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Sample records for aging human eye

  1. Elastic hysteresis in human eyes is age dependent value.

    PubMed

    Ishii, Kotaro; Saito, Kei; Kameda, Toshihiro; Oshika, Tetsuro

    2012-06-19

    Background:  The elastic hysteresis phenomenon is observed when cyclic loading is applied to a viscoelastic system. The purpose of this study was to quantitatively evaluate elastic hysteresis in living human eyes against an external force. Design:  Prospective case series. Participants:  Twenty-four eyes of 24 normal human subjects (mean age: 41.5 ± 10.6 years) were recruited. Methods:  A non-contact tonometry process was recorded with a high-speed camera. Central corneal thickness (CCT), corneal thickness at 4 mm from the center, corneal curvature, and anterior chamber depth (ACD) were measured. Intraocular pressure (IOP) was also measured using Goldmann applanation tonometry (GAT) and dynamic contour tonometer (DCT). Main Outcome Measures:  Energy loss due to elastic hysteresis was calculated and graphed. Results:  The mean CCT was 552.5 ± 36.1 µm, corneal curvature was 7.84 ± 0.26 mm, and ACD was 2.83 ± 0.29 mm. The mean GAT-IOP was 14.2 ± 2.7 mmHg and DCT-IOP was 16.3 ± 3.5 mmHg. The mean energy loss due to elastic hysteresis was 3.90 × 10(-6) ± 2.49 × 10(-6) Nm. Energy loss due to elastic hysteresis correlated significantly with age (Pearson correlation coefficient = 0.596, p = 0.0016). There were no significant correlations between energy loss due to elastic hysteresis and other measurements. Conclusion:  Energy loss due to elastic hysteresis in the eyes of subjects was found to positively correlate with age, independent of anterior eye structure or IOP. Therefore, it is believed that the viscosity of the eye increases with age. © 2010 The Authors. Clinical and Experimental Ophthalmology © 2010 Royal Australian and New Zealand College of Ophthalmologists.

  2. How the Human Eye Focuses.

    ERIC Educational Resources Information Center

    Koretz, Jane F.; Handelman, George H.

    1988-01-01

    Describes the decline in people's ability to focus their eyes as their age increases. Discusses probable causes of this effect including changes in the eye's geometry and biochemistry. Diagrammatically illustrates age related changes in the lens of the human eye. (CW)

  3. Distribution and Quantification of Choroidal Macrophages in Human Eyes With Age-Related Macular Degeneration

    PubMed Central

    McLeod, D. Scott; Bhutto, Imran; Edwards, Malia M.; Silver, Rachel E.; Seddon, Johanna M.; Lutty, Gerard A.

    2016-01-01

    Purpose Increasing evidence suggests a role for macrophages in the pathogenesis of age-related macular degeneration (AMD). This study examined choroidal macrophages and their activation in postmortem eyes from subjects with and without AMD. Methods Choroids were incubated with anti-ionized calcium-binding adapter molecule 1 (anti-IBA1) to label macrophages, anti-human leukocyte antigen-antigen D-related (anti-HLA-DR) as a macrophage activation marker, and Ulex europaeus agglutinin lectin to label blood vessels. Whole mounts were imaged using confocal microscopy. IBA1- and HLA-DR–positive (activated) cells were counted in submacula, paramacula, and nonmacula, and cell volume and sphericity were determined using computer-assisted image analysis. Results In aged control eyes, the mean number of submacular IBA1+ and HLA-DR+ macrophages was 433/mm2 and 152/mm2, respectively. In early AMD eyes, there was a significant increase in IBA1+ and HLA-DR+ cells in submacula compared to those in controls (P = 0.0015 and P = 0.008, respectively). In eyes with neovascular AMD, there were significantly more HLA-DR+ cells associated with submacular choroidal neovascularization (P = 0.001). Mean cell volume was significantly lower (P ≤ 0.02), and sphericity was significantly higher (P ≤ 0.005) in all AMD groups compared to controls. Conclusions The average number of IBA1+ macrophages in submacular and paramacular choroid was significantly higher in early/intermediate AMD compared to that in aged controls. HLA-DR+ submacular macrophages were significantly increased in all stages of AMD, and they were significantly more round and smaller in size in the submacular AMD choroid, suggesting their activation. These findings support the concept that AMD is an inflammatory disease. PMID:27802514

  4. Light scattering study of the normal human eye lens: Elastic properties and age dependence

    PubMed Central

    Bailey, Sheldon T.; Twa, Michael D.; Gump, Jared C.; Venkiteshwar, Manoj; Bullimore, Mark A.

    2015-01-01

    The human ocular lens is a tissue capable of changing its shape to dynamically adjust the optical power of the eye, a function known as accommodation, which gradually declines with age. This capability is the response of the lens tissue to external forces which, in turn, is modulated by the biomechanical characteristics of lens tissues. In order to investigate the contributions of lens sclerosis to loss of accommodation, we report on in vitro confocal Brillouin light scattering studies of human ocular lenses spanning over a 30-70 year age range. Using this non-destructive measurement method, we determined that the longitudinal bulk modulus (average ± SD) of the lens nucleus (2.79±0.14 GPa) was consistently greater than the bulk modulus of the lens cortex (2.36±0.09 GPa). Moreover, our results showed that these differences were not age dependent over the 40 year age range that we evaluated using healthy lens tissues. Our results are consistent with the hypothesis that an age-dependent change in the bulk modulus of lens tissues does not fully account for the natural decline of accommodation. PMID:20529725

  5. Analysis of normal human eye with different age groups using infrared images.

    PubMed

    Acharya, U Rajendra; Ng, E Y K; Yee, Gerk Chang; Hua, Tan Jian; Kagathi, Manjunath

    2009-06-01

    The human body temperature is a good health indicator. All objects emit thermal radiation as a function temperature and wavelength for all wavelengths. The wavelength of infrared rays lies between visible and microwave radiations ranging between 700 nm to 0.1 mm. Infrared (IR) imaging is relatively inexpensive, noninvasive and harmless. Nowadays, it is widely used in the medical field for diagnosis. In this work, we have applied image processing techniques on the IR images of the eye for the analysis of the ocular surface temperature (OST) of the normal subjects of three categories (young, middle and old ages). In our study, 67 IR normal images were analyzed. Two parameters, average ocular temperature and the temperature deviation were proposed to study the variability of OST in different normal category subjects. Our study shows that, the two parameters proposed, show distinct ranges for different groups with 'p' values less than 0.05.

  6. Preference for human eyes in human infants.

    PubMed

    Dupierrix, Eve; de Boisferon, Anne Hillairet; Méary, David; Lee, Kang; Quinn, Paul C; Di Giorgio, Elisa; Simion, Francesca; Tomonaga, Masaki; Pascalis, Olivier

    2014-07-01

    Despite evidence supporting an early attraction to human faces, the nature of the face representation in neonates and its development during the first year after birth remain poorly understood. One suggestion is that an early preference for human faces reflects an attraction toward human eyes because human eyes are distinctive compared with other animals. In accord with this proposal, prior empirical studies have demonstrated the importance of the eye region in face processing in adults and infants. However, an attraction for the human eye has never been shown directly in infants. The current study aimed to investigate whether an attraction for human eyes would be present in newborns and older infants. With the use of a preferential looking time paradigm, newborns and 3-, 6-, 9-, and 12-month-olds were simultaneously presented with a pair of nonhuman primate faces (chimpanzees and Barbary macaques) that differed only by the eyes, thereby pairing a face with original nonhuman primate eyes with the same face in which the eyes were replaced by human eyes. Our results revealed that no preference was observed in newborns, but a preference for nonhuman primate faces with human eyes emerged from 3months of age and remained stable thereafter. The findings are discussed in terms of how a preference for human eyes may emerge during the first few months after birth.

  7. Verification of the lack of correlation between age and longitudinal chromatic aberrations of the human eye from the visible to the infrared

    PubMed Central

    Nakajima, Masashi; Hiraoka, Takahiro; Hirohara, Yoko; Oshika, Tetsuro; Mihashi, Toshifumi

    2015-01-01

    Several researchers studied the longitudinal chromatic aberration (LCA) of the human eye and observed that it does not change due to age. We measured the LCA of 45 subjects’ normal right eyes at three distinct wavelengths (561, 690, and 840 nm) using a Hartmann–Shack wavefront aberrometer (HSWA) while consecutively switching between three light sources for wavefront sensing. We confirmed that the LCA of the human eye does not change due to age between 22 and 57 years. PMID:26203391

  8. Aging and dry eye disease

    PubMed Central

    Ding, Juan; Sullivan, David A.

    2012-01-01

    Dry eye disease is a prevalent eye disorder that in particular affects the elderly population. One of the major causes of dry eye, meibomian gland dysfunction (MGD), shows increased prevalence with aging. MGD is caused by hyperkeratinization of the ductal epithelium of meibomian gland and reduced quantity and/or quality of meibum, the holocrine product that stabilizes and prevents the evaporation of the tear film. Of note, retinoids which are used in current anti-aging cosmetics may promote the development of MGD and dry eye disease. In this review, we will discuss the possible mechanisms of age-related MGD. PMID:22569356

  9. Ageing changes in the eye

    PubMed Central

    Salvi, S M; Akhtar, S; Currie, Z

    2006-01-01

    Ageing changes occur in all the structures of the eye causing varied effects. This article attempts to review the parameters of what is considered within the “normal limits” of ageing so as to be able to distinguish those conditions from true disease processes. Improving understanding of the ageing changes will help understand some of the problems that the ageing population faces. PMID:16954455

  10. Age-related eye disease.

    PubMed

    Voleti, Vinod B; Hubschman, Jean-Pierre

    2013-05-01

    As with many organs, compromised function of the eye is accompanied with age and has become increasingly prevalent with the aging population. When decreased visual loss becomes significant, patients' ability to perform activities of daily living becomes compromised. This decrease in function is met with morbidity and mortality, as well as a large socioeconomic burden throughout the world. This review summarizes the most common age-related eye diseases, including cataract, glaucoma, diabetic retinopathy, retinal vein occlusion, and age-related macular degeneration. Although our understanding of the genetic and biochemical pathways of these diseases is sill at its primitive stages, we have become able to help our patients improve the quality of life as they age.

  11. Nutrition and age-related eye diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vision loss among the elderly is an important health problem. Approximately one person in three has some form of vision-reducing eye disease by the age of 65 [1]. Age-related cataract, age-related macular degeneration (AMD), diabetic retinopathy and glaucoma are the major diseases resulting in visu...

  12. Imaging in the aging eye

    SciTech Connect

    Elsner, Ann E.; Remky, Andreas; Walker, Joseph P.; Wing, Glenn L.; Kelley, Linda M.; Kiesel, Cheryl

    2000-07-01

    Retinal imaging may seem a simple endeavor, given that the eye is far more transparent and accessible than internal organs such as the heart. Optical imaging techniques allow high resolution, with measurements of living tissues reported in microns, in comparison to magnetic resonance imaging. Most retinal imaging techniques are less invasive than endoscopy. There is a long-standing acceptance of retinal imaging as an important set of techniques in research and medicine.(c) 2000 Optical Society of America.

  13. Optical models of the human eye.

    PubMed

    Atchison, David A; Thibos, Larry N

    2016-03-01

    Optical models of the human eye have been used in visual science for purposes such as providing a framework for explaining optical phenomena in vision, for predicting how refraction and aberrations are affected by change in ocular biometry and as computational tools for exploring the limitations imposed on vision by the optical system of the eye. We address the issue of what is understood by optical model eyes, discussing the 'encyclopaedia' and 'toy train' approaches to modelling. An extensive list of purposes of models is provided. We discuss many of the theoretical types of optical models (also schematic eyes) of varying anatomical accuracy, including single, three and four refracting surface variants. We cover the models with lens structure in the form of nested shells and gradient index. Many optical eye models give accurate predictions only for small angles and small fields of view. If aberrations and image quality are important to consider, such 'paraxial' model eyes must be replaced by 'finite model' eyes incorporating features such as aspheric surfaces, tilts and decentrations, wavelength-dependent media and curved retinas. Many optical model eyes are population averages and must become adaptable to account for age, gender, ethnicity, refractive error and accommodation. They can also be customised for the individual when extensive ocular biometry and optical performance data are available. We consider which optical model should be used for a particular purpose, adhering to the principle that the best model is the simplest fit for the task. We provide a glimpse into the future of optical models of the human eye. This review is interwoven with historical developments, highlighting the important people who have contributed so richly to our understanding of visual optics.

  14. Arthropods affecting the human eye.

    PubMed

    Panadero-Fontán, Rosario; Otranto, Domenico

    2015-02-28

    Ocular infestations by arthropods consist in the parasitization of the human eye, either directly (e.g., some insect larvae causing ophthalmomyiasis) or via arthropods feeding on lachrymal/conjunctival secretions (e.g., some eye-seeking insects, which also act as vectors of eye pathogens). In addition, demodicosis and phthiriasis may also cause eye discomfort in humans. Ophthalmomyiasis by larvae of the families Oestridae, Calliphoridae and Sarcophagidae, are frequent causative agents of human ocular infestations. Over the last decades, the extensive use of macrocyclic lactones in cattle has reduced the frequency of infestations by Hypoderma bovis and Hypoderma lineatum (family Oestridae), and consequently, human infestations by these species. A prompt diagnosis of ocular myiasis (e.g., by serological tests) is pivotal for positive prognoses, particularly when the larvae are not detectable during the ophthalmologic examination. Molecular diagnoses may also assist physicians and parasitologists in achieving time-efficient diagnoses of infestations by Oestridae causing myiasis. Finally, due to widespread international travel to exotic destinations, cases of myiasis are increasing in non-endemic areas, therefore requiring physicians to acquire a profound knowledge of the clinical symptoms linked to these infestations to prevent costly, inappropriate treatments or severe complications.

  15. A Model of the Human Eye

    NASA Astrophysics Data System (ADS)

    Colicchia, G.; Wiesner, H.; Waltner, C.; Zollman, D.

    2008-12-01

    We describe a model of the human eye that incorporates a variable converging lens. The model can be easily constructed by students with low-cost materials. It shows in a comprehensible way the functionality of the eye's optical system. Images of near and far objects can be focused. Also, the defects of near and farsighted eyes can be demonstrated.

  16. A Model of the Human Eye

    ERIC Educational Resources Information Center

    Colicchia, G.; Wiesner, H.; Waltner, C.; Zollman, D.

    2008-01-01

    We describe a model of the human eye that incorporates a variable converging lens. The model can be easily constructed by students with low-cost materials. It shows in a comprehensible way the functionality of the eye's optical system. Images of near and far objects can be focused. Also, the defects of near and farsighted eyes can be demonstrated.

  17. Analysis of RPE morphometry in human eyes

    PubMed Central

    Bhatia, Shagun K.; Rashid, Alia; Chrenek, Micah A.; Zhang, Qing; Bruce, Beau B.; Klein, Mitchel; Boatright, Jeffrey H.; Jiang, Yi; Grossniklaus, Hans E.

    2016-01-01

    Purpose To describe the RPE morphometry of healthy human eyes regarding age and topographic location using modern computational methods with high accuracy and objectivity. We tested whether there were regional and age-related differences in RPE cell area and shape. Methods Human cadaver donor eyes of varying ages were dissected, and the RPE flatmounts were immunostained for F-actin with AF635-phalloidin, nuclei stained with propidium iodide, and imaged with confocal microscopy. Image analysis was performed using ImageJ (NIH) and CellProfiler software. Quantitative parameters, including cell density, cell area, polygonality of cells, number of neighboring cells, and measures of cell shape, were obtained from these analyses to characterize individual and groups of RPE cells. Measurements were taken from selected areas spanning the length of the temporal retina through the macula and the mid-periphery to the far periphery. Results Nineteen eyes from 14 Caucasian donors of varying ages ranging from 29 to 80 years were used. Along a horizontal nasal to temporal meridian, there were differences in several cell shape and size characteristics. Generally, the cell area and shape was relatively constant and regular except in the far periphery. In the outer third of the retina, the cell area and shape differed from the inner two-thirds statistically significantly. In the macula and the far periphery, an overall decreasing trend in RPE cell density, percent hexagonal cells, and form factor was observed with increasing age. We also found a trend toward increasing cell area and eccentricity with age in the macula and the far periphery. When individuals were divided into two age groups, <60 years and ≥60 years, there was a higher cell density, lower cell area, lower eccentricity, and higher form factor in the younger group in the macula and the far periphery (p<0.05 for all measurements). No statistically significant differences in RPE morphometry between age groups were found

  18. Imaging systems of human eye: a review.

    PubMed

    Acharya, Rajendra U; Yun, Wong Li; Ng, E Y K; Yu, Wenwei; Suri, Jasjit S

    2008-08-01

    The eyes are complex sensory organs and are designed to optimize vision under conditions of varying light. There are a number of eye disorders that can influence vision. Eye disorders among the elderly are a major health problem. With advancing age, the normal function of eye tissues decreases and there is an increased incidence of ocular pathology. The most common causes of age related eye disorder and visual impairment in the elderly are cataracts and primary open angle glaucoma. Different imaging systems are available to visualize the different parts of the eye non-invasively with higher accuracy. This paper discusses the various techniques available namely, computed tomography, confocal laser scanning microscopy, magnetic resonance imaging, optical coherence tomography, ultrasound imaging, infrared thermography for the imaging of the different eye abnormalities.

