe alternative to the intravitreal injection for chronic retinal diseases such as age-related macular degeneration or diabetic macular edema. However, the drug delivered onto the sclera subjects to vigorous clearance by episcleral and choroidal circulation; in addition, the penetration from episclera to retina needs to overcome counter-directional ocular fluid current driven by intraocular pressure (IOP) as well as unfavorable drug disposition exerted by drug transporters before the drug reach retina. It is imperative to understand these processes and quantitate their influence for efficient designing of a sustained formulation or device to achieve efficient transscleral drug delivery. The current study was focused on the effects of intraocular pressure (IOP) and choroidal circulation on transscleral drug delivery using triamcinolone acetonide (TA) as a model drug. Rabbit eye IOP was modulated through cannulation in ex vivo study or through cryopexy of ciliary body in vivo studies before subtenon TA injection or episcleral TA-film implantation. In a subgroup of the rabbit eyes, localized choroid atrophy was induced by cryopexy before TA-film implantation. Each condition had a concurrent control group. The vitreous TA concentration was quantitated by ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC/MS/MS). The vitreous TA concentration was compared between the study and control groups for effect of IOP or choroid circulation. For ex vivo studies, higher IOP was a significant effect against TA penetration from episclera towards vitreous. TA was 8.5±5ng/mL in receptor chamber with a cross pressure of 50mmHg versus 15.9±10ng/mL with the cross pressure of 5mmHg; p=0.001, t-test. A multivariate regression demonstrated each mmHg of IOP increase would result in 3ng/mL lower concentration in the receptor chamber. Similar IOP effect was also identified in a 3-hour study using euthanized rabbit

  13. Real-time laser holographic interferometry for aerodynamics

    NASA Technical Reports Server (NTRS)

    Lee, George

    1987-01-01

    Recent developments in thermoplastic recording holograms and advancements in automated image digitalization and analysis make real-time laser holographic interferometry feasible for two-dimensional flows such as airfoil flows. Typical airfoil measurements would include airfoil pressure distributions, wake and boundary layer profiles, and flow field density contours. This paper addresses some of the problems and requirements of a real-time laser holographic interferometer.

  14. Clinical virology in real time.

    PubMed

    Niesters, Hubert G M

    2002-12-01

    The ability to detect nucleic acids has had and still has a major impact on diagnostics in clinical virology. Both quantitative and qualitative techniques, whether signal or target amplification based systems, are currently used routinely in most if not all virology laboratories. Technological improvements, from automated sample isolation to real time amplification technology, have given the ability to develop and introduce systems for most viruses of clinical interest, and to obtain clinical relevant information needed for optimal antiviral treatment options. Both polymerase chain reaction (PCR) and nucleic acid sequence-based amplification (NASBA) can currently be used together with real time detection to generate results in a short turn-around time and to determine whether variants relevant for antiviral resistance are present. These new technologies enable the introduction of an individual patient disease management concept. Within our clinical setting, we have introduced this e.g. for quantitative detection of Epstein-Barr Virus (EBV) in T-dell depleted allogeneic stem cell transplant patients. This enabled us to develop models for pre-emptive anti B-cell immunotherapy for EBV reactivation, thereby effectively reducing not the incidence of EBV-lymphoproliferative disease but the virus related mortality. Furthermore, additional clinically relevant viruses can now easily be detected simultaneously. It also becomes more feasible to introduce molecular testing for those viruses that can easily be detected using classical virological methods, like culture techniques or antigen detection. Prospective studies are needed to evaluate the clinical importance of the additional positive samples detected. It should however be made clear that a complete exchange of technologies is unlikely to occur, and that some complementary technologies should stay operational enabling the discovery of new viruses. The implementation of these molecular diagnostic technologies furthermore

  15. Mobile real time radiography system

    SciTech Connect

    Vigil, J.; Taggart, D.; Betts, S.

    1997-11-01

    A 450-keV Mobile Real Time Radiography (RTR) System was delivered to Los Alamos National Laboratory (LANL) in January 1996. It was purchased to inspect containers of radioactive waste produced at (LANL). Since its delivery it has been used to radiograph more than 600 drums of radioactive waste at various LANL sites. It has the capability of inspecting waste containers of various sizes from <1-gal. buckets up to standard waste boxes (SWB, dimensions 54.5 in. x 71 in. x 37 in.). It has three independent x-ray acquisition formats. The primary system used is a 12- in. image intensifier, the second is a 36-in. linear diode array (LDA) and the last is an open system. It is fully self contained with on board generator, HVAC, and a fire suppression system. It is on a 53-ft long x 8-ft. wide x 14-ft. high trailer that can be moved over any highway requiring only an easily obtainable overweight permit because it weights {approximately}38 tons. It was built to conform to industry standards for a cabinet system which does not require an exclusion zone. The fact that this unit is mobile has allowed us to operate where the waste is stored, rather than having to move the waste to a fixed facility.

  16. Evaluation of the associations between changes in intraocular pressure and metabolic syndrome parameters: a retrospective cohort study in Japan

    PubMed Central

    Yokomichi, Hiroshi; Kitamura, Kazuyoshi; Yoda, Yoshioki; Tsuji, Masahiro; Sato, Miri; Mizorogi, Sonoko; Suzuki, Kohta; Yamagata, Zentaro

    2016-01-01

    Objective The contributions of highly correlated cardiovascular risk factors to intraocular pressure (IOP) are not clear due to underlying confounding problems. The present study aimed to determine which metabolic syndrome parameters contribute to elevating IOP and to what extent. Design Retrospective cohort study. Setting A private healthcare centre in Japan. Participants Individuals who visited a private healthcare centre and underwent comprehensive medical check-ups between April 1999 and March 2009 were included (20 007 in the cross-sectional study and 15 747 in the longitudinal study). Primary and secondary outcome measures Changes in IOP were evaluated in terms of ageing and changes in metabolic syndrome parameters. Pearson's correlation coefficients and mixed-effects models were used to examine the relationship of changes in IOP with ageing and changes in metabolic syndrome parameters in cross-sectional and longitudinal studies, respectively. Results In the cross-sectional study, IOP was negatively correlated with age and positively correlated with waist circumference, high-density lipoprotein cholesterol (HDL-C) levels, triglyceride levels, systolic blood pressure (SBP), diastolic blood pressure (DBP) and fasting plasma glucose (FPG) levels. In the longitudinal multivariate analysis, the associated IOP changes were −0.12 (p<0.0001) mm Hg with male sex; −0.59 (p<0.0001) mm Hg with 10 years of ageing; +0.42 (p<0.0001) mm Hg with 1 mmol/L increase in HDL-C levels; +0.092 (p<0.0001) mm Hg with 1 mmol/L increase in triglyceride levels; +0.090 (p<0.0001) mm Hg with 10 mm Hg increase in SBP; +0.085 (p<0.0001) mm Hg with 10 mm Hg increase in DBP; and+0.091 (p<0.0001) mm Hg with 1 mmol/L increase in FPG levels. Conclusions Elevation of IOP was related to longitudinal worsening of serum triglyceride levels, blood pressure and FPG and improvement in serum HDL-C levels. PMID:27013596

  17. Real-Time Nonlinear Optical Information Processing.

    DTIC Science & Technology

    1979-06-01

    operations aree presented. One approach realizes the halftone method of nonlinear optical processing in real time by replacing the conventional...photographic recording medium with a real-time image transducer. In the second approach halftoning is eliminated and the real-time device is used directly

  18. Students Collecting Real time Data

    NASA Astrophysics Data System (ADS)

    Miller, P.

    2006-05-01

    Students Collecting Real-Time Data The Hawaiian Islands Humpback Whale National Marine Sanctuary has created opportunities for middle and high school students to become Student Researchers and to be involved in real-time marine data collection. It is important that we expose students to different fields of science and encourage them to enter scientific fields of study. The Humpback Whale Sanctuary has an education visitor center in Kihei, Maui. Located right on the beach, the site has become a living classroom facility. There is a traditional Hawaiian fishpond fronting the property. The fishpond wall is being restored, using traditional methods. The site has the incredible opportunity of incorporating Hawaiian cultural practices with scientific studies. The Sanctuary offers opportunities for students to get involved in monitoring and data collection studies. Invasive Seaweed Study: Students are collecting data on invasive seaweed for the University of Hawaii. They pull a large net through the shallow waters. Seaweed is sorted, identified and weighed. The invasive seaweeds are removed. The data is recorded and sent to UH. Remote controlled monitoring boats: The sanctuary has 6 boogie board sized remote controlled boats used to monitor reefs. Boats have a camera with lights on the underside. The boats have water quality monitoring devices and GPS units. The video from the underwater camera is transmitted via a wireless transmission. Students are able to monitor the fish, limu and invertebrate populations on the reef and collect water quality data via television monitors or computers. The boat can also pull a small plankton tow net. Data is being compiled into data bases. Artificial Reef Modules: The Sanctuary has a scientific permit from the state to build and deploy artificial reef modules. High school students are designing and building modules. These are deployed out in the Fishpond fronting the Sanctuary site and students are monitoring them on a weekly basis

  19. Real-time optical tweezing

    NASA Astrophysics Data System (ADS)

    Rahman, Shah Mohammed Tamzidur

    In this thesis a new approach called ‘space-time-wavelength mapping’ has been developed for real-time electronic control of optical tweezers. The proposed technique enables precise control of optical signals in space, time, and frequency through time-domain dispersion and diffractive optics, which in turn enables generation of controlled radiation forces acting on small particles. In this study we show that 150 fs ultrafast optical pulses can be dispersed in time and space to achieve a 20 μm x 2 μm focused elliptical beam. The force field at the focal plane of the beam is dependent on local intensity gradients along the plane. The spatial intensity profile can be electronically controlled by assigning local power levels to each wavelength using time-domain RF modulation of dispersed pulses, and sending each wavelength, and hence the assigned power level, to a specific location in space through diffractive optics. We show that by choosing the appropriate RF waveform, one is able to create force fields for cell stretching and compression as well as multiple force hot-spots (of >200 pN force per pulse) for attractive and repulsive forces. A detailed theoretical model and simulation results from a proposed experimental setup are presented. This approach is significantly more advantageous in terms of flexibility and control, compared to conventional optical tweezers that require mechanical steering or holographic optical tweezers that produce undesired ‘ghost traps’. In addition, it is shown how the technique can also be extended to create tunable 2D force field distributions using a virtually-imaged phased-array (VIPA).

  20. Holin triggering in real time.

    PubMed

    White, Rebecca; Chiba, Shinobu; Pang, Ting; Dewey, Jill S; Savva, Christos G; Holzenburg, Andreas; Pogliano, Kit; Young, Ry

    2011-01-11

    During λ infections, the holin S105 accumulates harmlessly in the membrane until, at an allele-specific time, suddenly triggering to form irregular holes of unprecedented size (>300 nm), releasing the endolysin from the cytoplasm, resulting in lysis within seconds. Here we used a functional S105-GFP chimera and real-time deconvolution fluorescence microscopy to show that the S105-GFP fusion accumulated in a uniformly distributed fashion, until suddenly, within 1 min, it formed aggregates, or rafts, at the time of lethal triggering. Moreover, the isogenic fusion to a nonlethal S105 mutant remained uniformly distributed, whereas a fusion to an early-lysing mutant showed early triggering and early raft formation. Protein accumulation rates of the WT, early, and nonlethal alleles were identical. Fluorescence recovery after photobleaching (FRAP) revealed that the nonlethal mutant and untriggered WT hybrids were highly mobile in the membrane, whereas the WT raft was essentially immobile. Finally, an antiholin allele, S105(ΔTMD1)-mcherryfp, in the product of which the S105 sequence deleted for the first transmembrane domain was fused to mCherryFP. This hybrid retained full antiholin activity, in that it blocked lethal hole formation by the S105-GFP fusion, accumulated uniformly throughout the host membrane and prevented the S105-GFP protein from forming rafts. These findings suggest that phage lysis occurs when the holin reaches a critical concentration and nucleates to form rafts, analogous to the initiation of purple membrane formation after the induction of bacteriorhodopsin in halobacteria. This model for holin function may be relevant for processes in mammalian cells, including the release of nonenveloped viruses and apoptosis.

  1. Real-Time Data Display

    NASA Technical Reports Server (NTRS)

    Pedings, Marc

    2007-01-01

    RT-Display is a MATLAB-based data acquisition environment designed to use a variety of commercial off-the-shelf (COTS) hardware to digitize analog signals to a standard data format usable by other post-acquisition data analysis tools. This software presents the acquired data in real time using a variety of signal-processing algorithms. The acquired data is stored in a standard Operator Interactive Signal Processing Software (OISPS) data-formatted file. RT-Display is primarily configured to use the Agilent VXI (or equivalent) data acquisition boards used in such systems as MIDDAS (Multi-channel Integrated Dynamic Data Acquisition System). The software is generalized and deployable in almost any testing environment, without limitations or proprietary configuration for a specific test program or project. With the Agilent hardware configured and in place, users can start the program and, in one step, immediately begin digitizing multiple channels of data. Once the acquisition is completed, data is converted into a common binary format that also can be translated to specific formats used by external analysis software, such as OISPS and PC-Signal (product of AI Signal Research Inc.). RT-Display at the time of this reporting was certified on Agilent hardware capable of acquisition up to 196,608 samples per second. Data signals are presented to the user on-screen simultaneously for 16 channels. Each channel can be viewed individually, with a maximum capability of 160 signal channels (depending on hardware configuration). Current signal presentations include: time data, fast Fourier transforms (FFT), and power spectral density plots (PSD). Additional processing algorithms can be easily incorporated into this environment.

  2. Assessment of intraocular pressure measured by Reichert Ocular Response Analyzer, Goldmann Applanation Tonometry, and Dynamic Contour Tonometry in healthy individuals

    PubMed Central

    Ouyang, Ping-Bo; Li, Cong-Yi; Zhu, Xiao-Hua; Duan, Xuan-Chu

    2012-01-01

    AIM To investigate the accuracy of intraocular pressure (IOP) as measured by a Reichert Ocular Response Analyzer (ORA), as well as the relationship between central corneal thickness (CCT) and IOP as measured by ORA, Goldmann applanation tonometry (GAT), and dynamic contour tonometry (DCT). METHODS A total of 158 healthy individuals (296 eyes) were chosen randomly for measurement of IOP. After CCT was measured using A-ultrasound (A-US), IOP was measured by ORA, GAT, and DCT devices in a randomized order. The IOP values acquired using each of the three tonometries were compared, and the relationship between CCT and IOP values were analyzed separately. Two IOP values, Goldmann-correlated IOP value (IOPg) and corneal-compensated intraocular pressure (IOPcc), were got using ORA. Three groups were defined according to CCT: 1) thin cornea (CCT<520µm); 2) normal-thickness cornea (CCT: 520–580µm); and 3) thick cornea (CCT>580µm) groups. RESULTS In normal subjects, IOP measurements were 14.95±2.99mmHg with ORA (IOPg), 15.21±2.77mmHg with ORA (IOPcc), 15.22±2.77mmHg with GAT, and 15.49±2.56mmHg with DCT. Mean differences were 0.01±2.29mmHg between IOPcc and GAT (P>0.05) and 0.28±2.20mmHg between IOPcc and DCT (P>0.05). There was a greater correlation between IOPcc and DCT (r=0.946, P=0.000) than that between IOPcc and GAT (r=0.845, P=0.000). DCT had a significant correlation with GAT (r=0.854, P=0.000). GAT was moderately correlated with CCT (r=0.296, P<0.001), while IOPcc showed a weak but significant correlation with CCT (r=−0.155, P=0.007). There was a strong negative correlation between CCT and the difference between IOPcc and GAT(r=-0.803, P=0.000), with every 10µm increase in CCT resulting in an increase in this difference of 0.35mmHg. The thick cornea group (CCT>580µm) showed the least significant correlation between IOPcc and GAT (r=0.859, P=0.000); while the thin cornea group (CCT<520µm) had the most significant correlation between IOPcc and GAT (r=0

  3. Validity of Tono-pachymetry for Measuring Corrected Intraocular Pressure in Non-surgical and Post-photorefractive Keratectomy Eyes

    PubMed Central

    Hahn, In Kyun; Kim, Jae Yong; Kim, Myoung Joon; Tchah, Hungwon

    2017-01-01

    Purpose To assess the validity of central corneal thickness (CCT) and corrected intraocular pressure (IOP) values obtained by tono-pachymetry in non-surgical and post-photorefractive keratectomy (PRK) eyes. Methods For the study, 108 young healthy participants and 108 patients who had PRK were enrolled. Measurements were randomly performed by tono-pachymetry, ultrasonic (US) pachymetry, and Goldmann applanation tonometry (GAT). CCT measurement by tono-pachymetry was compared to that of US pachymetry. The corrected IOP value obtained by tono-pachymetry was compared to that obtained by US pachymetry and GAT. The corrected IOP from US pachymetry and GAT was calculated using the identical compensation formula built into the tono-pachymetry. Bland-Altman plot and paired t-test were conducted to evaluate the between-method agreements. Results The mean CCT measurement using tono-pachymetry was significantly greater by 7.3 µm in non-surgical eyes (p < 0.001) and 17.8 µm in post-PRK eyes (p < 0.001) compared with US pachymetry. Differences were significant in both Bland-Altman plotand paired t-test. The mean difference of corrected IOP values obtained by tono-pachymetry and calculated from measurements by US pachymetry and GAT was 0.33 ± 0.87 mmHg in non-surgical eyes and 0.57 ± 1.08 mmHg in post-PRK eyes. The differences in the Bland-Altman plot were not significant. Conclusions The CCT measurement determined using tono-pachymetrywas significantly thicker than that of US pachymetry. The difference in CCT was greater in post-PRK eyes than in non-surgical eyes. However, the corrected IOP value obtained by tono-pachymetry showed reasonable agreement with that calculated from US pachymetry and GAT measurements. PMID:28243023

  4. Displacement of the Lamina Cribrosa in Response to Acute Intraocular Pressure Elevation in Normal Individuals of African and European Descent

    PubMed Central

    Fazio, Massimo A.; Johnstone, John K.; Smith, Brandon; Wang, Lan; Girkin, Christopher A.

    2016-01-01

    Purpose To assess if the in vivo mechanical displacement of the anterior laminar cribrosa surface (ALCS) as a response of an acute elevation in intraocular pressure (IOP) differs in individuals of European (ED) and African descent (AD). Methods Spectral-domain optical coherence tomography (SDOCT) scans were obtained from 24 eyes of 12 individuals of AD and 18 eyes of 9 individuals of ED at their normal baseline IOP and after 60 seconds IOP elevation using ophthalmodynamometry. Change in depth (displacement) of the LC and to the prelaminar tissue (PLT) were computed in association with the change (delta) in IOP (Δ IOP), race, age, corneal thickness, corneal rigidity (ocular response analyzer [ORA]), and axial. Results In the ED group for small IOP elevations (Δ IOP < 12 mm Hg), the ALCS initially displaced posteriorly but for larger increase of IOP an anterior displacement of the lamina followed. Inversely, in the AD group the ALCS did not show a significant posterior displacement for small Δ IOP, while for larger IOP increases the ALCS significantly displaced posteriorly. Posterior displacement of the lamina cribrosa (LC) was also significantly correlated with longer axial length, higher corneal thickness, and ORA parameters. Prelaminar tissue posteriorly displaced for any magnitude of Δ IOP, in both groups. Conclusions The African descent group demonstrated a greater acute posterior bowing of the LC after adjustment for age, axial length, Bruch's membrane opening (BMO) area, and ORA parameters. Greater PLT posterior displacement was also seen in the AD group with increasing IOP, which was tightly correlated with the displacement of the LC. PMID:27367500

  5. Feasibility study of sustained-release travoprost punctum plug for intraocular pressure reduction in an Asian population

    PubMed Central

    Perera, Shamira A; Ting, Daniel SW; Nongpiur, Monisha E; Chew, Paul T; Aquino, Maria Cecilia D; Sng, Chelvin CA; Ho, Sue-Wei; Aung, Tin

    2016-01-01

    Purpose To investigate the efficacy and safety of a punctum plug-based sustained drug release system for a prostaglandin analog, travoprost (OTX-TP), for intraocular pressure (IOP) reduction in an Asian population. Methods This is an initial feasibility, prospective, single-arm study involving 26 eyes and a bioresorbable punctum plug containing OTX-TP. An OTX-TP was placed in the vertical portion of the superior or inferior canaliculus of patients with primary open-angle glaucoma or ocular hypertension. The main outcome measure was the IOP-lowering efficacy of OTX-TP at 3 (8 am) and 10, 20, and 30 days (8 am, 10 am, and 4 pm), compared to baseline. Results A total of 26 OTX-TP were inserted for 17 subjects. The mean (standard deviation) age was 57.2 (13.8) years. At 10 days, all plugs were still present, and the IOP reduction from baseline was 6.2 (23%), 5.4 (21%), and 7.5 mmHg (28%) at 8 am, 10 am, and 4 pm, respectively. At 10 days, the mean IOP (standard error of mean) was 21.2 (1.2), 20.4 (0.8), and 19.7 (1.0) at 8 am, 10 am, and 4 pm, respectively, showing no discernible IOP trend during the course of the day. At 30 days, plug retention had declined to 42%, and the overall IOP reduction had decreased to 16%. Conclusion The sustained-release OTX-TP is able to reduce IOP by 24% (day 10) and 15.6% (day 30), respectively. It is a potentially well-tolerable ocular hypotensive for glaucoma patients with a history of poor compliance. PMID:27175058

  6. Intraocular Pressure and the Mechanisms Involved in Resistance of the Aqueous Humor Flow in the Trabecular Meshwork Outflow Pathways.

    PubMed

    Tamm, Ernst R; Braunger, Barbara M; Fuchshofer, Rudolf

    2015-01-01

    Intraocular pressure (IOP), the critical risk factor for glaucoma, is generated and maintained by the aqueous humor circulation system. Aqueous humor is secreted from the epithelial layers of the ciliary body and exits the eye through the trabecular meshwork or the uveoscleral outflow pathways. IOP builds up in response to a resistance to aqueous humor flow in the trabecular outflow pathways. The trabecular outflow resistance is localized in the inner wall region, which comprises the juxtacanalicular connective tissue (JCT) and the inner wall endothelium of Schlemm's canal (SC). Outflow resistance in this region is lowered through the relaxation of contractile myofibroblast-like cells in trabecular meshwork and the adjacent scleral spur, or the contraction of the ciliary muscle. In primary open-angle glaucoma, the most frequent form of glaucoma, outflow resistance of the inner wall region is typically higher than normal. There is evidence that the increase in resistance is related to characteristic biological changes in the resident cells of the JCT, which more and more acquire the structural and functional characteristics of contractile myofibroblasts. The changes involve an augmentation of their actin cytoskeleton and of their surrounding fibrillary extracellular matrix, which connects to JCT cells via integrins. This scenario leads to an overall stiffening of the inner wall region, and is modulated by transforming growth factor-β/connective tissue growth factor signaling. Essentially comparable changes appear to occur in SC endothelial cells. Stiffening of JCT and SC cells is very likely a critical causative factor for the increase in trabecular outflow resistance in POAG.

  7. Iris transillumination defect and its gene modulators do not correlate with intraocular pressure in the BXD family of mice

    PubMed Central

    Lu, Hong; Lu, Lu; Williams, Robert W.

    2016-01-01

    Purpose Intraocular pressure (IOP) is currently the only treatable phenotype associated with primary open angle glaucoma (POAG). Our group has developed the BXD murine panel for identifying genetic modulators of the various endophenotypes of glaucoma, including pigment dispersion, IOP, and retinal ganglion cell (RGC) death. The BXD family consists of the inbred progeny of crosses between the C57BL/6J (B6) strain and the glaucoma-prone DBA/2J (D2) strain that has mutations in Tyrp1 and Gpnmb. The role of these genes in the iris transillumination defect (TID) has been well documented; however, their possible roles in modulating IOP during glaucoma onset and progression are yet not well understood. Methods We used the IOP data sets and the Eye M430v2 (Sep08) RMA Database available on GeneNetwork to determine whether mutations in Tyrp1 and Gpnmb or TIDs have a direct role in the elevation of IOP in the BXD family. We also determined whether TIDs and IOP are coregulated. Results As expected, Tyrp1 and Gpnmb expression levels showed a high degree of correlation with TIDs. However, there was no correlation between the expression of these genes and IOP. Moreover, unlike TIDs, IOP did not map to either the Tyrp1 or Gpnmb locus. Although the Tyrp1 and Gpnmb mutations in BXD strains are a prerequisite for the development of TID, they are not required for or associated with elevated IOP. Conclusions Genetic modulators of IOP thus may be independently identified using the full array of BXD mice without concern for the presence of TIDs or mutations in Typr1 and/or Gpnmb. PMID:27011731

  8. Clinical utility and differential effects of prostaglandin analogs in the management of raised intraocular pressure and ocular hypertension

    PubMed Central

    Lee, Anne J; McCluskey, Peter

    2010-01-01

    Prostaglandin analogs (PGA) are powerful topical ocular hypotensive agents available for the treatment of elevated intraocular pressure (IOP). Latanoprost 0.005% and travoprost 0.004% are prodrugs and analogs of prostaglandin F2α. Bimatoprost 0.03% is regarded as a prostamide, and debate continues as to whether it is a prodrug. The free acids of all 3 PGAs reduce IOP by enhancing uveoscleral and trabecular outflow via direct effects on ciliary muscle relaxation and remodeling of extracellular matrix. The vast majority of clinical trials demonstrate IOP-lowering superiority of latanoprost, bimatoprost and travoprost compared with timolol 0.5%, brimonidine 0.2%, or dorzolamide 2% monotherapy. Bimatoprost appears to be more efficacious in IOP-lowering compared with latanoprost, with weighted mean difference in IOP reduction documented in one meta-analysis of 2.59% to 5.60% from 1- to 6-months study duration. PGAs reduce IOP further when used as adjunctive therapy. Fixed combinations of latanoprost, bimatoprost or travoprost formulated with timolol 0.5% and administered once daily are superior to monotherapy of its constituent parts. PGA have near absence of systemic side effects, although do have other commonly encountered ocular adverse effects. The adverse effects of PGA, and also those found more frequently with bimatoprost use include ocular hyperemia, eyelash growth, and peri-ocular pigmentary changes. Iris pigmentary change is unique to PGA treatment. Once daily administration and near absence of systemic side effects enhances tolerance and compliance. PGAs are often prescribed as first-line treatment for ocular hypertension and open-angle glaucoma. PMID:20689791

  9. Comparison study of intraocular pressure reduction efficacy and safety between latanoprost and tafluprost in Japanese with normal-tension glaucoma

    PubMed Central

    Ikeda, Yoko; Mori, Kazuhiko; Tada, Kaori; Ueno, Morio; Kinoshita, Shigeru; Sotozono, Chie

    2016-01-01

    Purpose To evaluate and compare the intraocular pressure (IOP) reduction efficacy and safety between the ophthalmic solutions 0.005% latanoprost (Lat) and 0.0015% tafluprost (Taf) in Japanese patients with normal-tension glaucoma (NTG). Methods In this randomized nonmasked study, we prospectively enrolled 30 Japanese NTG patients who had used Lat monotherapy for more than 4 weeks, and randomly divided them into the following two groups: 1) Lat-to-Taf group (LT group) and 2) Taf-to-Lat group (TL group). At the beginning of the study, both groups were switched from initial Lat to Lat or Taf for 12 weeks, and then switched over to the other drug (crossover) for 12 additional weeks. At 0, 4, 12, 16, and 24 weeks, we evaluated each patient’s IOP, conjunctival injection, and corneal epitheliopathy score, and at 0, 12, and 24 weeks, we evaluated their eyelash changes and pigmentation of the eyelids and irises. Results The mean IOP of the LT group (15 eyes) was 10.5, 10.6, and 11.1 mmHg, at 0, 12, and 24 weeks, respectively, whereas that of the TL group (15 eyes) was 11.7, 11.1, and 10.5 mmHg at 0, 12, and 24 weeks, respectively. No significant differences were found between the two groups and in the intragroup comparisons. Moreover, no significant differences were found between Lat and Taf in regard to the conjunctival injection score and corneal epitheliopathy score. Eyelash changes and eyelid and iris pigmentation were similar in both groups. Conclusion The findings of this study show that Lat and Taf have equivalent efficacy and safety in Japanese patients with NTG. PMID:27601879

  10. Changes in intraocular pressure and horizontal pupil diameter during use of topical mydriatics in the canine eye

    PubMed Central

    Kovalcuka, Liga; Ilgazs, Agris; Bandere, Dace; Williams, David L.

    2017-01-01

    The objective of this study was to determine the effects of topical 0.5% tropicamide, 1% atropine sulphate and 10% phenylephrine hydrochloride ophthalmic solutions on intraocular pressure (IOP) and horizontal pupil diameter (HPD) in the dog during the first hour after treatment. Forty clinically and ophthalmologically normal canine patients (between the ages of 2 and 6 years) of varying breed and sex were used in this study. Animals were randomly divided into four groups of ten and given one drop of tropicamide, atropine, phenylephrine or saline into one eye. IOP and HPD were measured in both eyes every 5 minutes for 60 minutes. Tropicamide increased IOP by 8.8±4.0 mmHg 35 minutes post-treatment compared to pre-treatment (P<0.01) only in treated eye. IOP in the contralateral eye did not increase. With atropine the maximum increase in IOP was 2.6±2.8 mmHg at 20 minutes post treatment in the treated eye (P<0.01). IOP in the contralateral eye did not increase. Phenylephrine increased IOP by 2.3±2.1 mmHg (P<0.05) 10 minutes after treatment. Also in the untreated eye IOP increased by 2.3±2.1 mmHg, 20 minutes post-treatment. Maximum HPD in eyes treated with tropicamide occurred at 55 minutes and with atropine at 60 minutes. There were no HPD changes in the contralateral, untreated eye. Topical 10% phenylephrine showed maximal pupil dilation 60 minutes after treatment, but the HPD of the – untreated eye slightly decreased at 15 minutes, but this change only reached statistical significance at 40 min post- treatment (P<0.05). Normal saline showed no influence on IOP or HPD. The drugs investigated here show a significant increase in IOP after mydriatics. PMID:28210543

  11. Alterations of the synapse of the inner retinal layers after chronic intraocular pressure elevation in glaucoma animal model

    PubMed Central

    2014-01-01

    Background Dendrites of retinal ganglion cells (RGCs) synapse with axon terminals of bipolar cells in the inner plexiform layer (IPL). Changes in RGC dendrites and synapses between bipolar cells in the inner retinal layer may critically alter the function of RGCs in glaucoma. Recently, synaptic plasticity has been observed in the adult central nervous system, including the outer retinal layers. However, few studies have focused on changes in the synapses between RGCs and bipolar cells in glaucoma. In the present study, we used a rat model of ocular hypertension induced by episcleral vein cauterization to investigate changes in synaptic structure and protein expression in the inner retinal layer at various time points after moderate intraocular pressure (IOP) elevation. Results Synaptophysin, a presynaptic vesicle protein, increased throughout the IPL, outer plexiform layer, and outer nuclear layer after IOP elevation. Increased synaptophysin after IOP elevation was expressed in bipolar cells in the innermost IPL. The RGC marker, SMI-32, co-localized with synaptophysin in RGC dendrites and were significantly increased at 1 week and 4 weeks after IOP elevation. Both synaptophysin and postsynaptic vesicle protein, PSD-95, were increased after IOP elevation by western blot analysis. Ribbon synapses in the IPL were quantified and structurally evaluated in retinal sections by transmission electron microscopy. After IOP elevation the total number of ribbon synapses decreased. There were increases in synapse diameter and synaptic vesicle number and decreases in active zone length and the number of docked vesicles after IOP elevation. Conclusions Although the total number of synapses decreased as RGCs were lost after IOP elevation, there are attempts to increase synaptic vesicle proteins and immature synapse formation between RGCs and bipolar cells in the inner retinal layers after glaucoma induction. PMID:25116810

  12. Serial Multifocal Electroretinograms during Long-term Elevation and Reduction of Intraocular Pressure in Non-human Primates

    PubMed Central

    Nork, T. Michael; Kim, Charlene B. Y.; Heatley, Gregg A.; Kaufman, Paul L.; Lucarelli, Mark J.; Levin, Leonard A.; Ver Hoeve, James N.