  19. OPTICAL EYE MODEL: Human eye aberrations: 2. Development of a dynamic model of the human eye based on measurements

    NASA Astrophysics Data System (ADS)

    Galetskii, S. O.; Cherezova, T. Yu; Kudryashov, A. V.

    2008-11-01

    A human eye model based on a flexible semipassive bimorph mirror is proposed and experimentally realised. The model can be used for the real-time reproduction of human eye aberrations and their fluctuations. The accuracy of the reproduction of individual Zernike polynomials and of total eye aberrations of inspected patients is discussed.

  20. Lipid peroxidation and cataracts: N-acetylcarnosine as a therapeutic tool to manage age-related cataracts in human and in canine eyes.

    PubMed

    Babizhayev, Mark A; Deyev, Anatoly I; Yermakova, Valentina N; Brikman, Igor V; Bours, Johan

    2004-01-01

    primary (diene conjugates, cetodienes) lipid peroxidation (LPO) products, while in later stages there is a prevalence of LPO fluorescent end-products. A reliable increase in oxiproducts of fatty acyl content of lenticular lipids was shown by a direct gas chromatography technique producing fatty acid fluorine-substituted derivatives. The lens opacity degree correlates with the level of the LPO fluorescent end-product accumulation in its tissue, accompanied by sulfhydryl group oxidation of lens proteins due to a decrease of reduced glutathione concentration in the lens. The injection of LPO products into the vitreous has been shown to induce cataract. It is concluded that peroxide damage of the lens fibre membranes may be the initial cause of cataract development. N-acetylcarnosine (as the ophthalmic drug Can-C), has been found to be suitable for the nonsurgical prevention and treatment of age-related cataracts. This molecule protects the crystalline lens from oxidative stress-induced damage, and in a recent clinical trial it was shown to produce an effective, safe and long-term improvement in sight. When administered topically to the eye in the form of Can-C, N-acetylcarnosine functions as a time-release prodrug form of L-carnosine resistant to hydrolysis with carnosinase. N-acetylcarnosine has potential as an in vivo universal antioxidant because of its ability to protect against oxidative stress in the lipid phase of biological cellular membranes and in the aqueous environment by a gradual intraocular turnover into L-carnosine. In our study the clinical effects of a topical solution of N-acetylcarnosine (Can-C) on lens opacities were examined in patients with cataracts and in canines with age-related cataracts. These data showed that N-acetylcarnosine is effective in the management of age-related cataract reversal and prevention both in human and in canine eyes.

  1. Age-related eye disease and gender.

    PubMed

    Zetterberg, Madeleine

    2016-01-01

    Worldwide, the prevalence of moderate to severe visual impairment and blindness is 285 millions, with 65% of visually impaired and 82% of all blind people being 50 years and older. Meta-analyses have shown that two out of three blind people are women, a gender discrepancy that holds true for both developed and developing countries. Cataract accounts for more than half of all blindness globally and gender inequity in access to cataract surgery is the major cause of the higher prevalence of blindness in women. In addition to gender differences in cataract surgical coverage, population-based studies on the prevalence of lens opacities indicate that women have a higher risk of developing cataract. Laboratory as well as epidemiologic studies suggest that estrogen may confer antioxidative protection against cataractogenesis, but the withdrawal effect of estrogen in menopause leads to increased risk of cataract in women. For the other major age-related eye diseases; glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy, data are inconclusive. Due to anatomic factors, angle closure glaucoma is more common in women, whereas the dominating glaucoma type; primary open-angle glaucoma (POAG), is more prevalent in men. Diabetic retinopathy also has a male predominance and vascular/circulatory factors have been implied both in diabetic retinopathy and in POAG. For AMD, data on gender differences are conflicting although some studies indicate increased prevalence of drusen and neovascular AMD in women. To conclude, both biologic and socioeconomic factors must be considered when investigating causes of gender differences in the prevalence of age-related eye disease.

  2. Development of an optical simulator of the human eye

    NASA Astrophysics Data System (ADS)

    Coelho, João. M. P.; Baião, André; Vieira, Pedro

    2013-11-01

    The optics of the human eye have for several years been the subject of careful physiological study. This study has led to the development of models characterizing its operation and allowed to predict its behavior. In general, these models are based on empirical data derived from statistical studies on specific populations. At the same time, different optical analysis techniques are being developed in order to study the eye. These techniques are based on projecting light into the eye or in using optical systems to observe the eye. Thus, it becomes important to have tools to simulate the human eye during the development of these techniques prior to its implementation using human subjects. Several simulators have been developed based on existing models, many of them using ZEMAX optical design program. However, in general, their use has been limited to simple models and/or dedicated analysis. However, the appearance of a toolbox that allows the programming software MatLab to command the optical design program opened a new range of control and analysis capabilities for systems modeled in ZEMAX. Using these tools, a dynamic simulator was developed that allows the user to optically characterize an eye based on age and distance to an object being observed accordingly with one existing model. The capabilities of both programs allowed obtaining a tool capable of not only helping the development of optical analysis techniques but also be used in developing new eye models or analyze eye safety issues. Its performance is presented and analysis examples shown.

  3. Eyes open versus eyes closed - Effect on human rotational responses

    NASA Technical Reports Server (NTRS)

    Wall, Conrad, III; Furman, Joseph M. R.

    1989-01-01

    The effect of eyelid closure on the response to rotational vestibular stimulation was assessed by evaluating 16 normal human subjects with both earth vertical axis (EVA) and earth horizontal axis (EHA) yaw rotations with either eyes closed (EC) or eyes open in the dark (EOD). Results indicated that for EVA rotation, the subjects' responses were of larger magnitude and less variable with EOD than with EC. However, for EHA rotation, responses were of larger magnitude and equally variable with EC as compared to EOD. Data also indicated that the quality of the EHA response with EC was altered because eyelid closure influenced the amount of periodic gaze. It is concluded that eyelid closure has an effect upon both canalocular and otolithocular reflexes and it is suggested that both EVA and EHA rotational testing be performed with EOD rather than with EC.

  4. Modelling human eye under blast loading.

    PubMed

    Esposito, L; Clemente, C; Bonora, N; Rossi, T

    2015-01-01

    Primary blast injury (PBI) is the general term that refers to injuries resulting from the mere interaction of a blast wave with the body. Although few instances of primary ocular blast injury, without a concomitant secondary blast injury from debris, are documented, some experimental studies demonstrate its occurrence. In order to investigate PBI to the eye, a finite element model of the human eye using simple constitutive models was developed. The material parameters were calibrated by a multi-objective optimisation performed on available eye impact test data. The behaviour of the human eye and the dynamics of mechanisms occurring under PBI loading conditions were modelled. For the generation of the blast waves, different combinations of explosive (trinitrotoluene) mass charge and distance from the eye were analysed. An interpretation of the resulting pressure, based on the propagation and reflection of the waves inside the eye bulb and orbit, is proposed. The peculiar geometry of the bony orbit (similar to a frustum cone) can induce a resonance cavity effect and generate a pressure standing wave potentially hurtful for eye tissues.

  5. Human eye via reality and art.

    PubMed

    Tamir, Abraham

    2012-07-01

    This article related to a man's head is a follow-up to previous articles published in this journal entitled "Numerical Survey of the Different Shapes of the Human Nose," "Ear Concha Shapes," and "Quantitative Survey of Human's Leg Toes Shape." The author believes that the different artistic display of the eye gives a better understanding and concept of our most important organ.

  6. Human-eye versus computerized color matching.

    PubMed

    Yap, A U; Sim, C P; Loh, W L; Teo, J H

    1999-01-01

    This project compared the difference in color matching between human-eye assessment and computerized colorimetry. Fifty dental personnel were asked to color match Vita Lumin shade tabs to seven different randomly arranged test tabs from the Z100 shade guide. All evaluators were blinded to the shades of the test tabs and were asked to match only body shade of the Vita Lumin tab to the middle third or body of each test tab. The results obtained were subsequently computed into L*a*b* values and compared with results obtained by computerized colorimetry. Results indicate that the difference in color matching between human-eye assessment and computerized colorimetry is shade dependent. Discrepancy was significant for b* coordinates for shades A1 and B2 and L* and b* coordinates for shade C4. For all shades evaluated, color difference between human-eye and computerized color matching is perceivable under clinical settings, as delta E values are greater than 3. There is a need for correction factors in the formal specification of the color-matching software due to the discrepancy between human-eye and computerized colorimetric color matching.

  7. Template aging in eye movement-driven biometrics

    NASA Astrophysics Data System (ADS)

    Komogortsev, Oleg V.; Holland, Corey D.; Karpov, Alex

    2014-05-01

    This paper presents a template aging study of eye movement biometrics, considering three distinct biometric techniques on multiple stimuli and eye tracking systems. Short-to-midterm aging effects are examined over two-weeks, on a highresolution eye tracking system, and seven-months, on a low-resolution eye tracking system. We find that, in all cases, aging effects are evident as early as two weeks after initial template collection, with an average 28% (±19%) increase in equal error rates and 34% (±12%) reduction in rank-1 identification rates. At seven months, we observe an average 18% (±8%) increase in equal error rates and 44% (±20%) reduction in rank-1 identification rates. The comparative results at two-weeks and seven-months suggests that there is little difference in aging effects between the two intervals; however, whether the rate of decay increases more drastically in the long-term remains to be seen.

  8. Communication Aid with Human Eyes Only

    NASA Astrophysics Data System (ADS)

    Arai, Kohei; Yajima, Kenro

    A communication aid with human eyes only is proposed. A set of candidate character is displayed onto computer screen of relatively small and light Head Mount Display: HMD that is mounted on glasses of which user wears on. When user looks at a candidate character with his/hers left eye while right eye picture is taken with small and light web camera that also is mounted on the glasses. The proposed system can selects 81 characters with two layers of 9 by 9 character candidate image. Other than these there is another selective image including control keys and frequently use of sentences. By using image matching between previously acquired template image for each candidate character and the currently acquired image, the proposed system realizes that which character in the candidates is selected. By using blinking and fix one's eye on combine together, the proposed system recognizes that user determines the selected key from the candidates. The blinking detection method employs a morphologic filter to avoid misunderstanding of dark eye detection due to eyebrows and shadows. Thus user can input sentences. User also may edit the sentences and then the sentences are read with Text to Speech: TTS software tool. Thus the system allows support conversations between handicapped and disabled persons without voice and the others peoples because only the function required for conversation is human eyes. Also the proposed system can be used as an input system for wearable computing systems. Test results by the 6 different able persons show that the proposed system does work with acceptable speed, around 1.5 second / character.

  9. Zoonotic helminths affecting the human eye

    PubMed Central

    2011-01-01

    Nowaday, zoonoses are an important cause of human parasitic diseases worldwide and a major threat to the socio-economic development, mainly in developing countries. Importantly, zoonotic helminths that affect human eyes (HIE) may cause blindness with severe socio-economic consequences to human communities. These infections include nematodes, cestodes and trematodes, which may be transmitted by vectors (dirofilariasis, onchocerciasis, thelaziasis), food consumption (sparganosis, trichinellosis) and those acquired indirectly from the environment (ascariasis, echinococcosis, fascioliasis). Adult and/or larval stages of HIE may localize into human ocular tissues externally (i.e., lachrymal glands, eyelids, conjunctival sacs) or into the ocular globe (i.e., intravitreous retina, anterior and or posterior chamber) causing symptoms due to the parasitic localization in the eyes or to the immune reaction they elicit in the host. Unfortunately, data on HIE are scant and mostly limited to case reports from different countries. The biology and epidemiology of the most frequently reported HIE are discussed as well as clinical description of the diseases, diagnostic considerations and video clips on their presentation and surgical treatment. Homines amplius oculis, quam auribus credunt Seneca Ep 6,5 Men believe their eyes more than their ears PMID:21429191

  10. Proteus species isolated from human eyes.

    PubMed

    Okumoto, M; Smolin, G; Belfort, R; Kim, H B; Siverio, C E

    1976-04-01

    Of 34 species of Proteus isolated from human eyes, 29 (85%) were P. mirabilis and five (15%) were P. morganii. In vitro antibiotic sensitivity studies showed that gentamicin best controlled both P. mirabilis and P. morganii of all the antibiotics tested. In vivo tests on experimental Proteus infections of rabbit coreas, treated with gentamicin and tobramycin, yielded comparable clinical results, but gentamicin was more effective in eliminating the organism from the experimental lesions.

  11. Therapeutic Strategies to Treat Dry Eye in an Aging Population

    PubMed Central

    Ezuddin, Nisreen S.; Alawa, Karam A.; Galor, Anat

    2015-01-01

    Dry eye (DE) is a prevalent ocular disease that primarily affects the elderly. Affecting up to 30% of adults aged 50 years and older, dry eye affects both visual function and quality of life. Symptoms of dry eye which include ocular pain (aching, burning), visual disturbances, and tearing can be addressed with therapeutic agents that target dysfunction of the meibomian glands, lacrimal glands, goblet cells, ocular surface and/or neural network. This review provides an overview of the efficacy, use, and limitations of current therapeutic interventions being used to treat DE. PMID:26123947

  12. Human eye color difference threshold measurement system

    NASA Astrophysics Data System (ADS)

    Liu, Lin; Zhou, Taogeng

    2013-12-01

    The human eye has the ability to distinguish millions of colors, with this feature we can identify very subtle color differences, and the measurement of human eye color difference threshold can provide a visual function diagnosis for testee. In recent years, people begin to focus on studies on visual threshold diagnostic equipment. This paper proposes a human eye color difference threshold measurement system which is based on dual integrating sphere. The system includes two pairs of dual integrating sphere and color control module. Dual integrating sphere uses to mix and produce color, and palette unit which produces primary colors (red (R), green (G), blue (B)) is embedded in dual integrating sphere. At the same time, the embedded palette unit which produces cyan (C), magenta (M), and yellow (Y) expands color area that the system can generate. One optical path based on dual integrating sphere generates standard color, the other path produces the matching color which is similar to a standard color. In the high-precision closed-loop color control module, photoelectric switch records stepper motor's origin position and limits move displacement. Precision stepper motor pushes the light-blocking panel of the palette unit to a predetermined position, while real-time monitoring the position of the light-blocking panel and mixing the ideal controllable color. Two colors that the system generates are projected onto the same target area. Subjects make a judgment on color difference threshold by observing the target eventually.

  13. Microwave cyclodestruction: evaluation on human eyes.

    PubMed Central

    Finger, P T; Perry, H D; Shakin, J L; Bisciotti, D R; Nattis, R J

    1995-01-01

    AIMS--The study was set up to evaluate the effect of microwave cyclodestruction on human eyes. METHODS--Two human eyes were studied. For treatment a horn shaped 5.8 GHz microwave applicator and fibre optic thermometry were used. Just before enucleation, the rectangular (2 x 3 mm) microwave aperture was placed onto the conjunctiva at a position 1-2 mm posterior to the corneal scleral limbus. Each of three to four treatment spots was targeted to receive a thermal dose of 54 degrees C for 1 minute. Clinical, gross, and histopathological evaluations were performed. RESULTS--Clinical evaluations of the treatment sites (immediately after microwave application) revealed no evidence of conjunctival or scleral damage. Trace fluorescein 2% uptake was noted within the targeted zones. The first eye was sectioned along the equatorial axis. Examination of the ciliary body and pars plana revealed whitening of the ciliary processes and depigmentation. Histopathological evaluations revealed ciliary epithelial necrosis with pigment dispersion. The vascularity of the ciliary processes showed focal disruption and haemorrhage. The underlying ciliary muscle and sclera appeared to be unaffected. No other findings could be attributed to microwave cyclodestruction. CONCLUSION--The results of this phase I toxicity study suggest that microwave heating can be used to damage preferentially the epithelial layers of the human ciliary body. Images PMID:7662635

  14. Scan of the back of human eye

    NASA Technical Reports Server (NTRS)

    2003-01-01

    ProVision Technologies, a NASA commercial space center at Sternis Space Center in Mississippi, has developed a new hyperspectral imaging (HSI) system that is much smaller than the original large units used aboard remote sensing aircraft and satellites. The new apparatus is about the size of a breadbox. HSI may be useful to ophthalmologists to study and diagnose eye health, both on Earth and in space, by examining the back of the eye to determine oxygen and blood flow quickly and without any invasion. ProVision's hyperspectral imaging system can scan the human eye and produce a graph showing optical density or light absorption, which can then be compared to a graph from a normal eye. Scans of the macula, optic disk or optic nerve head, and blood vessels can be used to detect anomalies and identify diseases in this delicate and important organ. ProVision has already developed a relationship with the University of Alabama at Birmingham, but is still on the lookout for a commercial partner in this application.

  15. The development of human fetal eye movement patterns.

    PubMed

    Birnholz, J C

    1981-08-07

    The eye can be visualized ultrasonically in more than 90 percent of fetuses 16 through 42 weeks of gestational age. Slow eye movements are present by 16 weeks. Rapid eye movements begin at 23 weeks and become more frequent between 24 and 35 weeks. Eye inactivity becomes more common after 36 weeks and is associated with sustained diaphragmatic excursions implying a "quiet sleep" state. Pathologic eye movements were seen in four fetuses with dysmorphic brain structure.