    2010-01-01

    The purpose of this study was to evaluate the relationship between elevations of intraocular pressure (IOP) and the multifocal electroretinogram (mfERG) in non-human primates. Experimental glaucoma was induced in 4 rhesus and 4 cynomolgus monkeys by laser trabecular meshwork destruction (LTD) in one eye. To evaluate the contribution of ganglion cells to mfERG changes, one monkey of each species had previously underwent unilateral optic nerve transection (ONT). After ≥ 44 weeks of elevation, the IOP was reduced by trabeculectomy in 2 non-transected animals. In the intact (non-transected) animals there was an increase in the amplitude of the early mfERG waveforms (N1 and P1) of the first order kernel (K1) throughout the period of IOP elevation in all of the rhesus, but not all of the cynomolgus monkeys. A species difference was also present as a decrease of the second order kernel, first slice (K2.1) in all of the cynomolgus monkeys but only in 1 of the rhesus monkeys (the 1 with the ONT). Similar IOP effects on the mfERG were seen in the ONT animals. Surgical lowering of IOP resulted in a return of the elevated K1 amplitudes to baseline levels. However, the depressed K2.1 RMS in the cynomolgus monkeys did not recover. These results demonstrate species-specific changes in cone-driven retinal function during periods of elevated IOP. These IOP-related effects can occur in the absence of retinal ganglion cells and may be reversible. PMID:20422254

  13. The Effect of Diurnal Fluctuation in Intraocular Pressure on the Evaluation of Risk Factors of Progression in Normal Tension Glaucoma

    PubMed Central

    Kim, Seung Hoon; Lee, Eun Jung; Han, Jong Chul; Sohn, Sae Woon; Rhee, Taekkwan; Kee, Changwon

    2016-01-01

    Purpose To investigate whether diurnal fluctuation in intraocular pressure (IOP) can influence the result of the correlations between IOP-related factors and progression of normal tension glaucoma (NTG). Methods Glaucoma progression was defined as visual field (VF) progression and changes in the optic disc and/or retinal nerve fiber layer (RNFL). Two different methods were used to evaluate the impact of the diurnal fluctuation in IOP. ‘Conventional method’ used in previous studies included all IOP measurements during the follow up time. ‘Time adjusted method’ was used to adjust diurnal fluctuation in IOP with the preferred time. Mean IOP, long term IOP fluctuation and the difference between the lowest and highest IOP were calculated using both methods. Cox regression analyses were performed to evaluate the association between IOP-related factors and NTG progression. Results One hundred and forty eyes of 140 patients with NTG were included in this study. 41% (58 of 140 eyes) of eyes underwent NTG progression. Long term IOP variation calculated by conventional method was not a significant risk factor for NTG progression (hazard ratio[HR], 0.311; 95% confidence interval[CI], 0.056–1.717; P = 0.180). Long term IOP variation calculated by time adjusted method, however, was related to progression, with an HR of 5.260 (95% CI,1.191–23.232; P = 0.029). Conclusion Although having the same IOP-related factors, if diurnal fluctuation is included, different results may be found on the relationship between IOP-related factors and NTG progression. Based on our results, diurnal fluctuation in IOP should be considered when IOP-related factors are studied in the future. PMID:27776182

  14. Repeatability, reproducibility and agreement of intraocular pressure measurement in rabbits by the TonoVet and Tono-Pen

    PubMed Central

    Ma, Di; Chen, Chong-Bo; Liang, Jiajian; Lu, Zhihao; Chen, Haoyu; Zhang, Mingzhi

    2016-01-01

    Tono-Pen and TonoVet have been used in rabbits to measure intraocular pressure (IOP) and investigate the effect of IOP lowering therapies. Therefore, their reliability and accuracy are very important and deserve careful evaluation. Our results showed that the with-subject deviation (Sw) and intraclass correlation coefficient (ICC) of the TonoVet and Tono-Pen were 0.61 mmHg/0.83 mmHg and 0.97/0.94, respectively for intrasession repeatability. For intersession reproducibility, the Sw and ICC of TonoVet and Tono-Pen were 1.42 mmHg/1.66 mmHg and 0.73/0.67, respectively. For interoperator reproducibility, the Sw and ICC of the TonoVet and Tono-Pen were 0.72 mmHg/1.11 mmHg and 0.91/0.82 respectively. Both TonoVet and Tono-Pen underestimated the IOP measured by manometry. The regression function was: y = 0.8249x + 0.1011 and y =0.6881x + 2.2290 for TonoVet and Tono-Pen, respectively. Our study suggests that both TonoVet and Tono-Pen had excellent intrasession repeatability and inter-operator reproducibility, but good intersession reproducibility. Both TonoVet and Tono-Pen correlated well with manometry, but underestimated the manometric IOP with presence of fixed and proportional biases. These factors should be considered when measuring IOP with Tono-Pen or TonoVet in rabbit eyes. PMID:27731381

  15. Characterization of intraocular pressure pattern and changes of retinal ganglion cells in DBA2J glaucoma mice

    PubMed Central

    Wang, Jing; Dong, Yu

    2016-01-01

    AIM To characterize the pattern of intraocular pressure (IOP) change and the deficit of retinal ganglion cells (RGCs) in DBA2J, which is most well-characterized chronic glaucoma mouse model and wild type (WT) C57bl/6 mice, and to study the relationship between IOP change and RGCs deficit. METHODS IOP was monitored with a rebound tonometer in WT C57bl/6 and DBA2J mice from 3 to 15-month-old. Retinal function was evaluated by dark-adapted electroretinogram (ERG) in DBA2J and WT mice of 15-month-old. A dye (Neurobiotin) was applied to optic nerve stump to retrograde label RGCs. TO-PRO-3 visualized all nuclei of cells in the RGC layer. RESULTS The IOP in WT mice was 9.03±0.6 mm Hg on average and did not increase significantly as aging. The IOP in DBA2J mice, arranging from 7.2 to 28 mm Hg, was increasing significantly as aging, and it was normal at 3-month-old compared with WT mice, slightly increased from 7-month-old and increased in 50% animals at 11-month-old and in 38% animals at 15-month-old. The RGCs density in DBA2J mice started reducing by 7-month-old, continuously decreased until reached about 20% of RGC in WT retina by 15-month-old. RGC density was not linearly correlated with IOP in 15-month-old DBA2J mice. The amplitude of positive scotopic threshold response, and negative scotopic threshold response of ERG were significantly reduced in DBA2J mice of 15-month-old than that in age-paired WT mice. CONCLUSION The present study found that DBA2J mice display pathological and functional deficits of the retina that was not linearly correlated with IOP. PMID:26949637

  16. Possible involvement of nitric oxide in morphine-induced miosis and reduction of intraocular pressure in rabbits.

    PubMed

    Bonfiglio, Vincenza; Bucolo, Claudio; Camillieri, Giovanni; Drago, Filippo

    2006-03-18

    The role of mu3 opioid receptors in morphine-induced intraocular pressure (IOP) lowering effect and miosis was evaluated in conscious, dark-adapted New Zealand white (NZW) rabbits using a masked-design study. IOP and pupil diameter (PD) measurements were taken at just before and 0.5, 1, 2, 4, 6 h after monolateral instillation of morphine (10, 50 and 100 microg/30 microl) as compared to vehicle administered in the contralateral eye. Morphine-induced ocular effects were challenged by a pre-treatment with the non-selective opioid receptor antagonist, naloxone (100 microg/30 microl), the nitric oxide synthase inhibitor, N(omega)-nitro-L-arginine methyl ester (L-NAME, 1%, 30 microl), or the non-selective mu3 opioid receptor inhibitor, reduced L-glutathione (GSH, 1%, 30 microl). Morphine induced a dose-dependent decrease in IOP and PD. Pre-treatment with naloxone totally prevented morphine-induced decrease in IOP and miosis. Ocular administration of L-NAME or GSH alone failed to affect IOP or PD of NZW rabbits. However, pre-treatment with either drugs significantly reduced, but not totally prevented ocular effects of morphine. These results suggest that biochemical mechanisms related to nitric oxide release are involved, at least in part, in morphine effects on the eye. Since the mu3 opioid receptor subtype is able to release nitric oxide and is sensitive to inactivation by GSH, it may be possible that mu3 opioid receptors are involved in morphine-induced miosis and reduction in IOP.

  17. Intraocular pressure fluctuation after water drinking test in primary angle-closure glaucoma and primary open-angle glaucoma

    PubMed Central

    Poon, Yi-Chieh; Teng, Mei-Ching; Lin, Pei-Wen; Tsai, Jen-Chia; Lai, Ing-Chou

    2016-01-01

    Context: Only a few studies have assessed intraocular pressure (IOP) changes during the water drinking test (WDT) in patients with primary angle-closure glaucoma (PACG). Aims: The aim of this study is to investigate IOP changes during WDT in patients with PACG versus primary open-angle glaucoma (POAG). Settings and Design: This was a prospective and single tertiary center study. Materials and Methods: PACG and POAG patients (n = 15 each) without prior glaucoma surgery were enrolled and subjected to WDT, wherein they consumed an amount of water proportional to their body weight within 10 min. IOP was measured at baseline and every 15 min for 1 h after water intake. Statistical Analysis Used: Intergroup comparisons were performed using Mann–Whitney U-test for continuous variables and Chi-square test for categorical variables. Wilcoxon signed-ranks test was used for comparisons of IOP before and after water intake in the two groups. Regression analysis was used to determine factors associated with IOP fluctuations during WDT. Results: IOP changes over 1 h after water intake showed no significant differences between groups. The mean maximum fluctuation from baseline was 3.61 ± 2.49 and 3.79 ± 1.91 mmHg, respectively, in the PACG and POAG groups. The mean peak IOP was 19.17 ± 4.32 and 19.87 ± 3.44 mmHg in the PACG and PAOG groups, respectively. The axial length and anterior chamber depth showed no correlations with IOP fluctuations. Conclusions: We found similar IOP fluctuation curves and peak IOP values in both PACG and POAG patients subjected to WDT. These findings suggest that WDT is a useful test to induce IOP peaks in both POAG and PACG patients. PMID:28112134

  18. Lens Position Parameters as Predictors of Intraocular Pressure Reduction After Cataract Surgery in Nonglaucomatous Patients With Open Angles

    PubMed Central

    Hsu, Chi-Hsin; Kakigi, Caitlin L.; Lin, Shuai-Chun; Wang, Yuan-Hung; Porco, Travis; Lin, Shan C.

    2015-01-01

    Purpose To evaluate the relationship between lens position parameters and intraocular pressure (IOP) reduction after cataract surgery in nonglaucomatous eyes with open angles. Methods The main outcome of the prospective study was percentage of IOP change, which was calculated using the preoperative IOP and the IOP 4 months after cataract surgery in nonglaucomatous eyes with open angles. Lens position (LP), defined as anterior chamber depth (ACD) + 1/2 lens thickness (LT), was assessed preoperatively using parameters from optical biometry. Preoperative IOP, central corneal thickness, ACD, LT, axial length (AXL), and the ratio of preoperative IOP to ACD (PD ratio) were also evaluated as potential predictors of percentage of IOP change. The predictive values of the parameters we found to be associated with the primary outcome were compared. Results Four months after cataract surgery, the average IOP reduction was 2.03 ± 2.42 mm Hg, a 12.74% reduction from the preoperative mean of 14.5 ± 3.05 mm Hg. Lens position was correlated with IOP reduction percentage after adjusting for confounders (P = 0.002). Higher preoperative IOP, shallower ACD, shorter AXL, and thicker LT were significantly associated with percentage of IOP decrease. Although not statistically significant, LP was a better predictor of percentage of IOP change compared to PD ratio, preoperative IOP, and ACD. Conclusions The percentage of IOP reduction after cataract surgery in nonglaucomatous eyes with open angles is greater in more anteriorly positioned lenses. Lens position, which is convenient to compute by basic ocular biometric data, is an accessible predictor with considerable predictive value for postoperative IOP change. PMID:26650901

  19. The Intraocular Pressure under Deep versus Moderate Neuromuscular Blockade during Low-Pressure Robot Assisted Laparoscopic Radical Prostatectomy in a Randomized Trial

    PubMed Central

    Shin, Seokyung; Choi, Young Deuk; Hong, Jung Hwa; Kim, Chan Yun; Park, HeeJoon; Bai, Sun-Joon

    2015-01-01

    Background This study aimed to determine whether continuous deep neuromuscular blockade (NMB) improves the surgical conditions and facilitates robotic-assisted laparoscopic radical prostatectomy (RALRP) under low intra-abdominal pressure (IAP) to attenuate the increase in intraocular pressure (IOP) during CO2 pneumoperitoneum in the steep Trendelenburg (ST) position. Methods Sixty-seven patients undergoing RALRP were randomly assigned to a moderate NMB group (Group M), including patients who received atracurium infusion until the end of the ST position, maintaining a train of four count of 1–2; and the deep NMB group (Group D), including patients who received rocuronium infusion, maintaining a post-tetanic count of 1–2. IOP was measured in all patients at nine separate time points. All RALRPs were performed by one surgeon, who rated the overall and worst surgical conditions at the end of the ST position. Results The highest IOP value was observed at T4 (60 min after the ST position) in both Group M (23.3 ± 2.7 mmHg) and Group D (19.8 ± 2.1 mmHg). RALRP was accomplished at an IAP of 8 mmHg in 88% Group D patients and 25% Group M patients. The overall surgical condition grade was 4.0 (3.0–5.0) in Group D and 3.0 (2.0–5.0) in Group M (P < 0.001). Conclusion The current study demonstrated that continuous deep NMB may improve surgical conditions and facilitate RALRP at a low IAP, resulting in significant attenuation of the increase on IOP. Moreover, low-pressure pneumoperitoneum, facilitated by deep NMB still provided acceptable surgical conditions. Trial Registration ClinicalTrials.gov NCT02109133 PMID:26317357

  20. Immediate Postoperative Intraocular Pressure Adjustment Reduces Risk of Cystoid Macular Edema after Uncomplicated Micro Incision Coaxial Phacoemulsification Cataract Surgery

    PubMed Central

    Jarstad, Allison R.; Chung, Gary W.; Tester, Robert A.; Day, Linda E.

    2017-01-01

    Purpose To determine the accuracy of visual estimation of immediate postoperative intraocular pressure (IOP) following microincision cataract surgery (MICS) and the effect of immediate postoperative IOP adjustment on prevention of cystoid macular edema (CME). Setting Ambulatory surgical center. Methods Prospective, randomized analysis of 170 eyes in 135 patients with MICS, performed in a Medicare approved outpatient ambulatory surgery center. Surgical parameters included a keratome incision of 1.5 mm to 2.8 mm, topical anesthetic, case completion IOP estimation by palpation and patient visualization of light, and IOP adjustment before exiting the operating theater. IOPs were classified into three groups: low (<16 mmHg), normal (16 to 21 mmHg), and elevated (>21 to 30 mmHg). IOP measurements were repeated 1 day after surgery. Optical coherence tomography (Stratus OCT, Zeiss) was measured at 2 weeks. An increase in foveal thickness greater than 15 µm was used to indicate CME. Statistical analysis was performed using one- and two-tailed Student's t-tests. Results Mean minimal foveal thickness averaged 207.15 µm in the low pressure group, 205.14 µm in the normal IOP group, and 210.48 µm in the elevated IOP group 2 weeks following surgery. CME occurred in 14 of 170 eyes (8.2%) at 2 weeks (low IOP, 35.7%; normal IOP, 14.2%; elevated IOP, 50.0%). Change in IOP from the operating theater to 1 day after surgery was within +/−5 mmHg in 54 eyes (31.7%), elevated by 6 to 15 mmHg in 22 eyes (12.9%), and elevated more than 15 mmHg in four eyes (2.3%). IOP was reduced by 6 mmHg to 15 mmHg in 39 eyes (22.9%) and reduced by more than 15 mmHg in nine eyes (5.3%). Conclusions Immediate postoperative adjustment of IOP may prevent CME in MICS. Physicians can improve their ability to estimate postoperative IOP with experience in tonometry to verify immediate postoperative IOP. There are patient safety and economic benefits to immediate IOP adjustment in the operating theater

  1. Analysis of the effects of non-supine sleeping positions on the stress, strain, deformation and intraocular pressure of the human eye

    NASA Astrophysics Data System (ADS)

    Volpe, Peter A.

    This thesis presents analytical models, finite element models and experimental data to investigate the response of the human eye to loads that can be experienced when in a non-supine sleeping position. The hypothesis being investigated is that non-supine sleeping positions can lead to stress, strain and deformation of the eye as well as changes in intraocular pressure (IOP) that may exacerbate vision loss in individuals who have glaucoma. To investigate the quasi-static changes in stress and internal pressure, a Fluid-Structure Interaction simulation was performed on an axisymmetrical model of an eye. Common Aerospace Engineering methods for analyzing pressure vessels and hyperelastic structural walls are applied to developing a suitable model. The quasi-static pressure increase was used in an iterative code to analyze changes in IOP over time.

  2. Effects of Systemic Administration of Dexmedetomidine on Intraocular Pressure and Ocular Perfusion Pressure during Laparoscopic Surgery in a Steep Trendelenburg Position: Prospective, Randomized, Double-Blinded Study

    PubMed Central

    2016-01-01

    Increased intraocular pressure (IOP) during surgery is a risk factor for postoperative ophthalmological complications. We assessed the efficacy of systemically infused dexmedetomidine in preventing the increase in IOP caused by a steep Trendelenburg position, and evaluated the influence of underlying hypertension on IOP during surgery. Sixty patients undergoing laparoscopic surgery in a steep Trendelenburg position were included. Patients in the dexmedetomidine group received a 1.0 µg/kg IV loading dose of dexmedetomidine before anesthesia, followed by an infusion of 0.5 µg/kg/hr throughout the operation. Patients in the saline group were infused with the same volume of normal saline. IOP and ocular perfusion pressure (OPP) were measured 16 times pre- and intraoperatively. In the saline group, IOP increased in the steep Trendelenburg position, and was 11.3 mmHg higher at the end of the time at the position compared with the baseline value (before anesthetic induction). This increase in IOP was attenuated in the dexmedetomidine group, for which IOP was only 4.2 mmHg higher (P < 0.001 vs. the saline group). The steep Trendelenburg position was associated with a decrease in OPP; the degree of decrease was comparable for both groups. In intragroup comparisons between patients with underlying hypertension and normotensive patients, the values of IOP at every time point were comparable. Dexmedetomidine infusion attenuated the increase in IOP during laparoscopic surgery in a steep Trendelenburg position, without further decreasing the OPP. Systemic hypertension did not seem to be associated with any additional increase in IOP during surgery. (Registration at the Clinical Research Information Service of Korea National Institute of Health ID: KCT0001482) PMID:27247511

  3. Research in Distributed Real-Time Systems

    NASA Technical Reports Server (NTRS)

    Mukkamala, R.

    1997-01-01

    This document summarizes the progress we have made on our study of issues concerning the schedulability of real-time systems. Our study has produced several results in the scalability issues of distributed real-time systems. In particular, we have used our techniques to resolve schedulability issues in distributed systems with end-to-end requirements. During the next year (1997-98), we propose to extend the current work to address the modeling and workload characterization issues in distributed real-time systems. In particular, we propose to investigate the effect of different workload models and component models on the design and the subsequent performance of distributed real-time systems.

  4. Effect of Glaucoma Medications on 24-h Intraocular Pressure-related Patterns Using a Contact Lens Sensor

    PubMed Central

    Mansouri, Kaweh; Medeiros, Felipe A.; Weinreb, Robert N.

    2015-01-01

    Background To study the circadian intraocular pressure-related (IOP) effects of ocular hypotensive medications using a contact lens sensor (CLS). Design University-based prospective, randomized, crossover trial. Participants Twenty-three patients with primary open-angle glaucoma Methods Patients underwent ambulatory recording of IOP-related patterns for 24 hours in one eye during 3 monthly sessions using a CLS. Patients were untreated in session 1 (S1), were randomized to one of 4 classes of glaucoma drops for S2, and had a prostaglandin analog add-on for S3. Outcome measures Changes in IOP-related patterns were defined using 1) slopes from wake/sitting to sleep/supine, 2) cosinor rhythmometry modeling, and 3) area under receiver operating curve (AUC) of sleep period. Results Mean patient age was 63.8±11.8 years. Positive linear slopes were seen from wake/sitting to sleep/supine at S1 (17.1±14.2 mVeq/h) and S2 (5.5±23.9 mVeq/h) and negative slopes at S3 (−1.9±29.4 mVeq/h) (S1 to S2, p=0.01; S1 to S3, p=0.02). In the prostaglandin group, slopes changed significantly with introduction of drops (S1 to S2, p<0.024) while they did not in a mixed group combining the 3 other classes (S1 to S2, p=0.060). Overall, cosinor amplitudes were 98.4±46.5 mVeq (S1), 113.0±35.6 mVeq (S2), and 109.6±58.3 mVeq (S3) (S1–S2, p=0.23; S1–S3, p=0.66; S2–S3, p=0.93). AUC was 91.8±63.0 mVeq (S1), 76.3±102.7mVeq (S2), and 19.9±135.8 mVeq (S3). Differences between sessions were not statistically significant (S1–S2, p=0.541; S1–3, p=0.083; S2–S3, p=0.092). Conclusions Prostaglandin analogs but not other medications seem to flatten the IOP-related increase at transition of the wake/sitting to the sleep/supine period but do not seem to have an effect on acrophase and amplitude. PMID:26152693

  5. Comparison of Keeler Pulsair EasyEye tonometer and Ocular Response Analyzer for measuring intraocular pressure in healthy eyes

    PubMed Central

    Lopez-De La Fuente, Carmen; Sanchez-Cano, Ana; Ferreras, Antonio; Fuertes-Lazaro, Isabel

    2012-01-01

    Purpose To evaluate the relationship between intraocular pressure (IOP) measurements obtained with Pulsair EasyEye (PEE) and Ocular Response Analyser (ORA) in healthy patients. Methods Sixty-five eyes from 65 patients underwent a full optometric examination, including central corneal thickness (CCT), and IOP measured with PEE and ORA. Differences between IOP measurements between both tonometers were analyzed. Pearson correlation coefficients between IOP values and ORA corneal biomechanics parameters were also obtained. Results Statistically significant differences were found between IOP of PEE (IOPk) and Goldmann-corrected IOP of ORA (IOPg; p = 0.001). IOPk and corneal resistance-corrected IOP of ORA (IOPcc) were also found to differ significantly (p = 0.025). Mean differences between IOPg-IOPk, IOPcc-IOPk and IOPg-IOPcc were 0.71 ± 1.66, 0.70 ± 2.46 and 0.01 ± 1.54 mmHg (mean ± standard deviation), respectively. Pearson correlation coefficients indicated that IOPk, IOPg, and IOPcc were significantly correlated among them (p < 0.001): r = 0.816 for IOPk-IOPg, r = 0.826 for IOPcc-IOPg and r = 0.587 IOPcc-IOPk. IOPk and IOPg were linearly associated with corneal resistance factor (CRF; r = 0.626 and r = 0.619, respectively) and with CCT (r = 0.531 and r = 0.579, respectively). IOPcc had a linear relationship with corneal hysteresis (CH) (r = −0.482) and similar results were found between CRF and CH (r = 0.841), CRF and CCT (r = 0.681) or between CH and CCT (r = 0.466). Conclusions Differences between mean values of IOP measured with PEE and ORA are statistically significant, with ORA tonometer taking higher IOP values than PEE in most of the cases. IOPk, IOPcc and IOPg have, al least, moderate positive linear correlations and ORA biomechanics parameters CRF, CH and CCT have a linear positive relation between them.

  6. A Comparison of the Corrected Intraocular Pressure Obtained by the Corvis ST and Reichert 7CR Tonometers in Glaucoma Patients

    PubMed Central

    Kiuchi, Yoshiaki; Okimoto, Satoshi

    2017-01-01

    The purpose of the study was to investigate the accuracy of two corrected intraocular pressure (IOP) measurements by Corvis Scheimpflug Technology (CST)-IOPpachy and by corneal-compensated IOP (IOPcc) using the Reichert 7CR (7CR) tonometers. We also investigated the effects of corneal anatomical and structural parameters on the IOP measurements. The participants included 90 primary open-angle glaucoma patients. We assessed the IOP measurements, obtained by the CST, 7CR, and Goldmann applanation tonometer (GAT), using a paired t-test with Bonferroni correction, Bland-Altman plots, and multiple regression analyses. The 7CR-IOPcc gave the highest value (15.5 ± 2.7 mmHg), followed by the 7CR-IOPg (13.7 ± 3.1 mmHg), GAT-IOP (13.6 ± 2.2 mmHg), CST-IOP (10.3 ± 2.6 mmHg), and CST-IOPpachy (9.7 ± 2.5 mmHg). The values of CST-IOPpachy were significantly lower than those obtained by the other IOP measurement methods (all, p < 0.01). The values of 7CR-IOPcc were significantly higher than those obtained by the other IOP measurement methods (all, p < 0.01). Bland-Altman plots showed a mean difference between the GAT-IOP and the other IOP measurements (CST-IOP, CST-IOPpachy, 7CR-IOPg, and 7CR-IOPcc), which were −3.20, −3.82, 0.14, and 2.00 mmHg, respectively. The widths of the 95% limits of agreement between all pairs of IOP measurements were greater than 3 mmHg. With the exception of the 7CR-IOPcc, all of the IOP variations were explained by regression coefficients involving gender, average corneal curvature, and central corneal thickness. The IOP values obtained by the GAT, CST, and 7CR were not interchangeable. Each new IOP measurement device that was corrected for ocular structure had its own limitations. PMID:28095506

  7. Effects of topical travoprost 0.004% on intraocular pressure and corneal biomechanical properties in an animal model

    PubMed Central

    Lazcano-Gomez, Gabriel; Ancona-Lezama, David; Gil-Carrasco, Felix; Jimenez-Roman, Jesus

    2016-01-01

    Purpose To determine whether topical application of travoprost 0.004% induces changes in corneal biomechanical properties affecting intraocular pressure (IOP) values in rabbits. Methods Both eyes of 10 New Zealand rabbits were measured 3 times with the Ocular Response Analyzer (ORA) before treatment. Each measurement included corneal hysteresis (CH), corneal resistance factor (CRF), corneal-corrected IOP (IOPcc), and Goldmann equivalent IOP (IOPg). A drop of travoprost 0.004% was applied once daily in right eyes for 3 months; left eyes received no treatments. After 3 months of treatment both eyes of all rabbits were again measured 3 times. After complete keratectomy of both eyes, tissues prepared with hematoxylin-eosin stain were analyzed by means of light microscopy. Results The mean pre- and post-treatment IOPg, respectively, for right eyes was 9.92 ± 5.64 mm Hg and 7.62 ± 2.99 mm Hg (P = 0.027); IOPcc, 19.81 ± 5.25 mm Hg and 17.79 ± 4.09 mm Hg (P = 0.063); CRF, 1.65 ± 1.63 mm Hg and 2.18 ± 2.50 mm Hg (P = 0.266); and CH, 2.79 ± 1.74 mm Hg and 2.64 ± 2.08 mm Hg (P = 0.72). Mean post-treatment right and left eye IOPg values were, respectively, 7.62 ± 2.99 and 10.30 ± 4.40 (P = 0.002); IOPcc, 17.79 ± 4.09 mm Hg and 20.37 ± 4.32 mm Hg (P = 0.009); CRF, 1.65 ± 1.63 mm Hg and 2.17 ± 2.47 mm Hg (P = 0.274); and CH, 2.79 ± 1.74 mm Hg and 2.54 ± 2.08 mm Hg (P = 0.575). No difference in CH and CRF was observed between treated and untreated eyes. Conclusions Post-treatment reduction of IOP in treated eyes was a direct hypotensive effect of travoprost 0.004% and was not affected by changes in corneal biomechanical properties (CH and CRF), resulting in real lower IOP values. PMID:27330476

  8. Eye rubbing-induced changes in intraocular pressure and corneal thickness measured at five locations, in subjects with ocular allergy

    PubMed Central

    Osuagwu, Uchechukwu L.; Alanazi, Saud A.

    2015-01-01

    AIM To assess the effects of eye rubbing on corneal thickness (CT) and intraocular pressure (IOP) measurements obtained 0-30min after habitual eye rubbing in symptomatic patients. METHODS Measurements of IOP and CT were obtained at five locations (central, temporal, superior, nasal and inferior) before, and every 5min for 30min interval after 30s of eye rubbing, for 25 randomly selected eyes of 14 subjects with ocular allergy and 11 age-matched normals. Differences in measurements were calculated in each group [Baseline measurements minus measurements recorded at each time interval after eye rubbing (for IOP), and for each corneal location (for CT)] and comparison were then made between groups (allergic versus control) for differences in any observed effects. RESULTS Within groups, baseline mean IOPs in the allergic patient-group (14.2±3.0 mm Hg) and in the control group (13.1±1.9 mm Hg) were similar at all times, after eye rubbing (P >0.05, for all). The maximum reduction in IOP was 0.8 mm Hg in the control subjects and the maximum increase was also 0.8 mm Hg in the allergic subjects. Between groups (allergic versus control), the changes in IOP remained under 1 mm Hg at all times (P=0.2) after 30min of eye rubbing. Between 0 and 30min of CT measurements after eye rubbing, the mean central CT (CCT), inferior CT (ICT), superior CT (SCT), temporal CT (TCT) and nasal CT (NCT) did not vary significantly from baseline values in the control and allergic-subject groups (P>0.05, for both). Between both groups, changes in CT were similar at all locations (P>0.05) except for the TC which was minimally thinner by about 4.4 µm (P=0.001) in the allergic subjects than in the control subjects, 30min following 30s of eye rubbing. CONCLUSION IOP measured in allergic subjects after 30s of habitual eye rubbing was comparable with that obtained in normal subjects at all times between 0 and 30min. Although, CT in the allergic subjects were similar to those of the control subjects at

  9. Twenty-four-hour intraocular pressure related changes following adjuvant selective laser trabeculoplasty for normal tension glaucoma.

    PubMed

    Lee, Jacky W Y; Fu, Lin; Chan, Jonathan C H; Lai, Jimmy S M

    2014-12-01

    To investigate intraocular pressure (IOP) related patterns before and after selective laser trabeculoplasty (SLT) for normal tension glaucoma (NTG).In this prospective cohort study, 18 NTG patients underwent SLT. Success was defined as IOP reduction ≥ 20% by Goldmann applanation tonometry. 24-hour IOP-related pattern recording with a contact lens sensor (CLS) (SENSIMED Triggerfish, Sensimed, Switzerland) was done before (baseline) and 1 month after SLT. A cosine function was fitted to the mean CLS patterns for each individual in the SLT success and non-success groups and the amplitude before and after SLT was calculated. Diurnal, nocturnal, and 24-hour CLS pattern local variability was determined for pre- and post-SLT sessions. Cosine amplitude and variability were compared before and after SLT by group using paired t-tests, with α = 0.05. Patients (11 women, 7 men) had a mean age of 65.1 ± 13.7 years. Mean IOP was 15.3 ± 2.2 mm Hg at baseline and was reduced by 17.0% to 12.7 ± 1.8 mm Hg 1 month after SLT (P = 0.001). SLT was successful in 8 patients (44%). The amplitude of the fitted cosine was reduced by 24.6% in the success group, but displayed an amplitude increase of 19.2% post-SLT in the non-success group. Higher diurnal local variability of the CLS pattern was observed after SLT in non-success subjects (P = 0.002), while nocturnal variability showed no significant change. The increase in diurnal variability in the non-success group led to an increase in 24-hour variability in this group (P = 0.001). No change in local variability (diurnal, nocturnal, and 24-hour) was seen in the success group. The IOP-related pattern cosinor amplitude was reduced in NTG patients with a successful SLT treatment whereas the non-success group exhibited an increase of cosine amplitude. Higher diurnal and 24-hour CLS pattern variability was observed in non-success patients 1 month post-SLT.

  10. Long-Term Changes in Intraocular Pressure after Vitrectomy for Rhegmatogenous Retinal Detachment, Epi-Retinal Membrane, or Macular Hole

    PubMed Central

    Yamamoto, Kentaro; Iwase, Takeshi; Terasaki, Hiroko

    2016-01-01

    Purpose To determine the long-term changes in the intraocular pressure (IOP) following vitrectomy for rhegmatogenous retinal detachment (RRD), epiretinal membrane (ERM), and macular hole (MH), and to investigate the relationship between the retinal disease and the incidence of late-onset IOP elevation. Methods This was a retrospective, observational, comparative study. We reviewed the medical records of 54 eyes of 54 RRD patients, 117 eyes of 117 ERM patients, and 75 eyes of 75 MH patients who underwent 20-, 23- or 25-gauge vitrectomy. The IOPs before surgery and 1, 3, 6, and 12 months following vitrectomy, and also at the final visit (average, 23.95 months) were evaluated. We defined a significant increase in the IOP as an increase of ≥4 mmHg from the preoperative IOP, and this increase was taken to be a ‘death’ event for the Kaplan-Meier survival analyses. Results The mean follow-up period was not significantly different among the groups. The mean IOP at 3 (P = 0.001) and 12 (P = 0.011) months following the vitrectomy and at the final visit (P = 0.002) were significantly higher than that before the vitrectomy in the RRD group. The mean IOP in the RRD group was significant higher than that in the ERM group at 1 (P = 0.005), 3 (P = 0.009), and 12 (P = 0.013) months following vitrectomy, and at the final visit (P = 0.032). Kaplan-Meier survival analyses showed that the RRD group had a significantly higher risk of an IOP increase following vitrectomy than the other groups (P<0.001 by log-rank test). Multivariate logistic regression analyses showed that a preoperative diagnosis of RRD was the only risk factor that was significantly associated with a postoperative IOP elevation after excluding eyes with a low preoperative IOP (odds ratio, 3.208; P = 0.003). Conclusions A late-onset IOP elevation following vitrectomy was observed only in eyes that underwent RRD surgery. The elevation was probably caused by the specific characteristics and surgical procedures of

  11. Real time programming environment for Windows

    SciTech Connect

    LaBelle, D.R.

    1998-04-01

    This document provides a description of the Real Time Programming Environment (RTProE). RTProE tools allow a programmer to create soft real time projects under general, multi-purpose operating systems. The basic features necessary for real time applications are provided by RTProE, leaving the programmer free to concentrate efforts on his specific project. The current version supports Microsoft Windows{trademark} 95 and NT. The tasks of real time synchronization and communication with other programs are handled by RTProE. RTProE includes a generic method for connecting a graphical user interface (GUI) to allow real time control and interaction with the programmer`s product. Topics covered in this paper include real time performance issues, portability, details of shared memory management, code scheduling, application control, Operating System specific concerns and the use of Computer Aided Software Engineering (CASE) tools. The development of RTProE is an important step in the expansion of the real time programming community. The financial costs associated with using the system are minimal. All source code for RTProE has been made publicly available. Any person with access to a personal computer, Windows 95 or NT, and C or FORTRAN compilers can quickly enter the world of real time modeling and simulation.

  12. Aqueous Angiography: Real-Time and Physiologic Aqueous Humor Outflow Imaging

    PubMed Central

    Saraswathy, Sindhu; Tan, James C. H.; Yu, Fei; Francis, Brian A.; Hinton, David R.; Weinreb, Robert N.; Huang, Alex S.

    2016-01-01

    Purpose Trabecular meshwork (TM) bypass surgeries attempt to enhance aqueous humor outflow (AHO) to lower intraocular pressure (IOP). While TM bypass results are promising, inconsistent success is seen. One hypothesis for this variability rests upon segmental (non-360 degrees uniform) AHO. We describe aqueous angiography as a real-time and physiologic AHO imaging technique in model eyes as a way to simulate live AHO imaging. Methods Pig (n = 46) and human (n = 6) enucleated eyes were obtained, orientated based upon inferior oblique insertion, and pre-perfused with balanced salt solution via a Lewicky AC maintainer through a 1mm side-port. Fluorescein (2.5%) was introduced intracamerally at 10 or 30 mm Hg. With an angiographer, infrared and fluorescent (486 nm) images were acquired. Image processing allowed for collection of pixel information based on intensity or location for statistical analyses. Concurrent OCT was performed, and fixable fluorescent dextrans were introduced into the eye for histological analysis of angiographically active areas. Results Aqueous angiography yielded high quality images with segmental patterns (p<0.0001; Kruskal-Wallis test). No single quadrant was consistently identified as the primary quadrant of angiographic signal (p = 0.06–0.86; Kruskal-Wallis test). Regions of high proximal signal did not necessarily correlate with regions of high distal signal. Angiographically positive but not negative areas demonstrated intrascleral lumens on OCT images. Aqueous angiography with fluorescent dextrans led to their trapping in AHO pathways. Conclusions Aqueous angiography is a real-time and physiologic AHO imaging technique in model eyes. PMID:26807586

  13. Phakic Intraocular Lenses

    MedlinePlus

    ... Implants and Prosthetics Phakic Intraocular Lenses Phakic Intraocular Lenses Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Phakic intraocular lenses are new devices used to correct nearsightedness. These ...

  14. Seismic monitoring and real time damage estimation for lifelines

    SciTech Connect

    Takada, Shiro; Ogawa, Yasuo

    1995-12-31

    This paper presents a methodology for estimating the number of damaged locations of lifeline systems based on seismic monitoring ground motions taking consideration of liquefaction phenomena. The liquefaction area and the number of damage to the lifeline facilities can be synthetically indicated by a personal computer program developed for this purpose. The method is based on the real time observed data of strong ground motions. Osaka Gas Company had been developing the real time damage simulation system by planning to set additional tele-meter seismographs when the Hanshin Great Earthquake occurred. Other lifelines such as electricity, telecommunication, water and sewage systems in quake-hit area had not such a real time damage simulation tool based on observed ground motions. On the other hand, these lifelines have their own damage detection system such as pressure, flow, relay signal, etc.

  15. A new real-time tsunami detection algorithm

    NASA Astrophysics Data System (ADS)

    Chierici, Francesco; Embriaco, Davide; Pignagnoli, Luca

    2017-01-01

    Real-time tsunami detection algorithms play a key role in any Tsunami Early Warning System. We have developed a new algorithm for tsunami detection based on the real-time tide removal and real-time band-pass filtering of seabed pressure recordings. The algorithm greatly increases the tsunami detection probability, shortens the detection delay and enhances detection reliability with respect to the most widely used tsunami detection algorithm, while containing the computational cost. The algorithm is designed to be used also in autonomous early warning systems with a set of input parameters and procedures which can be reconfigured in real time. We have also developed a methodology based on Monte Carlo simulations to test the tsunami detection algorithms. The algorithm performance is estimated by defining and evaluating statistical parameters, namely the detection probability, the detection delay, which are functions of the tsunami amplitude and wavelength, and the occurring rate of false alarms. Pressure data sets acquired by Bottom Pressure Recorders in different locations and environmental conditions have been used in order to consider real working scenarios in the test. We also present an application of the algorithm to the tsunami event which occurred at Haida Gwaii on 28 October 2012 using data recorded by the Bullseye underwater node of Ocean Networks Canada. The algorithm successfully ran for test purpose in year-long missions onboard abyssal observatories, deployed in the Gulf of Cadiz and in the Western Ionian Sea.

  16. The ALMA Real Time Control System

    NASA Astrophysics Data System (ADS)

    Kern, Jeffrey S.; Juerges, Thomas A.; Marson, Ralph G.

    2009-01-01

    The Atacama Large Millimeter Array (ALMA) is a revolutionary millimeter and submillimeter array being developed on the Atacama plateau of northern Chile. An international partnership lead by NRAO, ESO, and NAOJ this powerful and flexible telescope will provide unprecedented observations of this relatively unexplored frequency range. The control subsystem for the Atacama Large Millimeter Array must coordinate the monitor and control of at least sixty six antennas (in four different styles), two correlators, and all of the ancillary equipment (samplers, local oscillators, front ends, etc.). This equipment will be spread over tens of kilometers and operated remotely. Operation of the array requires a robust, scalable, and maintainable real time control system. The real time control system is responsible for monitoring and control of any devices where there are fixed deadlines. Examples in the ALMA context are antenna pointing and fringe tracking. Traditionally the real time portion of a large software system is an intricate and error prone portion of the software. As a result the real time portion is very expensive in terms of effort expended both during construction and during maintenance phases of a project. The ALMA real time control system uses a Linux based real time operating system to interact with the hardware and the CORBA based ALMA Common Software to communicate in the distributed computing environment. Mixing the requirements of real time computing and the non-deterministic CORBA middleware has produced an interesting design. We discuss the architecture, design, and implementation of the ALMA real time control system. Highlight some lessons learned along the way, and justify our assertion that this should be the last large scale real time control system in radio astronomy.

  17. Real-time monitoring of landslides

    USGS Publications Warehouse

    Reid, Mark E.; LaHusen, Richard G.; Baum, Rex L.; Kean, Jason W.; Schulz, William H.; Highland, Lynn M.

    2012-01-01

    Landslides cause fatalities and property damage throughout the Nation. To reduce the impact from hazardous landslides, the U.S. Geological Survey develops and uses real-time and near-real-time landslide monitoring systems. Monitoring can detect when hillslopes are primed for sliding and can provide early indications of rapid, catastrophic movement. Continuous information from up-to-the-minute or real-time monitoring provides prompt notification of landslide activity, advances our understanding of landslide behavior, and enables more effective engineering and planning efforts.

  18. Achieving real-time performance in FIESTA

    NASA Technical Reports Server (NTRS)

    Wilkinson, William; Happell, Nadine; Miksell, Steve; Quillin, Robert; Carlisle, Candace

    1988-01-01

    The Fault Isolation Expert System for TDRSS Applications (FIESTA) is targeted for operation in a real-time online environment. Initial stages of the prototype development concentrated on acquisition and representation of the knowledge necessary to isolate faults in the TDRSS Network. Recent efforts focused on achieving real-time performance including: a discussion of the meaning of FIESTA real-time requirements, determination of performance levels (benchmarking) and techniques for optimization. Optimization techniques presented include redesign of critical relations, filtering of redundant data and optimization of patterns used in rules. Results are summarized.

  19. Real-time medical applications and telecommunications.

    PubMed

    Stravs, M

    1999-01-01

    Telecommunications play an important role in telemedicine. Many forms of telecommunication services based on different telecommunication technologies are developed for various needs. The paper deals with complex real-time applications which demand high telecommunication requirements. At the beginning, medical applications are categorised and real-time applications qualified as multimedia applications. Requirements for multimedia elements are listed separately. Later on, short introduction of related telecommunication protocols is given. Real-time medical applications can show their ability in case of guaranteed quality of services delivered by telecommunication network as it is explained in the end.

  20. Real time sensor for therapeutic radiation delivery

    DOEpatents

    Bliss, M.; Craig, R.A.; Reeder, P.L.

    1998-01-06

    The invention is a real time sensor for therapeutic radiation. A probe is placed in or near the patient that senses in real time the dose at the location of the probe. The strength of the dose is determined by either an insertion or an exit probe. The location is determined by a series of vertical and horizontal sensing elements that gives the operator a real time read out dose location relative to placement of the patient. The increased accuracy prevents serious tissue damage to the patient by preventing overdose or delivery of a dose to a wrong location within the body. 14 figs.

  1. Real time sensor for therapeutic radiation delivery

    DOEpatents

    Bliss, Mary; Craig, Richard A.; Reeder, Paul L.

    1998-01-01

    The invention is a real time sensor for therapeutic radiation. A probe is placed in or near the patient that senses in real time the dose at the location of the probe. The strength of the dose is determined by either an insertion or an exit probe. The location is determined by a series of vertical and horizontal sensing elements that gives the operator a real time read out dose location relative to placement of the patient. The increased accuracy prevents serious tissue damage to the patient by preventing overdose or delivery of a dose to a wrong location within the body.

  2. The dark phase intraocular pressure elevation and retinal ganglion cell degeneration in a rat model of experimental glaucoma.

    PubMed

    Kwong, Jacky M K; Vo, Nancy; Quan, Ann; Nam, Michael; Kyung, Haksu; Yu, Fei; Piri, Natik; Caprioli, Joseph

    2013-07-01

    Intraocular pressure (IOP) elevation is considered as a major risk factor causing the progression of vision deterioration in glaucoma. Although it is known that the IOP level changes widely throughout the day and night, how the dark or light phase IOP elevation contributes to retinal ganglion cell (RGC) degeneration is still largely unclear. To examine the profile of IOP, modified laser photocoagulation was applied to the trabecular meshwork of Brown Norway rats and both light and dark phase IOPs were monitored approximately 1-2 times a week. The relationship between IOP elevation and RGC degeneration was investigated while RGC body loss was analyzed with Rbpms immunolabeling on retinal wholemount and axonal injury in the optic nerve was semi-quantified. The baseline awake dark and light IOPs were 30.4 ± 2.7 and 20.2 ± 2.1 mmHg respectively. The average dark IOP was increased to 38.2 ± 3.2 mmHg for five weeks after the laser treatment on 270° trabecular meshwork. However, there was no significant loss of RGC body and axonal injury. After laser treatment on 330° trabecular meshwork, the dark and light IOPs were significantly increased to 43.8 ± 4.6 and 23 ± 3.7 mmHg respectively for 5 weeks. The cumulative dark and light IOP elevations were 277 ± 86 and 113 ± 50 mmHg days respectively while the cumulative total (light and dark) IOP elevation was 213 ± 114 mmHg days. After 5 weeks, regional RGC body loss of 29.5 ± 15.5% and moderate axonal injury were observed. Axonal injury and loss of RGC body had a high correlation with the cumulative total IOP elevation (R(2) = 0.60 and 0.65 respectively). There was an association between the cumulative dark IOP elevation and RGC body loss (R(2) = 0.37) and axonal injury (R(2) = 0.51) whereas the associations between neuronal damages and the cumulative light IOP elevation were weak (for RGC body loss, R(2) = 0.01; for axonal injury, R(2) = 0.26). Simple linear regression model

  3. Nonpsychotropic cannabinoids, abnormal cannabidiol and canabigerol-dimethyl heptyl, act at novel cannabinoid receptors to reduce intraocular pressure.

    PubMed

    Szczesniak, Anna-Maria; Maor, Yehoshua; Robertson, Harold; Hung, Orlando; Kelly, Melanie E M

    2011-10-01

    The objective of our study was to examine the pharmacology of the intraocular pressure (IOP)-lowering actions of the behaviorally inactive cannabinoids, abnormal cannabidiol (abn-CBD), and a cannabigerol analog, cannabigerol-dimethyl heptyl (CBG-DMH), in comparison to that of the nonselective cannabinoid 1 receptor (CB(1)R) and CB(2)R agonist, WIN55,212-2, in Brown Norway rats. The IOP was measured noninvasively using a hand-held tonometer in nonanesthetized animals. The IOP measurements were taken every 15 min for a period of 2 h after drug administration. All drugs were administered via intraperitoneal (i.p.) injections, and abn-CBD and CBG-DMH were also given topically. Both abn-CBD and CBG-DMH reduced IOP when administrated i.p. at doses of ≥2.5 mg/kg or topically at concentrations of 1%-2%. The IOP-lowering effects of abn-CBD and CBG-DMH were reduced by i.p. administration of O-1918 (2.5 mg/kg), a selective antagonist of the abn-CBD-sensitive cannabinoid-related receptor (CBx), but were unaffected by the CB(1)R antagonist, AM251 (2.5 mg/kg), or the CB(2)R antagonist, AM630 (2.5 mg/kg). In contrast, the IOP-lowering action of WIN55,212-2 was completely blocked by the CB(1)R-selective antagonist, AM251, and was unaffected by the CBx receptor antagonist, O-1918. However, similar to the nonpsychotropic cannabinoids, the ocular hypotensive actions of WIN55,212-2 were also insensitive to block by the CB(2)R antagonist, AM630. Consistent with this, the selective CB(2)R agonist, HU-308 (2 mg/kg) failed to reduce IOP in Brown Norway rats. Concurrent application of a dose of WIN55,212-2 that was subthreshold to reduce IOP (0.25 mg/kg), together with a topical dose of either abn-CBD (0.5%) or CBG-DMH (0.25%), respectively, potentiated the ocular hypotensive effect of either compound applied alone. This study demonstrates that the atypical cannabinoid, abn-CBD, and the cannabigerol analog, CBG-DMH, decrease IOP in the normotensive Brown Norway rat eye independent of CB

  4. REAL-TIME TRACER MONITORING OF RESERVOIR STIMULATION PROCEDURES

    SciTech Connect

    George Scott III

    2002-08-01

    Ongoing Phase 2 work comprises the development and field-testing of a real-time reservoir stimulation diagnostic system. Phase 3 work commenced in June 2001, and involved conducting research, development and field-testing of real-time enhanced dual-fluid stimulation processes. Experimental field-testing to date includes three well tests. Application of these real-time stimulation processes and diagnostic technologies has been technically successful with commercial production from the ''marginal'' reservoirs in the first two well tests. The third well test proved downhole-mixing is an efficient process for acid stimulation of a carbonate reservoir that produced oil and gas with 2200 psi bottomhole reservoir pressure, however, subsequent shut-in pressure testing indicated the reservoir was characterized by low-permeability. Realtimezone continues to seek patent protection in foreign markets to the benefit of both RTZ and NETL. Realtimezone and the NETL have licensed the United States patented to Halliburton Energy Services (HES). Ongoing Phase 2 and Phase 3 field-testing continues to confirm applications of both real-time technologies, from well testing conducted over the last 12-month work period and including well test scheduled for year-end of 2002. Technical data transfer to industry is ongoing via Internet tech-transfer, public presentations and industry publications. Final Phase 3 test work will be focused on further field-testing the innovational process of blending stimulation fluids downhole. This system provides a number of advantages in comparison to older industry fracturing techniques and allows the operator to control reservoir fracture propagation and concentrations of proppant placed in the reservoir, in real-time. Another observed advantage is that lower friction pressures result, which results in lower pump treating pressures and safer reservoir hydraulic fracturing jobs.

  5. Real-time scheduling using minimum search

    NASA Technical Reports Server (NTRS)

    Tadepalli, Prasad; Joshi, Varad

    1992-01-01

    In this paper we consider a simple model of real-time scheduling. We present a real-time scheduling system called RTS which is based on Korf's Minimin algorithm. Experimental results show that the schedule quality initially improves with the amount of look-ahead search and tapers off quickly. So it sppears that reasonably good schedules can be produced with a relatively shallow search.

  6. The LAA real-time benchmarks

    SciTech Connect

    Block, R.K.; Krischer, W.; Lone, S.

    1989-04-01

    In the context of the LAA detector development program a subgroup Real Time Data Processing has tackled the problem of intelligent triggering. The main goal of this group is to show how fast digital devices, implemented as custom-made or commercial processors, can execute some basic algorithms, and how they can be embedded in the data flow between detector readout components and fully programmable commercial processors, which are expected to be the final data processing filter in real time.

  7. Real-Time Ada Problem Study

    DTIC Science & Technology

    1989-03-24

    define this set of problems. The authors were chosen because of their proven expertise in real-time development with Ada. They could enrich the results of...for Real-Time Embedded Systems". LabTek Corporation, the author , had proven expertise in embedded system design utilizing Motorola MC680XO- based...processors. The second report is entitledSoftware Enineering Problems Using Ada in Computers Integral to Weapons Systems. Its author , Sonicraft, had

  8. Analysis of real-time vibration data

    USGS Publications Warehouse

    Safak, E.

    2005-01-01

    In recent years, a few structures have been instrumented to provide continuous vibration data in real time, recording not only large-amplitude motions generated by extreme loads, but also small-amplitude motions generated by ambient loads. The main objective in continuous recording is to track any changes in structural characteristics, and to detect damage after an extreme event, such as an earthquake or explosion. The Fourier-based spectral analysis methods have been the primary tool to analyze vibration data from structures. In general, such methods do not work well for real-time data, because real-time data are mainly composed of ambient vibrations with very low amplitudes and signal-to-noise ratios. The long duration, linearity, and the stationarity of ambient data, however, allow us to utilize statistical signal processing tools, which can compensate for the adverse effects of low amplitudes and high noise. The analysis of real-time data requires tools and techniques that can be applied in real-time; i.e., data are processed and analyzed while being acquired. This paper presents some of the basic tools and techniques for processing and analyzing real-time vibration data. The topics discussed include utilization of running time windows, tracking mean and mean-square values, filtering, system identification, and damage detection.

  9. REAL TIME SYSTEM OPERATIONS 2006-2007

    SciTech Connect

    Eto, Joseph H.; Parashar, Manu; Lewis, Nancy Jo

    2008-08-15

    The Real Time System Operations (RTSO) 2006-2007 project focused on two parallel technical tasks: (1) Real-Time Applications of Phasors for Monitoring, Alarming and Control; and (2) Real-Time Voltage Security Assessment (RTVSA) Prototype Tool. The overall goal of the phasor applications project was to accelerate adoption and foster greater use of new, more accurate, time-synchronized phasor measurements by conducting research and prototyping applications on California ISO's phasor platform - Real-Time Dynamics Monitoring System (RTDMS) -- that provide previously unavailable information on the dynamic stability of the grid. Feasibility assessment studies were conducted on potential application of this technology for small-signal stability monitoring, validating/improving existing stability nomograms, conducting frequency response analysis, and obtaining real-time sensitivity information on key metrics to assess grid stress. Based on study findings, prototype applications for real-time visualization and alarming, small-signal stability monitoring, measurement based sensitivity analysis and frequency response assessment were developed, factory- and field-tested at the California ISO and at BPA. The goal of the RTVSA project was to provide California ISO with a prototype voltage security assessment tool that runs in real time within California ISO?s new reliability and congestion management system. CERTS conducted a technical assessment of appropriate algorithms, developed a prototype incorporating state-of-art algorithms (such as the continuation power flow, direct method, boundary orbiting method, and hyperplanes) into a framework most suitable for an operations environment. Based on study findings, a functional specification was prepared, which the California ISO has since used to procure a production-quality tool that is now a part of a suite of advanced computational tools that is used by California ISO for reliability and congestion management.

  10. Personnel real time dosimetry in interventional radiology.

    PubMed

    Servoli, L; Bissi, L; Fabiani, S; Magalotti, D; Placidi, P; Scorzoni, A; Calandra, A; Cicioni, R; Chiocchini, S; Dipilato, A C; Forini, N; Paolucci, M; Di Lorenzo, R; Cappotto, F P; Scarpignato, M; Maselli, A; Pentiricci, A

    2016-12-01

    Interventional radiology and hemodynamic procedures have rapidly grown in number in the past decade, increasing the importance of personnel dosimetry not only for patients but also for medical staff. The optimization of the absorbed dose during operations is one of the goals that fostered the development of real-time dosimetric systems. Indeed, introducing proper procedure optimization, like correlating dose rate measurements with medical staff position inside the operating room, the absorbed dose could be reduced. Real-time dose measurements would greatly facilitate this task through real-time monitoring and automatic data recording. Besides real-time dose monitoring could allow automatic data recording. In this work, we will describe the calibration and validation of a wireless real-time prototype dosimeter based on a new sensor device (CMOS imager). The validation measurement campaign in clinical conditions has demonstrated the prototype capability of measuring dose-rates with a frequency in the range of few Hz, and an uncertainty smaller than 10%.

  11. Real-time Enhanced Vision System

    NASA Technical Reports Server (NTRS)

    Hines, Glenn D.; Rahman, Zia-Ur; Jobson, Daniel J.; Woodell, Glenn A.; Harrah, Steven D.

    2005-01-01

    Flying in poor visibility conditions, such as rain, snow, fog or haze, is inherently dangerous. However these conditions can occur at nearly any location, so inevitably pilots must successfully navigate through them. At NASA Langley Research Center (LaRC), under support of the Aviation Safety and Security Program Office and the Systems Engineering Directorate, we are developing an Enhanced Vision System (EVS) that combines image enhancement and synthetic vision elements to assist pilots flying through adverse weather conditions. This system uses a combination of forward-looking infrared and visible sensors for data acquisition. A core function of the system is to enhance and fuse the sensor data in order to increase the information content and quality of the captured imagery. These operations must be performed in real-time for the pilot to use while flying. For image enhancement, we are using the LaRC patented Retinex algorithm since it performs exceptionally well for improving low-contrast range imagery typically seen during poor visibility conditions. In general, real-time operation of the Retinex requires specialized hardware. To date, we have successfully implemented a single-sensor real-time version of the Retinex on several different Digital Signal Processor (DSP) platforms. In this paper we give an overview of the EVS and its performance requirements for real-time enhancement and fusion and we discuss our current real-time Retinex implementations on DSPs.

  12. Visualization of Real-Time Data

    NASA Technical Reports Server (NTRS)

    Stansifer, Ryan; Engrand, Peter

    1996-01-01

    In this project we explored various approaches to presenting real-time data from the numerous systems monitored on the space shuttle to computer users. We examined the approach that several projects at the Kennedy Space Center (KSC) used to accomplish this. We undertook to build a prototype system to demonstrate that the Internet and the Java programming language could be used to present the real-time data conveniently. Several Java programs were developed that presented real-time data in different forms including one form that emulated the display screens of the PC GOAL system which is familiar to many at KSC. Also, we developed several communications programs to supply the data continuously. Furthermore, a framework was created using the World Wide Web (WWW) to organize the collection and presentation of the real-time data. We believe our demonstration project shows the great flexibility of the approach. We had no particular use of the data in mind, instead we wanted the most general and the least complex framework possible. People who wish to view data need only know how to use a WWW browser and the address (the URL). People wanting to build WWW documents containing real-time data need only know the values of a few parameters, they do not need to program in Java or any other language. These are stunning advantages over more monolithic systems.

  13. Characterization of real-time computers

    NASA Technical Reports Server (NTRS)

    Shin, K. G.; Krishna, C. M.

    1984-01-01

    A real-time system consists of a computer controller and controlled processes. Despite the synergistic relationship between these two components, they have been traditionally designed and analyzed independently of and separately from each other; namely, computer controllers by computer scientists/engineers and controlled processes by control scientists. As a remedy for this problem, in this report real-time computers are characterized by performance measures based on computer controller response time that are: (1) congruent to the real-time applications, (2) able to offer an objective comparison of rival computer systems, and (3) experimentally measurable/determinable. These measures, unlike others, provide the real-time computer controller with a natural link to controlled processes. In order to demonstrate their utility and power, these measures are first determined for example controlled processes on the basis of control performance functionals. They are then used for two important real-time multiprocessor design applications - the number-power tradeoff and fault-masking and synchronization.

  14. Real-Time Visualization of Tissue Ischemia

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory H. (Inventor); Chrien, Thomas D. (Inventor); Eastwood, Michael L. (Inventor)

    2000-01-01

    A real-time display of tissue ischemia which comprises three CCD video cameras, each with a narrow bandwidth filter at the correct wavelength is discussed. The cameras simultaneously view an area of tissue suspected of having ischemic areas through beamsplitters. The output from each camera is adjusted to give the correct signal intensity for combining with, the others into an image for display. If necessary a digital signal processor (DSP) can implement algorithms for image enhancement prior to display. Current DSP engines are fast enough to give real-time display. Measurement at three, wavelengths, combined into a real-time Red-Green-Blue (RGB) video display with a digital signal processing (DSP) board to implement image algorithms, provides direct visualization of ischemic areas.

  15. Real-time, high frequency QRS electrocardiograph

    NASA Technical Reports Server (NTRS)

    Schlegel, Todd T. (Inventor); DePalma, Jude L. (Inventor); Moradi, Saeed (Inventor)

    2006-01-01

    Real time cardiac electrical data are received from a patient, manipulated to determine various useful aspects of the ECG signal, and displayed in real time in a useful form on a computer screen or monitor. The monitor displays the high frequency data from the QRS complex in units of microvolts, juxtaposed with a display of conventional ECG data in units of millivolts or microvolts. The high frequency data are analyzed for their root mean square (RMS) voltage values and the discrete RMS values and related parameters are displayed in real time. The high frequency data from the QRS complex are analyzed with imbedded algorithms to determine the presence or absence of reduced amplitude zones, referred to herein as RAZs. RAZs are displayed as go, no-go signals on the computer monitor. The RMS and related values of the high frequency components are displayed as time varying signals, and the presence or absence of RAZs may be similarly displayed over time.

  16. Network protocols for real-time applications

    NASA Technical Reports Server (NTRS)

    Johnson, Marjory J.

    1987-01-01

    The Fiber Distributed Data Interface (FDDI) and the SAE AE-9B High Speed Ring Bus (HSRB) are emerging standards for high-performance token ring local area networks. FDDI was designed to be a general-purpose high-performance network. HSRB was designed specifically for military real-time applications. A workshop was conducted at NASA Ames Research Center in January, 1987 to compare and contrast these protocols with respect to their ability to support real-time applications. This report summarizes workshop presentations and includes an independent comparison of the two protocols. A conclusion reached at the workshop was that current protocols for the upper layers of the Open Systems Interconnection (OSI) network model are inadequate for real-time applications.

  17. Continuous, real time microwave plasma element sensor

    DOEpatents

    Woskov, Paul P.; Smatlak, Donna L.; Cohn, Daniel R.; Wittle, J. Kenneth; Titus, Charles H.; Surma, Jeffrey E.

    1995-01-01

    Microwave-induced plasma for continuous, real time trace element monitoring under harsh and variable conditions. The sensor includes a source of high power microwave energy and a shorted waveguide made of a microwave conductive, refractory material communicating with the source of the microwave energy to generate a plasma. The high power waveguide is constructed to be robust in a hot, hostile environment. It includes an aperture for the passage of gases to be analyzed and a spectrometer is connected to receive light from the plasma. Provision is made for real time in situ calibration. The spectrometer disperses the light, which is then analyzed by a computer. The sensor is capable of making continuous, real time quantitative measurements of desired elements, such as the heavy metals lead and mercury.

  18. Continuous, real time microwave plasma element sensor

    DOEpatents

    Woskov, P.P.; Smatlak, D.L.; Cohn, D.R.; Wittle, J.K.; Titus, C.H.; Surma, J.E.

    1995-12-26

    Microwave-induced plasma is described for continuous, real time trace element monitoring under harsh and variable conditions. The sensor includes a source of high power microwave energy and a shorted waveguide made of a microwave conductive, refractory material communicating with the source of the microwave energy to generate a plasma. The high power waveguide is constructed to be robust in a hot, hostile environment. It includes an aperture for the passage of gases to be analyzed and a spectrometer is connected to receive light from the plasma. Provision is made for real time in situ calibration. The spectrometer disperses the light, which is then analyzed by a computer. The sensor is capable of making continuous, real time quantitative measurements of desired elements, such as the heavy metals lead and mercury. 3 figs.

  19. Test of Real-Time Space Weather Predictors

    NASA Astrophysics Data System (ADS)

    Reiff, P. H.; Bala, R.

    2013-12-01

    We are testing four real-time empirical space weather prediction functions to see which has been most successful, running in real time, for the past two years. Data from the "Wing Model" (presently running at SWPC in Boulder); the "Boyle Model" have been running in real time for a number of years, with the Boyle Index given online with alerts since 2003. The "Ram Model" and the "Newell Model" (also running at Rice University) have all been providing Kp predictions in real time for one year. We are testing their relative effectiveness in predicting Kp, and also their "up time", by using their actual predictions posted in real time against the final version Kp values. The Boyle model is a neural network model with 12-hour lookback time, using the Boyle Index as the base function, and yields one-hour and three-hour ahead predictions. The Ram model is similar to the Boyle model, but adds a pressure term to the base function. The Newell model is also a 12-hour neural net, but using the Newell function as its base. The Wing model gives a one- and four-hour prediction, with the prediction time variable with the solar wind velocity. All three Rice models are available in real time at http://mms.rice.edu/realtime/forecast.html , and the Wing model at http://www.swpc.noaa.gov/wingkp/ . Early results indicate that any of the three Rice neural net predictors had a slightly better success rate in predicting Kp in real time than Wing. In the image below from August 1-7, 2013, Wing's correlation coefficient was 0.682, with three hours of missing data (shown as -1). The Boyle function's correlation coefficient was 0.782, the Ram function was 0.788 and the Newell function was 0.793. In addition, Wing's prediction has missing data more often (roughly 1% over a year of data) than the Rice predictions (roughly 0.1% over a year of data), meaning it had less reliability. All of the models could successfully predict one hour-ahead Kp, on average, to better than one step in Kp, and the

  20. Mobile waste inspection real time radiography system

    SciTech Connect

    Vigil, J.; Taggart, D.; Betts, S.; Rael, C.; Martinez, F.; Mendez, J.

    1995-10-01

    The 450-KeV Mobile Real Time Radiography System was designed and purchased to inspect containers of radioactive waste produced at Los Alamos National Laboratory (LANL). The Mobile Real Time Radiography System has the capability of inspecting waste containers of various sizes from 5-gal. buckets to standard waste boxes (SWB, dimensions 54.5 in. x 71 in. x 37 in.). The fact that this unit is mobile makes it an attractive alternative to the costly road closures associated with moving waste from the waste generator to storage or disposal facilities.

  1. Axial Tomography from Digitized Real Time Radiography

    DOE R&D Accomplishments Database

    Zolnay, A. S.; McDonald, W. M.; Doupont, P. A.; McKinney, R. L.; Lee, M. M.

    1985-01-18

    Axial tomography from digitized real time radiographs provides a useful tool for industrial radiography and tomography. The components of this system are: x-ray source, image intensifier, video camera, video line extractor and digitizer, data storage and reconstruction computers. With this system it is possible to view a two dimensional x-ray image in real time at each angle of rotation and select the tomography plane of interest by choosing which video line to digitize. The digitization of a video line requires less than a second making data acquisition relatively short. Further improvements on this system are planned and initial results are reported.

  2. Software Package For Real-Time Graphics

    NASA Technical Reports Server (NTRS)

    Malone, Jacqueline C.; Moore, Archie L.

    1991-01-01

    Software package for master graphics interactive console (MAGIC) at Western Aeronautical Test Range (WATR) of NASA Ames Research Center provides general-purpose graphical display system for real-time and post-real-time analysis of data. Written in C language and intended for use on workstation of interactive raster imaging system (IRIS) equipped with level-V Unix operating system. Enables flight researchers to create their own displays on basis of individual requirements. Applicable to monitoring of complicated processes in chemical industry.

  3. Imaging of living cells in real time

    NASA Astrophysics Data System (ADS)

    Tychinsky, Vladimir P.; Koufal, Georgy E.; Perevedentseva, Elena V.; Vyshenskaia, Tatiana V.; Nikandrov, Serguei L.

    1996-12-01

    Parameters of intrinsic cell motility is one of the cell activity characteristics which can be measured in real-time. For evaluation of certain organelles velocity we propose to use high sensitivity of computer-aided phase microscope airyscan to local phase changes connected with refractive index. This method is based on periodical scanning of cell profile in direction perpendicular to organelles movement. Analysis of the obtained 2-dimensional time-coordinate matrix allows us to define organelle velocity in quasi-real time and areas of cell activity. The experiments with onion cells confirm the method applicability for cell activity investigation.

  4. Machine vision for real time orbital operations

    NASA Technical Reports Server (NTRS)

    Vinz, Frank L.

    1988-01-01

    Machine vision for automation and robotic operation of Space Station era systems has the potential for increasing the efficiency of orbital servicing, repair, assembly and docking tasks. A machine vision research project is described in which a TV camera is used for inputing visual data to a computer so that image processing may be achieved for real time control of these orbital operations. A technique has resulted from this research which reduces computer memory requirements and greatly increases typical computational speed such that it has the potential for development into a real time orbital machine vision system. This technique is called AI BOSS (Analysis of Images by Box Scan and Syntax).

  5. Automated real-time software development

    NASA Technical Reports Server (NTRS)

    Jones, Denise R.; Walker, Carrie K.; Turkovich, John J.

    1993-01-01

    A Computer-Aided Software Engineering (CASE) system has been developed at the Charles Stark Draper Laboratory (CSDL) under the direction of the NASA Langley Research Center. The CSDL CASE tool provides an automated method of generating source code and hard copy documentation from functional application engineering specifications. The goal is to significantly reduce the cost of developing and maintaining real-time scientific and engineering software while increasing system reliability. This paper describes CSDL CASE and discusses demonstrations that used the tool to automatically generate real-time application code.

  6. Real-Time, Interactive Sonic Boom Display

    NASA Technical Reports Server (NTRS)

    Haering, Jr., Edward A. (Inventor); Plotkin, Kenneth J. (Inventor)

    2012-01-01

    The present invention is an improved real-time, interactive sonic boom display for aircraft. By using physical properties obtained via various sensors and databases, the invention determines, in real-time, sonic boom impacts locations and intensities for aircraft traveling at supersonic speeds. The information is provided to a pilot via a display that lists a selectable set of maneuvers available to the pilot to mitigate sonic boom issues. Upon selection of a maneuver, the information as to the result of the maneuver is displayed and the pilot may proceed with making the maneuver, or provide new data to the system in order to calculate a different maneuver.

  7. Real-Time Occupancy Change Analyzer

    SciTech Connect

    2005-03-30

    The Real-Time Occupancy Change Analyzer (ROCA) produces an occupancy grid map of an environment around the robot, scans the environment to generate a current obstacle map relative to a current robot position, and converts the current obstacle map to a current occupancy grid map. Changes in the occupancy grid can be reported in real time to support a number of tracking capabilities. The benefit of ROCA is that rather than only providing a vector to the detected change, it provides the actual x,y position of the change.

  8. Axial tomography from digitized real time radiography

    SciTech Connect

    Zolnay, A.S.; McDonald, W.M.; Doupont, P.A.; McKinney, R.L.; Lee, M.M.

    1985-01-18

    Axial tomography from digitized real time radiographs provides a useful tool for industrial radiography and tomography. The components of this system are: x-ray source, image intensifier, video camera, video line extractor and digitizer, data storage and reconstruction computers. With this system it is possible to view a two dimensional x-ray image in real time at each angle of rotation and select the tomography plane of interest by choosing which video line to digitize. The digitization of a video line requires less than a second making data acquisition relatively short. Further improvements on this system are planned and initial results are reported.

  9. Real-time analysis of telemetry data

    NASA Technical Reports Server (NTRS)

    Kao, Simon A.; Laffey, Thomas J.; Schmidt, James L.; Read, Jackson Y.; Dunham, Larry L.

    1987-01-01

    This paper descibes a knowledge-based system for performing real-time monitoring and analysis of telemetry data from the NASA Hubble Space Telescope (HST). In order to handle asynchronous inputs and perform in real time the system consists of three or more separate processes, which run concurrently and communicate via a message passing scheme. The data management process gathers, compresses, and scales the incoming telemetry data befoe sending it to the other tasks. The inferencing process uses the incoming data to perform a real-time analysis of the state and health of the Space Telescope. The I/O process receives telemetry monitors from the data management process, updates its graphical displays in real time, and acts as the interface to the console operator. The three processes may run on the same or different computers. This system is currently under development and is being used to monitor testcases produced by the Bass Telemetry System in the Hardware/Software Integration Facility at Lockheed Missile and Space Co. in Sunnyvale, California.