  16. Effects of aging on eye movements in the real world

    PubMed Central

    Dowiasch, Stefan; Marx, Svenja; Einhäuser, Wolfgang; Bremmer, Frank

    2015-01-01

    The effects of aging on eye movements are well studied in the laboratory. Increased saccade latencies or decreased smooth-pursuit gain are well established findings. The question remains whether these findings are influenced by the rather untypical environment of a laboratory; that is, whether or not they transfer to the real world. We measured 34 healthy participants between the age of 25 and 85 during two everyday tasks in the real world: (I) walking down a hallway with free gaze, (II) visual tracking of an earth-fixed object while walking straight-ahead. Eye movements were recorded with a mobile light-weight eye tracker, the EyeSeeCam (ESC). We find that age significantly influences saccade parameters. With increasing age, saccade frequency, amplitude, peak velocity, and mean velocity are reduced and the velocity/amplitude distribution as well as the velocity profile become less skewed. In contrast to laboratory results on smooth pursuit, we did not find a significant effect of age on tracking eye-movements in the real world. Taken together, age-related eye-movement changes as measured in the laboratory only partly resemble those in the real world. It is well-conceivable that in the real world additional sensory cues, such as head-movement or vestibular signals, may partially compensate for age-related effects, which, according to this view, would be specific to early motion processing. In any case, our results highlight the importance of validity for natural situations when studying the impact of aging on real-life performance. PMID:25713524

  17. Effects of aging on eye movements in the real world.

    PubMed

    Dowiasch, Stefan; Marx, Svenja; Einhäuser, Wolfgang; Bremmer, Frank

    2015-01-01

    The effects of aging on eye movements are well studied in the laboratory. Increased saccade latencies or decreased smooth-pursuit gain are well established findings. The question remains whether these findings are influenced by the rather untypical environment of a laboratory; that is, whether or not they transfer to the real world. We measured 34 healthy participants between the age of 25 and 85 during two everyday tasks in the real world: (I) walking down a hallway with free gaze, (II) visual tracking of an earth-fixed object while walking straight-ahead. Eye movements were recorded with a mobile light-weight eye tracker, the EyeSeeCam (ESC). We find that age significantly influences saccade parameters. With increasing age, saccade frequency, amplitude, peak velocity, and mean velocity are reduced and the velocity/amplitude distribution as well as the velocity profile become less skewed. In contrast to laboratory results on smooth pursuit, we did not find a significant effect of age on tracking eye-movements in the real world. Taken together, age-related eye-movement changes as measured in the laboratory only partly resemble those in the real world. It is well-conceivable that in the real world additional sensory cues, such as head-movement or vestibular signals, may partially compensate for age-related effects, which, according to this view, would be specific to early motion processing. In any case, our results highlight the importance of validity for natural situations when studying the impact of aging on real-life performance.

  18. Oxidative stress and its downstream signaling in aging eyes

    PubMed Central

    Pinazo-Durán, María Dolores; Gallego-Pinazo, Roberto; García-Medina, Jose Javier; Zanón-Moreno, Vicente; Nucci, Carlo; Dolz-Marco, Rosa; Martínez-Castillo, Sebastián; Galbis-Estrada, Carmen; Marco-Ramírez, Carla; López-Gálvez, Maria Isabel; Galarreta, David J; Díaz-Llópis, Manuel

    2014-01-01

    Background Oxidative stress (OS) and its biomarkers are the biochemical end point of the imbalance between reactive oxygen species (ROS) production and the ability of the antioxidant (AOX) biological systems to fight against oxidative injury. Objective We reviewed the role of OS and its downstream signaling in aging eyes. Methods A search of the literature and current knowledge on the physiological and pathological mechanisms of OS were revisited in relation to the eyes and the aging process. Most prevalent ocular diseases have been analyzed herein in relation to OS and nutraceutic supplements, such as dry-eye disorders, glaucoma, age-related macular degeneration, and diabetic retinopathy. Results Clinical, biochemical, and molecular data from anterior and posterior eye segment diseases point to OS as the common pathogenic mechanism in the majority of these ocular disorders, many of which are pathologies causing visual impairment, blindness, and subsequent loss of life quality. Studies with nutraceutic supplements in aging eye-related pathologies have also been reviewed. Conclusion OS, nutritional status, and nutraceutic supplements have to be considered within the standards of care of older ophthalmologic patients. OS biomarkers and surrogate end points may help in managing the aging population with ocular diseases. PMID:24748782

  19. The application of information fusion in human eye aberration measurement

    NASA Astrophysics Data System (ADS)

    Zhang, Peiming; Chen, Jiabi; Cao, Liang; Zhuang, Songlin

    2008-12-01

    A novel human eye aberration measurement method based on information fusion is presented here. We built a combined subjective and objective human eye aberration measurement system which is composed by an objective measurement part which measure human eye aberration by using Hartmann-Shack wavefront sensor and a subjective view test part through which can test the subject's vision. The deformable mirror can compensate the high order aberrations of human eye, and thus, can improve the visual acuity of human eye. We had weighting process on Zernike coefficients of both psychology stimulated results and objective results by the method of information fusion, and got combined Zernike coefficients, and finally the combined wavefront aberrations. The result shows that information fusion can combine advantages of both subjective and objective measurement, can have more comprehensive to characterized human eye visual performance, thus providing a more detailed advice for ideal individual human eye.

  20. Dating the time of birth: A radiocarbon calibration curve for human eye-lens crystallines

    NASA Astrophysics Data System (ADS)

    Kjeldsen, Henrik; Heinemeier, Jan; Heegaard, Steffen; Jacobsen, Christina; Lynnerup, Niels

    2010-04-01

    Radiocarbon bomb-pulse dating has been used to measure the formation age of human eye-lens crystallines. Lens crystallines are special proteins in the eye-lens that consist of virtually inert tissue. The experimental data show that the radiocarbon ages to a large extent reflect the time of birth, in accordance with expectations. Moreover, it has been possible to develop an age model for the formation of the eye-lens crystallines. From this model a radiocarbon calibration curve for lens crystallines has been calculated. As a consequence, the time of birth of humans can be determined with an accuracy of a few years by radiocarbon dating.

  1. Can human eyes prevent perceptual narrowing for monkey faces in human infants?

    PubMed

    Damon, Fabrice; Bayet, Laurie; Quinn, Paul C; Hillairet de Boisferon, Anne; Méary, David; Dupierrix, Eve; Lee, Kang; Pascalis, Olivier

    2015-07-01

    Perceptual narrowing has been observed in human infants for monkey faces: 6-month-olds can discriminate between them, whereas older infants from 9 months of age display difficulty discriminating between them. The difficulty infants from 9 months have processing monkey faces has not been clearly identified. It could be due to the structural characteristics of monkey faces, particularly the key facial features that differ from human faces. The current study aimed to investigate whether the information conveyed by the eyes is of importance. We examined whether the presence of Caucasian human eyes in monkey faces allows recognition to be maintained in 6-month-olds and facilitates recognition in 9- and 12-month-olds. Our results revealed that the presence of human eyes in monkey faces maintains recognition for those faces at 6 months of age and partially facilitates recognition of those faces at 9 months of age, but not at 12 months of age. The findings are interpreted in the context of perceptual narrowing and suggest that the attenuation of processing of other-species faces is not reversed by the presence of human eyes.

  2. Human eye anisoplanatism: eye as a lamellar structure

    NASA Astrophysics Data System (ADS)

    Dubinin, Alexander; Cherezova, Tatyana; Belyakov, Alexey; Kudryashov, Alexis

    2006-02-01

    In this paper we consider anisoplanatism effect as a fundamental limitation on the size of high resolution area (isoplanatic patch) of retinal images obtained using fundus cameras equipped with adaptive optics. Isoplanatic patch size was estimated using experimental results for on-axis and off-axis eye aberrations measured by Shack-Hartmann technique. Isoplanatic patch size varied among examined subjects in the range from 1.5 ° to 2.5 ° which is in good agreement with results obtained using ray-tracing technique1. We estimated isoplanatic patch size for Gullstrand eye model and found it to be close to the values obtained from experimental results for subjects with good vision. We also discuss the possibilities of Gullstrand eye model modifications for modeling anisoplanatism effect for each particular subject. We also estimated the efficiency of multibeacon correction method and found out that this method allows us to almost twice increase the area with high resolution.

  3. Age and beauty are in the eye of the beholder.

    PubMed

    Kwart, Dylan G; Foulsham, Tom; Kingstone, Alan

    2012-01-01

    How "old" and "attractive" an individual appears has increasingly become an individual concern leading to the utilisation of various cosmetic surgical procedures aimed at enhancing appearance. Using eyetracking, in the present study we aimed to investigate how individuals perceive age and attractiveness of younger and older faces and what "bottom-up" facial cues are used in this process. One hundred and twenty eight digital images of neutral faces of ages ranging from 20 to 89 years were paired and presented to subjects who judged age and attractiveness levels while having their eye movements recorded. There was an effect of face attractiveness on age-rating accuracy, with attractive faces being rated younger than their true age. Similarly, stimulus age affected attractiveness ratings, with younger faces being perceived as more attractive. Judgments of age and attractiveness were tightly linked to fixations on the eye region, along with the nose and mouth. It is thus likely that cosmetic surgical procedures targeted at the eyes, nose, and mouth may be most efficacious at enhancing one's physical appearance.

  4. What's on TV? Detecting age-related neurodegenerative eye disease using eye movement scanpaths

    PubMed Central

    Crabb, David P.; Smith, Nicholas D.; Zhu, Haogang

    2014-01-01

    Purpose: We test the hypothesis that age-related neurodegenerative eye disease can be detected by examining patterns of eye movement recorded whilst a person naturally watches a movie. Methods: Thirty-two elderly people with healthy vision (median age: 70, interquartile range [IQR] 64–75 years) and 44 patients with a clinical diagnosis of glaucoma (median age: 69, IQR 63–77 years) had standard vision examinations including automated perimetry. Disease severity was measured using a standard clinical measure (visual field mean deviation; MD). All study participants viewed three unmodified TV and film clips on a computer set up incorporating the Eyelink 1000 eyetracker (SR Research, Ontario, Canada). Eye movement scanpaths were plotted using novel methods that first filtered the data and then generated saccade density maps. Maps were then subjected to a feature extraction analysis using kernel principal component analysis (KPCA). Features from the KPCA were then classified using a standard machine based classifier trained and tested by a 10-fold cross validation which was repeated 100 times to estimate the confidence interval (CI) of classification sensitivity and specificity. Results: Patients had a range of disease severity from early to advanced (median [IQR] right eye and left eye MD was −7 [−13 to −5] dB and −9 [−15 to −4] dB, respectively). Average sensitivity for correctly identifying a glaucoma patient at a fixed specificity of 90% was 79% (95% CI: 58–86%). The area under the Receiver Operating Characteristic curve was 0.84 (95% CI: 0.82–0.87). Conclusions: Huge data from scanpaths of eye movements recorded whilst people freely watch TV type films can be processed into maps that contain a signature of vision loss. In this proof of principle study we have demonstrated that a group of patients with age-related neurodegenerative eye disease can be reasonably well separated from a group of healthy peers by considering these eye movement

  5. Modeling and simulation of the human eye

    NASA Astrophysics Data System (ADS)

    Duran, R.; Ventura, L.; Nonato, L.; Bruno, O.

    2007-02-01

    The computational modeling of the human eye has been wide studied for different sectors of the scientific and technological community. One of the main reasons for this increasing interest is the possibility to reproduce eye optic properties by means of computational simulations, becoming possible the development of efficient devices to treat and to correct the problems of the vision. This work explores this aspect still little investigated of the modeling of the visual system, considering a computational sketch that make possible the use of real data in the modeling and simulation of the human visual system. This new approach makes possible the individual inquiry of the optic system, assisting in the construction of new techniques used to infer vital data in medical investigations. Using corneal topography to collect real data from patients, a computational model of cornea is constructed and a set of simulations were build to ensure the correctness of the system and to investigate the effect of corneal abnormalities in retinal image formation, such as Plcido Discs, Point Spread Function, Wave front and the projection of a real image and it's visualization on retina.

  6. Virtual pharmacokinetic model of human eye.

    PubMed

    Kotha, Sreevani; Murtomäki, Lasse

    2014-07-01

    A virtual pharmacokinetic 3D model of the human eye is built using Comsol Multiphysics® software, which is based on the Finite Element Method (FEM). The model considers drug release from a polymer patch placed on sclera. The model concentrates on the posterior part of the eye, retina being the target tissue, and comprises the choroidal blood flow, partitioning of the drug between different tissues and active transport at the retina pigment epithelium (RPE)-choroid boundary. Although most straightforward, in order to check the mass balance, no protein binding or metabolism is yet included. It appeared that the most important issue in obtaining reliable simulation results is the finite element mesh, while time stepping has hardly any significance. Simulations were extended to 100,000 s. The concentration of a drug is shown as a function of time at various points of retina, as well as its average value, varying several parameters in the model. This work demonstrates how anybody with basic knowledge of calculus is able to build physically meaningful models of quite complex biological systems.

  7. Age-related changes in head and eye coordination.

    PubMed

    Proudlock, Frank A; Shekhar, Himanshu; Gottlob, Irene

    2004-01-01

    The effect of ageing upon head movements during gaze shifts is unknown. We have investigated age-related changes in head and eye coordination in a group of healthy volunteers. Horizontal head and eye movements were recorded in 53 subjects, aged between 20 and 83 years, during the performance of saccades, antisaccades, smooth pursuit and a reading task. The subjects were divided into three groups, young subjects (20-40 years), middle-aged subjects (41-60 years) and older subjects (over 60 years). Logarithmic transformations of the head gain were significantly greater in the older subjects compared to the young subjects during the saccadic task (P=0.001), antisaccadic task (P=0.004), smooth pursuit at 20 degrees/s (P=0.001) and 40 degrees/s (P=0.005), but not reading. For saccadic and antisaccadic tasks, the increase in transformed head gain was non-linear with significant differences between older and middle-aged subjects but not middle-aged and young subjects. Head movement tendencies were highly consistent for related tasks. Head movement gain during gaze shifts significantly increases with age, which may contribute to dizziness and balance problems experienced by the elderly.

  8. Determination of positions of optical elements of the human eye

    SciTech Connect

    Galetskii, S O; Cherezova, T Yu

    2009-02-28

    An original method for noninvasive determining the positions of elements of intraocular optics is proposed. The analytic dependence of the measurement error on the optical-scheme parameters and the restriction in distance from the element being measured are determined within the framework of the method proposed. It is shown that the method can be efficiently used for determining the position of elements in the classical Gullstrand eye model and personalised eye models. The positions of six optical surfaces of the Gullstrand eye model and four optical surfaces of the personalised eye model can be determined with an error of less than 0.25 mm. (human eye optics)

  9. Uveitis in the Aging Eye: Incidence, Patterns, and Differential Diagnosis

    PubMed Central

    Abdulaal, Marwan R.; Abiad, Bachir H.; Hamam, Rola N.

    2015-01-01

    Uveitis is a vision threatening inflammation of the eye that carries considerable morbidity. It is responsible for 10% of legal blindness in the United States and up to 25% in the developing world. Uveitis in patients more than 60 years of age is less common. The aging body has a changing response of the immune system, which might reflect a different pattern of uveitis in the elderly population. In this paper we review the incidence and patterns of uveitis in the elderly as reported in the literature and discuss changes with time. We also delineate a thorough differential diagnosis of de novo uveitis in the elderly. PMID:26090218

  10. Lipid domains in intact fiber-cell plasma membranes isolated from cortical and nuclear regions of human eye lenses of donors from different age groups.

    PubMed

    Raguz, Marija; Mainali, Laxman; O'Brien, William J; Subczynski, Witold K

    2015-03-01

    The results reported here clearly document changes in the properties and the organization of fiber-cell membrane lipids that occur with age, based on electron paramagnetic resonance (EPR) analysis of lens membranes of clear lenses from donors of age groups from 0 to 20, 21 to 40, and 61 to 80 years. The physical properties, including profiles of the alkyl chain order, fluidity, hydrophobicity, and oxygen transport parameter, were investigated using EPR spin-labeling methods, which also provide an opportunity to discriminate coexisting lipid domains and to evaluate the relative amounts of lipids in these domains. Fiber-cell membranes were found to contain three distinct lipid environments: bulk lipid domain, which appears minimally affected by membrane proteins, and two domains that appear due to the presence of membrane proteins, namely boundary and trapped lipid domains. In nuclear membranes the amount of boundary and trapped phospholipids as well as the amount of cholesterol in trapped lipid domains increased with the donors' age and was greater than that in cortical membranes. The difference between the amounts of lipids in domains uniquely formed due to the presence of membrane proteins in nuclear and cortical membranes increased with the donors' age. It was also shown that cholesterol was to a large degree excluded from trapped lipid domains in cortical membranes. It is evident that the rigidity of nuclear membranes was greater than that of cortical membranes for all age groups. The amount of lipids in domains of low oxygen permeability, mainly in trapped lipid domains, were greater in nuclear than cortical membranes and increased with the age of donors. These results indicate that the nuclear fiber cell plasma membranes were less permeable to oxygen than cortical membranes and become less permeable to oxygen with age. In clear lenses, age-related changes in the lens lipid and protein composition and organization appear to occur in ways that increase fiber

  11. Lipid Domains in Intact Fiber-Cell Plasma Membranes Isolated from Cortical and Nuclear Regions of Human Eye Lenses of Donors from Different Age Groups

    PubMed Central

    Raguz, Marija; Mainali, Laxman; O’Brien, William J.; Subczynski, Witold K.

    2015-01-01

    The results reported here clearly document changes in the properties and the organization of fiber-cell membrane lipids that occur with age, based on electron paramagnetic resonance (EPR) analysis of lens membranes of clear lenses from donors of age groups from 0 to 20, 21 to 40, and 61 to 80 years. The physical properties, including profiles of the alkyl chain order, fluidity, hydrophobicity, and oxygen transport parameter, were investigated using EPR spin-labeling methods, which also provide an opportunity to discriminate coexisting lipid domains and to evaluate the relative amounts of lipids in these domains. Fiber-cell membranes were found to contain three distinct lipid environments: bulk lipid domain, which appears minimally affected by membrane proteins, and two domains that appear due to the presence of membrane proteins, namely boundary and trapped lipid domains. In nuclear membranes the amount of boundary and trapped phospholipids as well as the amount of cholesterol in trapped lipid domains increased with the donors’ age and was greater than that in cortical membranes. The difference between the amounts of lipids in domains uniquely formed due to the presence of membrane proteins in nuclear and cortical membranes increased with the donors’ age. It was also shown that cholesterol was to a large degree excluded from trapped lipid domains in cortical membranes. It is evident that the rigidity of nuclear membranes was greater than that of cortical membranes for all age groups. The amount of lipids in domains of low oxygen permeability, mainly in trapped lipid domains, were greater in nuclear than cortical membranes and increased with the age of donors. These results indicate that the nuclear fiber cell plasma membranes were less permeable to oxygen than cortical membranes and become less permeable to oxygen with age. In clear lenses, age-related changes in the lens lipid and protein composition and organization appear to occur in ways that increase fiber

  12. Eye movement-invariant representations in the human visual system

    PubMed Central

    Nishimoto, Shinji; Huth, Alexander G.; Bilenko, Natalia Y.; Gallant, Jack L.

    2017-01-01

    During natural vision, humans make frequent eye movements but perceive a stable visual world. It is therefore likely that the human visual system contains representations of the visual world that are invariant to eye movements. Here we present an experiment designed to identify visual areas that might contain eye-movement-invariant representations. We used functional MRI to record brain activity from four human subjects who watched natural movies. In one condition subjects were required to fixate steadily, and in the other they were allowed to freely make voluntary eye movements. The movies used in each condition were identical. We reasoned that the brain activity recorded in a visual area that is invariant to eye movement should be similar under fixation and free viewing conditions. In contrast, activity in a visual area that is sensitive to eye movement should differ between fixation and free viewing. We therefore measured the similarity of brain activity across repeated presentations of the same movie within the fixation condition, and separately between the fixation and free viewing conditions. The ratio of these measures was used to determine which brain areas are most likely to contain eye movement-invariant representations. We found that voxels located in early visual areas are strongly affected by eye movements, while voxels in ventral temporal areas are only weakly affected by eye movements. These results suggest that the ventral temporal visual areas contain a stable representation of the visual world that is invariant to eye movements made during natural vision. PMID:28114479

  13. Eye movement-invariant representations in the human visual system.

    PubMed

    Nishimoto, Shinji; Huth, Alexander G; Bilenko, Natalia Y; Gallant, Jack L

    2017-01-01

    During natural vision, humans make frequent eye movements but perceive a stable visual world. It is therefore likely that the human visual system contains representations of the visual world that are invariant to eye movements. Here we present an experiment designed to identify visual areas that might contain eye-movement-invariant representations. We used functional MRI to record brain activity from four human subjects who watched natural movies. In one condition subjects were required to fixate steadily, and in the other they were allowed to freely make voluntary eye movements. The movies used in each condition were identical. We reasoned that the brain activity recorded in a visual area that is invariant to eye movement should be similar under fixation and free viewing conditions. In contrast, activity in a visual area that is sensitive to eye movement should differ between fixation and free viewing. We therefore measured the similarity of brain activity across repeated presentations of the same movie within the fixation condition, and separately between the fixation and free viewing conditions. The ratio of these measures was used to determine which brain areas are most likely to contain eye movement-invariant representations. We found that voxels located in early visual areas are strongly affected by eye movements, while voxels in ventral temporal areas are only weakly affected by eye movements. These results suggest that the ventral temporal visual areas contain a stable representation of the visual world that is invariant to eye movements made during natural vision.

  14. Development of a human eye model for visual performance assessment

    NASA Astrophysics Data System (ADS)

    Jiang, Chong-Jhih; Chen, Yi-Chun; Yang, Tsung-Hsun; Sun, Ching-Cherng

    2009-08-01

    A biometry-based human eye model was developed by using the empirical anatomic and optical data of ocular parameters. The gradient refractive index of the crystalline lens was modeled by concentric conicoid isoindical surfaces and was adaptive to accommodation and age. The chromatic dispersion of homogeneous ocular media was described by Cauchy equations. The gradient equations for the refractive index of crystalline lens were modified at particular wavelengths according to the same dispersion model. Mie scattering was introduced to simulate volumetric light scattering in the crystalline lens. The optical performance of the eye model was evaluated in CodeV and ASAP and presented by the modulation transfer function (MTF) at single and multiple wavelengths. The chromatic optical powers obtained from this model matched that of physiological eyes. The scattering property was assessed by means of glare veiling luminance and compared with CIE general disability glare equation. This model is highly potential for investigating visual performance in ordinary lighting and display conditions and under the influence of glare sources.

  15. Sleep and Human Aging.

    PubMed

    Mander, Bryce A; Winer, Joseph R; Walker, Matthew P

    2017-04-05

    Older adults do not sleep as well as younger adults. Why? What alterations in sleep quantity and quality occur as we age, and are there functional consequences? What are the underlying neural mechanisms that explain age-related sleep disruption? This review tackles these questions. First, we describe canonical changes in human sleep quantity and quality in cognitively normal older adults. Second, we explore the underlying neurobiological mechanisms that may account for these human sleep alterations. Third, we consider the functional consequences of age-related sleep disruption, focusing on memory impairment as an exemplar. We conclude with a discussion of a still-debated question: do older adults simply need less sleep, or rather, are they unable to generate the sleep that they still need?

  16. Wide-angle chromatic aberration corrector for the human eye.

    PubMed

    Benny, Yael; Manzanera, Silvestre; Prieto, Pedro M; Ribak, Erez N; Artal, Pablo

    2007-06-01

    The human eye is affected by large chromatic aberration. This may limit vision and makes it difficult to see fine retinal details in ophthalmoscopy. We designed and built a two-triplet system for correcting the average longitudinal chromatic aberration of the eye while keeping a reasonably wide field of view. Measurements in real eyes were conducted to examine the level and optical quality of the correction. We also performed some tests to evaluate the effect of the corrector on visual performance.

  17. Growth of the human eye lens

    PubMed Central

    2007-01-01

    Purpose To analyze human lens growth from the accumulation of wet weight as a function of age. Methods Wet weights were assembled for over 1,100 human lenses, ranging in age from 6 months prenatal to 99 years postnatal, and were examined using various growth models. Initially, prenatal and postnatal data were examined separately, to determine the growth modes and then all data were fitted to a single equation. Results Variations in weights due to tissue handling procedures and the unavailability of statistical data for averaged sets precluded the use of >500 values in the present analysis. Regression of age on log lens weight for the remaining 614 lenses indicated that, unlike other species, human lens growth appears to take place in two distinct phases. It was found that asymptotic growth during prenatal life and early childhood generates about 149 mg of tissue in a process, which can be modelled with a Gompertz function. Soon after birth, growth becomes linear, dropping to 1.38 mg/year, and this rate is maintained throughout the rest of life. The relationship of lens wet weight with age over the whole of the lifespan could best be described with the expression, W=1.38Ab + 149exp^[exp^(1.6-3Ac)], where W is lens weight in mg, Ab is postnatal age in years and Ac is the time since conception in years. Comparison of 138 male and 64 female lenses indicated that there was no statistically significant difference between male and female lens weights in the linear (adult) growth mode. Conclusions Human lens growth differs from growth in other species in that it occurs in two distinct modes. The first follows a sigmoidal relationship and provides an initial burst of rapid growth during prenatal development with an apparent termination at or shortly after birth. The second growth mode is linear, adding 1.38 mg/year to lens wet weight, throughout life. Because of the variability in available lens wet weight data, further studies, preferably using lens dry weights or protein

  18. The Human Eye Proteome Project: perspectives on an emerging proteome.

    PubMed

    Semba, Richard D; Enghild, Jan J; Venkatraman, Vidya; Dyrlund, Thomas F; Van Eyk, Jennifer E

    2013-08-01

    There are an estimated 285 million people with visual impairment worldwide, of whom 39 million are blind. The pathogenesis of many eye diseases remains poorly understood. The human eye is currently an emerging proteome that may provide key insight into the biological pathways of disease. We review proteomic investigations of the human eye and present a catalogue of 4842 nonredundant proteins identified in human eye tissues and biofluids to date. We highlight the need to identify new biomarkers for eye diseases using proteomics. Recent advances in proteomics do now allow the identification of hundreds to thousands of proteins in tissues and fluids, characterization of various PTMs and simultaneous quantification of multiple proteins. To facilitate proteomic studies of the eye, the Human Eye Proteome Project (HEPP) was organized in September 2012. The HEPP is one of the most recent components of the Biology/Disease-driven Human Proteome Project (B/D-HPP) whose overarching goal is to support the broad application of state-of-the-art measurements of proteins and proteomes by life scientists studying the molecular mechanisms of biological processes and human disease. The large repertoire of investigative proteomic tools has great potential to transform vision science and enhance understanding of physiology and disease processes that affect sight.

  19. Longitudinal chromatic aberration of the human infant eye.

    PubMed

    Wang, Jingyun; Candy, T Rowan; Teel, Danielle F W; Jacobs, Robert J

    2008-09-01

    Although the longitudinal chromatic aberration (LCA) of the adult eye has been studied, there are no data collected from the human infant eye. A chromatic retinoscope was used to measure cyclopleged infant and adult refractions with four pseudomonochromatic sources (centered at 472, 538, 589, and 652 nm) and with polychromatic light. The LCA of the infant eyes between 472 and 652 nm was a factor of 1.7 greater than the LCA found in the adult group: infant mean=1.62 D, SD+/- 0.14 D; adult mean=0.96 D, SD+/- 0.17 D. The elevated level of LCA in infant eyes is consistent with the greater optical power of the immature eye and indicates similar chromatic dispersion in infant and adult eyes. The implications for visual performance, defocus detection, and measurement of refraction are discussed.

  20. Simultaneous stereoinversion and isomerization at the Asp-4 residue in βB2-crystallin from the aged human eye lenses.

    PubMed

    Fujii, Norihiko; Kawaguchi, Takehiro; Sasaki, Hiroshi; Fujii, Noriko

    2011-10-11

    The lens proteins are composed of α-, β-, and γ-crystallins that interact with each other to maintain the transparency and refractive power of the lens. Because the lens crystallins are long-lived proteins, they undergo various post-translational modifications including racemization, isomerization, deamidation, oxidation, glycation, and truncation. In βB2-crystallin, which is the most abundant β-crystallin, the deamidation of asparagine and glutamine residues has been reported. Here, we found that the aspartyl (Asp) residue at position 4 of βB2-crystallin in the lenses of elderly human individuals undergoes a significant degree of inversion and isomerization to the biologically uncommon residue D-β-Asp. Surprisingly, the D/L ratio of β-Asp at position 4 in βB2-crystallin from elderly donors (67-77 year old) was 0.88-3.21. A D/L ratio of amino acids greater than 1.0 is defined as an inversion of configuration from the L- to D-form, rather than a racemization. These extremely high D/L ratios are equivalent to those of Asp-58 and Asp-151 (D/L ratio: 3.1 for Asp-58 and 5.7 for Asp-151) in αA-crystallin from elderly donors (~80 year old) as reported previously. Initially, we identified specific Asp residues in the β-crystallin family of proteins that undergo a high degree of inversion. These results show that the isomerization and inversion of Asp residues occurs both in the α- and β-crystallins of the lens. Inversion of these Asp residues directly affects the higher order structure of the protein. Hence, this modification may change crystallin-crystallin interactions and disrupt the function of crystallins in the lens.

  1. Distribution of galanin receptors in the human eye.

    PubMed

    Schrödl, Falk; Kaser-Eichberger, Alexandra; Trost, Andrea; Strohmaier, Clemens; Bogner, Barbara; Runge, Christian; Bruckner, Daniela; Motloch, Karolina; Holub, Barbara; Kofler, Barbara; Reitsamer, Herbert A

    2015-09-01

    The neuropeptide galanin (GAL) is widely distributed within intrinsic and extrinsic sources supplying the eye. It is involved in regulation of the vascular tone, thus important for ocular homeostasis. Since the presence/distribution of its receptors is unknown, we here screen for the presence of the various GAL receptors in the human eye. Meeting the Helsinki-Declaration, human eyes (n = 6; 45-83 years of age, of both sex, post mortem time 10-19 h) were obtained from the cornea bank and prepared for immunohistochemistry against GAL receptors 1-3 (GALR1-GALR3). Over-expressing cell assays served as positive controls and confocal laser-scanning microscopy was used for documentation. Cell assays reliably detected immunoreactivity for GALR1-3 and cross-reactions between antibodies used were not observed. In the cornea, GALR1-3 were detected in basal layers of the epithelium, stroma, endothelium, as well as in adjacent conjunctiva. In the iris, GALR1-3 were detected in iris sphincter and dilator, while iris vessels displayed immunoreactivity for GALR1 and GALR3. In the ciliary body, GALR1 was exclusively found in the non-pigmented epithelium while GALR3 was detected in the ciliary muscle and vessels. In the retina, GALR1 was present in fibers of the IPL, OPL, NFL, many cells of the INL and few cells of the ONL. GALR2 and GALR3 were present in few neurons of the INL, while GALR2 was also found surrounding retinal vessels. RPE displayed weak immunoreactivity for GALR2 but intense immunoreactivity for GALR3. In the choroid, GALR1-3 were detectable in intrinsic choroidal neurons and nerve fibers of the choroidal stroma, and all three receptors were detected surrounding choroidal blood vessels, while the choriocapillaris was immunoreactive for GALR3 only. This is the first report of the various GALRs in the human eye. While the presence of GALRs in cornea and conjunctiva might be relevant for wound healing or inflammatory processes, the detection in iris vessels (GALR1, 2

  2. Kids Should Be Screened for Lazy Eye by Age 5

    MedlinePlus

    ... affected, the experts said. With lazy eye, the brain and one eye don't communicate properly. Symptoms may include a wandering eye, eyes that don't seem to work together, or poor depth perception, the experts explained. It's estimated that up to ...

  3. P gene as an inherited biomarker of human eye color.

    PubMed

    Rebbeck, Timothy R; Kanetsky, Peter A; Walker, Amy H; Holmes, Robin; Halpern, Allan C; Schuchter, Lynn M; Elder, David E; Guerry, DuPont

    2002-08-01

    Human pigmentation, including eye color, has been associated with skin cancer risk. The P gene is the human homologue to the mouse pink-eye dilution locus and is responsible for oculocutaneous albinism type 2 and other phenotypes that confer eye hypopigmentation. The P gene is located on chromosome 15q11.2-q12, which is also the location of a putative eye pigmentation gene (EYCL3) inferred to exist by linkage analysis. Therefore, the P gene is a strong candidate for determination of human eye color. Using a sample of 629 normally pigmented individuals, we found that individuals were less likely to have blue or gray eyes if they had P gene variants Arg305Trp (P = 0.002), Arg419Gln (P = 0.001), or the combination of both variants (P = 0.003). These results suggest that P gene, in part, determines normal phenotypic variation in human eye color and may therefore represent an inherited biomarker of cutaneous cancer risk.

  4. Cortexin diffusion in human eye sclera

    SciTech Connect

    Genina, Elina A; Bashkatov, A N; Tuchin, Valerii V; Ghosn, M G; Larin, Kirill V; Kamenskikh, T G

    2011-05-31

    Investigation of the diffusion of cytamines, a typical representative of which is cortexin, is important for evaluating the drug dose, necessary to provide sufficient concentration of the preparation in the inner tissues of the eye. In the present paper, the cortexin diffusion rate in the eye sclera is measured using the methods of optical coherence tomography (OCT) and reflectance spectroscopy. The technique for determining the diffusion coefficient is based on the registration of temporal dependence of the eye sclera scattering parameters caused by partial replacement of interstitial fluid with the aqueous cortexin solution, which reduces the level of the OCT signal and decreases the reflectance of the sclera. The values of the cortexin diffusion coefficient obtained using two independent optical methods are in good agreement. (optical technologies in biophysics and medicine)

  5. A real-life illusion of assimilation in the human face: eye size illusion caused by eyebrows and eye shadow.

    PubMed

    Morikawa, Kazunori; Matsushita, Soyogu; Tomita, Akitoshi; Yamanami, Haruna

    2015-01-01

    Does an assimilative illusion like the Delboeuf illusion occur in the human face? We investigated factors that might influence the perceived size of the eyes in a realistic face. Experiment 1 manipulated the position of the eyebrows (high or low), the presence/absence of eye shadow, and the viewing distance (0.6 m or 5 m), then measured the perceived eye size using a psychophysical method. The results showed that low eyebrows (i.e., closer to the eyes) make the eyes appear larger, suggesting that the assimilation of eyes into the eyebrows is stronger when the eye-eyebrow distance is shorter. The results also demonstrated that the application of eye shadow also makes the eyes look larger. Moreover, the effect of eye shadow is more pronounced when viewed from a distance. In order to investigate the mechanism of the eye size illusion demonstrated in Experiment 1, Experiment 2 measured the magnitude of the Delboeuf illusion at a viewing distance of 0.6 m or 5 m, with or without gray gradation simulating the eye shadow that was used in Experiment 1. The experiment demonstrated that the Delboeuf illusion is modulated by viewing distance and gradation in the same way as the eye size illusion. These results suggest that the eye size illusion induced by the eyebrows and the Delboeuf illusion involve the same mechanism, and that eye shadow causes the assimilation of the eyes into itself and enhances assimilation between the eyes and the eyebrows.