  10. OPAD-EDIFIS Real-Time Processing

    NASA Technical Reports Server (NTRS)

    Katsinis, Constantine

    1997-01-01

    The Optical Plume Anomaly Detection (OPAD) detects engine hardware degradation of flight vehicles through identification and quantification of elemental species found in the plume by analyzing the plume emission spectra in a real-time mode. Real-time performance of OPAD relies on extensive software which must report metal amounts in the plume faster than once every 0.5 sec. OPAD software previously written by NASA scientists performed most necessary functions at speeds which were far below what is needed for real-time operation. The research presented in this report improved the execution speed of the software by optimizing the code without changing the algorithms and converting it into a parallelized form which is executed in a shared-memory multiprocessor system. The resulting code was subjected to extensive timing analysis. The report also provides suggestions for further performance improvement by (1) identifying areas of algorithm optimization, (2) recommending commercially available multiprocessor architectures and operating systems to support real-time execution and (3) presenting an initial study of fault-tolerance requirements.

  11. The Power of Real-Time PCR

    ERIC Educational Resources Information Center

    Valasek, Mark A.; Repa, Joyce J.

    2005-01-01

    In recent years, real-time polymerase chain reaction (PCR) has emerged as a robust and widely used methodology for biological investigation because it can detect and quantify very small amounts of specific nucleic acid sequences. As a research tool, a major application of this technology is the rapid and accurate assessment of changes in gene…

  12. Real Time Grid Reliability Management 2005

    SciTech Connect

    Eto, Joe; Eto, Joe; Lesieutre, Bernard; Lewis, Nancy Jo; Parashar, Manu

    2008-07-07

    The increased need to manage California?s electricity grid in real time is a result of the ongoing transition from a system operated by vertically-integrated utilities serving native loads to one operated by an independent system operator supporting competitive energy markets. During this transition period, the traditional approach to reliability management -- construction of new transmission lines -- has not been pursued due to unresolved issues related to the financing and recovery of transmission project costs. In the absence of investments in new transmission infrastructure, the best strategy for managing reliability is to equip system operators with better real-time information about actual operating margins so that they can better understand and manage the risk of operating closer to the edge. A companion strategy is to address known deficiencies in offline modeling tools that are needed to ground the use of improved real-time tools. This project: (1) developed and conducted first-ever demonstrations of two prototype real-time software tools for voltage security assessment and phasor monitoring; and (2) prepared a scoping study on improving load and generator response models. Additional funding through two separate subsequent work authorizations has already been provided to build upon the work initiated in this project.

  13. Real-time distributed multimedia systems

    SciTech Connect

    Rahurkar, S.S.; Bourbakis, N.G.

    1996-12-31

    This paper presents a survey on distributed multimedia systems and discusses real-time issues. In particular, different subsystems are reviewed that impact on multimedia networking, the networking for multimedia, the networked multimedia systems, and the leading edge research and developments efforts and issues in networking.

  14. Feedback as Real-Time Constructions

    ERIC Educational Resources Information Center

    Keiding, Tina Bering; Qvortrup, Ane

    2014-01-01

    This article offers a re-description of feedback and the significance of time in feedback constructions based on systems theory. It describes feedback as internal, real-time constructions in a learning system. From this perspective, feedback is neither immediate nor delayed, but occurs in the very moment it takes place. This article argues for a…

  15. REAL TIME CONTROL OF URBAN DRAINAGE NETWORKS

    EPA Science Inventory

    Real-time control (RTC) is a custom-designed, computer-assisted management technology for a specific sewerage network to meet the operational objectives of its collection/conveyance system. RTC can operate in several modes, including a mode that is activated during a wet weather ...

  16. Alfaxalone versus propofol in dogs: a randomised trial to assess effects on peri-induction tear production, intraocular pressure and globe position.

    PubMed

    Costa, Daniel; Leiva, Marta; Moll, Xavier; Aguilar, Adrià; Peña, Teresa; Andaluz, Anna

    2015-01-17

    The purpose of this randomised trial was to compare the effects of alfaxalone and propofol on tear production (STT-1), intraocular pressure (IOP) and globe position (GP) in healthy dogs. Fourteen Beagles were randomly divided into two groups; dogs in one group received alfaxalone (3 mg/kg) (n=7) and dogs in the other group received propofol (6 mg/kg) (n=7), both administered intravenously. IOP and GP were evaluated at basal time (Tb) and T2,5,10,15,20,25&30 (minutes after complete drug administration). STT-1 was evaluated at Tb and T10,20&30. STT-1 and IOP results were analysed using analysis of variance and GP was analysed using the likelihood ratio χ(2) test. Dogs in the alfaxalone group showed a significant reduction in STT-1 at T10&20 (P<0.05), while the propofol group did not show statistically significant differences in this parameter over time. Both anaesthetic drugs produced a transient elevation of IOP at T2 (P>0.05), which then decreased (P<0.01). While alfaxalone caused a ventral globe deviation that lasted from T2 to T10 (P<0.05) and was fully recovered at T30, propofol induced a ventral globe deviation from T2 to T5 (P<0.05), being restored at T20. These results suggest that both alfaxalone and propofol can be safely used for intraocular surgery, as they significantly reduce IOP. Furthermore, anaesthetic induction with propofol would be especially recommended for dogs with tear deficiencies.

  17. Evaluation of the relationship of corneal biomechanical metrics with physical intraocular pressure and central corneal thickness in ex vivo rabbit eye globes.

    PubMed

    Bao, FangJun; Deng, ManLi; Wang, QinMei; Huang, JinHai; Yang, Jing; Whitford, Charles; Geraghty, Brendan; Yu, Ayong; Elsheikh, Ahmed

    2015-08-01

    The relationship of corneal biomechanical metrics provided by the Ocular Response Analyzer (ORA) and Corvis ST (CVS) with physical intraocular pressure (IOPp) and central corneal thickness (CCT) was evaluated. Thirty fresh enucleated eyes of 30 rabbits were used in ex vivo whole globe inflation experiments. IOPp was measured with a pressure transducer and increased from 7.5 to 37.5 mmHg in steps of 7.5 mmHg while biomechanical data was acquired using the ORA and CVS. At least 3 examinations were performed at each pressure level, where CCT and twelve biomechanical metrics were recorded and analyzed as a function of IOPp. The biomechanical metrics included corneal hysteresis (CH) and corneal resistance factor (CRF), obtained by the ORA. They also included the applanation times (A1T, A2T), lengths (A1L, A2L) and velocities (A1V, A2V), in addition to the highest concavity time (HCT), peak distance (PD), radius (HR) and deformation amplitude (DA), obtained by the CVS. The variation of CCT and the twelve biomechanical metrics for the 30 rabbit eyes tested across the 5 pressure stages considered (inter-pressure differences) were statistically significant (P = 0.00). IOPp was highly to moderately correlated with most biomechanical metrics, especially CRF, A1T, A1V, A2V, PD and DA, while the relationships with CH, A2T, A1L and HCT were poor. IOP has important influences on most corneal biomechanical metrics provided by CVS and ORA. Two biomechanical metrics A1V and HR were influenced by CCT after correcting for the effect of IOP in most pressure stages, while the correlation with others were weak. Comparisons of research groups based on ORA and CVS with different IOPs and CCTs may lead to possible misinterpretations if both or one of which are not considered in the analysis.

  18. Real-time image subtraction using phase reversal technique

    NASA Astrophysics Data System (ADS)

    Venkateswara Rao, Vuyyuru; Krishna Mohan, Nandigana K.

    1999-10-01

    A simple coherent interferometric processing method for image subtraction in real-time is presented. The proposed method is based on interferometric principle using Mach- Zehnder interferometer. The phase reversal is accomplished by varying the pressure within an air-filled quartz cell inserted in one of the arms of the interferometer. Initially, the interferometer is aligned to obtain broad interference fringes in the cell region. Then the input imageries are introduced in both the arms of the interferometer and adjusted for exact registration as seen in the plane of observation. By introducing a phase change of (pi) -rad between the two arms of the interferometer, the difference between the inputs is detected in real-time on the monitor. Phase shift calibration and information processing of the proposed method is presented with the results.

  19. ALMA Correlator Real-Time Data Processor

    NASA Astrophysics Data System (ADS)

    Pisano, J.; Amestica, R.; Perez, J.

    2005-10-01

    The design of a real-time Linux application utilizing Real-Time Application Interface (RTAI) to process real-time data from the radio astronomy correlator for the Atacama Large Millimeter Array (ALMA) is described. The correlator is a custom-built digital signal processor which computes the cross-correlation function of two digitized signal streams. ALMA will have 64 antennas with 2080 signal streams each with a sample rate of 4 giga-samples per second. The correlator's aggregate data output will be 1 gigabyte per second. The software is defined by hard deadlines with high input and processing data rates, while requiring interfaces to non real-time external computers. The designed computer system - the Correlator Data Processor or CDP, consists of a cluster of 17 SMP computers, 16 of which are compute nodes plus a master controller node all running real-time Linux kernels. Each compute node uses an RTAI kernel module to interface to a 32-bit parallel interface which accepts raw data at 64 megabytes per second in 1 megabyte chunks every 16 milliseconds. These data are transferred to tasks running on multiple CPUs in hard real-time using RTAI's LXRT facility to perform quantization corrections, data windowing, FFTs, and phase corrections for a processing rate of approximately 1 GFLOPS. Highly accurate timing signals are distributed to all seventeen computer nodes in order to synchronize them to other time-dependent devices in the observatory array. RTAI kernel tasks interface to the timing signals providing sub-millisecond timing resolution. The CDP interfaces, via the master node, to other computer systems on an external intra-net for command and control, data storage, and further data (image) processing. The master node accesses these external systems utilizing ALMA Common Software (ACS), a CORBA-based client-server software infrastructure providing logging, monitoring, data delivery, and intra-computer function invocation. The software is being developed in tandem

  20. Real-Time Seismology in Portugal

    NASA Astrophysics Data System (ADS)

    Custodio, S.; Marreiros, C.; Carvalho, S.; Vales, D.; Lima, V.; Carrilho, F.

    2012-12-01

    Portugal is located next to the plate boundary between Eurasia (Iberia) and Africa (Nubia). The country has been repeatedly affected by some of the largest earthquakes, both onshore and offshore, in the historical European record, including the largest historical European earthquake, the great Lisbon earthquake of 1755 (~M8.5). The Portuguese territory has suffered directly the consequences of strong ground shaking (collapse of buildings, etc) and also some of the most destructive consequences of earthquakes (e.g. tsunamis, fires, etc). However, the rate of tectonic deformation in the Portuguese territory is low (the Eurasian-African plates converge at a rate of ~ 5 mm/yr), which results in long recurrence intervals between earthquakes. This low to moderate rate of seismic activity has two major negative effects: 1) it is difficult to study the regional seismo-tectonics with traditional passive methods; 2) the population is little aware of earthquake risk and unprepared to react in case of disaster. In this scenario, real-time seismology is key to monitoring earthquake crisis in real-time, providing early warnings about potentially destructive events, and assisting in the channeling of recovery efforts in case of disaster. In this paper we will present the real-time algorithms implemented at Instituto de Meteorologia (IM), the institution responsible for seismic monitoring in Portugal. In particular, we will focus on the following aspects: 1) Data collection and real-time transmission to the headquarters. Broadband seismological stations are owned and operated by five different institutions. The last years have witnessed an effort for integration, and presently most data arrives at IM lab in real-time. 2) Earthquake location and local magnitude determination. Data is automatically analyzed in order to obtain a first earthquake hypocenter and ML. While this process is mostly automatic, it still requires the revision by an operator, who is available 24h. 3

  1. Sensory stimulation for lowering intraocular pressure, improving blood flow to the optic nerve and neuroprotection in primary open-angle glaucoma.

    PubMed

    Rom, Edith

    2013-12-01

    Primary open-angle glaucoma is a group of optic neuropathies that can lead to irreversible blindness. Sensory stimulation in the form of acupuncture or ear acupressure may contribute to protecting patients from blindness when used as a complementary method to orthodox treatment in the form of drops, laser or surgery. The objective of this article is to provide a narrative overview of the available literature up to July 2012. It summarises reported evidence on the potential beneficial effects of sensory stimulation for glaucoma. Sensory stimulation appears to significantly enhance the pressure-lowering effect of orthodox treatments. Studies suggest that it may also improve blood flow to the eye and optic nerve head. Furthermore, it may play a role in neuroprotection through regulating nerve growth factor and brain-derived neurotrophic factor and their receptors, thereby encouraging the survival pathway in contrast to the pathway to apoptosis. Blood flow and neuroprotection are areas that are not directly influenced by orthodox treatment modalities. Numerous different treatment protocols were used to investigate the effect of sensory stimulation on intraocular pressure, blood flow or neuroprotection of the retina and optic nerve in the animal model and human pilot studies. Objective outcomes were reported to have been evaluated with Goldmann tonometry, Doppler ultrasound techniques and electrophysiology (pattern electroretinography, visually evoked potentials), and supported with histological studies in the animal model. Taken together, reported evidence from these studies strongly suggests that sensory stimulation is worthy of further research.

  2. The use of topical aqueous suppressants in the prevention of postoperative intraocular pressure elevation following pars plana vitrectomy with long-acting gas tamponade.

    PubMed Central

    Mittra, R A; Pollack, J S; Dev, S; Han, D P; Mieler, W F; Connor, T B

    1998-01-01

    PURPOSE: To determine if topical aqueous suppressant therapy applied after pars plana vitrectomy (PPV) with gas tamponade successfully prevents postoperative elevation of intraocular pressure (IOP). METHODS: A prospective, controlled study was performed on patients who met inclusion criteria and underwent PPV with gas tamponade (SF6 18%-20% or C3F8 12%-16%) over a 1-year period. Treatment eyes received topical aqueous suppressants at the end of surgery. Postoperative IOP checks were performed at 4 to 6 hours, 1 day, and 1 week. RESULTS: Twenty-one control (C) and 20 treatment (T) eyes met the inclusion criteria. The IOP (in mm Hg) measured at 4 to 6 hours (23.05 [C], 14.73 [T] and 1 day (23.24 [C], 17.28 [T]) postoperatively showed a statistically significant difference between the groups (P = .0038) at 4 to 6 hours, and a trend toward significance (P = .057) at 1 day. Eleven control and 3 treatment eyes had an IOP spike above 25 mm Hg at 4 to 6 hours or 1 day postoperatively (P = .02), and 6 control and 1 treatment eye had a postoperative IOP above 30 mm Hg. A pressure rise above 40 mm Hg was seen in 2 control eyes and no treatment eyes. CONCLUSIONS: Use of topical aqueous suppressants following PPV with long-acting gas tamponade is effective in preventing significant postoperative IOP elevation in a majority of cases. PMID:10360287

  3. Real-time remote scientific model validation

    NASA Technical Reports Server (NTRS)

    Frainier, Richard; Groleau, Nicolas

    1994-01-01

    This paper describes flight results from the use of a CLIPS-based validation facility to compare analyzed data from a space life sciences (SLS) experiment to an investigator's preflight model. The comparison, performed in real-time, either confirms or refutes the model and its predictions. This result then becomes the basis for continuing or modifying the investigator's experiment protocol. Typically, neither the astronaut crew in Spacelab nor the ground-based investigator team are able to react to their experiment data in real time. This facility, part of a larger science advisor system called Principal Investigator in a Box, was flown on the space shuttle in October, 1993. The software system aided the conduct of a human vestibular physiology experiment and was able to outperform humans in the tasks of data integrity assurance, data analysis, and scientific model validation. Of twelve preflight hypotheses associated with investigator's model, seven were confirmed and five were rejected or compromised.

  4. Real-time photo-magnetic imaging

    PubMed Central

    Nouizi, Farouk; Erkol, Hakan; Luk, Alex; Unlu, Mehmet B.; Gulsen, Gultekin

    2016-01-01

    We previously introduced a new high resolution diffuse optical imaging modality termed, photo-magnetic imaging (PMI). PMI irradiates the object under investigation with near-infrared light and monitors the variations of temperature using magnetic resonance thermometry (MRT). In this paper, we present a real-time PMI image reconstruction algorithm that uses analytic methods to solve the forward problem and assemble the Jacobian matrix much faster. The new algorithm is validated using real MRT measured temperature maps. In fact, it accelerates the reconstruction process by more than 250 times compared to a single iteration of the FEM-based algorithm, which opens the possibility for the real-time PMI. PMID:27867701

  5. Real Time Radiation Monitoring Using Nanotechnology

    NASA Technical Reports Server (NTRS)

    Li, Jing (Inventor); Wilkins, Richard T. (Inventor); Hanratty, James J. (Inventor); Lu, Yijiang (Inventor)

    2016-01-01

    System and method for monitoring receipt and estimating flux value, in real time, of incident radiation, using two or more nanostructures (NSs) and associated terminals to provide closed electrical paths and to measure one or more electrical property change values .DELTA.EPV, associated with irradiated NSs, during a sequence of irradiation time intervals. Effects of irradiation, without healing and with healing, of the NSs, are separately modeled for first order and second order healing. Change values.DELTA.EPV are related to flux, to cumulative dose received by NSs, and to radiation and healing effectivity parameters and/or.mu., associated with the NS material and to the flux. Flux and/or dose are estimated in real time, based on EPV change values, using measured .DELTA.EPV values. Threshold dose for specified changes of biological origin (usually undesired) can be estimated. Effects of time-dependent radiation flux are analyzed in pre-healing and healing regimes.

  6. AMON: Transition to real-time operations

    NASA Astrophysics Data System (ADS)

    Cowen, D. F.; Keivani, A.; Tešić, G.

    2016-04-01

    The Astrophysical Multimessenger Observatory Network (AMON) will link the world's leading high-energy neutrino, cosmic-ray, gamma-ray and gravitational wave observatories by performing real-time coincidence searches for multimessenger sources from observatories' subthreshold data streams. The resulting coincidences will be distributed to interested parties in the form of electronic alerts for real-time follow-up observation. We will present the science case, design elements, current and projected partner observatories, status of the AMON project, and an initial AMON-enabled analysis. The prototype of the AMON server has been online since August 2014 and processing archival data. Currently, we are deploying new high-uptime servers and will be ready to start issuing alerts as early as winter 2015/16.

  7. Real time gamma-ray signature identifier

    DOEpatents

    Rowland, Mark [Alamo, CA; Gosnell, Tom B [Moraga, CA; Ham, Cheryl [Livermore, CA; Perkins, Dwight [Livermore, CA; Wong, James [Dublin, CA

    2012-05-15

    A real time gamma-ray signature/source identification method and system using principal components analysis (PCA) for transforming and substantially reducing one or more comprehensive spectral libraries of nuclear materials types and configurations into a corresponding concise representation/signature(s) representing and indexing each individual predetermined spectrum in principal component (PC) space, wherein an unknown gamma-ray signature may be compared against the representative signature to find a match or at least characterize the unknown signature from among all the entries in the library with a single regression or simple projection into the PC space, so as to substantially reduce processing time and computing resources and enable real-time characterization and/or identification.

  8. System Equivalent for Real Time Digital Simulator

    NASA Astrophysics Data System (ADS)

    Lin, Xi

    2011-07-01

    The purpose of this research is to develop a method of making system equivalents for the Real Time Digital Simulator (RTDS), which should enhance its capability of simulating large power systems. The proposed equivalent combines a Frequency Dependent Network Equivalent (FDNE) for the high frequency electromagnetic transients and a Transient Stability Analysis (TSA) type simulation block for the electromechanical transients. The frequency dependent characteristic for FDNE is obtained by curve-fitting frequency domain admittance characteristics using the Vector Fitting method. An approach for approximating the frequency dependent characteristic of large power networks from readily available typical power-flow data is also introduced. A new scheme of incorporating TSA solution in RTDS is proposed. This report shows how the TSA algorithm can be adapted to a real time platform. The validity of this method is confirmed with examples, including the study of a multi in-feed HVDC system based network.

  9. Real-Time Gauge/Gravity Duality

    SciTech Connect

    Skenderis, Kostas; Rees, Balt C. van

    2008-08-22

    We present a general prescription for the holographic computation of real-time n-point functions in nontrivial states. In quantum field theory such real-time computations involve a choice of a time contour in the complex time plane. The holographic prescription amounts to 'filling in' this contour with bulk solutions: real segments of the contour are filled in with Lorentzian solutions while imaginary segments are filled in with Riemannian solutions and appropriate matching conditions are imposed at the corners of the contour. We illustrate the general discussion by computing the 2-point function of a scalar operator using this prescription and by showing that this leads to an unambiguous answer with the correct i{epsilon} insertions.

  10. Real Time Radiation Exposure And Health Risks

    NASA Technical Reports Server (NTRS)

    Hu, Shaowen; Barzilla, Janet E.; Semones, Edward J.

    2015-01-01

    Radiation from solar particle events (SPEs) poses a serious threat to future manned missions outside of low Earth orbit (LEO). Accurate characterization of the radiation environment in the inner heliosphere and timely monitoring the health risks to crew are essential steps to ensure the safety of future Mars missions. In this project we plan to develop an approach that can use the particle data from multiple satellites and perform near real-time simulations of radiation exposure and health risks for various exposure scenarios. Time-course profiles of dose rates will be calculated with HZETRN and PDOSE from the energy spectrum and compositions of the particles archived from satellites, and will be validated from recent radiation exposure measurements in space. Real-time estimation of radiation risks will be investigated using ARRBOD. This cross discipline integrated approach can improve risk mitigation by providing critical information for risk assessment and medical guidance to crew during SPEs.

  11. Real time processor for array speckle interferometry

    NASA Technical Reports Server (NTRS)

    Chin, Gordon; Florez, Jose; Borelli, Renan; Fong, Wai; Miko, Joseph; Trujillo, Carlos

    1989-01-01

    The authors are constructing a real-time processor to acquire image frames, perform array flat-fielding, execute a 64 x 64 element two-dimensional complex FFT (fast Fourier transform) and average the power spectrum, all within the 25 ms coherence time for speckles at near-IR (infrared) wavelength. The processor will be a compact unit controlled by a PC with real-time display and data storage capability. This will provide the ability to optimize observations and obtain results on the telescope rather than waiting several weeks before the data can be analyzed and viewed with offline methods. The image acquisition and processing, design criteria, and processor architecture are described.

  12. Distributed Real-Time Computing with Harness

    SciTech Connect

    Di Saverio, Emanuele; Cesati, Marco; Di Biagio, Christian; Pennella, Guido; Engelmann, Christian

    2007-01-01

    Modern parallel and distributed computing solutions are often built onto a ''middleware'' software layer providing a higher and common level of service between computational nodes. Harness is an adaptable, plugin-based middleware framework for parallel and distributed computing. This paper reports recent research and development results of using Harness for real-time distributed computing applications in the context of an industrial environment with the needs to perform several safety critical tasks. The presented work exploits the modular architecture of Harness in conjunction with a lightweight threaded implementation to resolve several real-time issues by adding three new Harness plug-ins to provide a prioritized lightweight execution environment, low latency communication facilities, and local timestamped event logging.

  13. Real-time imaging of quantum entanglement.

    PubMed

    Fickler, Robert; Krenn, Mario; Lapkiewicz, Radek; Ramelow, Sven; Zeilinger, Anton

    2013-01-01

    Quantum Entanglement is widely regarded as one of the most prominent features of quantum mechanics and quantum information science. Although, photonic entanglement is routinely studied in many experiments nowadays, its signature has been out of the grasp for real-time imaging. Here we show that modern technology, namely triggered intensified charge coupled device (ICCD) cameras are fast and sensitive enough to image in real-time the effect of the measurement of one photon on its entangled partner. To quantitatively verify the non-classicality of the measurements we determine the detected photon number and error margin from the registered intensity image within a certain region. Additionally, the use of the ICCD camera allows us to demonstrate the high flexibility of the setup in creating any desired spatial-mode entanglement, which suggests as well that visual imaging in quantum optics not only provides a better intuitive understanding of entanglement but will improve applications of quantum science.

  14. Neural Network Retinal Model Real Time Implementation

    DTIC Science & Technology

    1992-09-02

    addresses the specific needs of vision processing. The goal of this SBIR Phase I project has been to take a significant neural network vision...application and to map it onto dedicated hardware for real time implementation. The neural network was already demonstrated using software simulation on a...general purpose computer. During Phase 1, HNC took a neural network model of the retina and, using HNC’s Vision Processor (ViP) prototype hardware

  15. Real-Time Ocean Modeling Systems

    DTIC Science & Technology

    2013-10-22

    2002 2. REPORT TYPE 3. DATES COVERED (From - To) Journal Article 4 . TITLE AND SUBTITLE Real-time 16iebaf Modeling Systems \\&&»A 5a...Director NCST E.O. Hartwig, 7000 Public Affairs (Unclassified/ Unlimited Only), Code 7n30 4 Division, Code Author, Code HQ-NRL 5511/6 (Rev. 12-93...according to the routing in Section 4 . 1. NRL Reports Submit the diskette (if available), manuscript, typed double-spaced, complete with tables

  16. Real-Time X-Ray Inspection

    NASA Technical Reports Server (NTRS)

    Bulthuis, Ronald V.

    1988-01-01

    X-ray imaging instrument adapted to continuous scanning. Modern version of fluoroscope enables rapid x-ray inspection of parts. Developed for detection of buckling in insulated ducts. Uses radiation from radioactive gadolinium or thallium source. Instrument weighs only 6 1/2 lb. Quickly scanned by hand along duct surface, providing real-time image. Based on Lixiscope, developed at Goddard Space Flight Center.

  17. Nonlinear Real-Time Optical Signal Processing.

    DTIC Science & Technology

    1981-06-30

    bandwidth and space-bandwidth products. Real-time homonorphic and loga- rithmic filtering by halftone nonlinear processing has been achieved. A...Page ABSTRACT 1 1. RESEARCH OBJECTIVES AND PROGRESS 3 I-- 1.1 Introduction and Project overview 3 1.2 Halftone Processing 9 1.3 Direct Nonlinear...time homomorphic and logarithmic filtering by halftone nonlinear processing has been achieved. A detailed analysis of degradation due to the finite gamma

  18. Applications of real-time holography

    NASA Astrophysics Data System (ADS)

    Feinberg, J.

    1985-01-01

    Holographic principles are discussed, with a description of the steps of hologram production and reconstruction and the materials used in storage of the images. Real-time holography applications, including photolithography, double-exposure interferometry, time-averaged holography, parallel optical processing, optical phase conjugation, beam steering, and moving holograms, are described in detail. In addition, current areas of active research and some experimental applications are discussed.

  19. Nonlinear Real-Time Optical Signal Processing.

    DTIC Science & Technology

    1984-10-01

    DTIC ELECTE I B IIMAGE PROCESSING INSTITUTE 84 11 26 107 UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE (When Dota Entered), REPORT DOCUMENTATION...30, 1984 N NONLINEAR REAL-TIME OPTICAL SIGNAL PROCESSING i E~ A.A. Sawchuk, Principal Investigator T.C. Strand and A.R. Tanguay. Jr. October 1, 1984...RDepartment of Electrical Engineering Image Processing institute University of Southern California University Park-MC 0272 Los Angeles, California

  20. Intraocular magnet of Parel.

    PubMed Central

    Crock, G. W.; Janakiraman, P.; Reddy, P.

    1986-01-01

    The intraocular magnet (IOM) is a new device based on permanent magnetism providing controlled energy for removal of magnetic intraocular foreign bodies. Its use is reported in 11 cases. Images PMID:3801364

  1. Software Analyzes Complex Systems in Real Time

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Expert system software programs, also known as knowledge-based systems, are computer programs that emulate the knowledge and analytical skills of one or more human experts, related to a specific subject. SHINE (Spacecraft Health Inference Engine) is one such program, a software inference engine (expert system) designed by NASA for the purpose of monitoring, analyzing, and diagnosing both real-time and non-real-time systems. It was developed to meet many of the Agency s demanding and rigorous artificial intelligence goals for current and future needs. NASA developed the sophisticated and reusable software based on the experience and requirements of its Jet Propulsion Laboratory s (JPL) Artificial Intelligence Research Group in developing expert systems for space flight operations specifically, the diagnosis of spacecraft health. It was designed to be efficient enough to operate in demanding real time and in limited hardware environments, and to be utilized by non-expert systems applications written in conventional programming languages. The technology is currently used in several ongoing NASA applications, including the Mars Exploration Rovers and the Spacecraft Health Automatic Reasoning Pilot (SHARP) program for the diagnosis of telecommunication anomalies during the Neptune Voyager Encounter. It is also finding applications outside of the Space Agency.

  2. Real-time Interactive Tree Animation.

    PubMed

    Quigley, Ed; Yu, Yue; Huang, Jingwei; Lin, Winnie; Fedkiw, Ronald

    2017-01-30

    We present a novel method for posing and animating botanical tree models interactively in real time. Unlike other state of the art methods which tend to produce trees that are overly flexible, bending and deforming as if they were underwater plants, our approach allows for arbitrarily high stiffness while still maintaining real-time frame rates without spurious artifacts, even on quite large trees with over ten thousand branches. This is accomplished by using an articulated rigid body model with as-stiff-as-desired rotational springs in conjunction with our newly proposed simulation technique, which is motivated both by position based dynamics and the typical O(N) algorithms for articulated rigid bodies. The efficiency of our algorithm allows us to pose and animate trees with millions of branches or alternatively simulate a small forest comprised of many highly detailed trees. Even using only a single CPU core, we can simulate ten thousand branches in real time while still maintaining quite crisp user interactivity. This has allowed us to incorporate our framework into a commodity game engine to run interactively even on a low-budget tablet. We show that our method is amenable to the incorporation of a large variety of desirable effects such as wind, leaves, fictitious forces, collisions, fracture, etc.

  3. Real-time monitoring system for microfluidics

    NASA Astrophysics Data System (ADS)

    Sapuppo, F.; Cantelli, G.; Fortuna, L.; Arena, P.; Bucolo, M.

    2007-05-01

    A new non-invasive real-time system for the monitoring and control of microfluidodynamic phenomena is proposed. The general purpose design of such system is suitable for in vitro and in vivo experimental setup and therefore for microfluidic application in the biomedical field such as lab-on-chip and for research studies in the field of microcirculation. The system consists of an ad hoc optical setup for image magnification providing images suitable for image acquisition and processing. The optic system was designed and developed using discrete opto-mechanic components mounted on a breadboard in order to provide an optic path accessible at any point where the information needs to be acquired. The optic sensing, acquisition, and processing were performed using an integrated vision system based on the Cellular Nonlinear Networks (CNNs) analogic technology called Focal Plane Processor (FPP, Eye-RIS, Anafocus) and inserted in the optic path. Ad hoc algorithms were implemented for the real-time analysis and extraction of fluido-dynamic parameters in micro-channels. They were tested on images recorded during in vivo microcirculation experiments on hamsters and then they were applied on images optically acquired and processed in real-time during in vitro experiments on a continuous microfluidic device (serpentine mixer, ThinXXS) with a two-phase fluid.

  4. Real-time speckle photography: a breakthrough

    NASA Astrophysics Data System (ADS)

    Petrov, Valery

    1996-12-01

    Speckle photography for small displacements can be carried out rather easily. It is a well established method. Unfortunately problems arise when specklegrams must be obtained in real time. Silver halide media infer lengthy multi-stage photoprocessing of specklegrams. Real time speckle photography utilizing non-silver media can be implemented but the techniques involved are rather complicated. Extremely simple and inexpensive approaches to speckle photography are introduced here. They combine positive features of speckle photography and momental holography. This permits the user to produce quasi real time specklegrams within a few seconds. High quality speckle photographs were obtained with different laser sources on high resolution silver halide media: Russian PFG-03, PFG-03 C (color), Agfa-Gevaert 8E 75 HD films and plates. Very good specklegrams were obtained also in lighted environment. Hybrid holospecklegrams i.e. holograms and speckle photographs of the same object were obtained simultaneously on the same media. Such holospecklegrams were also produced within fa few seconds. Quite unexpectedly good specklegrams were recorded even in water. Photographs of momentally produced specklegrams are given.

  5. Real-time preprocessing of holographic information

    NASA Astrophysics Data System (ADS)

    Schilling, Bradley W.; Poon, Ting-Chung

    1995-11-01

    Optical scanning holography (OSH) is a holographic recording technique that uses active optical heterodyne scanning to generate holographic information pertaining to an object. The holographic information manifests itself as an electrical signal suitable for real-time image reconstruction using a spatial light modulator. The electrical signal that carries the holographic information can also be digitized for computer storage and processing, allowing the image reconstruction to be performed numerically. In previous experiments with this technique, holographic information has been recorded using the interference pattern of a plane wave and a spherical wave of different temporal frequencies to scan an object. However, the proper manipulation of the pupil functions in the recording stage can result in real-time processing of the holographic edge extraction technique as an important example of real-time preprocessing of holographic information that utilizes alternate pupils in the OSH recording stage. We investigate the theory of holographic preprocessing using a spatial frequency-domain analysis based on the recording system's optical transfer function. The theory is reinforced through computer simulation.

  6. Real-time optical image processing techniques

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang

    1988-01-01

    Nonlinear real-time optical processing on spatial pulse frequency modulation has been pursued through the analysis, design, and fabrication of pulse frequency modulated halftone screens and the modification of micro-channel spatial light modulators (MSLMs). Micro-channel spatial light modulators are modified via the Fabry-Perot method to achieve the high gamma operation required for non-linear operation. Real-time nonlinear processing was performed using the halftone screen and MSLM. The experiments showed the effectiveness of the thresholding and also showed the needs of higher SBP for image processing. The Hughes LCLV has been characterized and found to yield high gamma (about 1.7) when operated in low frequency and low bias mode. Cascading of two LCLVs should also provide enough gamma for nonlinear processing. In this case, the SBP of the LCLV is sufficient but the uniformity of the LCLV needs improvement. These include image correlation, computer generation of holograms, pseudo-color image encoding for image enhancement, and associative-retrieval in neural processing. The discovery of the only known optical method for dynamic range compression of an input image in real-time by using GaAs photorefractive crystals is reported. Finally, a new architecture for non-linear multiple sensory, neural processing has been suggested.

  7. Real-time Tsunami Inundation Prediction Using High Performance Computers

    NASA Astrophysics Data System (ADS)

    Oishi, Y.; Imamura, F.; Sugawara, D.

    2014-12-01

    Recently off-shore tsunami observation stations based on cabled ocean bottom pressure gauges are actively being deployed especially in Japan. These cabled systems are designed to provide real-time tsunami data before tsunamis reach coastlines for disaster mitigation purposes. To receive real benefits of these observations, real-time analysis techniques to make an effective use of these data are necessary. A representative study was made by Tsushima et al. (2009) that proposed a method to provide instant tsunami source prediction based on achieving tsunami waveform data. As time passes, the prediction is improved by using updated waveform data. After a tsunami source is predicted, tsunami waveforms are synthesized from pre-computed tsunami Green functions of linear long wave equations. Tsushima et al. (2014) updated the method by combining the tsunami waveform inversion with an instant inversion of coseismic crustal deformation and improved the prediction accuracy and speed in the early stages. For disaster mitigation purposes, real-time predictions of tsunami inundation are also important. In this study, we discuss the possibility of real-time tsunami inundation predictions, which require faster-than-real-time tsunami inundation simulation in addition to instant tsunami source analysis. Although the computational amount is large to solve non-linear shallow water equations for inundation predictions, it has become executable through the recent developments of high performance computing technologies. We conducted parallel computations of tsunami inundation and achieved 6.0 TFLOPS by using 19,000 CPU cores. We employed a leap-frog finite difference method with nested staggered grids of which resolution range from 405 m to 5 m. The resolution ratio of each nested domain was 1/3. Total number of grid points were 13 million, and the time step was 0.1 seconds. Tsunami sources of 2011 Tohoku-oki earthquake were tested. The inundation prediction up to 2 hours after the

  8. The Formation of Social Conventions in Real-Time Environments

    PubMed Central

    Hawkins, Robert X. D.; Goldstone, Robert L.

    2016-01-01

    Why are some behaviors governed by strong social conventions while others are not? We experimentally investigate two factors contributing to the formation of conventions in a game of impure coordination: the continuity of interaction within each round of play (simultaneous vs. real-time) and the stakes of the interaction (high vs. low differences between payoffs). To maximize efficiency and fairness in this game, players must coordinate on one of two equally advantageous equilibria. In agreement with other studies manipulating continuity of interaction, we find that players who were allowed to interact continuously within rounds achieved outcomes with greater efficiency and fairness than players who were forced to make simultaneous decisions. However, the stability of equilibria in the real-time condition varied systematically and dramatically with stakes: players converged on more stable patterns of behavior when stakes are high. To account for this result, we present a novel analysis of the dynamics of continuous interaction and signaling within rounds. We discuss this previously unconsidered interaction between within-trial and across-trial dynamics as a form of social canalization. When stakes are low in a real-time environment, players can satisfactorily coordinate ‘on the fly’, but when stakes are high there is increased pressure to establish and adhere to shared expectations that persist across rounds. PMID:27002729

  9. Acting to gain information: Real-time reasoning meets real-time perception

    NASA Technical Reports Server (NTRS)

    Rosenschein, Stan

    1994-01-01

    Recent advances in intelligent reactive systems suggest new approaches to the problem of deriving task-relevant information from perceptual systems in real time. The author will describe work in progress aimed at coupling intelligent control mechanisms to real-time perception systems, with special emphasis on frame rate visual measurement systems. A model for integrated reasoning and perception will be discussed, and recent progress in applying these ideas to problems of sensor utilization for efficient recognition and tracking will be described.

  10. Comparison of Four Different Supraglottic Airway Devices in Terms of Efficacy, Intra-ocular Pressure and Haemodynamic Parameters in Children Undergoing Ophthalmic Surgery

    PubMed Central

    Peker, Gökhan; Takmaz, Suna Akın; Baltacı, Bülent; Başar, Hülya; Kotanoğlu, Mustafa

    2015-01-01

    Objective The aim of this study was to compare insertion parameters of four different types of supraglottic airway devices (SGAD) (Classic LMA, I-gel LMA, Proseal LMA, Cobra PLA) in children undergoing ophthalmic surgery and to determine the effect on intra-ocular pressure (IOP) and haemodynamic responses during insertion. Methods Sixty American society of Anesthesiologists (ASA) I–II children aged 1–10 years undergoing extra-ocular ophthalmic surgery were randomly divided into four groups (Group LMA, Group I-gel LMA, Group PLMA and Group CPLA) in this prospective, randomised study. Anaesthesia was induced with decreasing sevoflurane concentrations (8%–2%) in a mixture of 50% N2O-O2. All SGADs were inserted under deep anaesthesia. The characteristics of insertion (number of attempts, ease and time), oropharyngeal leak pressure (OLP) and complications were recorded. IOP in both eyes, heart rate (HR), mean arterial pressure (MAP) and EtCO2 were measured before and 2 and 5 min after insertion of the SGADs. Results There was no difference between the groups in terms of the characteristics of insertion. The mean IOP did not increase significantly in all groups. MAP and HR changes were similar among the groups during follow-up. In all groups, HR increased 2 min after insertion (statistically insignificant) and returned to the baseline value 5 min after insertion. A statistically significant correlation was seen between HR increase and IOP values before and after insertion of the SGADs (p=0.006, correlation coefficient=0.352). Desaturation was seen in one patient in Groups LMA, PLMA and CPLA, and laryngospasm was seen in two patients in Group CPLA and in one patient in Group LMA. Conclusion It was seen that during insertion of Classic LMA, I-gel LMA, Proseal LMA and Cobra PLA, IOP did not increase and haemodynamic stability was maintained in children undergoing extra-ocular ophthalmic surgery. PMID:27366519

  11. Exploring Earthquakes in Real-Time

    NASA Astrophysics Data System (ADS)

    Bravo, T. K.; Kafka, A. L.; Coleman, B.; Taber, J. J.

    2013-12-01

    Earthquakes capture the attention of students and inspire them to explore the Earth. Adding the ability to view and explore recordings of significant and newsworthy earthquakes in real-time makes the subject even more compelling. To address this opportunity, the Incorporated Research Institutions for Seismology (IRIS), in collaboration with Moravian College, developed ';jAmaSeis', a cross-platform application that enables students to access real-time earthquake waveform data. Students can watch as the seismic waves are recorded on their computer, and can be among the first to analyze the data from an earthquake. jAmaSeis facilitates student centered investigations of seismological concepts using either a low-cost educational seismograph or streamed data from other educational seismographs or from any seismic station that sends data to the IRIS Data Management System. After an earthquake, students can analyze the seismograms to determine characteristics of earthquakes such as time of occurrence, distance from the epicenter to the station, magnitude, and location. The software has been designed to provide graphical clues to guide students in the analysis and assist in their interpretations. Since jAmaSeis can simultaneously record up to three stations from anywhere on the planet, there are numerous opportunities for student driven investigations. For example, students can explore differences in the seismograms from different distances from an earthquake and compare waveforms from different azimuthal directions. Students can simultaneously monitor seismicity at a tectonic plate boundary and in the middle of the plate regardless of their school location. This can help students discover for themselves the ideas underlying seismic wave propagation, regional earthquake hazards, magnitude-frequency relationships, and the details of plate tectonics. The real-time nature of the data keeps the investigations dynamic, and offers students countless opportunities to explore.

  12. Systems Analyze Water Quality in Real Time

    NASA Technical Reports Server (NTRS)

    2010-01-01

    A water analyzer developed under Small Business Innovation Research (SBIR) contracts with Kennedy Space Center now monitors treatment processes at water and wastewater facilities around the world. Originally designed to provide real-time detection of nutrient levels in hydroponic solutions for growing plants in space, the ChemScan analyzer, produced by ASA Analytics Inc., of Waukesha, Wisconsin, utilizes spectrometry and chemometric algorithms to automatically analyze multiple parameters in the water treatment process with little need for maintenance, calibration, or operator intervention. The company has experienced a compound annual growth rate of 40 percent over its 15-year history as a direct result of the technology's success.

  13. Real-Time Ada Demonstration Project

    DTIC Science & Technology

    1989-05-31

    CENER OR OFTAREENGINEERING ADVANCED SOFTWARE TECHNOLOGY Subject: Final Report - Real-Time Ada Demonstration Proj e-t- --.-. SEP 0 1989 D SEA)~ CIN...C02 0921I 6))00 I 31 MAY 1989 *:i ’C O~ 0"ed ~ 842 190 ?’ 45 DEMONSTRATION PROJECT FINAL REPORT PREPARED FOR: U.S. Army HQ CECOM Center for Software ...Engineering Advanced Software Technology Fort Monmouth, NJ 07703-5000 Accession For NTIS G1A&I DTIC TAB PREPARED BY: unannou:1r2d E LabTek Corporation

  14. Real-time teleteaching in medical physics.

    PubMed

    Woo, M; Ng, Kh

    2008-01-01

    Medical physics is a relatively small professional community, usually with a scarcity of expertise that could greatly benefit students entering the field. However, the reach of the profession can span great geographical distances, making the training of students a difficult task. In addition to the requirement of training new students, the evolving field of medical physics, with its many emerging advanced techniques and technologies, could benefit greatly from ongoing continuing education as well as consultation with experts.Many continuing education courses and workshops are constantly being offered, including many web-based study courses and virtual libraries. However, one mode of education and communication that has not been widely used is the real-time interactive process. Video-based conferencing systems do exist, but these usually require a substantial amount of effort and cost to set up.The authors have been working on promoting the ever-expanding capability of the Internet to facilitate the education of medical physics to students entering the field. A pilot project has been carried out for six years and reported previously. The project is a collaboration between the Department of Medical Physics at the Toronto Odette Cancer Centre in Canada and the Department of Biomedical Imaging at the University of Malaya in Malaysia. Since 2001, medical physics graduate students at the University of Malaya have been taught by lecturers from Toronto every year, using the Internet as the main tool of communication.The pilot study explored the different methods that can be used to provide real-time interactive remote education, and delivered traditional classroom lectures as well as hands-on workshops.Another similar project was started in 2007 to offer real-time teaching to a class of medical physics students at Wuhan University in Hubei, China. There are new challenges as well as new opportunities associated with this project. By building an inventory of tools and

  15. Real-time failure control (SAFD)

    NASA Technical Reports Server (NTRS)

    Panossian, Hagop V.; Kemp, Victoria R.; Eckerling, Sherry J.

    1990-01-01

    The Real Time Failure Control program involves development of a failure detection algorithm, referred as System for Failure and Anomaly Detection (SAFD), for the Space Shuttle Main Engine (SSME). This failure detection approach is signal-based and it entails monitoring SSME measurement signals based on predetermined and computed mean values and standard deviations. Twenty four engine measurements are included in the algorithm and provisions are made to add more parameters if needed. Six major sections of research are presented: (1) SAFD algorithm development; (2) SAFD simulations; (3) Digital Transient Model failure simulation; (4) closed-loop simulation; (5) SAFD current limitations; and (6) enhancements planned for.

  16. Low cost real time interactive analysis system

    NASA Technical Reports Server (NTRS)

    Stetina, F.

    1988-01-01

    Efforts continue to develop a low cost real time interactive analysis system for the reception of satellite data. A multi-purpose ingest hardware software frame formatter was demonstrated for GOES and TIROS data and work is proceeding on extending the capability to receive GMS data. A similar system was proposed as an archival and analysis system for use with INSAT data and studies are underway to modify the system to receive the planned SeaWiFS (ocean color) data. This system was proposed as the core of a number of international programs in support of U.S. AID activities. Systems delivered or nearing final testing are listed.

  17. Real-Time Surface Traffic Adviser

    NASA Technical Reports Server (NTRS)

    Glass, Brian J. (Inventor); Spirkovska, Liljana (Inventor); McDermott, William J. (Inventor); Reisman, Ronald J. (Inventor); Gibson, James (Inventor); Iverson, David L. (Inventor)

    2001-01-01

    A real-time data management system which uses data generated at different rates by multiple heterogeneous incompatible data sources are presented. In one embodiment, the invention is as an airport surface traffic data management system (traffic adviser) that electronically interconnects air traffic control, airline, and airport operations user communities to facilitate information sharing and improve taxi queuing. The system uses an expert system to fuse dam from a variety of airline, airport operations, ramp control, and air traffic control sources, in order to establish, predict, and update reference data values for every aircraft surface operation.

  18. Real-time video image processing

    NASA Astrophysics Data System (ADS)

    Smedley, Kirk G.; Yool, Stephen R.

    1990-11-01

    Lockheed has designed and implemented a prototype real-time Video Enhancement Workbench (VEW) using commercial offtheshelf hardware and custom software. The hardware components include a Sun workstation Aspex PIPE image processor time base corrector VCR video camera and realtime disk subsystem. A cornprehensive set of image processing functions can be invoked by the analyst at any time during processing enabling interactive enhancement and exploitation of video sequences. Processed images can be transmitted and stored within the system in digital or video form. VEW also provides image output to a laser printer and to Interleaf technical publishing software.

  19. Real-Time Reed-Solomon Decoder

    NASA Technical Reports Server (NTRS)

    Maki, Gary K.; Cameron, Kelly B.; Owsley, Patrick A.

    1994-01-01

    Generic Reed-Solomon decoder fast enough to correct errors in real time in practical applications designed to be implemented in fewer and smaller very-large-scale integrated, VLSI, circuit chips. Configured to operate in pipelined manner. One outstanding aspect of decoder design is that Euclid multiplier and divider modules contain Galoisfield multipliers configured as combinational-logic cells. Operates at speeds greater than older multipliers. Cellular configuration highly regular and requires little interconnection area, making it ideal for implementation in extraordinarily dense VLSI circuitry. Flight electronics single chip version of this technology implemented and available.

  20. First-line treatment for elevated intraocular pressure (IOP) associated with open-angle glaucoma or ocular hypertension: focus on bimatoprost

    PubMed Central

    Law, Simon K

    2007-01-01

    The goal of treatment for open-angle glaucoma or ocular hypertension is to improve quality of life through reduction of intraocular pressure (IOP) to preserve visual function. Prostaglandins, as a newer class of ocular hypotensive agents, have been shown to be effective in IOP reduction by the primary mechanism of action of increase the uveoscleral outflow. Bimatoprost is a member this class, but different from the other members by having an ethyl amide group rather than an isopropyl ester at the C-1 carbon of the alpha chain. Bimatoprost used once daily has been shown to be more effect in IOP reduction than other classes of topical ocular hypotensive agents including beta-blockers, carbonic anhydrase inhibitors, and alpha agonists. Comparing with other topical prostaglandins, bimatoprost may be slightly more effective in IOP reduction, but the clinical significance is uncertain. The commonly reported adverse events associated with bimatoprost are localized to the eye and include conjunctival hyperemia, changes in the pigmentation of the periocular skin and iris, and eyelash darkening and growth. It is currently approved by the Food and Drug Administration (FDA) and the European Commission (EC) for first-line therapy for the reduction of elevated IOP in patients with open-angle glaucoma or ocular hypertension. PMID:19668476

  1. Design and realization of a handheld vibrometer system for noncontact in-vivo detection of microvibrations of the human eye to determine the intraocular pressure (IOP)

    NASA Astrophysics Data System (ADS)

    Gundlach, Arnd; Rawer, Rainer; Hey, Stefan; Stork, Wilhelm; Mueller-Glaser, Klaus-Dieter

    2002-06-01

    To allow measurements of the intraocular pressure (IOP) by glaucoma patients themselves (self-tonometry) a handheld-interferometer system for non-contact in vivo measurements of microvibrations of the human eye was realized. The measurement principle is based on the dependence of the resonance frequencies of the human eye on the IOP. To analyze this, the human eye is stimulated by ultrasonic waves and the induced microvibrations are measured with a vibrometer and processed by a DSP unit. Beside a stabilized diode laser and a low noise photodetector an exact three-dimensional positioning system had to be developed to guarantee reliable measurements. To investigate the corresponding requirements a camera-based system for the detection of human eye movements was developed and test series with several persons were made. Based on these results an adjustment unit was integrated in a miniaturized interferometer system: After a short self-adjusting procedure lateral to the setup by overlaying two targets of a highly sensitive optical system the correct measuring distance between the cornea and the vibrometer parallel to the optical axis is determined automatically by an astigmatic auto-focus system. With this handheld-vibrometer in vivo measurements with several test persons were made with very good results concerning the reliability and handling capability.

  2. Noninvasive observations on eyes of cats after long-term maintenance of reduced intraocular pressure by topical application of prostaglandin E2.

    PubMed

    Bito, L Z; Srinivasan, B D; Baroody, R A; Schubert, H

    1983-03-01

    Daily or twice daily prostaglandin E2 (PGE2) application to cat eyes was shown to maintain a reduced intraocular pressure (IOP) for several months without causing substantial flare or cellular response. We report now on detailed ophthalmic examinations performed on these cats after 5-9 months of such treatment (ie, after 150 to 250 unilateral PGE2 applications; 100 micrograms/treatment per eye). A comparison of the treated and contralateral control eyes revealed no differences in the axial length of ocular compartments, in the biomicroscopic appearance of the lens, vitreous, retina, or optic nerve head, in the rate of light-induced pupillary constriction or in the wave form of the electroretinogram. The cell density of the corneal endothelium was not decreased, but the endothelial surface did contain a few small "dark spots." A slight iridial heterochromia was generally apparent. In three of the cats PGE2 application had a sialagogic effect that became a conditioned reflex. Cats tended to keep their lids closed after each treatment; lid closure was more prolonged in the PGE2-treated eye than in the contralateral eye that received the same volume (50 microliters) of vehicle solution. It is concluded that daily treatment with PGE2, in doses sufficient to cause a maintained reduction in IOP, does have some side effects. However, none of these side effects are of sufficient importance to exclude the use of eicosanoids as potential anti-glaucoma agents.

  3. Bilateral intraocular pressure elevation and decrease of facility of aqueous humour outflow as a consequence of regional lymphoedema of head and neck.

    PubMed

    Holló, G

    1993-06-01

    Aqueous humour drainage to the deep cervical lymphatics has been proven in animal experiments, but there have been no observations of changes in intraocular pressure (IOP) or aqueous humour drainage as a consequence of lymph drainage dysfunction. The history of a patient with non-Hodgkin's lymphoma, who underwent a left-sided radical neck dissection in January 1991, is reported. From the end of 1991 lymphoedema of the head and neck, predominantly on the right side, developed without venous stasis but with significant bilateral IOP elevation and aqueous humour outflow reduction, refract to conventional treatment. Two days after cytostatic treatment the lymphoedema disappeared, and IOP and aqueous humour outflow became normal. Four days later the patient died because of an acute bronchopneumonia. The pathological examination revealed an intact internal jugular venous system, enlarged lymph nodes and, as a consequence of previous irradiation, cicatrization in the right side of the neck. On the left side, there was absence of the internal jugular vein and jugular lymphatic trunk due to previous radical neck dissection. Our case suggests that regional lymphatic stasis and the absence of the collateral drainage to the contralateral side significantly reduces the aqueous humour outflow and leads to a bilateral, secondary IOP elevation.

  4. Sustained reduction of intraocular pressure by supraciliary delivery of brimonidine-loaded poly(lactic acid) microspheres for the treatment of glaucoma.

    PubMed

    Chiang, B; Kim, Y C; Doty, A C; Grossniklaus, H E; Schwendeman, S P; Prausnitz, M R

    2016-04-28

    Although effective drugs that lower intraocular pressure (IOP) in the management of glaucoma exist, their efficacy is limited by poor patient adherence to the prescribed eye drop regimen. To replace the need for eye drops, in this study we tested the hypothesis that IOP can be reduced for one month after a single targeted injection using a microneedle for administration of a glaucoma medication (i.e., brimonidine) formulated for sustained release in the supraciliary space of the eye adjacent to the drug's site of action at the ciliary body. To test this hypothesis, brimonidine-loaded microspheres were formulated using poly(lactic acid) (PLA) to release brimonidine at a constant rate for 35 days and microneedles were designed to penetrate through the sclera, without penetrating into the choroid/retina, in order to target injection into the supraciliary space. A single administration of these microspheres using a hollow microneedle was performed in the eye of New Zealand White rabbits and was found to reduce IOP initially by 6 mmHg and then by progressively smaller amounts for more than one month. All administrations were well tolerated without significant adverse events, although histological examination showed a foreign-body reaction to the microspheres. This study demonstrates, for the first time, that the highly-targeted delivery of brimonidine-loaded microspheres into the supraciliary space using a microneedle is able to reduce IOP for one month as an alternative to daily eye drops.

  5. Mice Homozygous for a Deletion in the Glaucoma Susceptibility Locus INK4 Show Increased Vulnerability of Retinal Ganglion Cells to Elevated Intraocular Pressure.

    PubMed

    Gao, Shan; Jakobs, Tatjana C

    2016-04-01

    A genomic region located on chromosome 9p21 is associated with primary open-angle glaucoma and normal tension glaucoma in genome-wide association studies. The genomic region contains the gene for a long noncoding RNA called CDKN2B-AS, two genes that code for cyclin-dependent kinase inhibitors 2A and 2B (CDKN2A/p16(INK4A) and CDKN2B/p15(INK4B)) and an additional protein (p14(ARF)). We used a transgenic mouse model in which 70 kb of murine chromosome 4, syntenic to human chromosome 9p21, are deleted to study whether this deletion leads to a discernible phenotype in ocular structures implicated in glaucoma. Homozygous mice of this strain were previously reported to show persistent hyperplastic primary vitreous. Fundus photography and optical coherence tomography confirmed that finding but showed no abnormalities for heterozygous mice. Optokinetic response, eletroretinogram, and histology indicated that the heterozygous and mutant retinas were normal functionally and morphologically, whereas glial cells were activated in the retina and optic nerve head of mutant eyes. In quantitative PCR, CDKN2B expression was reduced by approximately 50% in the heterozygous mice and by 90% in the homozygous mice, which suggested that the CDKN2B knock down had no deleterious consequences for the retina under normal conditions. However, compared with wild-type and heterozygous animals, the homozygous mice are more vulnerable to retinal ganglion cell loss in response to elevated intraocular pressure.

  6. Comparison of Intraocular Pressure before and after Laser In Situ Keratomileusis Refractive Surgery Measured with Perkins Tonometry, Noncontact Tonometry, and Transpalpebral Tonometry

    PubMed Central

    Cacho, Isabel; Sanchez-Naves, Juan; Batres, Laura; Pintor, Jesús; Carracedo, Gonzalo

    2015-01-01

    Purpose. To compare the intraocular pressure (IOP) before and after Laser In Situ Keratomileusis (LASIK), measured by Diaton, Perkins, and noncontact air pulse tonometers. Methods. Fifty-seven patients with a mean age of 34.88 were scheduled for myopia LASIK treatment. Spherical equivalent refraction (SER), corneal curvature (K), and central corneal thickness (CCT) and superior corneal thickness (SCT) were obtained before and after LASIK surgery. IOP values before and after surgery were measured using Diaton, Perkins, and noncontact air pulse tonometers. Results. The IOP values before and after LASIK surgery using Perkins tonometer and air tonometers were statistically significant (p < 0.05). However, no significant differences were found (p > 0.05) for IOP values measured with Diaton tonometer. CCT decreases significantly after surgery (p < 0.05) but no statistical differences were found in SCT (p = 0.08). Correlations between pre- and postsurgery were found for all tonometers used, with p = 0.001 and r = 0.434 for the air pulse tonometer, p = 0.008 and r = 0.355 for Perkins, and p < 0.001 and r = 0.637 for Diaton. Conclusion. Transpalpebral tonometry may be useful for measuring postsurgery IOP after myopic LASIK ablation because this technique is not influenced by the treatment. PMID:26167293

  7. Real-Time Flight Envelope Monitoring System

    NASA Technical Reports Server (NTRS)

    Kerho, Michael; Bragg, Michael B.; Ansell, Phillip J.

    2012-01-01

    The objective of this effort was to show that real-time aircraft control-surface hinge-moment information could be used to provide a robust and reliable prediction of vehicle performance and control authority degradation. For a given airfoil section with a control surface -- be it a wing with an aileron, rudder, or elevator -- the control-surface hinge moment is sensitive to the aerodynamic characteristics of the section. As a result, changes in the aerodynamics of the section due to angle-of-attack or environmental effects such as icing, heavy rain, surface contaminants, bird strikes, or battle damage will affect the control surface hinge moment. These changes include both the magnitude of the hinge moment and its sign in a time-averaged sense, and the variation of the hinge moment with time. The current program attempts to take the real-time hinge moment information from the aircraft control surfaces and develop a system to predict aircraft envelope boundaries across a range of conditions, alerting the flight crew to reductions in aircraft controllability and flight boundaries.

  8. Reconfigurable real-time distributed processing network

    NASA Astrophysics Data System (ADS)

    Page, S. F.; Seely, R. D.; Hickman, D.

    2011-06-01

    This paper describes a novel real-time image and signal processing network, RONINTM, which facilitates the rapid design and deployment of systems providing advanced geospatial surveillance and situational awareness capability. RONINTM is a distributed software architecture consisting of multiple agents or nodes, which can be configured to implement a variety of state-of-the-art computer vision and signal processing algorithms. The nodes operate in an asynchronous fashion and can run on a variety of hardware platforms, thus providing a great deal of scalability and flexibility. Complex algorithmic configuration chains can be assembled using an intuitive graphical interface in a plug-and- play manner. RONINTM has been successfully exploited for a number of applications, ranging from remote event detection to complex multiple-camera real-time 3D object reconstruction. This paper describes the motivation behind the creation of the network, the core design features, and presents details of an example application. Finally, the on-going development of the network is discussed, which is focussed on dynamic network reconfiguration. This allows to the network to automatically adapt itself to node or communications failure by intelligently re-routing network communications and through adaptive resource management.

  9. Real Time Simulation of Power Grid Disruptions

    SciTech Connect

    Chinthavali, Supriya; Dimitrovski, Aleksandar D; Fernandez, Steven J; Groer, Christopher S; Nutaro, James J; Olama, Mohammed M; Omitaomu, Olufemi A; Shankar, Mallikarjun; Spafford, Kyle L; Vacaliuc, Bogdan

    2012-11-01

    DOE-OE and DOE-SC workshops (Reference 1-3) identified the key power grid problem that requires insight addressable by the next generation of exascale computing is coupling of real-time data streams (1-2 TB per hour) as the streams are ingested to dynamic models. These models would then identify predicted disruptions in time (2-4 seconds) to trigger the smart grid s self healing functions. This project attempted to establish the feasibility of this approach and defined the scientific issues, and demonstrated example solutions to important smart grid simulation problems. These objectives were accomplished by 1) using the existing frequency recorders on the national grid to establish a representative and scalable real-time data stream; 2) invoking ORNL signature identification algorithms; 3) modeling dynamically a representative region of the Eastern interconnect using an institutional cluster, measuring the scalability and computational benchmarks for a national capability; and 4) constructing a prototype simulation for the system s concept of smart grid deployment. The delivered ORNL enduring capability included: 1) data processing and simulation metrics to design a national capability justifying exascale applications; 2) Software and intellectual property built around the example solutions; 3) demonstrated dynamic models to design few second self-healing.

  10. REal-time COsmic Ray Database (RECORD)

    NASA Astrophysics Data System (ADS)

    Usoskin, I.; Kozlov, Valery; Ksenofontov, Leonid, Kudela, Karel; Starodubtsev, Sergei; Turpanov, Alexey; Yanke, Victor

    2003-07-01

    In this paper we present a first distributed REal-time COsmic Ray Database (RECORD). The aim of the project is to develop a unified database with data from different neutron monitors collected together, in unified format and to provide a user with several commonly used data access methods. The database contains not only original cosmic ray data but also auxiliary data necessary for scientific data analysis. Currently the database includes Lomn.Stit, Moscow, Oulu; Tixie Bay, Yakutsk stations. The main database server is located in IKFIA SB RAS (Yakutsk) but there will be several mirrors of the database. The database and all its mirrors are up dated on the nearly real-time (1 hour) basis. The data access software includes WWW-interface, Perl scripts and C library, which may be linked to a user program. Most of frequently used functions are implemented to make it operable to users without SQL language knowledge. A draft of the data representation standard is suggested, based on common practice of neutron monitor community. The database engine is freely distributed open-sourced PostgreSQL server coupled with a set of replication to ols developed at Bio engineering division of the IRCCS E.Medea, Italy.

  11. Machine learning for real time remote detection

    NASA Astrophysics Data System (ADS)

    Labbé, Benjamin; Fournier, Jérôme; Henaff, Gilles; Bascle, Bénédicte; Canu, Stéphane

    2010-10-01

    Infrared systems are key to providing enhanced capability to military forces such as automatic control of threats and prevention from air, naval and ground attacks. Key requirements for such a system to produce operational benefits are real-time processing as well as high efficiency in terms of detection and false alarm rate. These are serious issues since the system must deal with a large number of objects and categories to be recognized (small vehicles, armored vehicles, planes, buildings, etc.). Statistical learning based algorithms are promising candidates to meet these requirements when using selected discriminant features and real-time implementation. This paper proposes a new decision architecture benefiting from recent advances in machine learning by using an effective method for level set estimation. While building decision function, the proposed approach performs variable selection based on a discriminative criterion. Moreover, the use of level set makes it possible to manage rejection of unknown or ambiguous objects thus preserving the false alarm rate. Experimental evidences reported on real world infrared images demonstrate the validity of our approach.

  12. Real-time applications of neural nets

    SciTech Connect

    Spencer, J.E.

    1989-05-01

    Producing, accelerating and colliding very high power, low emittance beams for long periods is a formidable problem in real-time control. As energy has grown exponentially in time so has the complexity of the machines and their control systems. Similar growth rates have occurred in many areas, e.g., improved integrated circuits have been paid for with comparable increases in complexity. However, in this case, reliability, capability and cost have improved due to reduced size, high production and increased integration which allow various kinds of feedback. In contrast, most large complex systems (LCS) are perceived to lack such possibilities because only one copy is made. Neural nets, as a metaphor for LCS, suggest ways to circumvent such limitations. It is argued that they are logically equivalent to multi-loop feedback/forward control of faulty systems. While complimentary to AI, they mesh nicely with characteristics desired for real-time systems. Such issues are considered, examples given and possibilities discussed. 21 refs., 6 figs.

  13. Real-time applications of neural nets

    SciTech Connect

    Spencer, J.E. )

    1989-10-01

    Producing, accelerating and colliding very high power, low emittance beams for long periods is a formidable problem in real-time control. As energy has grown exponentially in time so has the complexity of the machines and their control systems. Similar growth rates have occurred in many areas e.g. improved integrated circuits have been paid for with comparable increases in complexity. However, in this case, reliability, capability and cost have improved due to reduced size, high production and increased integration which allow various kinds of feedback. In contrast, most large complex systems (LCS) are perceived to lack such possibilities because only one copy is made. Neural nets, as a metaphor for LCS, suggest ways to circumvent such limitations. It is argued that they are logically equivalent to multi-loop feedback/forward control of faulty systems. While complimentary to AI, they mesh nicely with characteristics desired for real-time systems. In this paper, such issues are considered, examples given and possibilities discussed.

  14. Real-time design with peer tasks

    NASA Technical Reports Server (NTRS)

    Goforth, Andre; Howes, Norman R.; Wood, Jonathan D.; Barnes, Michael J.

    1995-01-01

    We introduce a real-time design methodology for large scale, distributed, parallel architecture, real-time systems (LDPARTS), as an alternative to those methods using rate or dead-line monotonic analysis. In our method the fundamental units of prioritization, work items, are domain specific objects with timing requirements (deadlines) found in user's specification. A work item consists of a collection of tasks of equal priority. Current scheduling theories are applied with artifact deadlines introduced by the designer whereas our method schedules work items to meet user's specification deadlines (sometimes called end-to-end deadlines). Our method supports these scheduling properties. Work item scheduling is based on domain specific importance instead of task level urgency and still meets as many user specification deadlines as can be met by scheduling tasks with respect to urgency. Second, the minimum (closest) on-line deadline that can be guaranteed for a work item of highest importance, scheduled at run time, is approximately the inverse of the throughput, measured in work items per second. Third, throughput is not degraded during overload and instead of resorting to task shedding during overload, the designer can specify which work items to shed. We prove these properties in a mathematical model.

  15. Real-time animation of complex hairstyles.

    PubMed

    Volino, Pascal; Magnenat-Thalmann, Nadia

    2006-01-01

    True real-time animation of complex hairstyles on animated characters is the goal of this work, and the challenge is to build a mechanical model of the hairstyle which is sufficiently fast for real-time performance while preserving the particular behavior of the hair medium and maintaining sufficient versatility for simulating any kind of complex hairstyles. Rather than building a complex mechanical model directly related to the structure of the hair strands, we take advantage of a volume free-form deformation scheme. We detail the construction of an efficient lattice mechanical deformation model which represents the volume behavior of the hair strands. The lattice is deformed as a particle system using state-of-the-art numerical methods, and animates the hairs using quadratic B-Spline interpolation. The hairstyle reacts to the body skin through collisions with a metaball-based approximation. The model is highly scalable and allows hairstyles of any complexity to be simulated in any rendering context with the appropriate trade off between accuracy and computation speed, fitting the need of Level-of-Detail optimization schemes.

  16. Real-time PCR in microfluidic devices

    NASA Astrophysics Data System (ADS)

    Becker, Holger; Hlawatsch, Nadine; Klemm, Richard; Moche, Christian; Hansen-Hagge, Thomas; Gärtner, Claudia

    2014-03-01

    A central method in a standard biochemical laboratory is represented by the polymerase chain reaction (PCR), therefore many attempts have been performed so far to implement this technique in lab-on-a-chip (LOC) devices. PCR is an ideal candidate for miniaturization because of a reduction of assay time and decreased costs for expensive bio-chemicals. In case of the "classical" PCR, detection is done by identification of DNA fragments electrophoretically separated in agarose gels. This method is meanwhile frequently replaced by the so-called Real-Time-PCR because here the exponential increase of amplificates can be observed directly by measurement of DNA interacting fluorescent dyes. Two main methods for on-chip PCRs are available: traditional "batch" PCR in chambers on a chip using thermal cycling, requiring about 30 minutes for a typical PCR protocol and continuous-flow PCR, where the liquid is guided over stationary temperature zones. In the latter case, the PCR protocol can be as fast as 5 minutes. In the presented work, a proof of concept is demonstrated for a real-time-detection of PCR products in microfluidic systems.