  6. Arctic Engineering--Through Human Eyes.

    ERIC Educational Resources Information Center

    Simmonds, W. H. C.

    Adopting technology to people and examining projects through the eyes of those concerned are two ways new technology and engineering can be installed and successfully operated under the adverse conditions of northern Canada and in the face of predicted labor shortages in the 1980's. Adopting a more flexible technology provides the opportunity for…

  7. Human amygdala activation during rapid eye movements of rapid eye movement sleep: an intracranial study.

    PubMed

    Corsi-Cabrera, María; Velasco, Francisco; Del Río-Portilla, Yolanda; Armony, Jorge L; Trejo-Martínez, David; Guevara, Miguel A; Velasco, Ana L

    2016-10-01

    The amygdaloid complex plays a crucial role in processing emotional signals and in the formation of emotional memories. Neuroimaging studies have shown human amygdala activation during rapid eye movement sleep (REM). Stereotactically implanted electrodes for presurgical evaluation in epileptic patients provide a unique opportunity to directly record amygdala activity. The present study analysed amygdala activity associated with REM sleep eye movements on the millisecond scale. We propose that phasic activation associated with rapid eye movements may provide the amygdala with endogenous excitation during REM sleep. Standard polysomnography and stereo-electroencephalograph (SEEG) were recorded simultaneously during spontaneous sleep in the left amygdala of four patients. Time-frequency analysis and absolute power of gamma activity were obtained for 250 ms time windows preceding and following eye movement onset in REM sleep, and in spontaneous waking eye movements in the dark. Absolute power of the 44-48 Hz band increased significantly during the 250 ms time window after REM sleep rapid eye movements onset, but not during waking eye movements. Transient activation of the amygdala provides physiological support for the proposed participation of the amygdala in emotional expression, in the emotional content of dreams and for the reactivation and consolidation of emotional memories during REM sleep, as well as for next-day emotional regulation, and its possible role in the bidirectional interaction between REM sleep and such sleep disorders as nightmares, anxiety and post-traumatic sleep disorder. These results provide unique, direct evidence of increased activation of the human amygdala time-locked to REM sleep rapid eye movements.

  8. Anatomy of the lamina cribrosa in human eyes.

    PubMed

    Radius, R L; Gonzales, M

    1981-12-01

    Light microscopy of specimens of human eyes cut in cross section at the level of the lamina cribrosa showed variation in structural anatomy, as demonstrated previously in certain primate eyes. Connective tissue and glial cell structural elements were greater in nasal-temporal as compared with inferior and superior quadrants of the disc. This regional variation suggests a hypothesis for the specificity of early patterns of optic nerve dysfunction characteristic of glaucomatous optic neuropathy. In glaucomatous eyes, nerve head regions with relatively less structural tissue elements may yield early to detrimental effects of persistent pressure elevation.

  9. Complex spectral OCT in human eye imaging in vivo

    NASA Astrophysics Data System (ADS)

    Targowski, Piotr; Wojtkowski, Maciej; Kowalczyk, Andrzej; Bajraszewski, Tomasz; Szkulmowski, Maciej; Gorczyńska, Iwona

    2004-01-01

    Complex spectral optical coherence tomography in comparison to spectral optical coherence tomography produces images free of parasitic terms with extended measurement range. This technique requires stability of the object during at least three consecutive measurements. In this paper we present how to improve this technique to make measurements less sensitive to involuntary eye movements. The first images of human skin and anterior chamber of the eye in vivo based on complex spectral optical coherence tomography are presented.

  10. Genetic analyses of the human eye colours using a novel objective method for eye colour classification.

    PubMed

    Andersen, Jeppe D; Johansen, Peter; Harder, Stine; Christoffersen, Susanne R; Delgado, Mikaela C; Henriksen, Sarah T; Nielsen, Mette M; Sørensen, Erik; Ullum, Henrik; Hansen, Thomas; Dahl, Anders L; Paulsen, Rasmus R; Børsting, Claus; Morling, Niels

    2013-09-01

    In this study, we present a new objective method for measuring the eye colour on a continuous scale that allows researchers to associate genetic markers with different shades of eye colour. With the use of the custom designed software Digital Iris Analysis Tool (DIAT), the iris was automatically identified and extracted from high resolution digital images. DIAT was made user friendly with a graphical user interface. The software counted the number of blue and brown pixels in the iris image and calculated a Pixel Index of the Eye (PIE-score) that described the eye colour quantitatively. The PIE-score ranged from -1 to 1 (brown to blue). The software eliminated the need for user based interpretation and qualitative eye colour categories. In 94% (570) of 605 analyzed eye images, the iris region was successfully extracted and a PIE-score was calculated. A very high correlation between the PIE-score and the human perception of eye colour was observed. The correlations between the PIE-scores and the six IrisPlex SNPs (HERC2 rs12913832, OCA2 rs1800407, SLC24A4 rs12896399, TYR rs1393350, SLC45A2 rs16891982 and IRF4 rs12203592) were analyzed in 570 individuals. Significant differences (p<10(-6)) in the PIE-scores of the individuals typed as HERC2 rs12913832 G (PIE=0.99) and rs12913832 GA (PIE=-0.71) or A (PIE=-0.87) were observed. We adjusted for the effect of HERC2 rs12913832 and showed that the quantitative PIE-scores were significantly associated with SNPs with minor effects (OCA2 rs1800407, SLC24A4 rs12896399 and TYR rs1393350) on the eye colour. We evaluated the two published prediction models for eye colour (IrisPlex [1] and Snipper[2]) and compared the predictions with the PIE-scores. We found good concordance with the prediction from individuals typed as HERC2 rs12913832 G. However, both methods had difficulties in categorizing individuals typed as HERC2 rs12913832 GA because of the large variation in eye colour in HERC2 rs12913832 GA individuals. With the use of

  11. Objective evaluation of the visual acuity in human eyes

    NASA Astrophysics Data System (ADS)

    Rosales, M. A.; López-Olazagasti, E.; Ramírez-Zavaleta, G.; Varillas, G.; Tepichín, E.

    2009-08-01

    Traditionally, the quality of the human vision is evaluated by a subjective test in which the examiner asks the patient to read a series of characters of different sizes, located at a certain distance of the patient. Typically, we need to ensure a subtended angle of vision of 5 minutes, which implies an object of 8.8 mm high located at 6 meters (normal or 20/20 visual acuity). These characters constitute what is known as the Snellen chart, universally used to evaluate the spatial resolution of the human eyes. The mentioned process of identification of characters is carried out by means of the eye - brain system, giving an evaluation of the subjective visual performance. In this work we consider the eye as an isolated image-forming system, and show that it is possible to isolate the function of the eye from that of the brain in this process. By knowing the impulse response of the eye´s system we can obtain, in advance, the image of the Snellen chart simultaneously. From this information, we obtain the objective performance of the eye as the optical system under test. This type of results might help to detect anomalous situations of the human vision, like the so called "cerebral myopia".

  12. Reliance on head versus eyes in the gaze following of great apes and human infants: the cooperative eye hypothesis.

    PubMed

    Tomasello, Michael; Hare, Brian; Lehmann, Hagen; Call, Josep

    2007-03-01

    As compared with other primates, humans have especially visible eyes (e.g., white sclera). One hypothesis is that this feature of human eyes evolved to make it easier for conspecifics to follow an individual's gaze direction in close-range joint attentional and communicative interactions, which would seem to imply especially cooperative (mututalistic) conspecifics. In the current study, we tested one aspect of this cooperative eye hypothesis by comparing the gaze following behavior of great apes to that of human infants. A human experimenter "looked" to the ceiling either with his eyes only, head only (eyes closed), both head and eyes, or neither. Great apes followed gaze to the ceiling based mainly on the human's head direction (although eye direction played some role as well). In contrast, human infants relied almost exclusively on eye direction in these same situations. These results demonstrate that humans are especially reliant on eyes in gaze following situations, and thus, suggest that eyes evolved a new social function in human evolution, most likely to support cooperative (mututalistic) social interactions.

  13. Human eye colour and HERC2, OCA2 and MATP.

    PubMed

    Mengel-From, Jonas; Børsting, Claus; Sanchez, Juan J; Eiberg, Hans; Morling, Niels

    2010-10-01

    Prediction of human eye colour by forensic genetic methods is of great value in certain crime investigations. Strong associations between blue/brown eye colour and the SNP loci rs1129038 and rs12913832 in the HERC2 gene were recently described. Weaker associations between eye colour and other genetic markers also exist. In 395 randomly selected Danes, we investigated the predictive values of various combinations of SNP alleles in the HERC2, OCA2 and MATP (SLC45A2) genes and compared the results to the eye colours as they were described by the individuals themselves. The highest predictive value of typing either the HERC2 SNPs rs1129038 and/or rs12913832 that are in strong linkage disequilibrium was observed when eye colour was divided into two groups, (1) blue, grey and green (light) and (2) brown and hazel (dark). Sequence variations in rs11636232 and rs7170852 in HERC2, rs1800407 in OCA2 and rs16891982 in MATP showed additional association with eye colours in addition to the effect of HERC2 rs1129038. Diplotype analysis of three sequence variations in HERC2 and one sequence variation in OCA2 showed the best discrimination between light and dark eye colours with a likelihood ratio of 29.3.

  14. Photolithography for the static compensation of human eye aberrations

    NASA Astrophysics Data System (ADS)

    Bara, Salvador; Jaroszewicz, Zbigniew

    2004-08-01

    Recent developments in human eye aberration measurements allow to design and fabricate compensating elements aiming to achieve aberration-limited imaging. This is important not merely from a subject's viewpoint (improving the sharpness of the outer world images formed at the retina) but mainly for clinical instrumentation purposes, especially those dealing with high-resolution retinal imaging (eye fundus cameras, scanning laser ophtlalmosopes, etc.). Here we report recent developments in the correction of the static component of the eye aberrations. Aberration data of several subjects were used for manufacturing personally customized phase plates designed to compensate for the wave aberration in the human eye. These plates were made by gray-level single-mask photosculpture in photoresist and then placed in front of the eye. The effects of misalignments as well as the strategy to design wide-field correcting elements are briefly revised. Applications include improving images in scanning laser ophtalmoscopes. The future plans of research including application of axicons for compensation of the lack of accommodation and kinoforms cancelling high amounts of eye's aberrations in monochromatic illumination are also sketched.

  15. The proteomes of the human eye, a highly compartmentalized organ

    PubMed Central

    Omenn, Gilbert S.

    2017-01-01

    Proteomics has now published a series of Dataset Briefs on the EyeOme from the HUPO Human Proteome Project with high-quality analyses of the proteomes of these compartments of the human eye: retina, iris, ciliary body, retinal pigment epithelium/choroid, retrobulbar optic nerve, and sclera, with 3436, 2929, 2867, 2755, 2711, and 1945 proteins, respectively. These proteomics resources represent a useful starting point for a broad range of research aimed at developing preventive and therapeutic interventions for the various causes of blindness. PMID:27860232

  16. Monitoring the accumulation of lipofuscin in aging murine eyes by fluorescence spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The integrated fluorescence of murine eyes is collected as a function of age. This fluorescence is attributed to pigments generally referred to as lipofuscin and is observed to increase with age. No difference in fluorescence intensity is observed between the eyes of males or females. This work p...

  17. The eye lens: age-related trends and individual variations in refractive index and shape parameters

    PubMed Central

    Pierscionek, Barbara; Bahrami, Mehdi; Hoshino, Masato; Uesugi, Kentaro; Regini, Justyn; Yagi, Naoto

    2015-01-01

    The eye lens grows throughout life by cell accrual on its surface and can change shape to adjust the focussing power of the eye. Varying concentrations of proteins in successive cell layers create a refractive index gradient. The continued growth of the lens and age-related changes in proteins render it less able to alter shape with loss of capacity by the end of the sixth decade of life. Growth and protein ageing alter the refractive index but as accurate measurement of this parameter is difficult, the nature of such alterations remains uncertain. The most accurate method to date for measuring refractive index in intact lenses has been developed at the SPring-8 synchrotron. The technique, based on Talbot interferometry, has an X-ray source and was used to measure refractive index in sixty-six human lenses, aged from 16 to 91 years. Height and width were measured for forty-five lenses. Refractive index contours show decentration in some older lenses but individual variations mask age-related trends. Refractive index profiles along the optic axis have relatively flat central sections with distinct micro-fluctuations and a steep gradient in the cortex but do not exhibit an age-related trend. The refractive index profiles in the equatorial aspect show statistical significance with age, particularly for lenses below the age of sixty that had capacity to alter shape in vivo. The maximum refractive index in the lens centre decreases slightly with age with considerable scatter in the data and there are age-related variations in sagittal thickness and equatorial height. PMID:26416418

  18. Face and eye scanning in gorillas (Gorilla gorilla), orangutans (Pongo abelii), and humans (Homo sapiens): unique eye-viewing patterns in humans among hominids.

    PubMed

    Kano, Fumihiro; Call, Josep; Tomonaga, Masaki

    2012-11-01

    Because the faces and eyes of primates convey a rich array of social information, the way in which primates view faces and eyes reflects species-specific strategies for facial communication. How are humans and closely related species such as great apes similar and different in their viewing patterns for faces and eyes? Following previous studies comparing chimpanzees (Pan troglodytes) with humans (Homo sapiens), this study used the eye-tracking method to directly compare the patterns of face and eye scanning by humans, gorillas (Gorilla gorilla), and orangutans (Pongo abelii). Human and ape participants freely viewed pictures of whole bodies and full faces of conspecifics and allospecifics under the same experimental conditions. All species were strikingly similar in that they viewed predominantly faces and eyes. No particular difference was identified between gorillas and orangutans, and they also did not differ from the chimpanzees tested in previous studies. However, humans were somewhat different from apes, especially with respect to prolonged eye viewing. We also examined how species-specific facial morphologies, such as the male flange of orangutans and the black-white contrast of human eyes, affected viewing patterns. Whereas the male flange of orangutans affected viewing patterns, the color contrast of human eyes did not. Humans showed prolonged eye viewing independently of the eye color of presented faces, indicating that this pattern is internally driven rather than stimulus dependent. Overall, the results show general similarities among the species and also identify unique eye-viewing patterns in humans.

  19. Aqueous Angiography–Mediated Guidance of Trabecular Bypass Improves Angiographic Outflow in Human Enucleated Eyes

    PubMed Central

    Huang, Alex S.; Saraswathy, Sindhu; Dastiridou, Anna; Begian, Alan; Mohindroo, Chirayu; Tan, James C. H.; Francis, Brian A.; Hinton, David R.; Weinreb, Robert N.

    2016-01-01

    Purpose To assess the ability of trabecular micro-bypass stents to improve aqueous humor outflow (AHO) in regions initially devoid of AHO as assessed by aqueous angiography. Methods Enucleated human eyes (14 total from 7 males and 3 females [ages 52–84]) were obtained from an eye bank within 48 hours of death. Eyes were oriented by inferior oblique insertion, and aqueous angiography was performed with indocyanine green (ICG; 0.4%) or fluorescein (2.5%) at 10 mm Hg. With an angiographer, infrared and fluorescent images were acquired. Concurrent anterior segment optical coherence tomography (OCT) was performed, and fixable fluorescent dextrans were introduced into the eye for histologic analysis of angiographically positive and negative areas. Experimentally, some eyes (n = 11) first received ICG aqueous angiography to determine angiographic patterns. These eyes then underwent trabecular micro-bypass sham or stent placement in regions initially devoid of angiographic signal. This was followed by fluorescein aqueous angiography to query the effects. Results Aqueous angiography in human eyes yielded high-quality images with segmental patterns. Distally, angiographically positive but not negative areas demonstrated intrascleral lumens on OCT images. Aqueous angiography with fluorescent dextrans led to their trapping in AHO pathways. Trabecular bypass but not sham in regions initially devoid of ICG aqueous angiography led to increased aqueous angiography as assessed by fluorescein (P = 0.043). Conclusions Using sequential aqueous angiography in an enucleated human eye model system, regions initially without angiographic flow or signal could be recruited for AHO using a trabecular bypass stent. PMID:27588614

  20. Using the Human Eye to Characterize Displays

    NASA Technical Reports Server (NTRS)

    Gille, Jennifer; Larimer, James

    2001-01-01

    Monitor characterization has taken on new importance for non-professional users, who are not usually equipped to make photometric measurements. Our purpose was to examine some of the visual judgments used in characterization schemes that have been proposed for web users. We studied adjusting brightness to set the black level, banding effects due to digitization, and gamma estimation in the light and in the dark, and a color-matching task in the light, on a desktop CRT and a laptop LCD. Observers demonstrated the sensitivity of the visual system for comparative judgments in black-level adjustment, banding visibility, and gamma estimation. The results of the color-matching task were ambiguous. In the brightness adjustment task, the action of the adjustment was not as presumed; however, perceptual judgments were as expected under the actual conditions. When the gamma estimates of observers were compared to photometric measurements, problems with the definition of gamma were identified. Information about absolute light levels that would be important for characterizing a display, given the shortcomings of gamma in measuring apparent contrast, are not measurable by eye alone. The LCD was not studied as extensively as the CRT because of viewing-angle problems, and its transfer function did not follow a power law, rendering gamma estimation meaningless.