  17. An efficient real time superresolution ASIC system

    NASA Astrophysics Data System (ADS)

    Reddy, Dikpal; Yue, Zhanfeng; Topiwala, Pankaj

    2008-04-01

    Superresolution of images is an important step in many applications like target recognition where the input images are often grainy and of low quality due to bandwidth constraints. In this paper, we present a real-time superresolution application implemented in ASIC/FPGA hardware, and capable of 30 fps of superresolution by 16X in total pixels. Consecutive frames from the video sequence are grouped and the registered values between them are used to fill the pixels in the higher resolution image. The registration between consecutive frames is evaluated using the algorithm proposed by Schaum et al. The pixels are filled by averaging a fixed number of frames associated with the smallest error distances. The number of frames (the number of nearest neighbors) is a user defined parameter whereas the weights in the averaging process are decided by inverting the corresponding smallest error distances. Wiener filter is used to post process the image. Different input parameters, such as size of input image, enlarging factor and the number of nearest neighbors, can be tuned conveniently by the user. We use a maximum word size of 32 bits to implement the algorithm in Matlab Simulink as well as the hardware, which gives us a fine balance between the number of bits and performance. The algorithm performs with real time speed with very impressive superresolution results.

  18. Real-time Raman sensing without spectrometer

    NASA Astrophysics Data System (ADS)

    Kim, Min Ju; Kim, Sungho; Yang, Timothy K.; Kumar, Dinesh; Bae, Sung Chul

    2015-03-01

    Raman spectroscopy has been a powerful tool in various fields of science and technology ranging from analytical chemistry to biomedical imaging. In spite of unique features, Raman spectroscopy has also some limitations. Among them are weak Raman signal compared to strong fluorescence and relatively complicated setup with expensive and bulky spectrometer. In order to increase the sensitivity of Raman technique, many clever attempts have been made and some of them were very successful including CARS, SRS, and so on. However, these still requires expensive and more complicated setup. In this work, we have attempted to build a real-time compact Raman sensor without spectrometer. Conventional spectrometer was replaced with a narrow-band optical filter and alternatively modulated two lasers with slightly different wavelengths. At one laser, Raman signal from a target molecule was transmitted through the optical filter. At the other laser, this signal was blocked by the optical filter and could not be detected by photon detector. The alternative modulation of two lasers will modulate the Raman signal from a target molecule at the same modulation frequency. This modulated weak Raman signal was amplified by a lock-in amplifier. The advantages of this setup include compactness, low cost, real-time monitoring, and so on. We have tested the sensitivity of this setup and we found that it doesn't have enough sensitivity to detect single molecule-level, but it is still good enough to monitor the change of major chemical composition in the sample.

  19. Real-time sensor data validation

    NASA Technical Reports Server (NTRS)

    Bickmore, Timothy W.

    1994-01-01

    This report describes the status of an on-going effort to develop software capable of detecting sensor failures on rocket engines in real time. This software could be used in a rocket engine controller to prevent the erroneous shutdown of an engine due to sensor failures which would otherwise be interpreted as engine failures by the control software. The approach taken combines analytical redundancy with Bayesian belief networks to provide a solution which has well defined real-time characteristics and well-defined error rates. Analytical redundancy is a technique in which a sensor's value is predicted by using values from other sensors and known or empirically derived mathematical relations. A set of sensors and a set of relations among them form a network of cross-checks which can be used to periodically validate all of the sensors in the network. Bayesian belief networks provide a method of determining if each of the sensors in the network is valid, given the results of the cross-checks. This approach has been successfully demonstrated on the Technology Test Bed Engine at the NASA Marshall Space Flight Center. Current efforts are focused on extending the system to provide a validation capability for 100 sensors on the Space Shuttle Main Engine.

  20. Real-Time and Near Real-Time Data for Space Weather Applications and Services

    NASA Astrophysics Data System (ADS)

    Singer, H. J.; Balch, C. C.; Biesecker, D. A.; Matsuo, T.; Onsager, T. G.

    2015-12-01

    Space weather can be defined as conditions in the vicinity of Earth and in the interplanetary environment that are caused primarily by solar processes and influenced by conditions on Earth and its atmosphere. Examples of space weather are the conditions that result from geomagnetic storms, solar particle events, and bursts of intense solar flare radiation. These conditions can have impacts on modern-day technologies such as GPS or electric power grids and on human activities such as astronauts living on the International Space Station or explorers traveling to the moon or Mars. While the ultimate space weather goal is accurate prediction of future space weather conditions, for many applications and services, we rely on real-time and near-real time observations and model results for the specification of current conditions. In this presentation, we will describe the space weather system and the need for real-time and near-real time data that drive the system, characterize conditions in the space environment, and are used by models for assimilation and validation. Currently available data will be assessed and a vision for future needs will be given. The challenges for establishing real-time data requirements, as well as acquiring, processing, and disseminating the data will be described, including national and international collaborations. In addition to describing how the data are used for official government products, we will also give examples of how these data are used by both the public and private sector for new applications that serve the public.

  1. Real-time forecasts of dengue epidemics

    NASA Astrophysics Data System (ADS)

    Yamana, T. K.; Shaman, J. L.

    2015-12-01

    Dengue is a mosquito-borne viral disease prevalent in the tropics and subtropics, with an estimated 2.5 billion people at risk of transmission. In many areas with endemic dengue, disease transmission is seasonal but prone to high inter-annual variability with occasional severe epidemics. Predicting and preparing for periods of higher than average transmission is a significant public health challenge. Here we present a model of dengue transmission and a framework for optimizing model simulations with real-time observational data of dengue cases and environmental variables in order to generate ensemble-based forecasts of the timing and severity of disease outbreaks. The model-inference system is validated using synthetic data and dengue outbreak records. Retrospective forecasts are generated for a number of locations and the accuracy of these forecasts is quantified.

  2. Near real-time traffic routing

    NASA Technical Reports Server (NTRS)

    Yang, Chaowei (Inventor); Cao, Ying (Inventor); Xie, Jibo (Inventor); Zhou, Bin (Inventor)

    2012-01-01

    A near real-time physical transportation network routing system comprising: a traffic simulation computing grid and a dynamic traffic routing service computing grid. The traffic simulator produces traffic network travel time predictions for a physical transportation network using a traffic simulation model and common input data. The physical transportation network is divided into a multiple sections. Each section has a primary zone and a buffer zone. The traffic simulation computing grid includes multiple of traffic simulation computing nodes. The common input data includes static network characteristics, an origin-destination data table, dynamic traffic information data and historical traffic data. The dynamic traffic routing service computing grid includes multiple dynamic traffic routing computing nodes and generates traffic route(s) using the traffic network travel time predictions.

  3. Real Time Correction of Aircraft Flight Fonfiguration

    NASA Technical Reports Server (NTRS)

    Schipper, John F. (Inventor)

    2009-01-01

    Method and system for monitoring and analyzing, in real time, variation with time of an aircraft flight parameter. A time-dependent recovery band, defined by first and second recovery band boundaries that are spaced apart at at least one time point, is constructed for a selected flight parameter and for a selected time recovery time interval length .DELTA.t(FP;rec). A flight parameter, having a value FP(t=t.sub.p) at a time t=t.sub.p, is likely to be able to recover to a reference flight parameter value FP(t';ref), lying in a band of reference flight parameter values FP(t';ref;CB), within a time interval given by t.sub.p.ltoreq.t'.ltoreq.t.sub.p.DELTA.t(FP;rec), if (or only if) the flight parameter value lies between the first and second recovery band boundary traces.

  4. Real-time value-driven diagnosis

    NASA Technical Reports Server (NTRS)

    Dambrosio, Bruce

    1995-01-01

    Diagnosis is often thought of as an isolated task in theoretical reasoning (reasoning with the goal of updating our beliefs about the world). We present a decision-theoretic interpretation of diagnosis as a task in practical reasoning (reasoning with the goal of acting in the world), and sketch components of our approach to this task. These components include an abstract problem description, a decision-theoretic model of the basic task, a set of inference methods suitable for evaluating the decision representation in real-time, and a control architecture to provide the needed continuing coordination between the agent and its environment. A principal contribution of this work is the representation and inference methods we have developed, which extend previously available probabilistic inference methods and narrow, somewhat, the gap between probabilistic and logical models of diagnosis.

  5. Real time speech formant analyzer and display

    DOEpatents

    Holland, George E.; Struve, Walter S.; Homer, John F.

    1987-01-01

    A speech analyzer for interpretation of sound includes a sound input which converts the sound into a signal representing the sound. The signal is passed through a plurality of frequency pass filters to derive a plurality of frequency formants. These formants are converted to voltage signals by frequency-to-voltage converters and then are prepared for visual display in continuous real time. Parameters from the inputted sound are also derived and displayed. The display may then be interpreted by the user. The preferred embodiment includes a microprocessor which is interfaced with a television set for displaying of the sound formants. The microprocessor software enables the sound analyzer to present a variety of display modes for interpretive and therapeutic used by the user.

  6. REAL TIME DATA FOR REMEDIATION ACTIVITIES [11505

    SciTech Connect

    BROCK CT

    2011-01-13

    Health physicists from the CH2M HILL Plateau Remediation Company collaborated with Berkeley Nucleonics Corporation to modify the SAM 940 isotope identifier instrument to be used for nuclear waste remediation. These modifications coupled with existing capabilities of the SAM 940 have proven to be invaluable during remediation activities, reducing disposal costs by allowing swift remediation of targeted areas that have been identified as having isotopes of concern (IOC), and eliminating multiple visits to sites by declaring an excavation site clear of IOCs before demobilizing from the site. These advantages are enabled by accumulating spectral data for specific isotopes that is nearly 100 percent free of false positives, which are filtered out in 'real time.'

  7. Identifying financial crises in real time

    NASA Astrophysics Data System (ADS)

    da Fonseca, Eder Lucio; Ferreira, Fernando F.; Muruganandam, Paulsamy; Cerdeira, Hilda A.

    2013-03-01

    Following the thermodynamic formulation of a multifractal measure that was shown to enable the detection of large fluctuations at an early stage, here we propose a new index which permits us to distinguish events like financial crises in real time. We calculate the partition function from which we can obtain thermodynamic quantities analogous to the free energy and specific heat. The index is defined as the normalized energy variation and it can be used to study the behavior of stochastic time series, such as financial market daily data. Famous financial market crashes-Black Thursday (1929), Black Monday (1987) and the subprime crisis (2008)-are identified with clear and robust results. The method is also applied to the market fluctuations of 2011. From these results it appears as if the apparent crisis of 2011 is of a different nature to the other three. We also show that the analysis has forecasting capabilities.

  8. Terrestrial Real-Time Volcano Monitoring

    NASA Astrophysics Data System (ADS)

    Franke, M.

    2013-12-01

    As volcano monitoring involves more and different sensors from seismic to GPS receivers, from video and thermal cameras to multi-parameter probes measuring temperature, ph values and humidity in the ground and the air, it becomes important to design real-time networks that integrate and leverage the multitude of available parameters. In order to do so some simple principles need to be observed: a) a common time base for all measurements, b) a packetized general data communication protocol for acquisition and distribution, c) an open and well documented interface to the data permitting standard and emerging innovative processing, and d) an intuitive visualization platform for scientists and civil defense personnel. Although mentioned as simple principles, the list above does not necessarily lead to obvious solutions or integrated systems, which is, however, required to take advantage of the available data. Only once the different data streams are put into context to each other in terms of time and location can a broader view be obtained and additional information extracted. The presentation is a summary of currently available technologies and how they can achieve the goal of an integrated real-time volcano monitoring system. A common time base are standard for seismic and GPS networks. In different projects we extended this to video feeds and time-lapse photography. Other probes have been integrated with vault interface enclosures (VIE) as used in the Transportable Array (TA) of the USArray. The VIE can accommodate the sensors employed in volcano monitoring. The TA has shown that Antelope is a versatile and robust middleware. It provides the required packetized general communication protocol that is independent from the actual physical communication link leaving the network design to adopt appropriate and possible hybrid solutions. This applies for the data acquisition and the data/information dissemination providing both a much needed collaboration platform, as

  9. Real-time, face recognition technology

    SciTech Connect

    Brady, S.

    1995-11-01

    The Institute for Scientific Computing Research (ISCR) at Lawrence Livermore National Laboratory recently developed the real-time, face recognition technology KEN. KEN uses novel imaging devices such as silicon retinas developed at Caltech or off-the-shelf CCD cameras to acquire images of a face and to compare them to a database of known faces in a robust fashion. The KEN-Online project makes that recognition technology accessible through the World Wide Web (WWW), an internet service that has recently seen explosive growth. A WWW client can submit face images, add them to the database of known faces and submit other pictures that the system tries to recognize. KEN-Online serves to evaluate the recognition technology and grow a large face database. KEN-Online includes the use of public domain tools such as mSQL for its name-database and perl scripts to assist the uploading of images.

  10. Optimal, real-time control--colliders

    SciTech Connect

    Spencer, J.E.

    1991-05-01

    With reasonable definitions, optimal control is possible for both classical and quantal systems with new approaches called PISC(Parallel) and NISC(Neural) from analogy with RISC (Reduced Instruction Set Computing). If control equals interaction, observation and comparison to some figure of merit with interaction via external fields, then optimization comes from varying these fields to give design or operating goals. Structural stability can then give us tolerance and design constraints. But simulations use simplified models, are not in real-time and assume fixed or stationary conditions, so optimal control goes far beyond convergence rates of algorithms. It is inseparable from design and this has many implications for colliders. 12 refs., 3 figs.

  11. A Flexible Real-Time Architecture

    SciTech Connect

    WICKSTROM,GREGORY L.

    2000-08-17

    Assuring hard real-time characteristics of I/O associated with embedded software is often a difficult task. Input-Output related statements are often intermixed with the computational code, resulting in I/O timing that is dependent on the execution path and computational load. One way to mitigate this problem is through the use of interrupts. However, the non-determinism that is introduced by interrupt driven I/O may be so difficult to analyze that it is prohibited in some high consequence systems. This paper describes a balanced hardware/software solution to obtain consistent interrupt-free I/O timing, and results in software that is much more amenable to analysis.

  12. Real-time color holographic interferometry

    NASA Astrophysics Data System (ADS)

    Desse, Jean-Michel; Albe, Felix; Tribillon, Jean-Louis

    2002-09-01

    A new optical technique based on real-time color holographic interferometry has been developed for analyzing unsteady aerodynamic wakes in fluid mechanics or for measuring displacements and deformations in solid mechanics. The technique's feasibility is demonstrated here. It uses three coherent wavelengths produced simultaneously by a cw laser (mixed argon and krypton). Holograms are recorded on single-layer panchromatic silver halide (Slavich PFG 03C) plates. Results show the optical setup can be adjusted to obtain a uniform background color. The interference fringe pattern visualized is large and colored and exhibits a single central white fringe, which makes the zero order of the interferogram easy to identify. An application in a subsonic wind tunnel is presented, in which the unsteady wake past a cylinder is recorded at high rate.

  13. Real-time color holographic interferometry.

    PubMed

    Desse, Jean-Michel; Albe, Félix; Tribillon, Jean-Louis

    2002-09-01

    A new optical technique based on real-time color holographic interferometry has been developed for analyzing unsteady aerodynamic wakes in fluid mechanics or for measuring displacements and deformations in solid mechanics. The technique's feasibility is demonstrated here. It uses three coherent wavelengths produced simultaneously by a cw laser (mixed argon and krypton). Holograms are recorded on single-layer panchromatic silver halide (Slavich PFG 03C) plates. Results show the optical setup can be adjusted to obtain a uniform background color. The interference fringe pattern visualized is large and colored and exhibits a single central white fringe, which makes the zero order of the interferogram easy to identify. An application in a subsonic wind tunnel is presented, in which the unsteady wake past a cylinder is recorded at high rate.

  14. In-line real time air monitor

    DOEpatents

    Wise, Marcus B.; Thompson, Cyril V.

    1998-01-01

    An in-line gas monitor capable of accurate gas composition analysis in a continuous real time manner even under strong applied vacuum conditions operates by mixing an air sample with helium forming a sample gas in two complementary sample loops embedded in a manifold which includes two pairs of 3-way solenoid valves. The sample gas is then analyzed in an ion trap mass spectrometer on a continuous basis. Two valve drivers actuate the two pairs of 3-way valves in a reciprocating fashion, so that there is always flow through the in-line gas monitor via one or the other of the sample loops. The duty cycle for the two pairs of 3-way valves is varied by tuning the two valve drivers to a duty cycle typically between 0.2 to 0.7 seconds.

  15. In-line real time air monitor

    DOEpatents

    Wise, M.B.; Thompson, C.V.

    1998-07-14

    An in-line gas monitor capable of accurate gas composition analysis in a continuous real time manner even under strong applied vacuum conditions operates by mixing an air sample with helium forming a sample gas in two complementary sample loops embedded in a manifold which includes two pairs of 3-way solenoid valves. The sample gas is then analyzed in an ion trap mass spectrometer on a continuous basis. Two valve drivers actuate the two pairs of 3-way valves in a reciprocating fashion, so that there is always flow through the in-line gas monitor via one or the other of the sample loops. The duty cycle for the two pairs of 3-way valves is varied by tuning the two valve drivers to a duty cycle typically between 0.2 to 0.7 seconds. 3 figs.

  16. Real time speech formant analyzer and display

    DOEpatents

    Holland, G.E.; Struve, W.S.; Homer, J.F.

    1987-02-03

    A speech analyzer for interpretation of sound includes a sound input which converts the sound into a signal representing the sound. The signal is passed through a plurality of frequency pass filters to derive a plurality of frequency formants. These formants are converted to voltage signals by frequency-to-voltage converters and then are prepared for visual display in continuous real time. Parameters from the inputted sound are also derived and displayed. The display may then be interpreted by the user. The preferred embodiment includes a microprocessor which is interfaced with a television set for displaying of the sound formants. The microprocessor software enables the sound analyzer to present a variety of display modes for interpretive and therapeutic used by the user. 19 figs.

  17. A Measure of Real-Time Intelligence

    NASA Astrophysics Data System (ADS)

    Gavane, Vaibhav

    2013-03-01

    We propose a new measure of intelligence for general reinforcement learning agents, based on the notion that an agent's environment can change at any step of execution of the agent. That is, an agent is considered to be interacting with its environment in real-time. In this sense, the resulting intelligence measure is more general than the universal intelligence measure (Legg and Hutter, 2007) and the anytime universal intelligence test (Hernández-Orallo and Dowe, 2010). A major advantage of the measure is that an agent's computational complexity is factored into the measure in a natural manner. We show that there exist agents with intelligence arbitrarily close to the theoretical maximum, and that the intelligence of agents depends on their parallel processing capability. We thus believe that the measure can provide a better evaluation of agents and guidance for building practical agents with high intelligence.

  18. Near Real Time Quantitative Gas Analysis Techniques

    NASA Astrophysics Data System (ADS)

    Herget, William F.; Tromp, Marianne L.; Anderson, Charles R.

    1985-12-01

    A Fourier transform infrared (FT-IR) - based system has been developed and is undergoing evaluation for near real time multicomponent quantitative analysis of undiluted gaseous automotive exhaust emissions. The total system includes: (1) a gas conditioning system (GCS) for tracer gas injection, gas mixing, and temperature stabilization; and (2) an exhaust gas analyzer (EGA) consisting of a sample cell, an FT-IR system, and a computerized data processing system. Tests have shown that the system can monitor about 20 individual species (concentrations down to the 1-20 ppm range) with a time resolution of one second. Tests have been conducted on a chassis dynamometer system utilizing different autos, different fuels, and different driving cycles. Results were compared with those obtained using a standard constant volume sampling (CVS) system.

  19. Near real-time stereo vision system

    NASA Technical Reports Server (NTRS)

    Anderson, Charles H. (Inventor); Matthies, Larry H. (Inventor)

    1993-01-01

    The apparatus for a near real-time stereo vision system for use with a robotic vehicle is described. The system is comprised of two cameras mounted on three-axis rotation platforms, image-processing boards, a CPU, and specialized stereo vision algorithms. Bandpass-filtered image pyramids are computed, stereo matching is performed by least-squares correlation, and confidence ranges are estimated by means of Bayes' theorem. In particular, Laplacian image pyramids are built and disparity maps are produced from the 60 x 64 level of the pyramids at rates of up to 2 seconds per image pair. The first autonomous cross-country robotic traverses (of up to 100 meters) have been achieved using the stereo vision system of the present invention with all computing done onboard the vehicle. The overall approach disclosed herein provides a unifying paradigm for practical domain-independent stereo ranging.

  20. Otolaryngology consultations by real-time telemedicine.

    PubMed Central

    Ullah, R.; Gilliland, D.; Adams, D.

    2002-01-01

    We aimed to assess the value of real-time telemedicine using low cost videoconferencing equipment for otorhinolaryngology consultations. A general practitioner, using low cost videoconferencing equipment, presented patients to an otorhinolaryngologist. After history taking and clinical examination, investigations were requested if required and a diagnosis and management plan formulated. The patients were then seen, by the same otorhinolaryngologist, for a conventional face-to-face consultation. Differences in the history, clinical examination and investigation requests were reported. The accuracy of diagnosis and correlation of management plans between the two consultations were analysed. Forty-three patients were admitted to the study but one, a young child, refused examination either by tele-link or the conventional approach and had to be excluded. There were thus 42 patients with 55 diagnoses included in the trial, 26 (62%) females and 16 (38%) males. Age range was 5 months to 70 years. There was no difficulty with any of the patients in obtaining an accurate history and ordering investigations, if required, via the telelink. Clinical examination during the tele-link consultation was inadequate for eight out of the first 20 patients, resulting in a wrong diagnosis in three patients and a missed diagnosis in five patients. All of the next 22 patients had a correct diagnosis and management plan. Comparison of data from the two types of consultation showed that a correct diagnosis and management plan was made in 34 patients. Low cost real-time telemedicine is a useful technique, providing reliable otorhinolaryngology consultations in a general practice setting. However initial difficulties due to inexperience in using the equipment need to be overcome. PMID:12137160

  1. Towards real time speckle controlled retinal photocoagulation

    NASA Astrophysics Data System (ADS)

    Bliedtner, Katharina; Seifert, Eric; Stockmann, Leoni; Effe, Lisa; Brinkmann, Ralf

    2016-03-01

    Photocoagulation is a laser treatment widely used for the therapy of several retinal diseases. Intra- and inter-individual variations of the ocular transmission, light scattering and the retinal absorption makes it impossible to achieve a uniform effective exposure and hence a uniform damage throughout the therapy. A real-time monitoring and control of the induced damage is highly requested. Here, an approach to realize a real time optical feedback using dynamic speckle analysis is presented. A 532 nm continuous wave Nd:YAG laser is used for coagulation. During coagulation, speckle dynamics are monitored by a coherent object illumination using a 633nm HeNe laser and analyzed by a CMOS camera with a frame rate up to 1 kHz. It is obvious that a control system needs to determine whether the desired damage is achieved to shut down the system in a fraction of the exposure time. Here we use a fast and simple adaption of the generalized difference algorithm to analyze the speckle movements. This algorithm runs on a FPGA and is able to calculate a feedback value which is correlated to the thermal and coagulation induced tissue motion and thus the achieved damage. For different spot sizes (50-200 μm) and different exposure times (50-500 ms) the algorithm shows the ability to discriminate between different categories of retinal pigment epithelial damage ex-vivo in enucleated porcine eyes. Furthermore in-vivo experiments in rabbits show the ability of the system to determine tissue changes in living tissue during coagulation.

  2. Real-time visualization of joint cavitation.

    PubMed

    Kawchuk, Gregory N; Fryer, Jerome; Jaremko, Jacob L; Zeng, Hongbo; Rowe, Lindsay; Thompson, Richard

    2015-01-01

    Cracking sounds emitted from human synovial joints have been attributed historically to the sudden collapse of a cavitation bubble formed as articular surfaces are separated. Unfortunately, bubble collapse as the source of joint cracking is inconsistent with many physical phenomena that define the joint cracking phenomenon. Here we present direct evidence from real-time magnetic resonance imaging that the mechanism of joint cracking is related to cavity formation rather than bubble collapse. In this study, ten metacarpophalangeal joints were studied by inserting the finger of interest into a flexible tube tightened around a length of cable used to provide long-axis traction. Before and after traction, static 3D T1-weighted magnetic resonance images were acquired. During traction, rapid cine magnetic resonance images were obtained from the joint midline at a rate of 3.2 frames per second until the cracking event occurred. As traction forces increased, real-time cine magnetic resonance imaging demonstrated rapid cavity inception at the time of joint separation and sound production after which the resulting cavity remained visible. Our results offer direct experimental evidence that joint cracking is associated with cavity inception rather than collapse of a pre-existing bubble. These observations are consistent with tribonucleation, a known process where opposing surfaces resist separation until a critical point where they then separate rapidly creating sustained gas cavities. Observed previously in vitro, this is the first in-vivo macroscopic demonstration of tribonucleation and as such, provides a new theoretical framework to investigate health outcomes associated with joint cracking.

  3. Real-time data flow and product generating for GNSS

    NASA Technical Reports Server (NTRS)

    Muellerschoen, Ronald J.; Caissy, Mark

    2004-01-01

    The last IGS workshop with the theme 'Towards Real-Time' resulted in the design of a prototype for real-time data and sharing within the IGS. A prototype real-time network is being established that will serve as a test bed for real-time activities within the IGS. We review the developments of the prototype and discuss some of the existing methods and related products of real-time GNSS systems. Recommendations are made concerning real-time data distribution and product generation.

  4. A tool for modeling concurrent real-time computation

    NASA Technical Reports Server (NTRS)

    Sharma, D. D.; Huang, Shie-Rei; Bhatt, Rahul; Sridharan, N. S.

    1990-01-01

    Real-time computation is a significant area of research in general, and in AI in particular. The complexity of practical real-time problems demands use of knowledge-based problem solving techniques while satisfying real-time performance constraints. Since the demands of a complex real-time problem cannot be predicted (owing to the dynamic nature of the environment) powerful dynamic resource control techniques are needed to monitor and control the performance. A real-time computation model for a real-time tool, an implementation of the QP-Net simulator on a Symbolics machine, and an implementation on a Butterfly multiprocessor machine are briefly described.

  5. Real-time monitoring of changes in brain extracellular sodium and potassium concentrations and intracranial pressure after selective vasopressin-1a receptor inhibition following focal traumatic brain injury in rats.

    PubMed

    Filippidis, Aristotelis S; Liang, Xiuyin; Wang, Weili; Parveen, Shanaaz; Baumgarten, Clive M; Marmarou, Christina R

    2014-07-15

    Brain swelling and increased intracranial pressure (ICP) following traumatic brain injury (TBI) contribute to poor outcome. Vasopressin-1a receptors (V1aR) and aquaporin-4 (AQP4) regulate water transport and brain edema formation, perhaps in part by modulating cation fluxes. After focal TBI, V1aR inhibitors diminish V1aR and AQP4, reduce astrocytic swelling and brain edema. We determined whether V1aR inhibition with SR49059 after lateral controlled-cortical-impact (CCI) injury affects extracellular Na(+) and K(+) concentrations ([Na(+)]e; [K(+)]e). Ion-selective Na(+) and K(+) electrodes (ISE) and an ICP probe were implanted in rat parietal cortex, and [Na(+)]e, [K(+)]e, and physiological parameters were monitored for 5 h post-CCI. Sham-vehicle-ISE, CCI-vehicle-ISE and CCI-SR49059-ISE groups were studied, and SR49059 was administered 5 min to 5 h post-injury. We found a significant injury-induced decrease in [Na(+)]e to 80.1 ± 15 and 87.9 ± 7.9 mM and increase in [K(+)]e to 20.9 ± 3.8 and 13.4 ± 3.4 mM at 5 min post-CCI in CCI-vehicle-ISE and CCI-SR49059-ISE groups, respectively (p<0.001 vs. baseline; ns between groups). Importantly, [Na(+)]e in CCI-SR49059-ISE was reduced 5-20 min post-injury and increased to baseline at 25 min, whereas recovery in CCI-vehicle-ISE required more than 1 hr, suggesting SR49059 accelerated [Na(+)]e recovery. In contrast, [K(+)]e recovery took 45 min in both groups. Further, ICP was lower in the CCI-SR49059-ISE group. Thus, selective V1aR inhibition allowed faster [Na(+)]e recovery and reduced ICP. By augmenting the [Na(+)]e recovery rate, SR49059 may reduce trauma-induced ionic imbalance, blunting cellular water influx and edema after TBI. These findings suggest SR49059 and V1aR inhibitors are potential tools for treating cellular edema post-TBI.

  6. Refinement of Intraocular Pressure Measurements made by Ocular Response Analyzer following Laser in Situ Keratomileusis using M2 90 Moria Microkeratome for Egyptian Myopic and Astigmatic Patients

    PubMed Central

    Refai, Tamer Adel; Hassanin, Olfat A.

    2016-01-01

    Introduction The Goldmann applanation tonometer readings were noted to be markedly reduced after Lasik surgery using a thin flap technique which is widely used nowadays, to correct a wide range of myopia and astigmatism. The Ocular Response Analyzer (ORA) is considered one of the important tools for refinement of Intraocular Pressure (IOP) measurements. The aim of this study is to evaluate and refine ORA measurements for IOP changes post- M2 90 Moria microkeratome Lasik procedure for Egyptian myopic and astigmatic patients trying to aid in glaucoma diagnosis and management. Methods Thirty-five eyes of nineteen Egyptian patients with myopia or myopic astigmatism who had undergone Lasik procedure using M2 90 Moria microkeratome were included in this consecutive case series study. All cases were subjected to full ophthalmological examination including uncorrected and best corrected visual acuity, refraction, slit lamp examination, Scheimpflug imaging and ORA (Reichert Ophthalmic Instruments, Inc., Buffalo, NY, USA). The refractive errors were measured using an auto refractometer and were confirmed by trial. For the ocular response analyzer, the Goldmann-correlated IOP measurement (IOPg) which simulates IOP measured by Goldmann tonometer and the Corneal-Compensated Intraocular Pressure (IOPcc) that takes corneal biomechanical properties into consideration were reported as well as the Corneal Hysteresis (CH) and the Corneal Resistance Factor (CRF). Cases were examined preoperatively and again about one month after Lasik, after stabilization of eye condition. The collected data were tabulated and analysed with the suitable statistical methods. The mean values and standard deviation were calculated for quantitative data. Comparison tests (t-test) and correlation tests (Pearson) were also performed. Results In our study, involving M2 90 Moria microkeratome Lasik procedure, a highly significant post-Lasik reduction in IOPg (t-test = 8.62 (p<0.01), and a statistically

  7. Approaching near real-time biosensing: microfluidic microsphere based biosensor for real-time analyte detection.

    PubMed

    Cohen, Noa; Sabhachandani, Pooja; Golberg, Alexander; Konry, Tania

    2015-04-15

    In this study we describe a simple lab-on-a-chip (LOC) biosensor approach utilizing well mixed microfluidic device and a microsphere-based assay capable of performing near real-time diagnostics of clinically relevant analytes such cytokines and antibodies. We were able to overcome the adsorption kinetics reaction rate-limiting mechanism, which is diffusion-controlled in standard immunoassays, by introducing the microsphere-based assay into well-mixed yet simple microfluidic device with turbulent flow profiles in the reaction regions. The integrated microsphere-based LOC device performs dynamic detection of the analyte in minimal amount of biological specimen by continuously sampling micro-liter volumes of sample per minute to detect dynamic changes in target analyte concentration. Furthermore we developed a mathematical model for the well-mixed reaction to describe the near real time detection mechanism observed in the developed LOC method. To demonstrate the specificity and sensitivity of the developed real time monitoring LOC approach, we applied the device for clinically relevant analytes: Tumor Necrosis Factor (TNF)-α cytokine and its clinically used inhibitor, anti-TNF-α antibody. Based on the reported results herein, the developed LOC device provides continuous sensitive and specific near real-time monitoring method for analytes such as cytokines and antibodies, reduces reagent volumes by nearly three orders of magnitude as well as eliminates the washing steps required by standard immunoassays.

  8. Fixed combination of travoprost and timolol maleate reduces intraocular pressure in Japanese patients with primary open-angle glaucoma or ocular hypertension: analysis by prostaglandin analogue

    PubMed Central

    Nakano, Tadashi; Mizoue, Shiro; Fuse, Nobuo; Iwase, Aiko; Matsumoto, Shun; Yoshikawa, Keiji

    2017-01-01

    Background We have shown a decrease in mean intraocular pressure (IOP) by switching to travoprost/timolol fixed combination (TTFC) in subjects receiving prostaglandin analogue (PGA) monotherapy and requiring additional medication in a previous report. For analyzing factors affecting IOP reduction, baseline IOP and preceding PGA were selected as statistically and clinically significant factors. In this report, we examine IOP-lowering effect and adverse drug reactions by preceding PGA. Methods Patients with primary open angle glaucoma or ocular hypertension who received monotherapy with one of four PGAs (travoprost, latanoprost, tafluprost, or bimatoprost) for at least 3 months at 26 institutions and were determined to require additional medication by their primary physician were included. IOP reduction and adverse events were examined at 4, 8, and 12 weeks for each of four PGAs after switching to TTFC. Results In total, 157 patients who could be followed up for at least 4 weeks after switching to TTFC were included in the efficacy analysis. Multiple regression analysis was performed, and baseline IOP and PGA were found to be significant factors to IOP reduction. IOP reduction at week 12, adjusted with the regression model, was −3.5, −1.8, and −1.4 mmHg in the tafluprost, latanoprost, and travoprost groups, whereas it was −0.5 mmHg in the bimatoprost group. Along with differences in baseline IOP between groups, an IOP-lowering effect of >1 mmHg was noted in the tafluprost, latanoprost, and travoprost groups after the switch. IOP was maintained at 13.8–14.8 mmHg throughout the follow-up period. No serious adverse events or noteworthy issues were observed in any group after the switch. Conclusion Clinically significant IOP-reducing effects of TTFC were observed in the latanoprost, travoprost, and tafluprost groups when switching from each PGA monotherapy, while there were some differences in effects between groups, with minimal safety concerns. PMID:28053501

  9. Effects of unilateral topical administration of 0.5% tropicamide on anterior segment morphology and intraocular pressure in normal cats and cats with primary congenital glaucoma

    PubMed Central

    Gomes, Filipe Espinheira; Bentley, Ellison; Lin, Ting-Li; McLellan, Gillian J.