  1. Using the Human Eye to Characterize Displays

    NASA Technical Reports Server (NTRS)

    Gille, Jennifer; Larimer, James; Rutkowski, Michael (Technical Monitor)

    2001-01-01

    Monitor characterization has taken on new importance for non-professional users, who are not usually equipped to make photometric measurements. We studied adjusting brightness to set the black level, banding effects due to digitization, and gamma estimation in the light and in the dark, and a color-matching task in the light, on a desktop CRT (Cathode-Ray Tube) and a laptop LCD (Liquid Crystal Display). Observers demonstrated the sensitivity of the visual system for comparative judgments in black-level adjustment, banding visibility, and gamma estimation. The results of the color-matching task were ambiguous. In the brightness adjustment task, the action of the adjustment was not as presumed; however, perceptual judgments were as expected under the actual conditions. When the gamma estimates of observers were compared to photometric measurements, problems with the definition of gamma were identified. Information about absolute light levels that would be important for characterizing a displays, given the shortcomings of gamma in measuring apparent contrast, are not measurable by eye alone. The LCD was not studied as extensively as the CRT because of viewing-angle problems, and its transfer function did not follow a power law, rendering gamma estimation meaningless.

  2. Keep an eye on human resources 'yardsticks'.

    PubMed

    McKimmy, D L

    1979-01-01

    By monitoring certain human resources "yardsticks", personnel administrators can demonstrate the results of institutional and departmental goals and objectives. Thus, taking an economic approach to personnel management can help the hospital in the struggle to contain costs.

  3. Differential gene expression in anatomical compartments of the human eye

    PubMed Central

    Diehn, Jennifer J; Diehn, Maximilian; Marmor, Michael F; Brown, Patrick O

    2005-01-01

    Background The human eye is composed of multiple compartments, diverse in form, function, and embryologic origin, that work in concert to provide us with our sense of sight. We set out to systematically characterize the global gene expression patterns that specify the distinctive characteristics of the various eye compartments. Results We used DNA microarrays representing approximately 30,000 human genes to analyze gene expression in the cornea, lens, iris, ciliary body, retina, and optic nerve. The distinctive patterns of expression in each compartment could be interpreted in relation to the physiology and cellular composition of each tissue. Notably, the sets of genes selectively expressed in the retina and in the lens were particularly large and diverse. Genes with roles in immune defense, particularly complement components, were expressed at especially high levels in the anterior segment tissues. We also found consistent differences between the gene expression patterns of the macula and peripheral retina, paralleling the differences in cell layer densities between these regions. Based on the hypothesis that genes responsible for diseases that affect a particular eye compartment are likely to be selectively expressed in that compartment, we compared our gene expression signatures with genetic mapping studies to identify candidate genes for diseases affecting the cornea, lens, and retina. Conclusion Through genome-scale gene expression profiling, we were able to discover distinct gene expression 'signatures' for each eye compartment and identified candidate disease genes that can serve as a reference database for investigating the physiology and pathophysiology of the eye. PMID:16168081

  4. Model of the Human Eye Based on ABCD Matrix

    NASA Astrophysics Data System (ADS)

    González, G. Díaz; Castillo, M. David Iturbe

    2008-04-01

    At the moment several models of the human eye exist, nevertheless the gradient index models of the human lens (crystalline) have received little attention in optometry and vision sciences, although they consider how the refractive index and the refracting power can change with the accommodation. On the other hand, in study fields like ophthalmology and optometry, exist cases where there is a lack of information about the factors that influence the change of refractive power and therefore the focal length of the eye. By such reason, in this paper we present a model of the human eye based on the ABCD matrix in order to describe the propagation of light rays, that can be understood by professional people in optics, ophthalmology and optometry, and the dispersions of the different ocular mediums are taken into account,. The aim of the model is to obtain data about the refractive power of the eye under different considerations, such as: changes in wavelength, radius of curvature and thicknesses of the ocular mediums. We present results of simulations in Matlab of our model, assuming that the object is punctual and is placed to a certain distance of the eye, and considering at the beginning to the crystalline like a medium with fixed refractive index, and after like a gradient lens. By means of graphs, we show the total refractive power of the eye and its form and type of dependence with respect to variations in radius of curvature and thicknesses of the cornea and crystalline, as well as variations in the thickness of the previous and later cameras.

  5. Variation of Laminar Depth in Normal Eyes With Age and Race

    PubMed Central

    Rhodes, Lindsay A.; Huisingh, Carrie; Johnstone, John; Fazio, Massimo; Smith, Brandon; Clark, Mark; Downs, J. Crawford; Owsley, Cynthia; Girard, Michael J. A.; Mari, Jean Martial; Girkin, Christopher

    2014-01-01

    Purpose. To determine if laminar depth (LD) and prelaminar tissue volume (PTV) are associated with age and race in healthy human eyes. Methods. Optic nerve head images from enhanced depth imaging spectral-domain optical coherence tomography of 166 normal eyes from 84 subjects of African descent (AD) and European descent (ED) were manually delineated to identify the principal surfaces: internal limiting membrane, Bruch's membrane (BM), anterior sclera (AS), and anterior surface of the lamina cribrosa. These four surfaces defined the LD and PTV using Bruch's membrane opening (BMO) and AS for reference structures. Generalized estimating equations were used to evaluate whether the effect of age on each outcome was differential by race. Results. When age was analyzed as a continuous variable, the interaction term between age and race was statistically significant for mean LDBMO (P = 0.015) and mean LDAS (P = 0.0062) after adjusting for axial length and BMO area. For every 1-year increase in age, the LDAS was greater on average by 1.78 μm in AD subjects and less by 1.71 μm in ED subjects. Mean PTV was lower in the older subjects (1248 × 106 μm3 AD, 881 × 106 μm3 ED) compared to the younger subjects (1316 × 106 μm3 AD, 1102 × 106 μm3 ED) in both groups. Conclusions. With increasing age, the LD changes differently across racial groups in normal subjects. The LD in ED subjects showed a significantly decreasing slope suggesting that the lamina moves anteriorly with age in this group. PMID:25414182

  6. Toward a digital camera to rival the human eye

    NASA Astrophysics Data System (ADS)

    Skorka, Orit; Joseph, Dileepan

    2011-07-01

    All things considered, electronic imaging systems do not rival the human visual system despite notable progress over 40 years since the invention of the CCD. This work presents a method that allows design engineers to evaluate the performance gap between a digital camera and the human eye. The method identifies limiting factors of the electronic systems by benchmarking against the human system. It considers power consumption, visual field, spatial resolution, temporal resolution, and properties related to signal and noise power. A figure of merit is defined as the performance gap of the weakest parameter. Experimental work done with observers and cadavers is reviewed to assess the parameters of the human eye, and assessment techniques are also covered for digital cameras. The method is applied to 24 modern image sensors of various types, where an ideal lens is assumed to complete a digital camera. Results indicate that dynamic range and dark limit are the most limiting factors. The substantial functional gap, from 1.6 to 4.5 orders of magnitude, between the human eye and digital cameras may arise from architectural differences between the human retina, arranged in a multiple-layer structure, and image sensors, mostly fabricated in planar technologies. Functionality of image sensors may be significantly improved by exploiting technologies that allow vertical stacking of active tiers.

  7. Physical model of human eye with implantable intraocular lenses

    NASA Astrophysics Data System (ADS)

    Barcik, Agnieszka; Nowak, Jerzy; Siedlecki, Damian; Zając, Marek; Zarówny, Józef

    2008-12-01

    An optomechanical model of human eye containing artificial cornea and a cuvette with immersion liquid is developed. An artificial implantable intraoculer lens (IOL) inserted into the cuvette stands for the eye crystalline lens. A special mechanical handle holding the IOL enables to move and rotate it thus simulationg possible errors during lens implantation procedure. The "retinal" image is recorded with the high resolution CCD camera. The image of Siemens star serves as qualitative measure of "retinal" image, while more quantitatively data come from Modulation Transfer Function obtained by the analysis of the images of sinusoidal tests generated on the computer screen. The whole eye model can be used for investigation of the impact of type and location of the IOL on the optical performance.

  8. Binocular micromovement recording of human eyes:--methods.

    PubMed

    Simon, F; Schulz, E; Rassow, B; Haase, W

    1984-01-01

    An apparatus is described for binocular recording of micromovements of human eyes, with the contact lens mirror technique used frequently. Horizontal and vertical micromovements of both eyes are recorded simultaneously by means of instruments measuring light-spot positions. Spatial resolution of the measuring instrument is 12 s of arc, while the time resolution is 0.5 ms for this apparatus. The fixation mark (Snellen character) is at a distance of 5 m without any restrictions to the view. The micromovement data are registered by a microcomputer. A second computer enables precise calculation of the results which are given as multicoloured graphs (X/Y-, X/t-graph, velocity/t-graph, frequency analysis, phase correlation of both eyes). In this way the requirements are met for the clinical application of this measuring instrument on patients.

  9. Different topological organization of human brain functional networks with eyes open versus eyes closed.

    PubMed

    Xu, Pengfei; Huang, Ruiwang; Wang, Jinhui; Van Dam, Nicholas T; Xie, Teng; Dong, Zhangye; Chen, Chunping; Gu, Ruolei; Zang, Yu-Feng; He, Yong; Fan, Jin; Luo, Yue-jia

    2014-04-15

    Opening and closing the eyes are fundamental behaviors for directing attention to the external versus internal world. However, it remains unclear whether the states of eyes-open (EO) relative to eyes-closed (EC) are associated with different topological organizations of functional neural networks for exteroceptive and interoceptive processing (processing the external world and internal state, respectively). Here, we used resting-state functional magnetic resonance imaging and neural network analysis to investigate the topological properties of functional networks of the human brain when the eyes were open versus closed. The brain networks exhibited higher cliquishness and local efficiency, but lower global efficiency during the EO state compared to the EC state. These properties suggest an increase in specialized information processing along with a decrease in integrated information processing in EO (vs. EC). More importantly, the "exteroceptive" network, including the attentional system (e.g., superior parietal gyrus and inferior parietal lobule), ocular motor system (e.g., precentral gyrus and superior frontal gyrus), and arousal system (e.g., insula and thalamus), showed higher regional nodal properties (nodal degree, efficiency and betweenness centrality) in EO relative to EC. In contrast, the "interoceptive" network, composed of visual system (e.g., lingual gyrus, fusiform gyrus and cuneus), auditory system (e.g., Heschl's gyurs), somatosensory system (e.g., postcentral gyrus), and part of the default mode network (e.g., angular gyrus and anterior cingulate gyrus), showed significantly higher regional properties in EC vs. EO. In addition, the connections across sensory modalities were altered by volitional eye opening. The synchronicity between the visual system and the motor, somatosensory and auditory systems, characteristic of EC, was attenuated in EO. Further, the connections between the visual system and the attention, arousal and subcortical systems were

  10. The Development of Fine-Grained Sensitivity to Eye Contact after 6 Years of Age

    ERIC Educational Resources Information Center

    Vida, Mark D.; Maurer, Daphne

    2012-01-01

    Adults use eye contact as a cue to the mental and emotional states of others. Here, we examined developmental changes in the ability to discriminate between eye contact and averted gaze. Children (6-, 8-, 10-, and 14-year-olds) and adults (n=18/age) viewed photographs of a model fixating the center of a camera lens and a series of positions to the…

  11. Age-dependent modulation of the somatosensory network upon eye closure.

    PubMed

    Brodoehl, Stefan; Klingner, Carsten; Witte, Otto W

    2016-02-01

    Eye closure even in complete darkness can improve somatosensory perception by switching the brain to a uni-sensory processing mode. This causes an increased information flow between the thalamus and the somatosensory cortex while decreasing modulation by the visual cortex. Previous work suggests that these modulations are age-dependent and that the benefit in somatosensory performance due to eye closing diminishes with age. The cause of this age-dependency and to what extent somatosensory processing is involved remains unclear. Therefore, we intended to characterize the underlying age-dependent modifications in the interaction and connectivity of different sensory networks caused by eye closure. We performed functional MR-imaging with tactile stimulation of the right hand under the conditions of opened and closed eyes in healthy young and elderly participants. Conditional Granger causality analysis was performed to assess the somatosensory and visual networks, including the thalamus. Independent of age, eye closure improved the information transfer from the thalamus to and within the somatosensory cortex. However, beyond that, we found an age-dependent recruitment strategy. Whereas young participants were characterized by an optimized information flow within the relays of the somatosensory network, elderly participants revealed a stronger modulatory influence of the visual network upon the somatosensory cortex. Our results demonstrate that the modulation of the somatosensory and visual networks by eye closure diminishes with age and that the dominance of the visual system is more pronounced in the aging brain.

  12. Evaluation of peripheral fundus autofluorescence in eyes with wet age-related macular degeneration

    PubMed Central

    Suetsugu, Tetsuyuki; Kato, Aki; Yoshida, Munenori; Yasukawa, Tsutomu; Nishiwaki, Akiko; Hasegawa, Norio; Usui, Hideaki; Ogura, Yuichiro

    2016-01-01

    Purpose We aimed to evaluate the prevalence of abnormal peripheral fundus autofluorescence (FAF) in wet age-related macular degeneration (AMD) using wide-field imaging instrument. Patients and methods A retrospective, case-controlled study involving 66 eyes of 46 Japanese wet AMD patients and 32 eyes of 20 control patients was performed. Wide-field FAF images were obtained for typical AMD (37 eyes/28 patients), polypoidal choroidal vasculopathy (PCV) (22 eyes/20 patients), and retinal angiomatous proliferation (RAP) (seven eyes/four patients). Two masked ophthalmologists independently graded the images for mottled, granular, and nummular patterns. Main outcome measures were abnormal peripheral FAF frequencies and relative risks by disease subgroups and treatments. Results Abnormal peripheral FAF patterns were found in 51.5% of wet AMD eyes compared with 18.8% of control eyes (P<0.001). Mottled, granular, and nummular patterns were found in 45.5%, 31.8%, and 16.7%, respectively, of wet AMD eyes. Each disease subgroup (typical AMD, 54.1%; PCV, 36.4%; and RAP, 85.7%) showed significantly higher frequencies of peripheral FAF (P<0.001, P=0.03, and P<0.001, respectively) than control eyes (18.8%). There were no significant differences (P=0.76) between the frequencies in untreated and treated eyes. Conclusion Eyes of Japanese wet AMD patients had a higher abnormal FAF prevalence compared with control eyes. Among the three disease subtypes, abnormal patterns were least prevalent in PCV eyes. PMID:28008222

  13. Insect-Human Hybrid Eye (IHHE): an adaptive optofluidic lens combining the structural characteristics of insect and human eyes.

    PubMed

    Wei, Kang; Zeng, Hansong; Zhao, Yi

    2014-09-21

    Insect compound eyes and human camera eyes are two exquisite optical systems created by nature. The compound eye boasts an angle of view (AOV) up to 180° thanks to its hemispherical arrangement of hundreds of prime microscale lenses. The camera eye, on the other hand, can change shape to focus on objects at various depths, yet accepts light within a smaller AOV. Imitations of either imaging system have been abundant but with limited success. Here, we describe a reconfigurable polymeric optofluidic device that combines the architectural merits of both vision mechanisms, featuring a large AOV (up to 120°) with adaptive focusing capabilities (from 0 to 275 diopter (D)). This device consists of bi-layered microfluidics: an array of millimeter-sized fluidic lenses is integrated into the top layer and arranged on an elastomeric membrane embedded within the bottom layer. The membrane can be deformed from a planar surface into a series of dome-shaped geometries, rearranging individual fluidic lenses in desired curvilinear layouts. Meanwhile, each fluidic lens can vary its radius of curvature for a monocular depth sensation. Such a design presents a new perspective of tunable optofluidics for a broad range of applications, such as robotic vision and medical laparoendoscopy, where adaptive focalization with a large viewing angle is a clear advantage.

  14. Chromatic-Spatial Vision of the Aging Eye

    NASA Astrophysics Data System (ADS)

    Werner, John S.; Delahunt, Peter B.; Hardy, Joseph L.

    2004-07-01

    The human visual system undergoes continuous anatomical, physiological and functional changes throughout the life span. There is also continuous change in the spectral distribution and intensity of light reaching the retina from infancy through senescence, primarily due to changes in the absorption of short-wave light by the lens. Despite these changes in the retinal stimulus and the signals leaving the retina for perceptual analysis, color appearance is relatively stable during aging as measured by broadband reflective or self-luminous samples, the wavelengths of unique blue and yellow, and the achromatic locus. Measures of ocular media density for younger and older observers show, indeed, that color appearance is independent of ocular media density. This may be explained by a renormalization process that was demonstrated by measuring the chromaticity of the achromatic point before and after cataract surgery. There was a shift following cataract surgery (removal of a brunescent lens) that was initially toward yellow in color space, but over the course of months, drifted back in the direction of the achromatic point before surgery. The spatial characteristics of color mechanisms were quantified for younger and older observers in terms of chromatic perceptive fields and the chromatic contrast sensitivity functions. Younger and older observers differed with small spots or with chromatic spatial gratings near threshold, but there were no significant differences with larger spots or suprathreshold spatial gratings.

  15. Netarsudil Increases Outflow Facility in Human Eyes Through Multiple Mechanisms

    PubMed Central

    Ren, Ruiyi; Li, Guorong; Le, Thuy Duong; Kopczynski, Casey; Stamer, W. Daniel; Gong, Haiyan

    2016-01-01

    Purpose Netarsudil is a Rho kinase/norepinephrine transporter inhibitor currently in phase 3 clinical development for glaucoma treatment. We investigated the effects of its active metabolite, netarsudil-M1, on outflow facility (C), outflow hydrodynamics, and morphology of the conventional outflow pathway in enucleated human eyes. Methods Paired human eyes (n = 5) were perfused with either 0.3 μM netarsudil-M1 or vehicle solution at constant pressure (15 mm Hg). After 3 hours, fluorescent microspheres were added to perfusion media to trace the outflow patterns before perfusion-fixation. The percentage effective filtration length (PEFL) was calculated from the measured lengths of tracer distribution in the trabecular meshwork (TM), episcleral veins (ESVs), and along the inner wall (IW) of Schlemm's canal after global and confocal imaging. Morphologic changes along the trabecular outflow pathway were investigated by confocal, light, and electron microscopy. Results Perfusion with netarsudil-M1 significantly increased C when compared to baseline (51%, P < 0.01) and to paired controls (102%, P < 0.01), as well as significantly increased PEFL in both IW (P < 0.05) and ESVs (P < 0.01). In treated eyes, PEFL was significantly higher in ESVs than in the IW (P < 0.01) and was associated with increased cross-sectional area of ESVs (P < 0.01). Percentage effective filtration length in ESVs positively correlated with the percentage change in C (R2 = 0.58, P = 0.01). A significant increase in juxtacanalicular connective tissue (JCT) thickness (P < 0.05) was found in treated eyes compared to controls. Conclusions Netarsudil acutely increased C by expansion of the JCT and dilating the ESVs, which led to redistribution of aqueous outflow through a larger area of the IW and ESVs. PMID:27842161

  16. Eye-Specific IOP-Induced Displacements and Deformations of Human Lamina Cribrosa

    PubMed Central

    Sigal, Ian A.; Grimm, Jonathan L.; Jan, Ning-Jiun; Reid, Korey; Minckler, Don S.; Brown, Donald J.

    2014-01-01

    Purpose. To measure high-resolution eye-specific displacements and deformations induced within the human LC microstructure by an acute increase in IOP. Methods. Six eyes from donors aged 23 to 82 were scanned using second harmonic-generated (SHG) imaging at various levels of IOP from 10 to 50 mm Hg. An image registration technique was developed, tested, and used to find the deformation mapping between maximum intensity projection images acquired at low and elevated IOP. The mappings were analyzed to determine the magnitude and distribution of the IOP-induced displacements and deformations and contralateral similarity. Results. Images of the LC were obtained and the registration technique was successful. IOP increases produced substantial, and potentially biologically significant, levels of in-plane LC stretch and compression (reaching 10%–25% medians and 20%–30% 75th percentiles). Deformations were sometimes highly focal and concentrated in regions as small as a few pores. Regions of largest displacement, stretch, compression, and shear did not colocalize. Displacements and strains were not normally distributed. Contralateral eyes did not always have more similar responses to IOP than unrelated eyes. Under elevated IOP, some LC regions were under bi-axial stretch, others under bi-axial compression. Conclusions. We obtained eye-specific measurements of the complex effects of IOP on the LC with unprecedented resolution in uncut and unfixed human eyes. Our technique was robust to electronic and speckle noise. Elevated IOP produced substantial in-plane LC stretch and compression. Further research will explore the effects of IOP on the LC in a three-dimensional framework. PMID:24334450

  17. Polarization sensitive optical coherence tomography in the human eye

    PubMed Central

    Pircher, Michael; Hitzenberger, Christoph K.; Schmidt-Erfurth, Ursula

    2011-01-01

    Optical coherence tomography (OCT) has become a well established imaging tool in ophthalmology. The unprecedented depth resolution that is provided by this technique yields valuable information on different ocular tissues ranging from the anterior to the posterior eye segment. Polarization sensitive OCT (PS-OCT) extends the concept of OCT and utilizes the information that is carried by polarized light to obtain additional information on the tissue. Several structures in the eye (e.g. cornea, retinal nerve fiber layer, retinal pigment epithelium) alter the polarization state of the light and show therefore a tissue specific contrast in PS-OCT images. First this review outlines the basic concepts of polarization changing light–tissue interactions and gives a short introduction in PS-OCT instruments for ophthalmic imaging. In a second part a variety of different applications of this technique are presented in ocular imaging that are ranging from the anterior to the posterior eye segment. Finally the benefits of the method for imaging different diseases as, e.g., age related macula degeneration (AMD) or glaucoma is demonstrated. PMID:21729763

  18. Protect Your Eyes: Age-Related Macular Degeneration (AMD) Facts and Prevention Tips

    MedlinePlus

    PROTECT YOUR EYES Age-Related Macular Degeneration ( AMD ) FACTS & PREVENTION TIPS A LEADING CAUSE OF VISION LOSS IN THE U.S . AMD is a ... Black 2% Other 89% White As the population ages, the number of cases is expected to increase ...

  19. Eye movements reveal epistemic curiosity in human observers.

    PubMed

    Baranes, Adrien; Oudeyer, Pierre-Yves; Gottlieb, Jacqueline

    2015-12-01

    Saccadic (rapid) eye movements are primary means by which humans and non-human primates sample visual information. However, while saccadic decisions are intensively investigated in instrumental contexts where saccades guide subsequent actions, it is largely unknown how they may be influenced by curiosity - the intrinsic desire to learn. While saccades are sensitive to visual novelty and visual surprise, no study has examined their relation to epistemic curiosity - interest in symbolic, semantic information. To investigate this question, we tracked the eye movements of human observers while they read trivia questions and, after a brief delay, were visually given the answer. We show that higher curiosity was associated with earlier anticipatory orienting of gaze toward the answer location without changes in other metrics of saccades or fixations, and that these influences were distinct from those produced by variations in confidence and surprise. Across subjects, the enhancement of anticipatory gaze was correlated with measures of trait curiosity from personality questionnaires. Finally, a machine learning algorithm could predict curiosity in a cross-subject manner, relying primarily on statistical features of the gaze position before the answer onset and independently of covariations in confidence or surprise, suggesting potential practical applications for educational technologies, recommender systems and research in cognitive sciences. With this article, we provide full access to the annotated database allowing readers to reproduce the results. Epistemic curiosity produces specific effects on oculomotor anticipation that can be used to read out curiosity states.

  20. Immunohistochemical Detection of CTGF in the Human Eye.

    PubMed

    van Setten, Gysbert B; Trost, Andrea; Schrödl, Falk; Kaser-Eichberger, Alexandra; Bogner, Barbara; van Setten, Mercedes; Heindl, Ludwig M; Grabner, Günther; Reitsamer, Herbert A

    2016-12-01

    Purpose/Aim of the study: Connective tissue growth factor (CTGF) is a key player in the control of extracellular matrix remodeling, fibrosis, and angiogenesis. It is also involved in the modification of the trabecular meshwork, thus potentially modulating outflow facility and intraocular pressure (IOP). As a consequence, CTGF might be relevant for the development of elevated IOP, a major risk factor in glaucoma-pathogenesis. While comprehensive information on the origins of CTGF in the human eye is not available, the goal of this study is to identify ocular sources of CTGF using morphological methods.

  1. Comparative analysis of gene expression for convergent evolution of camera eye between octopus and human.

    PubMed

    Ogura, Atsushi; Ikeo, Kazuho; Gojobori, Takashi

    2004-08-01

    Although the camera eye of the octopus is very similar to that of humans, phylogenetic and embryological analyses have suggested that their camera eyes have been acquired independently. It has been known as a typical example of convergent evolution. To study the molecular basis of convergent evolution of camera eyes, we conducted a comparative analysis of gene expression in octopus and human camera eyes. We sequenced 16,432 ESTs of the octopus eye, leading to 1052 nonredundant genes that have matches in the protein database. Comparing these 1052 genes with 13,303 already-known ESTs of the human eye, 729 (69.3%) genes were commonly expressed between the human and octopus eyes. On the contrary, when we compared octopus eye ESTs with human connective tissue ESTs, the expression similarity was quite low. To trace the evolutionary changes that are potentially responsible for camera eye formation, we also compared octopus-eye ESTs with the completed genome sequences of other organisms. We found that 1019 out of the 1052 genes had already existed at the common ancestor of bilateria, and 875 genes were conserved between humans and octopuses. It suggests that a larger number of conserved genes and their similar gene expression may be responsible for the convergent evolution of the camera eye.

  2. Natural Images from the Birthplace of the Human Eye

    PubMed Central

    Tkačik, Gašper; Garrigan, Patrick; Ratliff, Charles; Milčinski, Grega; Klein, Jennifer M.; Seyfarth, Lucia H.; Sterling, Peter; Brainard, David H.; Balasubramanian, Vijay

    2011-01-01

    Here we introduce a database of calibrated natural images publicly available through an easy-to-use web interface. Using a Nikon D70 digital SLR camera, we acquired about six-megapixel images of Okavango Delta of Botswana, a tropical savanna habitat similar to where the human eye is thought to have evolved. Some sequences of images were captured unsystematically while following a baboon troop, while others were designed to vary a single parameter such as aperture, object distance, time of day or position on the horizon. Images are available in the raw RGB format and in grayscale. Images are also available in units relevant to the physiology of human cone photoreceptors, where pixel values represent the expected number of photoisomerizations per second for cones sensitive to long (L), medium (M) and short (S) wavelengths. This database is distributed under a Creative Commons Attribution-Noncommercial Unported license to facilitate research in computer vision, psychophysics of perception, and visual neuroscience. PMID:21698187

  3. Basic study of the portable fatigue meter: effects of illumination, distance from eyes and age.

    PubMed

    Hosokawa, T; Mikami, K; Saito, K

    1997-09-01

    Several aspects of a new, small and inexpensive fatigue assessment tool, the Portable Fatigue Meter (PFM), were studied. In the first experiment the effects of room illumination and distance between the PFM and the eyes on critical flicker fusion frequency (CFF) values were examined. The results revealed that the PFM CFF value varied significantly as a function of the distance between the indicator and the eyes, but it was not affected by room illumination. The effect of ageing on the PFM CFF value was assessed in a second experiment. The results suggested that PFM CFF values are significantly smaller in middle-aged females than in younger females.

  4. Age-related eye diseases: an emerging challenge for public health professionals.

    PubMed

    Gohdes, Dorothy M; Balamurugan, Appathurai; Larsen, Barbara A; Maylahn, Christopher

    2005-07-01

    In April 2004, The Eye Disease Prevalence Research Group published a series of articles that included age-specific estimates for the prevalence of low vision and blindness in whites, African Americans, and Hispanics living in the United States. Also included were age-, sex-, and ethnic-specific incidences of the following age-related eye diseases: diabetic retinopathy, macular degeneration, cataracts, and glaucoma. We reviewed the group's series of articles and highlighted key findings on the overall prevalence of and risk factors for age-related eye diseases, as well as opportunities to preserve and restore vision. We examined publications that show the public health impact of age-related eye diseases and the importance of projected increases in prevalence of low vision and blindness. Approximately 1 in 28 Americans aged older than 40 years is affected by low vision or blindness. Among community-dwelling adults, the prevalence of low vision and blindness increases dramatically with age in all racial and ethnic groups. Whites have higher rates of macular degeneration than African Americans, but glaucoma is more common among older African Americans. Between 2000 and 2020, the prevalence of blindness is expected to double. Age-related eye diseases are costly to treat, threaten the ability of older adults to live independently, and increase the risk for accidents and falls. To prevent vision loss and support rehabilitative services for people with low vision, it is imperative for the public health community to address the issue through surveillance, public education, and coordination of screening, examination, and treatment.

  5. Laser pointers and the human eye: a clinicopathologic study.

    PubMed

    Robertson, D M; Lim, T H; Salomao, D R; Link, T P; Rowe, R L; McLaren, J W

    2000-12-01

    We report the absence of photic retinal injury after exposing the retina to light from class 3A laser pointers for durations of up to 15 minutes. Three patients with uveal melanomas were scheduled to have an enucleation. Each agreed to have his or her retina exposed to laser light from a class 3A laser pointer prior to enucleation. Continuous exposure was directed to the fovea for 1 minute, to the retina 5 degrees below fixation for 5 minutes, and to the retina 5 degrees above fixation for 15 minutes. Ophthalmoscopic evaluation of the cornea, lens, and retina and fluorescein angiographic studies of the retina were conducted before, 24 hours after, and 11 days after laser exposure in the first case; before and 86 hours after exposure in the second case; and before, 96 hours after, and 15 days after exposure in the third case. Other than transient afterimages that lasted only a few minutes, we were unable to document any functional, ophthalmoscopic, fluorescein angiographic, or histologic evidence of damage to any structures of the eyes. Transmission electron microscopic studies of retinal sites targeted by the laser pointers in the second and third cases revealed ultrastructural abnormalities in the outer retina and the pigment epithelium that were similar to abnormalities seen in the retina approximately 8 mm away from the targeted sites. The risk to the human eye from transient exposure to light from commercially available class 3A laser pointers having powers of 1, 2, and 5 mW seems negligible.

  6. Photoreceptor disc shedding in the living human eye

    PubMed Central

    Kocaoglu, Omer P.; Liu, Zhuolin; Zhang, Furu; Kurokawa, Kazuhiro; Jonnal, Ravi S.; Miller, Donald T.

    2016-01-01

    Cone photoreceptors undergo a daily cycle of renewal and shedding of membranous discs in their outer segments (OS), the portion responsible for light capture. These physiological processes are fundamental to maintaining photoreceptor health, and their dysfunction is associated with numerous retinal diseases. While both processes have been extensively studied in animal models and postmortem eyes, little is known about them in the living eye, in particular human. In this study, we report discovery of the optical signature associated with disc shedding using a method based on adaptive optics optical coherence tomography (AO-OCT) in conjunction with post-processing methods to track and monitor individual cone cells in 4D. The optical signature of disc shedding is characterized by an abrupt transient loss in the cone outer segment tip (COST) reflection followed by its return that is axially displaced anteriorly. Using this signature, we measured the temporal and spatial properties of shedding events in three normal subjects. Average duration of the shedding event was 8.8 ± 13.4 minutes, and average length loss of the OS was 2.1 μm (7.0% of OS length). Prevalence of cone shedding was highest in the morning (14.3%) followed by the afternoon (5.7%) and evening (4.0%), with load distributed across the imaged patch. To the best of our knowledge these are the first images of photoreceptor disc shedding in the living retina. PMID:27895995

  7. Eye-spots in Lepidoptera attract attention in humans

    PubMed Central

    Yorzinski, Jessica L.; Platt, Michael L.; Adams, Geoffrey K.

    2015-01-01

    Many prey species exhibit defensive traits to decrease their chances of predation. Conspicuous eye-spots, concentric rings of contrasting colours, are one type of defensive trait that some species exhibit to deter predators. We examined the function of eye-spots in Lepidoptera to determine whether they are effective at deterring predators because they resemble eyes (‘eye mimicry hypothesis’) or are highly salient (‘conspicuous signal hypothesis’). We recorded the gaze behaviour of men and women as they viewed natural images of butterflies and moths as well as images in which the eye-spots of these insects were modified. The eye-spots were modified by removing them, scrambling their colours, or replacing them with elliptical or triangular shapes that had either dark or light centres. Participants were generally more likely to look at, spend more time looking at and be faster to first fixate the eye-spots of butterflies and moths that were natural compared with ones that were modified, including the elliptical eye-spots with dark centres that most resembled eyes as well as the scrambled eye-spots that had the same contrast as the natural eye-spots. Participants were most likely to look at eye-spots that were numerous, had a large surface area and were located close to the insects' heads. Participants' pupils were larger when viewing eye-spots compared with the rest of the insects' body, suggesting a greater arousal when viewing eye-spots. Our results provide some support for the conspicuous signal hypothesis (and minimal support for the eye mimicry hypothesis) and suggest that eye-spots may be effective at deterring predators because they are highly conspicuous signals that draw attention. PMID:26543589

  8. Aquaporin-1 Expression and Conventional Aqueous Outflow in Human Eyes

    PubMed Central

    Stamer, W. Daniel; Chan, Darren W.H.; Conley, Shannon M.; Coons, Serena; Ethier, C. Ross

    2008-01-01

    Aquaporin channels facilitate the enhanced permeability of secretory and absorptive tissues to water. In the conventional drainage tract, aquaporin-1 is expressed but its contribution to outflow facility is unknown. The purpose of the present study was to determine the effect of elevated aquaporin-1 expression by cells of the human conventional drainage pathway on outflow facility. Using thirteen pairs of human anterior segments in organ culture, we modified aquaporin-1 protein expression in outflow cells using adenovirus encoding human aquaporin-1. Contralateral anterior segments served as controls and were transduced with adenovirus encoding beta galactosidase. By confocal immunofluorescence microscopy, we observed that inner trabecular meshwork cells from anterior segments exposed to adenovirus (via injection into the inlet tubing during perfusion) had increased aquaporin-1 protein expression compared to endogenous levels. In contrast, elevation of aquaporin-1 protein in outer meshwork cells (juxtacanalicular region) and Schlemm’s canal required transduction of adenovirus into anterior segments using retroperfusion via episcleral veins. Regardless of exposure route, outflow facility of experimental segments was not different than control. Specifically, overexpression of aquaporin-1 in the inner meshwork resulted in an average facility change of −2.0 ± 9.2 %, while overexpression of aquaporin-1 in the resistance-generating region changed outflow facility by −3.2 ± 11.2 %. Taken together, these results indicate that a transcellular pathway, mediated by aquaporin-1, does not contribute significantly to bulk outflow through the conventional aqueous outflow tract of human eyes. PMID:18657536

  9. Eye Care Disparities and Health-Related Consequences in Elderly Patients with Age-Related Eye Disease.

    PubMed

    Umfress, Allison C; Brantley, Milam A

    2016-01-01

    The elderly population in the United States (age 65 and older) is growing rapidly, estimated by the U.S. Census Department to reach 83.7 million by 2050.(1) Visual impairment increases with age among all racial and ethnic groups.(2) In the elderly, the most common culprits for vision loss are cataract, glaucoma, and age-related macular degeneration (AMD).(2) In the developed world, vision loss from cataract has been dramatically reduced by increased access to cataract surgery. However, AMD and glaucoma lead to irreversible vision loss without early diagnosis and intervention. In the U.S., cases of AMD are expected to double by 2050, reaching 17.8 million among patients age 50 or older.(3) Similarly, cases of glaucoma are expected to reach 5.5 million by 2050, an increase of over 90% from 2014.(3) The visually impaired elderly face disparities in access to eye care, and subsequent general medical and psychosocial complications.