    2012-01-01

    Objective To determine the effects of topical 0.5% tropicamide on anterior segment morphology (ASM) and intraocular pressure (IOP) in normal and glaucomatous cats. Animals used Normal cats and cats with inherited primary congenital glaucoma (PCG). Procedures Control IOP curves were performed in untreated normal and PCG cats. In the first experiment, tropicamide was applied OD in eight normal and nine PCG cats. IOP and pupillary diameter (PD) were measured at 0, 30, and 60 min, then hourly until 8 h post-treatment. In a second experiment, six normal and seven PCG cats received tropicamide OD. High-resolution ultrasound images were obtained at 0, 1, 5, and 10 h post-treatment to measure ASM changes. IOP and PD were measured OD at 0, 1, 2, 3, 5, 7, and 9 h. Results In untreated normal cats IOP OU decreased throughout the day. In PCG cats IOP OU had wide fluctuations over time. In normal cats IOP response varied in the treated eye but did not change significantly in untreated eyes. IOP significantly increased from baseline in both eyes of all treated PCG cats. Increases in IOP were associated with some ASM changes. Cats with PCG had a significantly smaller angle recess areas, diminished ciliary clefts and decreased iris-lens contact. ASM changes were not strongly correlated with IOP in all cats. Conclusions The ASM of PCG cats is markedly different from normal cats, and clinically significant increases in IOP OU occur in cats with PCG after tropicamide treatment. The mechanism for this increase remains unclear. PMID:21923827

  10. Anterior Chamber Angle Evaluation following Phakic Posterior Chamber Collamer Lens with CentraFLOW and Its Correlation with ICL Vault and Intraocular Pressure

    PubMed Central

    El-Deeb, Mohamed W. A.

    2016-01-01

    Purpose. To assess intraocular pressure (IOP), lens vaulting, and anterior chamber (AC) angle width, following V4C implantable Collamer lens (ICL) procedure for myopic refractive error. Methods. A prospective case series that enrolled 54 eyes of 27 patients that were evaluated before and after V4C phakic posterior chamber Collamer lens implantation for correction of myopic refractive error. Preoperative measurement of IOP was done using Goldmann applanation tonometer and anterior chamber angle width using both Van Herick slit lamp grading system and Scheimpflug tomography imaging (Oculus Pentacam). Follow-up of the aforementioned variables was at 1, 6, and 18 months postoperatively, together with ICL vault measurements. Results. The mean baseline IOP of 11.69 ± 2.15 showed a statistically significant (P = 0.002) increase after 1 month that remained unchanged at 6 and 18 months postoperatively, with mean value of 16.07 ± 4.12, 16.07 ± 4.10, and 16.07 ± 4.13, respectively. Pentacam AC angle width showed a statistically significant decrease at 1 (P = 0.025), 6 (P = 0.016), and 18 (P = 0.010) months postoperatively, with mean preoperative value of 40.14 ± 5.49 that decreased to 25.28 ± 5.33, 25.46 ± 5.44, and 25.49 ± 5.38, at 1, 6, and 18 months, respectively. Mean ICL vault showed moderate correlation with Pentacam AC angle width at 1 (r = −0.435) and 6 (r = −0.424) months. Conclusion. V4C ICL implantation resulted in decrease in AC angle width and increase in IOP, within acceptable physiological values at all time points. PMID:28053776

  11. Comparison of self-measured diurnal intraocular pressure profiles using rebound tonometry between primary angle closure glaucoma and primary open angle glaucoma patients

    PubMed Central

    Tan, Shaoying; Baig, Nafees; Hansapinyo, Linda; Jhanji, Vishal; Wei, Shihui; Tham, Clement C.

    2017-01-01

    Purpose To document the diurnal intraocular pressure (IOP) profile with rebound tonometry performed by primary glaucoma patients in non-clinic environment. Patients and methods Fifty-three medically-treated eyes of 31 primary angle closure glaucoma (PACG) and 22 primary open angle glaucoma (POAG) patients with no previous eye surgery were recruited. Diurnal IOP was measured 5 times per day at four-hourly intervals from 08:00 to 24:00 for 1 week in patients’ study eye using rebound tonometry in a non-clinic environment. The diurnal IOP profiles were compared between PACG and POAG eyes. Results For both PACG and POAG eyes, mean patient-measured IOP was highest in the morning, gradually decreased over the course of a day, and was lowest by midnight (p < 0.001). The diurnal IOP fluctuation ± 1 standard deviation (SD), as documented by SD in daily IOP values, was lower in PACG group (1.6 ± 1.1 mmHg) than in POAG group (2.0 ± 1.2 mmHg; p = 0.049). The mean trough IOP ± 1 SD was higher in PACG group (12.9 ± 2.8 mmHg), compared to POAG group (11.5 ± 3.8 mmHg; p = 0.041). The mean IOP level at midnight ± 1 SD in PACG group (14.0 ± 3.2 mmHg) was higher than that in POAG group (12.1 ± 3.7 mmHg; p = 0.013). Conclusions IOP in primary glaucoma patients was highest in the morning, and decreased over the course of a day in non-clinic environment. Treated diurnal IOP fluctuation seemed to be greater in POAG than PACG eyes. PMID:28333942

  12. A retrospective analysis of intraocular pressure changes after cataract surgery with the use of prednisolone acetate 1% versus difluprednate 0.05%

    PubMed Central

    Kusne, Yael; Kang, Paul; Fintelmann, Robert E

    2016-01-01

    Purpose To compare the effect of topical prednisolone acetate 1% (PA) used after routine cataract surgery to the effect of difluprednate 0.05% (DFBA) used for the same indication on intraocular pressure (IOP). Methods An electronic query was created to gather information from all cataract surgeries between January 2010 and January 2015 within the electronic health record database at Barnet Dulaney Perkins, a multicenter, multiphysician private practice in Phoenix, Arizona. Information collected included age, sex, diabetes status, glaucoma history, medication regimen (use of PA or DFBA), and IOP before surgery, 5–10 days postoperatively (TP1) and 3–6 weeks postoperatively (TP2). Postoperative IOP measurements were compared to baseline IOP measurement in each patient. Results Regardless of steroid used, all patients in this study experienced an increase in IOP within TP1 and returned to baseline IOP (±2.0 mmHg) by TP2. Patients who received DFBA showed a statistically significant increase in IOP at TP1 compared to those on PA (P<0.001) with the mean IOP an average 0.60 mmHg higher (95% CI =0.3, 0.9). The odds ratio of a clinically significantly increased IOP at TP1 (defined as overall IOP ≥21 mmHg and an increase of ≥10 mmHg) in DFBA-treated patients was 1.84 (95% CI =1.4, 2.6). In patients treated with PA, 3% reached a significantly increased IOP, compared to 4.4% of patients in the DFBA group (P<0.05). Risk factors for increased IOP were identified, and include advanced age (>75) (P<0.005) and a history of glaucoma (P<0.001). Conclusion In postoperative cataract patients, use of DFBA increased the risk of a clinically significant IOP increase. PMID:27920493

  13. Astrocyte Structural and Molecular Response to Elevated Intraocular Pressure Occurs Rapidly and Precedes Axonal Tubulin Rearrangement within the Optic Nerve Head in a Rat Model

    PubMed Central

    Tehrani, Shandiz; Davis, Lauren; Cepurna, William O.; Choe, Tiffany E.; Lozano, Diana C.; Monfared, Ashley; Cooper, Lauren; Cheng, Joshua; Johnson, Elaine C.; Morrison, John C.

    2016-01-01

    Glaucomatous axon injury occurs at the level of the optic nerve head (ONH) in response to uncontrolled intraocular pressure (IOP). The temporal response of ONH astrocytes (glial cells responsible for axonal support) to elevated IOP remains unknown. Here, we evaluate the response of actin-based astrocyte extensions and integrin-based signaling within the ONH to 8 hours of IOP elevation in a rat model. IOP elevation of 60 mm Hg was achieved under isoflurane anesthesia using anterior chamber cannulation connected to a saline reservoir. ONH astrocytic extension orientation was significantly and regionally rearranged immediately after IOP elevation (inferior ONH, 43.2° ± 13.3° with respect to the anterior-posterior axis versus 84.1° ± 1.3° in controls, p<0.05), and re-orientated back to baseline orientation 1 day post IOP normalization. ONH axonal microtubule filament label intensity was significantly reduced 1 and 3 days post IOP normalization, and returned to control levels on day 5. Phosphorylated focal adhesion kinase (FAK) levels steadily decreased after IOP normalization, while levels of phosphorylated paxillin (a downstream target of FAK involved in focal adhesion dynamics) were significantly elevated 5 days post IOP normalization. The levels of phosphorylated cortactin (a downstream target of Src kinase involved in actin polymerization) were significantly elevated 1 and 3 days post IOP normalization and returned to control levels by day 5. No significant axon degeneration was noted by morphologic assessment up to 5 days post IOP normalization. Actin-based astrocyte structure and signaling within the ONH are significantly altered within hours after IOP elevation and prior to axonal cytoskeletal rearrangement, producing some responses that recover rapidly and others that persist for days despite IOP normalization. PMID:27893827

  14. Agreement between diurnal variations of intraocular pressure by Tono-Pen and Goldmann applanation tonometer in patients on topical anti-glaucoma medication.

    PubMed

    Gupta, Shikha; Sinha, Gautam; Sharma, Reetika; Nayak, Bhagabat; Patil, Bharat; Kashyap, Bibhuti; Shameer, Abdul; Dada, Tanuj

    2016-02-01

    To estimate agreement in diurnal variations of intraocular pressure (IOP) by Tono-Pen (TP) and Goldmann applanation tonometer (GAT) in glaucoma patients on topical anti-glaucoma medication(s). IOP was measured at every 3 h from 7 a.m. to 10 a.m. in 50 eyes of glaucoma patients on topical medication(s). Diurnal fluctuation of IOP by each method was calculated as maximum-minimum IOP in a day. Central corneal thickness (CCT) was measured by ultrasonic pachymeter. There was good correlation between TP and GAT at all times during a day, minimum, and maximum IOPs during a day (Correlation coefficient, 0.706 at 7 a.m., 0.624 at 10 a.m., 0.682 at 1 p.m., 0.814 at 4 p.m., 0.652 at 7 p.m., 0.572 at 10 p.m., 0.668 minimum IOP, 0.689 maximum IOP). Mean IOPs by TP were always higher than GAT at all times during a day. Bland-Altman plots suggested a close relationship between the two sets of readings, and that this relationship was consistent at different times in a day, in maximum IOPs, minimum IOPs and also in fluctuation of IOPs. Linear regression analysis between the differences of diurnal fluctuation (diurnal fluctuation by GAT-diurnal fluctuation by TP) and CCT showed strong association (R 2 = 0.857, p < 0.001). The mean change in difference of diurnal fluctuation (GAT-TP) for a 10-micron increase in CCT was 0.69 mmHg. TP can be considered a reliable alternative to GAT in glaucoma patients for knowing the diurnal control of IOP; however these two methods should not be used interchangeably. Difference of diurnal fluctuation between two methods is dependent on CCT.

  15. Sustained Elevation of Intraocular Pressure Associated with Intravitreal Administration of Anti-vascular Endothelial Growth Factor: A Systematic Review and Meta-Analysis

    PubMed Central

    Zhou, Yandan; Zhou, Minwen; Xia, Shigang; Jing, Qiancheng; Gao, Ling

    2016-01-01

    This study aimed to assess whether repetitive intravitreal injections (IVI) of anti-vascular endothelial growth factor (anti-VEGF) cause sustained elevation of intraocular pressure (SE-IOP). We conducted a systematic review and meta-analysis based on five randomized controlled trials (RCTs) assessing 1428 subjects and 17 non-RCTs evaluating 8358 cases. In the RCTs, an increased risk of SE-IOP was found in the anti-VEGF group (summary risk ratio [RR] = 3.00, 95% confidence interval [CI]: 1.63–5.53) compared with the sham injection or laser group. The increased risk of SE-IOP was correlated with follow-up duration (RR = 2.14, 95% CI 0.69–6.57 at 6 months; RR = 3.15, 95% CI 0.99–10.09 at 12 months; RR = 3.48, 95% CI 1.38–8.78 at 23 months). The risk of SE-IOP after non-exclusion of pre-existing glaucoma patients (RR = 3.48, 95% CI 1.38–8.78) was higher than that obtained after excluding pre-existing glaucoma patients (RR = 2.6, 95% CI 1.16–5.81). In non-RCTs, the pooled prevalence of SE-IOP was 4.7% (95% CI 3.7–5.8) regardless of diagnosis criteria. In conclusion, repeated intravitreal injections of anti-VEGF agents cause a 2-fold elevation in SE-IOP risk. PMID:28000707

  16. Three Toxic Heavy Metals in Open-Angle Glaucoma with Low-Teen and High-Teen Intraocular Pressure: A Cross-Sectional Study from South Korea

    PubMed Central

    Lee, Si Hyung; Kang, Eun Min; Kim, Gyu Ah; Kwak, Seung Woo; Kim, Joon Mo; Bae, Hyoung Won; Seong, Gong Je; Kim, Chan Yun

    2016-01-01

    Background To investigate the association between heavy metal levels and open-angle glaucoma (OAG) with low- and high-teen baseline intraocular pressure (IOP) using a population-based study design. Methods This cross-sectional study included 5,198 participants older than 19 years of age who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) from 2008 to 2012 and had blood heavy metal levels available. The OAG with normal baseline IOP (IOP ≤ 21 mmHg) subjects were stratified into low-teen OAG (baseline IOP ≤ 15 mmHg) and high-teen OAG (15 mmHg < baseline IOP ≤ 21 mmHg), and the association between blood lead, mercury, and cadmium levels and glaucoma prevalence was assessed for low- and high-teen OAG. Results The adjusted geometric mean of blood cadmium levels was significantly higher in subjects with low-teen OAG than that of the non-glaucomatous group (P = 0.028), whereas there were no significant differences in blood lead and mercury levels. After adjusting for potential confounders, the low-teen OAG was positively associated with log-transformed blood cadmium levels (OR, 1.41; 95% confidence interval (CI), 1.03–1.93; P = 0.026). For high-teen OAG, log-transformed blood levels of the three heavy metals were not associated with disease prevalence. The association between log-transformed blood cadmium levels and low-teen OAG was significant only in men (OR, 1.65; 95% CI, 1.10–2.48; P = 0.016), and not in women (OR, 1.10; 95% CI, 0.66–1.85; P = 0.709). Conclusions The results of this study suggest that cadmium toxicity could play a role in glaucoma pathogenesis, particularly in men and in OAG with low-teen baseline IOP. PMID:27768724

  17. Numerical analysis of specific absorption rate in the human head due to a 13.56 MHz RFID-based intra-ocular pressure measurement system

    NASA Astrophysics Data System (ADS)

    Hirtl, Rene; Schmid, Gernot

    2013-09-01

    A modern wireless intra-ocular pressure monitoring system, based on 13.56 MHz inductively coupled data transmission, was dosimetrically analyzed with respect to the specific absorption rate (SAR) induced inside the head and the eye due to the electromagnetic field exposure caused by the reader antenna of the transmission system. The analysis was based on numerical finite difference time domain computations using a high resolution anatomical eye model integrated in a modern commercially available anatomical model of a male head. Three different reader antenna configurations, a 7-turn elliptic (30 mm × 50 mm) antenna at 12 mm distance from the eye, a flexible circular antenna (60 mm diameter, 8 turns on 2 mm substrate) directly attached to the skin, and a circular 7-turn antenna (30 mm diameter at 12 mm distance to the eye) were analyzed, respectively. Possible influences of the eye-lid status (closed or opened) and the transponder antenna contained in a contact lens directly attached to the eye were taken into account. The results clearly demonstrated that for typical reader antenna currents required for proper data transmission, the SAR values remain far below the limits for localized exposure of the head, as defined by the International Commission for Non-Ionizing Radiation Protection. Particularly the induced SAR inside the eye was found to be substantially (orders of magnitudes for typical reader antenna currents in the order of 1 A turn) below values which have been reported to be critical with respect to thermally induced adverse health effects in eye tissues.

  18. A genome-wide association study of intra-ocular pressure suggests a novel association in the gene FAM125B in the TwinsUK cohort.

    PubMed

    Nag, Abhishek; Venturini, Cristina; Small, Kerrin S; Young, Terri L; Viswanathan, Ananth C; Mackey, David A; Hysi, Pirro G; Hammond, Christopher

    2014-06-15

    Glaucoma is a major cause of blindness in the world. To date, common genetic variants associated with glaucoma only explain a small proportion of its heritability. We performed a genome-wide association study of intra-ocular pressure (IOP), an underlying endophenotype for glaucoma. The discovery phase of the study was carried out in the TwinsUK cohort (N = 2774) analyzing association between IOP and single nucleotide polymorphisms (SNPs) imputed to HapMap2. The results were validated in 12 independent replication cohorts of European ancestry (combined N = 22 789) that were a part of the International Glaucoma Genetics Consortium. Expression quantitative trait locus (eQTL) analyses of the significantly associated SNPs were performed using data from the Multiple Tissue Human Expression Resource (MuTHER) Study. In the TwinsUK cohort, IOP was significantly associated with a number of SNPs at 9q33.3 (P = 3.48 × 10(-8) for rs2286885, the most significantly associated SNP at this locus), within the genomic sequence of the FAM125B gene. Independent replication in a composite panel of 12 cohorts revealed consistent direction of effect and significant association (P = 0.003, for fixed-effect meta-analysis). Suggestive evidence for an eQTL effect of rs2286885 was observed for one of the probes targeting the coding region of the FAM125B gene. This gene codes for a component of a membrane complex involved in vesicular trafficking process, a function similar to that of the Caveolin genes (CAV1 and CAV2) which have previously been associated with primary open-angle glaucoma. This study suggests a novel association between SNPs in FAM125B and IOP in the TwinsUK cohort, though further studies to elucidate the functional role of this gene in glaucoma are necessary.

  19. Clinical experience with real-time ultrasound

    NASA Astrophysics Data System (ADS)

    Chimiak, William J.; Wolfman, Neil T.; Covitz, Wesley

    1995-05-01

    After testing the extended multimedia interface (EMMI) product which is an asynchronous transmission mode (ATM) user to network interface (UNI) of AT&T at the Society for Computer Applications in Radiology conference in Winston-Salem, the Department of Radiology together with AT&T are implementing a tele-ultrasound system to combine real- time ultrasound with the static imaging features of more traditional digital ultrasound systems. Our current ultrasound system archives digital images to an optical disk system. Static images are sent using our digital radiology systems. This could be transferring images from one digital imaging and communications (DICOM)-compliant machine to another, or the current image transfer methodologies. The prototype of a live ultrasound system using the EMMI demonstrated the feasibility of doing live ultrasound. We now are developing the scenarios using a mix of the two methodologies. Utilizing EMMI technology, radiologists at the BGSM review at a workstation both static images and real-time scanning done by a technologist on patients at a remote site in order to render on-line primary diagnosis. Our goal is to test the feasibility of operating an ultrasound laboratory at a remote site utilizing a trained technologist without the necessity of having a full-time radiologist at that site. Initial plans are for a radiologist to review an initial set of static images on a patient taken by the technologist. If further scanning is required, the EMMI is used to transmit real-time imaging and audio using the audio input of a standard microphone system and the National Television Standards Committee (NTSC) output of the ultrasound equipment from the remote site to the radiologist in the department review station. The EMMI digitally encodes this data and places it in an ATM format. This ATM data stream goes to the GCNS2000 and then to the other EMMI where the ATM data stream is decoded into the live studies and voice communication which are then

  20. CRANS - CONFIGURABLE REAL-TIME ANALYSIS SYSTEM

    NASA Technical Reports Server (NTRS)

    Mccluney, K.

    1994-01-01

    In a real-time environment, the results of changes or failures in a complex, interconnected system need evaluation quickly. Tabulations showing the effects of changes and/or failures of a given item in the system are generally only useful for a single input, and only with regard to that item. Subsequent changes become harder to evaluate as combinations of failures produce a cascade effect. When confronted by multiple indicated failures in the system, it becomes necessary to determine a single cause. In this case, failure tables are not very helpful. CRANS, the Configurable Real-time ANalysis System, can interpret a logic tree, constructed by the user, describing a complex system and determine the effects of changes and failures in it. Items in the tree are related to each other by Boolean operators. The user is then able to change the state of these items (ON/OFF FAILED/UNFAILED). The program then evaluates the logic tree based on these changes and determines any resultant changes to other items in the tree. CRANS can also search for a common cause for multiple item failures, and allow the user to explore the logic tree from within the program. A "help" mode and a reference check provide the user with a means of exploring an item's underlying logic from within the program. A commonality check determines single point failures for an item or group of items. Output is in the form of a user-defined matrix or matrices of colored boxes, each box representing an item or set of items from the logic tree. Input is via mouse selection of the matrix boxes, using the mouse buttons to toggle the state of the item. CRANS is written in C-language and requires the MIT X Window System, Version 11 Revision 4 or Revision 5. It requires 78K of RAM for execution and a three button mouse. It has been successfully implemented on Sun4 workstations running SunOS, HP9000 workstations running HP-UX, and DECstations running ULTRIX. No executable is provided on the distribution medium; however

  1. Real-Time Principal-Component Analysis

    NASA Technical Reports Server (NTRS)

    Duong, Vu; Duong, Tuan

    2005-01-01

    A recently written computer program implements dominant-element-based gradient descent and dynamic initial learning rate (DOGEDYN), which was described in Method of Real-Time Principal-Component Analysis (NPO-40034) NASA Tech Briefs, Vol. 29, No. 1 (January 2005), page 59. To recapitulate: DOGEDYN is a method of sequential principal-component analysis (PCA) suitable for such applications as data compression and extraction of features from sets of data. In DOGEDYN, input data are represented as a sequence of vectors acquired at sampling times. The learning algorithm in DOGEDYN involves sequential extraction of principal vectors by means of a gradient descent in which only the dominant element is used at each iteration. Each iteration includes updating of elements of a weight matrix by amounts proportional to a dynamic initial learning rate chosen to increase the rate of convergence by compensating for the energy lost through the previous extraction of principal components. In comparison with a prior method of gradient-descent-based sequential PCA, DOGEDYN involves less computation and offers a greater rate of learning convergence. The sequential DOGEDYN computations require less memory than would parallel computations for the same purpose. The DOGEDYN software can be executed on a personal computer.

  2. Real-time adaptive radiometric compensation.

    PubMed

    Grundhöfer, Anselm; Bimber, Oliver

    2008-01-01

    Recent radiometric compensation techniques make it possible to project images onto colored and textured surfaces. This is realized with projector-camera systems by scanning the projection surface on a per-pixel basis. Using the captured information, a compensation image is calculated that neutralizes geometric distortions and color blending caused by the underlying surface. As a result, the brightness and the contrast of the input image is reduced compared to a conventional projection onto a white canvas. If the input image is not manipulated in its intensities, the compensation image can contain values that are outside the dynamic range of the projector. These will lead to clipping errors and to visible artifacts on the surface. In this article, we present an innovative algorithm that dynamically adjusts the content of the input images before radiometric compensation is carried out. This reduces the perceived visual artifacts while simultaneously preserving a maximum of luminance and contrast. The algorithm is implemented entirely on the GPU and is the first of its kind to run in real-time.

  3. Real-Time Accumulative Computation Motion Detectors

    PubMed Central

    Fernández-Caballero, Antonio; López, María Teresa; Castillo, José Carlos; Maldonado-Bascón, Saturnino

    2009-01-01

    The neurally inspired accumulative computation (AC) method and its application to motion detection have been introduced in the past years. This paper revisits the fact that many researchers have explored the relationship between neural networks and finite state machines. Indeed, finite state machines constitute the best characterized computational model, whereas artificial neural networks have become a very successful tool for modeling and problem solving. The article shows how to reach real-time performance after using a model described as a finite state machine. This paper introduces two steps towards that direction: (a) A simplification of the general AC method is performed by formally transforming it into a finite state machine. (b) A hardware implementation in FPGA of such a designed AC module, as well as an 8-AC motion detector, providing promising performance results. We also offer two case studies of the use of AC motion detectors in surveillance applications, namely infrared-based people segmentation and color-based people tracking, respectively. PMID:22303161

  4. Real-time virtual Doppler ultrasound

    NASA Astrophysics Data System (ADS)

    Khoshniat, Mahdieh; Thorne, Meghan L.; Poepping, Tamie L.; Holdsworth, David W.; Steinman, David A.

    2004-04-01

    Doppler ultrasound (DUS) is widely used to diagnose and plan treatments for vascular diseases, but the relationship between complex blood flow dynamics and the observed DUS signal is not completely understood. In this paper, we demonstrate that Doppler ultrasound can be realistically simulated in a real-time manner via the coupling of a known, previously computed velocity field with a simple model of the ultrasound physics. In the present case a 3D computational fluid dynamics (CFD) model of physiologically pulsatile flow a stenosed carotid bifurcation was interrogated using a sample volume of known geometry and power distribution. Velocity vectors at points within the sample volume were interpolated using a fast geometric search algorithm and, using the specified US probe characteristics and orientation, converted into Doppler shifts for subsequent display as a Doppler spectrogram or color DUS image. The important effect of the intrinsic spectral broadening was simulated by convolving the velocity at each point within the sample volume by a triangle function whose width was proportional to velocity. A spherical sample volume with a Gaussian power distribution was found to be adequate for producing realistic Doppler spectrogram in regions of uniform, jet, and recirculation flow. Fewer than 1000 points seeded uniformly within a radius comprising more than 99% of the total power were required, allowing spectra to be generated from high resolution CFD data at 100Hz frame rates on an inexpensive desktop workstation.

  5. High sensitivity real-time NVR monitor

    NASA Technical Reports Server (NTRS)

    Bowers, William D. (Inventor); Chuan, Raymond L. (Inventor)

    1997-01-01

    A real time non-volatile residue (NVR) monitor, which utilizes surface acoustic wave (SAW) resonators to detect molecular contamination in a given environment. The SAW resonators operate at a resonant frequency of approximately 200 MHz-2,000 MHz which enables the NVR monitor to detect molecular contamination on the order of 10.sup.-11 g-cm.sup.-2 to 10.sup.-13 g-cm.sup.2. The NVR monitor utilizes active temperature control of (SAW) resonators to achieve a stable resonant frequency. The temperature control system of the NVR monitor is able to directly heat and cool the SAW resonators utilizing a thermoelectric element to maintain the resonators at a present temperature independent of the environmental conditions. In order to enable the direct heating and cooling of the SAW resonators, the SAW resonators are operatively mounted to a heat sink. In one embodiment, the heat sink is located in between the SAW resonators and an electronic circuit board which contains at least a portion of the SAW control electronics. The electrical leads of the SAW resonators are connected through the heat sink to the circuit board via an electronic path which prevents inaccurate frequency measurement.

  6. Recommendations for Real-Time Speech MRI

    PubMed Central

    Lingala, Sajan Goud; Sutton, Brad P.; Miquel, Marc E.; Nayak, Krishna S.

    2016-01-01

    Real-time magnetic resonance imaging (RT-MRI) is being increasingly used for speech and vocal production research studies. Several imaging protocols have emerged based on advances in RT-MRI acquisition, reconstruction, and audio-processing methods. This review summarizes the state-of-the-art, discusses technical considerations, and provides specific guidance for new groups entering this field. We provide recommendations for performing RT-MRI of the upper airway. This is a consensus statement stemming from the ISMRM-endorsed Speech MRI summit held in Los Angeles, February 2014. A major unmet need identified at the summit was the need for consensus on protocols that can be easily adapted by researchers equipped with conventional MRI systems. To this end, we provide a discussion of tradeoffs in RT-MRI in terms of acquisition requirements, a priori assumptions, artifacts, computational load, and performance for different speech tasks. We provide four recommended protocols and identify appropriate acquisition and reconstruction tools. We list pointers to open-source software that facilitate implementation. We conclude by discussing current open challenges in the methodological aspects of RT-MRI of speech. PMID:26174802

  7. Real-time DIRCM system modeling

    NASA Astrophysics Data System (ADS)

    Petersson, Mikael

    2004-12-01

    Directed infrared countermeasures (DIRCM) play an increasingly important role in electronic warfare to counteract threats posed by infrared seekers. The usefulness and performance of such countermeasures depend, for example, on atmospheric conditions (attenuation and turbulence) and platform vibrations, causing pointing and tracking errors for the laser beam and reducing the power transferred to the seeker aperture. These problems make it interesting to simulate the performance of a DIRCM system in order to understand how easy or difficult it is to counteract an approaching threat and evaluate limiting factors in various situations. This paper describes a DIRCM model that has been developed, including atmospheric effects such as attenuation and turbulence as well as closed loop tracking algorithms, where the retro reflex of the laser is used for the pointing control of the beam. The DIRCM model is part of a large simulation framework (EWSim), which also incorporates several descriptions of different seekers (e.g. reticle, rosette, centroid, nutating cross) and models of robot dynamics. Effects of a jamming laser on a specific threat can be readily verified by simulations within this framework. The duel between missile and countermeasure is simulated in near real-time and visualized graphically in 3D. A typical simulation with a reticle seeker jammed by a modulated laser is included in the paper.

  8. Near Real Time Ship Detection Experiments

    NASA Astrophysics Data System (ADS)

    Brusch, S.; Lehner, S.; Schwarz, E.; Fritz, T.

    2010-04-01

    A new Near Real Time (NRT) ship detection processor SAINT (SAR AIS Integrated Toolbox) was developed in the framework of the ESA project MARISS. Data are received at DLRs ground segment DLR-BN (Neustrelitz, Germany). Results of the ship detection are available on ftp server within 30 min after the acquisition started. The detectability of ships on Synthetic Aperture Radar (SAR) ERS-2, ENVISAT ASAR and TerraSAR-X (TS-X) images is validated by coastal (live) AIS and space AIS. The monitoring areas chosen for surveillance are the North-, Baltic Sea, and Cape Town. The detectability in respect to environmental parameters like wind field, sea state, currents and changing coastlines due to tidal effects is investigated. In the South Atlantic a tracking experiment of the German research vessel Polarstern has been performed. Issues of piracy in particular in respect to ships hijacked at the Somali coast are discussed. Some examples using high resolution images from TerraSAR-X are given.

  9. Real-Time 3D Visualization

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Butler Hine, former director of the Intelligent Mechanism Group (IMG) at Ames Research Center, and five others partnered to start Fourth Planet, Inc., a visualization company that specializes in the intuitive visual representation of dynamic, real-time data over the Internet and Intranet. Over a five-year period, the then NASA researchers performed ten robotic field missions in harsh climes to mimic the end- to-end operations of automated vehicles trekking across another world under control from Earth. The core software technology for these missions was the Virtual Environment Vehicle Interface (VEVI). Fourth Planet has released VEVI4, the fourth generation of the VEVI software, and NetVision. VEVI4 is a cutting-edge computer graphics simulation and remote control applications tool. The NetVision package allows large companies to view and analyze in virtual 3D space such things as the health or performance of their computer network or locate a trouble spot on an electric power grid. Other products are forthcoming. Fourth Planet is currently part of the NASA/Ames Technology Commercialization Center, a business incubator for start-up companies.

  10. Real-time optoacoustic monitoring of stroke

    NASA Astrophysics Data System (ADS)

    Kneipp, Moritz; Turner, Jake; Hambauer, Sebastian; Krieg, Sandro M.; Lehmberg, Jens; Lindauer, Ute; Razansky, Daniel

    2014-03-01

    Characterizing disease progression and identifying possible therapeutic interventions in stroke is greatly aided by the use of longitudinal function imaging studies. In this study, we investigate the applicability of real-time multispectral optoacoustic tomography (MSOT) as a tool for non-invasive monitoring of the progression of stroke in the whole brain. The middle cerebral artery occlusion (MCAO) method was used to induce stroke. Mice were imaged under isoflurane anesthesia preoperatively and at several time points during and after the 60-minute occlusion. The animals were sacrificed after 24 hours and their excised brains frozen at -80°C for sectioning. The cryosection were stained using H&E staining to identify the ischemic lesion. Major vessels are readily identifiable in the whole mouse head in the in vivo optoacoustic scans. During ischemia, a reduction in cerebral blood volume is detectable in the cortex. Post ischemia, spectral unmixing of the optoacoustic signals shows an asymmetry of the deoxygenated hemoglobin in the hemisphere affected by MCAO. This hypoxic area was mainly located around the boundary of the ischemic lesion and was therefore identified as the ischemic penumbra. Non-invasive functional MSOT imaging is able to visualize the hypoxic penumbra in brains affected by stroke. Stopping the spread of the infarct area and revitalizing the penumbra is central in stroke research, this new imaging technique may therefore prove to be a valuable tool in the monitoring and developing new treatments.

  11. Ames Lab 101: Real-Time 3D Imaging

    SciTech Connect

    Zhang, Song

    2010-01-01

    Ames Laboratory scientist Song Zhang explains his real-time 3-D imaging technology. The technique can be used to create high-resolution, real-time, precise, 3-D images for use in healthcare, security, and entertainment applications.

  12. Ames Lab 101: Real-Time 3D Imaging

    ScienceCinema

    Zhang, Song

    2016-07-12

    Ames Laboratory scientist Song Zhang explains his real-time 3-D imaging technology. The technique can be used to create high-resolution, real-time, precise, 3-D images for use in healthcare, security, and entertainment applications.

  13. Real time reconstruction of quasiperiodic multi parameter physiological signals

    NASA Astrophysics Data System (ADS)

    Ganeshapillai, Gartheeban; Guttag, John

    2012-12-01

    A modern intensive care unit (ICU) has automated analysis systems that depend on continuous uninterrupted real time monitoring of physiological signals such as electrocardiogram (ECG), arterial blood pressure (ABP), and photo-plethysmogram (PPG). These signals are often corrupted by noise, artifacts, and missing data. We present an automated learning framework for real time reconstruction of corrupted multi-parameter nonstationary quasiperiodic physiological signals. The key idea is to learn a patient-specific model of the relationships between signals, and then reconstruct corrupted segments using the information available in correlated signals. We evaluated our method on MIT-BIH arrhythmia data, a two-channel ECG dataset with many clinically significant arrhythmias, and on the CinC challenge 2010 data, a multi-parameter dataset containing ECG, ABP, and PPG. For each, we evaluated both the residual distance between the original signals and the reconstructed signals, and the performance of a heartbeat classifier on a reconstructed ECG signal. At an SNR of 0 dB, the average residual distance on the CinC data was roughly 3% of the energy in the signal, and on the arrhythmia database it was roughly 16%. The difference is attributable to the large amount of diversity in the arrhythmia database. Remarkably, despite the relatively high residual difference, the classification accuracy on the arrhythmia database was still 98%, indicating that our method restored the physiologically important aspects of the signal.

  14. Impact of intraocular pressure on changes of blood flow in the retina, choroid, and optic nerve head in rats investigated by optical microangiography.

    PubMed

    Zhi, Zhongwei; Cepurna, William O; Johnson, Elaine C; Morrison, John C; Wang, Ruikang K

    2012-09-01

    In this paper, we demonstrate the use of optical coherence tomography/optical microangiography (OCT/OMAG) to image and measure the effects of acute intraocular pressure (IOP) elevation on retinal, choroidal and optic nerve head (ONH) perfusion in the rat eye. In the experiments, IOP was elevated from 10 to 100 mmHg in 10 mmHg increments. At each IOP level, three-dimensional data volumes were captured using an ultrahigh sensitive (UHS) OMAG scanning protocol for 3D volumetric perfusion imaging, followed by repeated B-scans for Doppler OMAG analysis to determine blood flow velocity. Velocity and vessel diameter measurements were used to calculate blood flow in selected retinal blood vessels. Choroidal perfusion was calculated by determining the peripapillary choroidal filling at each pressure level and calculating this as a percentage of area filling at baseline (10 mmHg). ONH blood perfusion was calculated as the percentage of blood flow area over a segmented ONH area to a depth 150 microns posterior to the choroidal opening. We show that volumetric blood flow reconstructions revealed detailed 3D maps, to the capillary level, of the retinal, choroidal and ONH microvasculature, revealing retinal arterioles, capillaries and veins, the choroidal opening and a consistent presence of the central retinal artery inferior to the ONH. While OCT structural images revealed a reversible compression of the ONH and vasculature with elevated IOP, OMAG successfully documented changes in retinal, choroidal and ONH blood perfusion and allowed quantitative measurements of these changes. Starting from 30 mm Hg, retinal blood flow (RBF) diminished linearly with increasing IOP and was nearly extinguished at 100 mm Hg, with full recovery after return of IOP to baseline. Choroidal filling was unaffected until IOP reached 60 mmHg, then decreased to 20% of baseline at IOP 100 mmHg, and normalized when IOP returned to baseline. A reduction in ONH blood perfusion at higher IOP's was also

  15. 76 FR 42536 - Real-Time System Management Information Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-19

    ... Federal Highway Administration 23 CFR Part 511 RIN 2125-AF19 Real-Time System Management Information... available and share traffic and travel conditions information via real-time information programs as required... additional comments relating to the costs and benefits of the Real-Time System Management Information...

  16. Real-time support for high performance aircraft operation

    NASA Technical Reports Server (NTRS)

    Vidal, Jacques J.

    1989-01-01

    The feasibility of real-time processing schemes using artificial neural networks (ANNs) is investigated. A rationale for digital neural nets is presented and a general processor architecture for control applications is illustrated. Research results on ANN structures for real-time applications are given. Research results on ANN algorithms for real-time control are also shown.

  17. 17 CFR 38.157 - Real-time market monitoring.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 1 2014-04-01 2014-04-01 false Real-time market monitoring... DESIGNATED CONTRACT MARKETS Compliance With Rules § 38.157 Real-time market monitoring. A designated contract market must conduct real-time market monitoring of all trading activity on its electronic...

  18. 17 CFR 38.157 - Real-time market monitoring.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 1 2013-04-01 2013-04-01 false Real-time market monitoring... DESIGNATED CONTRACT MARKETS Compliance With Rules § 38.157 Real-time market monitoring. A designated contract market must conduct real-time market monitoring of all trading activity on its electronic...

  19. Apparatus Characterizes Transient Voltages in Real Time

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro

    2005-01-01

    is received, a volatile memory is filled with data for a total time of 200 ms. After the data are transferred to nonvolatile memory, the recorder rearms itself within 400 ms to enable recording of subsequent transients. Unfortunately, the recorded data must be retrieved through a serial communication link. Depending on the amount of data recorded, the memory can be filled before retrieval is completed. Although large amounts of data are recorded and retrieved, only a small part of the information (the selected parameters) is usually required. The present transient-voltage recorder provides the required information, without incurring the overhead associated with the recording, storage, and retrieval of complete transient-waveform data. In operation, this apparatus processes transient voltage waveforms in real time to extract and record the selected parameters. An analog-to-digital converter that operates at a speed of as much as 100 mega-samples per second is used to sample a transient waveform. A real-time comparator and peak detector are implemented by use of fast field-programmable gate arrays.

  20. Real-Time Processing of Pressure-Sensitive Paint Images

    DTIC Science & Technology

    2006-12-01

    in transonic wind tunnels .1-7 Most commonly, the luminescence from the painted test article is captured using digital cameras. Thus, PSP is...that the paint response is given by Eq. (2) and that the calibration function, P(R,T), has been determined prior to the wind tunnel test. 2.3.2...16C fighter jet and NASA’s X-38 Crew Return Vehicle (see Fig. 4). Both tests were conducted in the 16-ft Transonic Wind Tunnel (16T) at AEDC, with

  1. Real-time volumetric scintillation dosimetry

    NASA Astrophysics Data System (ADS)

    Beddar, S.

    2015-01-01

    The goal of this brief review is to review the current status of real-time 3D scintillation dosimetry and what has been done so far in this area. The basic concept is to use a large volume of a scintillator material (liquid or solid) to measure or image the dose distributions from external radiation therapy (RT) beams in three dimensions. In this configuration, the scintillator material fulfills the dual role of being the detector and the phantom material in which the measurements are being performed. In this case, dose perturbations caused by the introduction of a detector within a phantom will not be at issue. All the detector configurations that have been conceived to date used a Charge-Coupled Device (CCD) camera to measure the light produced within the scintillator. In order to accurately measure the scintillation light, one must correct for various optical artefacts that arise as the light propagates from the scintillating centers through the optical chain to the CCD chip. Quenching, defined in its simplest form as a nonlinear response to high-linear energy transfer (LET) charged particles, is one of the disadvantages when such systems are used to measure the absorbed dose from high-LET particles such protons. However, correction methods that restore the linear dose response through the whole proton range have been proven to be effective for both liquid and plastic scintillators. Volumetric scintillation dosimetry has the potential to provide fast, high-resolution and accurate 3D imaging of RT dose distributions. Further research is warranted to optimize the necessary image reconstruction methods and optical corrections needed to achieve its full potential.

  2. Public Science with Real-Time Experiments

    NASA Astrophysics Data System (ADS)

    Lenardic, A.

    2013-12-01

    One of the best ways for professional scientists to engage in public outreach is to get outside of the university and/or lab walls and go out into the public. That is, go to public spaces to do some science experiments with the public - this includes students of all ages that constitute that public. Technological advance in portable measurement gear now allow one to do real, or near real, time experiments in outdoor, public spaces. We have been running a meta-experiment of this sort, aimed at the public display of science, for about a year now in Houston TX at the Lee and Joe Jamail Skatepark. The project goes under the title of Sk8Lab Houston and has introduced students of all ages to the power of scientific experimentation. We bring a portable science pack with us to the park. The pack has a range of wireless measurement gear that allow experiments to be done on the spot. Some of the experiments are designed by us but many are designed on by whoever suggests them to us that day. Over time the Sk8Lab scientists have built up a level of "trust" with the people who frequent the park (no one feels like we are gonna grade them at the park and they know that the learning is not on some regimented clock). This has broken down some learning walls and allowed for a more informal mode of exploration and a more genuine mode of experimentation (as compared to what often happens in class labs when students feel like they are just being forced to reproduce some known result). We will describe some of the test case experiments we have run and also discuss some of the trials, tribulations, and happy successes (many unplanned) along the way.

  3. A real-time prediction of UTC

    NASA Astrophysics Data System (ADS)

    Thomas, Claudine; Allan, David W.

    1994-05-01

    The reference time scale for all scientific and technologic applications on the Earth, the Universal Coordinated Time (UTC), must be as stable, reliable, and accurate as possible. With this in view the BIPM and before it the BIH, have always calculated and then disseminated UTC with a delay of about 80 days. There are three fundamental reasons for doing this: (1) It takes some weeks for data, gathered from some 200 clocks spread world-wide, to be collected and for errors to be eliminated; (2) changes in clock rates can only be measured with high precision well after the fact; and (3) the measurement noise originating in time links, in particular using Loran-C, is smoothed out only when averaging over an extended period. Until mid-1992, the ultimate stability of UTC was reached at averaging times of about 100 days and corresponded to an Allan deviation sigma(sub y)(tau) of about 1,5x10(exp -14) then compared to the best primary clock in the world, the PTB CS2. For several years now, a predicted UTC has been computed by the USNO through an extrapolation of the values as published in deferred time by the BIPM. This is made available through the USNO Series 4, through the USNO Automated Data Service, and through GPS signals. Due to the instability of UTC, the poor predictability of the available clocks, and the intentional SA degradation of GPS signals, the real-time access to this extrapolated UTC has represented the true deferred-time UTC only to within several hundreds of nanoseconds.

  4. Real-Time Feature Tracking Using Homography

    NASA Technical Reports Server (NTRS)

    Clouse, Daniel S.; Cheng, Yang; Ansar, Adnan I.; Trotz, David C.; Padgett, Curtis W.

    2010-01-01

    This software finds feature point correspondences in sequences of images. It is designed for feature matching in aerial imagery. Feature matching is a fundamental step in a number of important image processing operations: calibrating the cameras in a camera array, stabilizing images in aerial movies, geo-registration of images, and generating high-fidelity surface maps from aerial movies. The method uses a Shi-Tomasi corner detector and normalized cross-correlation. This process is likely to result in the production of some mismatches. The feature set is cleaned up using the assumption that there is a large planar patch visible in both images. At high altitude, this assumption is often reasonable. A mathematical transformation, called an homography, is developed that allows us to predict the position in image 2 of any point on the plane in image 1. Any feature pair that is inconsistent with the homography is thrown out. The output of the process is a set of feature pairs, and the homography. The algorithms in this innovation are well known, but the new implementation improves the process in several ways. It runs in real-time at 2 Hz on 64-megapixel imagery. The new Shi-Tomasi corner detector tries to produce the requested number of features by automatically adjusting the minimum distance between found features. The homography-finding code now uses an implementation of the RANSAC algorithm that adjusts the number of iterations automatically to achieve a pre-set probability of missing a set of inliers. The new interface allows the caller to pass in a set of predetermined points in one of the images. This allows the ability to track the same set of points through multiple frames.

  5. Variational optical flow computation in real time.

    PubMed

    Bruhn, Andrés; Weickert, Joachim; Feddern, Christian; Kohlberger, Timo; Schnörr, Christoph

    2005-05-01

    This paper investigates the usefulness of bidirectional multigrid methods for variational optical flow computations. Although these numerical schemes are among the fastest methods for solving equation systems, they are rarely applied in the field of computer vision. We demonstrate how to employ those numerical methods for the treatment of variational optical flow formulations and show that the efficiency of this approach even allows for real-time performance on standard PCs. As a representative for variational optic flow methods, we consider the recently introduced combined local-global method. It can be considered as a noise-robust generalization of the Horn and Schunck technique. We present a decoupled, as well as a coupled, version of the classical Gauss-Seidel solver, and we develop several multgrid implementations based on a discretization coarse grid approximation. In contrast, with standard bidirectional multigrid algorithms, we take advantage of intergrid transfer operators that allow for nondyadic grid hierarchies. As a consequence, no restrictions concerning the image size or the number of traversed levels have to be imposed. In the experimental section, we juxtapose the developed multigrid schemes and demonstrate their superior performance when compared to unidirectional multgrid methods and nonhierachical solvers. For the well-known 316 x 252 Yosemite sequence, we succeeded in computing the complete set of dense flow fields in three quarters of a second on a 3.06-GHz Pentium4 PC. This corresponds to a frame rate of 18 flow fields per second which outperforms the widely-used Gauss-Seidel method by almost three orders of magnitude.

  6. Real time PV manufacturing diagnostic system

    SciTech Connect

    Kochergin, Vladimir; Crawford, Michael A.

    2015-09-01

    The main obstacle Photovoltaic (PV) industry is facing at present is the higher cost of PV energy compared to that of fossil energy. While solar cell efficiencies continue to make incremental gains these improvements are so far insufficient to drive PV costs down to match that of fossil energy. Improved in-line diagnostics however, has the potential to significantly increase the productivity and reduce cost by improving the yield of the process. On this Phase I/Phase II SBIR project MicroXact developed and demonstrated at CIGS pilot manufacturing line a high-throughput in-line PV manufacturing diagnostic system, which was verified to provide fast and accurate data on the spatial uniformity of thickness, an composition of the thin films comprising the solar cell as the solar cell is processed reel-to-reel. In Phase II project MicroXact developed a stand-alone system prototype and demonstrated the following technical characteristics: 1) ability of real time defect/composition inconsistency detection over 60cm wide web at web speeds up to 3m/minute; 2) Better than 1mm spatial resolution on 60cm wide web; 3) an average better than 20nm spectral resolution resulting in more than sufficient sensitivity to composition imperfections (copper-rich and copper-poor regions were detected). The system was verified to be high vacuum compatible. Phase II results completely validated both technical and economic feasibility of the proposed concept. MicroXact’s solution is an enabling technique for in-line PV manufacturing diagnostics to increase the productivity of PV manufacturing lines and reduce the cost of solar energy, thus reducing the US dependency on foreign oil while simultaneously reducing emission of greenhouse gasses.

  7. A real-time prediction of UTC

    NASA Technical Reports Server (NTRS)

    Thomas, Claudine; Allan, David W.

    1994-01-01

    The reference time scale for all scientific and technologic applications on the Earth, the Universal Coordinated Time (UTC), must be as stable, reliable, and accurate as possible. With this in view the BIPM and before it the BIH, have always calculated and then disseminated UTC with a delay of about 80 days. There are three fundamental reasons for doing this: (1) It takes some weeks for data, gathered from some 200 clocks spread world-wide, to be collected and for errors to be eliminated; (2) changes in clock rates can only be measured with high precision well after the fact; and (3) the measurement noise originating in time links, in particular using Loran-C, is smoothed out only when averaging over an extended period. Until mid-1992, the ultimate stability of UTC was reached at averaging times of about 100 days and corresponded to an Allan deviation sigma(sub y)(tau) of about 1,5x10(exp -14) then compared to the best primary clock in the world, the PTB CS2. For several years now, a predicted UTC has been computed by the USNO through an extrapolation of the values as published in deferred time by the BIPM. This is made available through the USNO Series 4, through the USNO Automated Data Service, and through GPS signals. Due to the instability of UTC, the poor predictability of the available clocks, and the intentional SA degradation of GPS signals, the real-time access to this extrapolated UTC has represented the true deferred-time UTC only to within several hundreds of nanoseconds.

  8. NASDA technician test real-time radiation monitoring device

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A technician from the National Space Development Agency of Japan (NASDA) tests the real-time radiation monitoring device on SPACEHAB at Kennedy Space Center in preparation for the STS-89 mission, slated to be the first Shuttle launch of 1998. STS-89 will be the eighth of nine scheduled Mir dockings and will include a double module of SPACEHAB, used mainly as a large pressurized cargo container for science, logistical equipment and supplies to be exchanged between the orbiter Endeavour and the Russian Space Station Mir. The nine-day flight of STS-89 also is scheduled to include the transfer of the seventh American to live and work aboard the Russian orbiting outpost. Liftoff of Endeavour and its seven-member crew is targeted for Jan. 15, 1998, at 1:03 a.m. EDT from Launch Pad 39A.

  9. Simulation of MC-1 Engine on Real-Time Station

    NASA Technical Reports Server (NTRS)

    Ly, William; Roe, Fred (Technical Monitor)

    2001-01-01

    The MC-1 rocket engine is a new, 60,000-pound-thrust engine designed to boost small spacecraft carrying payloads weighing up to 500 pounds. The engine was designed in-house at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, and built by SUMMA Technology, Inc. A vital part of the success of the engine development was the verification of the Propulsion System Controller (PSC) used to control the MC-1 engine during development testing at test facilities in Mississippi and California. The MC-1 engine simulation software was developed on the Applied Dynamics, Inc.'s Real-Time Station (RTS) computer system (ESL) to verify the PSC's hardware and software performance in the Marshall Avionics System Testbed's (MAST) Engine Simulation Lab at the MSFC. The engine model includes the simulation of pressure transducers, thermocouple sensors and valve-positions.

  10. Characterizing intraocular tumors with photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Xu, Guan; Xue, Yafang; Gursel, Zeynep; Slimani, Naziha; Wang, Xueding; Demirci, Hakan

    2016-03-01

    Intraocular tumors are life-threatening conditions. Long-term mortality from uveal melanoma, which accounts for 80% of primary intraocular tumors, could be as high as 25% depending on the size, ciliary body involvement and extraocular extension. The treatments of intraocular tumors include eye-sparing approaches such as radiotherapy and thermotherapy, and the more aggressive enucleation. The accurate diagnosis of intraocular tumors is thereby critical in the management and follow-up of the patients. The diagnosis of intraocular tumors is usually based on clinical examination with acoustic backscattering based ultrasonography. By analyzing the high frequency fluctuations within the ultrasound (US) signals, microarchitecture information inside the tumor can be characterized. However, US cannot interrogate the histochemical components formulating the microarchitecture. One representative example is the inability of US imaging (and other contemporary imaging modalities as well) in differentiating nevoid and melanoma cells as the two types of cells possesses similar acoustic backscattering properties. Combining optical and US imaging, photoacoustic (PA) measurements encode both the microarchitecture and histochemical component information in biological tissue. This study attempts to characterize ocular tumors by analyzing the high frequency signal components in the multispectral PA images. Ex vivo human eye globes with melanoma and retinoblastoma tumors were scanned using less than 6 mJ per square centimeters laser energy with tunable range of 600-1700 nm. A PA-US parallel imaging system with US probes CL15-7 and L22-14 were used to acquire the high frequency PA signals in real time. Preliminary results show that the proposed method can identify uveal melanoma against retinoblastoma tumors.

  11. Instrumentation development for real time brainwave monitoring.

    SciTech Connect

    Anderson, Lawrence Frederick; Clough, Benjamin W.

    2005-12-01

    The human brain functions through a chemically-induced biological process which operates in a manner similar to electrical systems. The signal resulting from this biochemical process can actually be monitored and read using tools and having patterns similar to those found in electrical and electronics engineering. The primary signature of this electrical activity is the ''brain wave'', which looks remarkably similar to the output of many electrical systems. Likewise, the device currently used in medical arenas to read brain electrical activity is the electroencephalogram (EEG) which is synonymous with a multi-channel oscilloscope reading. Brain wave readings and recordings for medical purposes are traditionally taken in clinical settings such as hospitals, laboratories or diagnostic clinics. The signal is captured via externally applied scalp electrodes using semi-viscous gel to reduce impedance. The signal will be in the 10 to 100 microvolt range. In other instances, where surgeons are attempting to isolate particular types of minute brain signals, the electrodes may actually be temporarily implanted in the brain during a preliminary procedure. The current configurations of equipment required for EEGs involve large recording instruments, many electrodes, wires, and large amounts of hard disk space devoted to storing large files of brain wave data which are then eventually analyzed for patterns of concern. Advances in sensors, signal processing, data storage and microelectronics over the last decade would seem to have paved the way for the realization of devices capable of ''real time'' external monitoring, and possible assessment, of brain activity. A myriad of applications for such a capability are likewise presenting themselves, including the ability to assess brain functioning, level of functioning and malfunctioning. Our plan is to develop the sensors, signal processing, and portable instrumentation package which could capture, analyze, and communicate

  12. Real-time {sup 90}Sr Counter

    SciTech Connect

    Kaneko, Naomi; Kawai, Hideyuki; Kodama, Satoshi; Kobayashi, Atsushi; Tabata, Makoto; Ito, Hiroshi; Han, Soorim

    2015-07-01

    Radioisotopes have been emitted around Japan due to a nuclear accident at the Fukushima Daiichi nuclear power station in March 2011. A problem is the contaminated water including the atomic nucleus which relatively has a long half- life time and soluble such as {sup 90}Sr, {sup 137}Cs. Internal exposures by {sup 90}Sr are more dangerous than {sup 137}Cs's because Sr has effective half-life time of 18 years and property of accumulation in a born. We have developed real-time {sup 90}Sr counter which is sensitive beta-ray of maximum kinematic energy of 2.28 MeV from {sup 90}Sr and insensitive of beta-ray of maximum kinematic energy of 1.17 MeV and gamma-ray from {sup 90}Sr by Cherenkov detection. This counter composes of Cerenkov counter, trigger scintillation counter and veto counter. Silica aerogel for Cherenkov counter can obtain refractive index between 1.017 and 1.049 easily. And wavelength shifting fiber (WLSF) is used as a light guide for extending effective area and producing lower cost. A mechanism of the identification of {sup 90}Sr is explained in following. In case of {sup 90}Sr, when the trigger counter reacts on the beta-ray from {sup 90}Sr, aerogel emits the Cherenkov light and WLSF reacts and read the Cherenkov light. On the other hand, in case of {sup 137}Cs, the trigger counter reacts on the beta-ray, aerogel stops the beta- ray and Cherenkov light is not emitted. Therefore, aerogel has a function as a radiator and shielding material. the gamma-ray is not reacted on the lower density detector. Cosmic rays would be also reacted by the veto counter. A prototype counter whose the effective area is 30 cm x 10 cm was obtained (2.0±1.2){sup 3} of mis-identification as {sup 137}Cs/{sup 90}Sr. Detection limit in the surface contamination inspection depends on measurement time and effective area mainly. The sensitivity of wide range, 10{sup -2} - 10{sup 4} Bq/cm{sup 2}, is obtained by adjustment of detection level in circuit of this counter. A lower

  13. Real-time Forensic Disaster Analysis

    NASA Astrophysics Data System (ADS)

    Wenzel, F.; Daniell, J.; Khazai, B.; Mühr, B.; Kunz-Plapp, T.; Markus, M.; Vervaeck, A.

    2012-04-01

    The Center for Disaster Management and Risk Reduction Technology (CEDIM, www.cedim.de) - an interdisciplinary research center founded by the German Research Centre for Geoscience (GFZ) and Karlsruhe Institute of Technology (KIT) - has embarked on a new style of disaster research known as Forensic Disaster Analysis. The notion has been coined by the Integrated Research on Disaster Risk initiative (IRDR, www.irdrinternational.org) launched by ICSU in 2010. It has been defined as an approach to studying natural disasters that aims at uncovering the root causes of disasters through in-depth investigations that go beyond the reconnaissance reports and case studies typically conducted after disasters. In adopting this comprehensive understanding of disasters CEDIM adds a real-time component to the assessment and evaluation process. By comprehensive we mean that most if not all relevant aspects of disasters are considered and jointly analysed. This includes the impact (human, economy, and infrastructure), comparisons with recent historic events, social vulnerability, reconstruction and long-term impacts on livelihood issues. The forensic disaster analysis research mode is thus best characterized as "event-based research" through systematic investigation of critical issues arising after a disaster across various inter-related areas. The forensic approach requires (a) availability of global data bases regarding previous earthquake losses, socio-economic parameters, building stock information, etc.; (b) leveraging platforms such as the EERI clearing house, relief-web, and the many sources of local and international sources where information is organized; and (c) rapid access to critical information (e.g., crowd sourcing techniques) to improve our understanding of the complex dynamics of disasters. The main scientific questions being addressed are: What are critical factors that control loss of life, of infrastructure, and for economy? What are the critical interactions

  14. Benchmarking real-time HEVC streaming

    NASA Astrophysics Data System (ADS)

    Nightingale, James; Wang, Qi; Grecos, Christos

    2012-06-01

    Work towards the standardisation of High Efficiency Video Coding (HEVC), the next generation video coding scheme, is currently gaining pace. HEVC offers the prospect of a 50% improvement in compression over the current H.264 Advanced Video Coding standard (H.264/AVC). Thus far, work on HEVC has concentrated on improvements to the coding efficiency and has not yet addressed transmission in networks other than to mandate byte stream compliance with Annex B of H.264/AVC. For practical networked HEVC applications a number of essential building blocks have yet to be defined. In this work, we design and prototype a real-time HEVC streaming system and empirically evaluate its performance, in particular we consider the robustness of the current Test Model under Consideration (TMuC HM4.0) for HEVC to packet loss caused by a reduction in available bandwidth both in terms of decoder resilience and degradation in perceptual video quality. A NAL unit packetisation and streaming framework for HEVC encoded video streams is designed, implemented and empirically tested in a number of streaming environments including wired, wireless, single path and multiple path network scenarios. As a first step the HEVC decoder's error resilience is tested under a comprehensive set of packet loss conditions and a simple error concealment method for HEVC is implemented. Similarly to H.264 encoded streams, the size and distribution of NAL units within an HEVC stream and the nature of the NAL unit dependencies influences the packetisation and streaming strategies which may be employed for such streams. The relationships between HEVC encoding mode and the quality of the received video are shown under a wide range of bandwidth constraints. HEVC streaming is evaluated in both single and multipath network configuration scenarios. Through the use of extensive experimentation, we establish a comprehensive set of benchmarks for HEVC streaming in loss prone network environments. We show the visual quality

  15. Real Time Wide Area Radiation Surveillance System

    NASA Astrophysics Data System (ADS)

    Biafore, M.

    2012-04-01

    We present the REWARD project, financed within the FP7 programme, theme SEC-2011.1.5-1 (Development of detection capabilities of difficult to detect radioactive sources and nuclear materials - Capability Project). Within this project, we propose a novel mobile system for real time, wide area radiation surveillance. The system is based on the integration of new miniaturized solid-state radiation sensors: a CdZnTe detector for gamma radiation and a high efficiency neutron detector based on novel silicon technologies. The sensing unit will include a wireless communication interface to send the data remotely to a monitoring base station which also uses a GPS system to calculate the position of the tag. The system will also incorporate middleware and high level software to provide web-service interfaces for the exchange of information, and that will offer top level functionalities as management of users, mobile tags and environment data and alarms, database storage and management and a web-based graphical user interface. Effort will be spent to ensure that the software is modular and re-usable across as many architectural levels as possible. Finally, an expert system will continuously analyze the information from the radiation sensor and correlate it with historical data from the tag location in order to generate an alarm when an abnormal situation is detected. The system will be useful for many different scenarios, including such lost radioactive sources and radioactive contamination. It will be possible to deploy in emergency units and in general in any type of mobile or static equipment. The sensing units will be highly portable thanks to their low size and low energy consumption. The complete system will be scalable in terms of complexity and cost and will offer very high precision on both the measurement and the location of the radiation. The modularity and flexibility of the system will allow for a realistic introduction to the market. Authorities may start with a

  16. Central corneal thickness, intraocular pressure, and degree of myopia in an adult myopic population aged 20 to 40 years in southeast Spain: determination and relationships

    PubMed Central

    Garcia-Medina, Manuel; Garcia-Medina, Jose Javier; Garrido-Fernandez, Pablo; Galvan-Espinosa, Jose; Martin-Molina, Jesus; Garcia-Maturana, Carlos; Perez-Pardo, Sergio; Pinazo-Duran, Maria Dolores

    2011-01-01

    Objective: To determine the values of, and study the relationships among, central corneal thickness (CCT), intraocular pressure (IOP), and degree of myopia (DM) in an adult myopic population aged 20 to 40 years in Almeria (southeast Spain). To our knowledge this is first study of this kind in this region. Methods: An observational, descriptive, cross-sectional study was done in which a sample of 310 myopic patients (620 eyes) aged 20 to 40 years was selected by gender- and age-stratified sampling, which was proportionally fixed to the size of the population strata for which a 20% prevalence of myopia, 5% epsilon, and a 95% confidence interval were hypothesized. We studied IOP, CCT, and DM and their relationships by calculating the mean, standard deviation, 95% confidence interval for the mean, median, Fisher’s asymmetry coefficient, range (maximum, minimum), and the Brown-Forsythe’s robust test for each variable (IOP, CCT, and DM). Results: In the adult myopic population of Almeria aged 20 to 40 years (mean of 29.8), the mean overall CCT was 550.12 μm. The corneas of men were thicker than those of women (P = 0.014). CCT was stable as no significant differences were seen in the 20- to 40-year-old subjects’ CCT values. The mean overall IOP was 13.60 mmHg. Men had a higher IOP than women (P = 0.002). Subjects over 30 years (13.83) had a higher IOP than those under 30 (13.38) (P = 0.04). The mean overall DM was −4.18 diopters. Men had less myopia than women (P < 0.001). Myopia was stable in the 20- to 40-year-old study population (P = 0.089). A linear relationship was found between CCT and IOP (R2 = 0.152, P ≤ 0.001). CCT influenced the IOP value by 15.2%. However no linear relationship between DM and IOP, or between CCT and DM, was found. Conclusions: CCT was found to be similar to that reported in other studies in different populations. IOP tends to increase after the age of 30 and is not accounted for by alterations in CCT values. PMID:21468330

  17. An observational study of bimatoprost 0.01% in patients on prior intraocular pressure-lowering therapy: the Canadian Lumigan® RC Early Analysis Review (CLEAR) trial

    PubMed Central

    Crichton, Andrew C; Nixon, Donald R; Simonyi, Susan; Bhogal, Meetu; Sigouin, Christopher S; Discepola, Marino J; Hutnik, Cindy ML; Baptiste, Darryl C; Yan, David B

    2014-01-01

    Purpose To evaluate the ocular hyperemia and intraocular pressure (IOP)-lowering efficacy of bimatoprost 0.01% in subjects with elevated IOP due to primary open-angle glaucoma (POAG) or ocular hypertension (OHT) in a real-world clinical setting. Subjects and methods This open-label, 12-week, observational study was conducted at 67 centers in Canada. Subjects with elevated IOP due to POAG or OHT instilled bimatoprost 0.01% as monotherapy once daily. Ocular hyperemia was graded by the investigator at baseline, week 6, and week 12 using a standardized photographic 5-point grading scale. Change in IOP from baseline was also evaluated at these time points. This analysis includes the subgroup of 268 subjects who had been previously treated with latanoprost 0.005%, bimatoprost 0.03%, travoprost 0.004%, and travoprost 0.004% with SofZia™ or nonselective beta-adrenergic receptor blockers prior to the study. Results After 12 weeks of treatment with 0.01% bimatoprost, ocular hyperemia was graded as none-to-mild hyperemia (grades 0, +0.5, or +1) for 94.1% of subjects and as moderate-to-severe hyperemia (grades +2 or +3) for 5.9%. No statistically significant shifts in ocular hyperemia ratings were observed at week 12 for any of the prior IOP-lowering therapies except bimatoprost 0.03%, in which 20.8% of subjects experienced an improvement. The mean percentage change from baseline IOP at week 12 following the switch to bimatoprost 0.01% monotherapy ranged from −2.3%±17.3% to −26.3%±12.4%. Furthermore, the decreased mean percentage change from baseline IOP was statistically significant across all prior IOP-lowering medications, except for bimatoprost 0.03% at the 6- and 12-week visits and travoprost 0.004% at the 6-week visit. Conclusion This observational study demonstrates that bimatoprost 0.01% was well tolerated among POAG and OHT subjects who switched from prior IOP-lowering medication. Furthermore, a switch in ocular hypertensive treatment to bimatoprost 0.01% was

  18. Association Between Cardiovascular and Intraocular Pressure Changes in a 14-Day 6 deg Head Down Tilt (HDT) Bed Rest Study: Possible Implications in Retinal Anatomy

    NASA Technical Reports Server (NTRS)

    Cromwell, Ronita; Zanello, Susana; Yarbough, Patrice; Ploutz-Snyder, Robert; Taibbi, Giovanni; Vizzeri, Gianmarco

    2013-01-01

    Visual symptoms and intracranial pressure increase reported in astronauts returning from long duration missions in low Earth-orbit are thought to be related to fluid shifts within the body due to microgravity exposure. Because of this possible relation to fluid shifts, studies conducted in head-down tilt (HDT) bed rest are being monitored for potential changes in ocular health. These measures will also serve to determine whether HDT is a suitable ground-based analog to model subclinical cardiovascular and ocular changes that could shed light on the etiology of the VIIP syndrome observed in spaceflight. Sixteen healthy normotensive (12M, 4F, age range 29-54 years), non-smoker and normal weight subjects, volunteered to participate in a 14 day 6 deg head HDT study conducted at the NASA Flight Analogs Research Unit (FARU). This facility provides standard bed rest conditions (diet, wake/sleep time, time allowed in sunlight) during the time that the subjects stay at the FARU. Cardiovascular parameters were obtained in supine posture at BR-5, BR+0, and BR+3 and ocular monitoring was performed weekly. Intraocular pressure (IOP) increased from pre-bed rest BR-3) to the third day into bed rest (BR+3). Values reached a plateau towards the end of the bed rest phase (BR10) and decreased within the first three days of recovery (BR+2) returning to levels comparable to baseline at BR-3. As expected, most cardiovascular parameters were affected by 14 days of HDT bed rest. Plasma volume decreased as a result of bed rest but recovered to baseline levels by BR+3. Indications of cardiovascular deconditioning included increase in both systolic and diastolic blood pressure and heart rate, and a decrease in stroke volume and cardiac output between BR-5 and BR+3. Due to the experimental design of this study, we were not able to test the hypothesis that fluid shifts might be involved in the IOP increase during the bed rest phase, since cardiovascular measures were not available for those

  19. Real Time Flux Control in PM Motors

    SciTech Connect

    Otaduy, P.J.

    2005-09-27

    Significant research at the Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) is being conducted to develop ways to increase (1) torque, (2) speed range, and (3) efficiency of traction electric motors for hybrid electric vehicles (HEV) within existing current and voltage bounds. Current is limited by the inverter semiconductor devices' capability and voltage is limited by the stator wire insulation's ability to withstand the maximum back-electromotive force (emf), which occurs at the upper end of the speed range. One research track has been to explore ways to control the path and magnitude of magnetic flux while the motor is operating. The phrase, real time flux control (RTFC), refers to this mode of operation in which system parameters are changed while the motor is operating to improve its performance and speed range. RTFC has potential to meet an increased torque demand by introducing additional flux through the main air gap from an external source. It can augment the speed range by diverting flux away from the main air gap to reduce back-emf at high speeds. Conventional RTFC technology is known as vector control [1]. Vector control decomposes the stator current into two components; one that produces torque and a second that opposes (weakens) the magnetic field generated by the rotor, thereby requiring more overall stator current and reducing the efficiency. Efficiency can be improved by selecting a RTFC method that reduces the back-emf without increasing the average current. This favors methods that use pulse currents or very low currents to achieve field weakening. Foremost in ORNL's effort to develop flux control is the work of J. S. Hsu. Early research [2,3] introduced direct control of air-gap flux in permanent magnet (PM) machines and demonstrated it with a flux-controlled generator. The configuration eliminates the problem of demagnetization because it diverts all the flux from the magnets instead of

  20. Real-Time