  10. More than meets the eye: age differences in the capture and suppression of oculomotor action.

    PubMed

    Ridderinkhof, K Richard; Wijnen, Jasper G

    2011-01-01

    Salient visual stimuli capture attention and trigger an eye-movement toward its location reflexively, regardless of an observer's intentions. Here we aim to investigate the effect of aging (1) on the extent to which salient yet task-irrelevant stimuli capture saccades, and (2) on the ability to selectively suppress such oculomotor responses. Young and older adults were asked to direct their eyes to a target appearing in a stimulus array. Analysis of overall performance shows that saccades to the target object were disrupted by the appearance of a task-irrelevant abrupt-onset distractor when the location of this distractor did not coincide with that of the target object. Conditional capture function analyses revealed that, compared to young adults, older adults were more susceptible to oculomotor capture, and exhibited deficient selective suppression of the responses captured by task-irrelevant distractors. These effects were uncorrelated, suggesting two independent sources off age-related decline. Thus, with advancing age, salient visual distractors become more distracting; in part because they trigger reflexive eye-movements more potently; in part because of failing top-down control over such reflexes. The fact that these process-specific age effects remained concealed in overall oculomotor performance analyses emphasizes the utility of looking beyond the surface; indeed, there may be more than meets the eye.

  11. Normal and diseased personal eye modeling using age-appropriate lens parameters

    PubMed Central

    Chen, Ying-Ling; Shi, L.; Lewis, J. W. L.; Wang, M.

    2012-01-01

    Personalized eye modeling of normal and diseased eye conditions is attractive due to the recent availability of detailed ocular measurements in clinic environments and the promise of its medical and industrial applications. In the customized modeling, the optical properties of the crystalline lens including the gradient refractive index, the lens bio-geometry and orientation are typically assigned with average lens parameters from literature since typically they are not clinically available. Although, through the optical optimization by assigning lens parameters as variables, the clinical measured wavefront aberration can be achieved, the optimized lens biometry and orientation often end up at edges of the statistical distribution. Without an effective validation of these models today, the fidelity of the final lens (and therefore the model) remains questionable. To develop a more reliable customized model without detailed lens information, we incorporate age-appropriate lens parameters as the initial condition of optical optimization. A biconic lens optimization was first performed to provide a correct lens profile for accurate lower order aberration and then followed by the wavefront optimization. Clinical subjects were selected from all ages with both normal and diseased corneal and refractive conditions. 19 ammetropic eyes ( + 4D to −11D), and 16 keratoconus eyes (mild to moderate with cylinder 0.25 to 6D) were modeled. Age- and gender-corrected refractive index was evaluated. Final models attained the lens shapes comparable to the statistical distribution in their age. PMID:22714237

  12. Effects of Aging and Noise on Real-Time Spoken Word Recognition: Evidence from Eye Movements

    ERIC Educational Resources Information Center

    Ben-David, Boaz M.; Chambers, Craig G.; Daneman, Meredyth; Pichora-Fuller, M. Kathleen; Reingold, Eyal M.; Schneider, Bruce A.

    2011-01-01

    Purpose: To use eye tracking to investigate age differences in real-time lexical processing in quiet and in noise in light of the fact that older adults find it more difficult than younger adults to understand conversations in noisy situations. Method: Twenty-four younger and 24 older adults followed spoken instructions referring to depicted…

  13. More than Meets the Eye: Age Differences in the Capture and Suppression of Oculomotor Action

    PubMed Central

    Ridderinkhof, K. Richard; Wijnen, Jasper G.

    2011-01-01

    Salient visual stimuli capture attention and trigger an eye-movement toward its location reflexively, regardless of an observer’s intentions. Here we aim to investigate the effect of aging (1) on the extent to which salient yet task-irrelevant stimuli capture saccades, and (2) on the ability to selectively suppress such oculomotor responses. Young and older adults were asked to direct their eyes to a target appearing in a stimulus array. Analysis of overall performance shows that saccades to the target object were disrupted by the appearance of a task-irrelevant abrupt-onset distractor when the location of this distractor did not coincide with that of the target object. Conditional capture function analyses revealed that, compared to young adults, older adults were more susceptible to oculomotor capture, and exhibited deficient selective suppression of the responses captured by task-irrelevant distractors. These effects were uncorrelated, suggesting two independent sources off age-related decline. Thus, with advancing age, salient visual distractors become more distracting; in part because they trigger reflexive eye-movements more potently; in part because of failing top-down control over such reflexes. The fact that these process-specific age effects remained concealed in overall oculomotor performance analyses emphasizes the utility of looking beyond the surface; indeed, there may be more than meets the eye. PMID:22046165

  14. Human vertical eye movement responses to earth horizontal pitch

    NASA Technical Reports Server (NTRS)

    Wall, C. 3rd; Petropoulos, A. E.

    1993-01-01

    The vertical eye movements in humans produced in response to head-over-heels constant velocity pitch rotation about a horizontal axis resemble those from other species. At 60 degrees/s these are persistent and tend to have non-reversing slow components that are compensatory to the direction of rotation. In most, but not all subjects, the slow component velocity was well characterized by a rapid build-up followed by an exponential decay to a non-zero baseline. Super-imposed was a cyclic or modulation component whose frequency corresponded to the time for one revolution and whose maximum amplitude occurred during a specific head orientation. All response components (exponential decay, baseline and modulation) were larger during pitch backward compared to pitch forward runs. Decay time constants were shorter during the backward runs, thus, unlike left to right yaw axis rotation, pitch responses display significant asymmetries between paired forward and backward runs.

  15. Common cell biologic and biochemical changes in aging and age-related diseases of the eye: Toward new therapeutic approaches to age-related ocular diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reviews of information about age related macular degeneration (AMD), cataract, and glaucoma make it apparent that while each eye tissue has its own characteristic metabolism, structure and function, there are common perturbations to homeostasis that are associated with age-related dysfunction. The c...

  16. A Theoretical Analysis of a New Polarimetric Optical Scheme for Glucose Sensing in the Human Eye

    NASA Technical Reports Server (NTRS)

    Rovati, Luigi L.; Boeckle, Stefan; Ansari, Rafat R.; Salzman, Jack A. (Technical Monitor)

    2002-01-01

    The challenging task of in vivo polarimetric glucose sensing is the identification and selection of a scheme to optically access the aqueous humor of the human eye. In this short communication an earlier approach of Cote et al. is theoretically compared with our new optical scheme. Simulations of the new scheme using the eye model of Navarro, suggest that the new optical geometry can overcome the limitations of the previous approach for in vivo measurements of glucose in a human eye.

  17. [Symptomatic and asymptomatic infections of Demodex spp. in eye lashes of patients of different age groups].

    PubMed

    Kuźna-Grygiel, Wanda; Kosik-Bogacka, Danuta; Czepita, Damian; Sambor, Izabella

    2004-01-01

    Demodex folliculorum and Demodex brevis were looked for on eyelashes sampled from 481 people, aged 3 through 96. The persons studied were divided into 9 age groups. Magnitude of the infection symptoms was assessed based on macroscopic changes of eye-lid edges and on interviews with patients. An increase of the prevalence of infection and intensification of the symptoms were observed to coincide with the age increase of the persons studied. No significant differences were demonstrated between the infection frequencies of women and men. Symptoms of ocular demodecosis were more frequent only in women of group III (aged 21-30) and group V (41-50) (p < 0.05).

  18. Faces and Eyes in Human Lateral Prefrontal Cortex

    PubMed Central

    Chan, Annie W.-Y.; Downing, Paul E.

    2011-01-01

    Much of the work on face-selective neural activity has focused on posterior, ventral areas of the human and non-human primate brain. However, electrophysiological and fMRI studies have identified face responses in the prefrontal cortex. Here we used fMRI to characterize these responses in the human prefrontal cortex compared with face selectivity in posterior ventral region. We examined a region at the junction of the right inferior frontal sulcus and the precentral sulcus (right inferior frontal junction or rIFJ) that responds more to faces than to several other object categories. We find that the rIFJ and the right fusiform face area (rFFA) are broadly similar in their responses to whole faces, headless bodies, tools, and scenes. Strikingly, however, while the rFFA preferentially responds to the whole face, the rIFJ response to faces appears to be driven primarily by the eyes. This dissociation provides clues to the functional role of the rIFJ face response. We speculate on this role with reference to emotion perception, gaze perception, and to behavioral relevance more generally. PMID:21687796

  19. The development of fine-grained sensitivity to eye contact after 6 years of age.

    PubMed

    Vida, Mark D; Maurer, Daphne

    2012-06-01

    Adults use eye contact as a cue to the mental and emotional states of others. Here, we examined developmental changes in the ability to discriminate between eye contact and averted gaze. Children (6-, 8-, 10-, and 14-year-olds) and adults (n=18/age) viewed photographs of a model fixating the center of a camera lens and a series of positions to the left/right or upward/downward and judged whether the model's gaze was direct or averted to the left/right or upward/downward. The horizontal range of fixation positions leading to the perception of direct gaze (the cone of gaze) was more than 50% larger in 6-year-olds than in adults, but it was adult-like and smaller than the vertical cone of gaze by 8 years of age. The vertical cone of gaze was large and statistically adult-like by age 6, with only a small linear reduction thereafter. In all age groups, the horizontal cone of gaze was centered on the bridge of the participant's nose and the vertical cone was centered slightly below the participant's eye height. These findings indicate that until after age 6, relatively poor sensitivity to direct versus averted gaze limits children's ability to use gaze cues to make social judgments.

  20. Preface: The aging eye: normal changes, age-related diseases and sight-saving approaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This volume presents chapters based on a workshop held on June 14-16, 2013 in Rancho Palos Verde, CA sponsored by the Ocular Research Symposia Foundation (ORSF). The mission of the ORSF is to focus attention on unmet needs and current research opportunities in eye research with the objective of acce...

  1. Development of a human eye model incorporated with intraocular scattering for visual performance assessment

    NASA Astrophysics Data System (ADS)

    Chen, Yi-Chun; Jiang, Chong-Jhih; Yang, Tsung-Hsun; Sun, Ching-Cherng

    2012-07-01

    A biometry-based human eye model was developed by using the empirical anatomic and optical data of ocular parameters. The gradient refractive index of the crystalline lens was modeled by concentric conicoid isoindical surfaces and was adaptive to accommodation and age. The chromatic dispersion of ocular media was described by Cauchy equations. The intraocular scattering model was composed of volumetric Mie scattering in the cornea and the crystalline lens, and a diffusive-surface model at the retina fundus. The retina was regarded as a Lambertian surface and was assigned its corresponding reflectance at each wavelength. The optical performance of the eye model was evaluated in CodeV and ASAP and presented by the modulation transfer functions at single and multiple wavelengths. The chromatic optical powers obtained from this model resembled that of the average physiological eyes. The scattering property was assessed by means of glare veiling luminance and compared with the CIE general disability glare equation. By replacing the transparent lens with a cataractous lens, the disability glare curve of cataracts was generated to compare with the normal disability glare curve. This model has high potential for investigating visual performance in ordinary lighting and display conditions and under the influence of glare sources.

  2. Blue eyes in lemurs and humans: same phenotype, different genetic mechanism.

    PubMed

    Bradley, Brenda J; Pedersen, Anja; Mundy, Nicholas I

    2009-06-01

    Almost all mammals have brown or darkly-pigmented eyes (irises), but among primates, there are some prominent blue-eyed exceptions. The blue eyes of some humans and lemurs are a striking example of convergent evolution of a rare phenotype on distant branches of the primate tree. Recent work on humans indicates that blue eye color is associated with, and likely caused by, a single nucleotide polymorphism (rs12913832) in an intron of the gene HERC2, which likely regulates expression of the neighboring pigmentation gene OCA2. This raises the immediate question of whether blue eyes in lemurs might have a similar genetic basis. We addressed this by sequencing the homologous genetic region in the blue-eyed black lemur (Eulemur macaco flavifrons; N = 4) and the closely-related black lemur (Eulemur macaco macaco; N = 4), which has brown eyes. We then compared a 166-bp segment corresponding to and flanking the human eye-color-associated region in these lemurs, as well as other primates (human, chimpanzee, orangutan, macaque, ring-tailed lemur, mouse lemur). Aligned sequences indicated that this region is strongly conserved in both Eulemur macaco subspecies as well as the other primates (except blue-eyed humans). Therefore, it is unlikely that this regulatory segment plays a major role in eye color differences among lemurs as it does in humans. Although convergent phenotypes can sometimes come about via the same or similar genetic changes occurring independently, this does not seem to be the case here, as we have shown that the genetic basis of blue eyes in lemurs differs from that of humans.

  3. Comparison of in vitro eye irritation potential by bovine corneal opacity and permeability (BCOP) assay to erythema scores in human eye sting test of surfactant-based formulations.

    PubMed

    Cater, Kathleen C; Harbell, John W

    2008-01-01

    The bovine corneal opacity and permeability (BCOP) assay can be used to predict relative eye irritation potential of surfactant-based personal care formulations relative to a corporate benchmark. The human eye sting test is typically used to evaluate product claims of no tears/no stinging for children's bath products. A preliminary investigation was conducted to test a hypothesis that the BCOP assay could be used as a prediction model for relative ranking of human eye irritation responses under conditions of a standard human eye sting test to surfactant-based formulations. BCOP assays and human eye sting tests were conducted on 4 commercial and 1 prototype body wash (BW) developed specifically for children or as mild bath products. In the human eye sting test, 10 mul of a 10% dosing solution is instilled into one eye of each panelist (n = 20), and the contralateral eye is dosed with sterile water as a control. Bulbar conjunctival erythema responses of each eye are graded at 30 seconds by an ophthalmologist. The BCOP assay permeability values (optical density at 490 nm [OD(490)]) for the 5 BWs ranged from 0.438 to 1.252 (i.e., least to most irritating). By comparison, the number of panelists exhibiting erythema responses (mild to moderately pink) ranged from 3 of 20 panelists for the least irritating BW to 10 of 20 panelists for the most irritating BW tested. The relative ranking of eye irritation potential of the 5 BWs in the BCOP assay compares favorably with the relative ranking of the BWs in the human eye sting test. Based on these findings, the permeability endpoint of the BCOP assay, as described for surfactant-based formulations, showed promise as a prediction model for relative ranking of conjunctival erythema responses in the human eye. Consequently, screening of prototype formulations in the BCOP assay would allow for formula optimization of mild bath products prior to investment in a human eye sting test.

  4. Implicit prosody mining based on the human eye image capture technology

    NASA Astrophysics Data System (ADS)

    Gao, Pei-pei; Liu, Feng

    2013-08-01

    The technology of eye tracker has become the main methods of analyzing the recognition issues in human-computer interaction. Human eye image capture is the key problem of the eye tracking. Based on further research, a new human-computer interaction method introduced to enrich the form of speech synthetic. We propose a method of Implicit Prosody mining based on the human eye image capture technology to extract the parameters from the image of human eyes when reading, control and drive prosody generation in speech synthesis, and establish prosodic model with high simulation accuracy. Duration model is key issues for prosody generation. For the duration model, this paper put forward a new idea for obtaining gaze duration of eyes when reading based on the eye image capture technology, and synchronous controlling this duration and pronunciation duration in speech synthesis. The movement of human eyes during reading is a comprehensive multi-factor interactive process, such as gaze, twitching and backsight. Therefore, how to extract the appropriate information from the image of human eyes need to be considered and the gaze regularity of eyes need to be obtained as references of modeling. Based on the analysis of current three kinds of eye movement control model and the characteristics of the Implicit Prosody reading, relative independence between speech processing system of text and eye movement control system was discussed. It was proved that under the same text familiarity condition, gaze duration of eyes when reading and internal voice pronunciation duration are synchronous. The eye gaze duration model based on the Chinese language level prosodic structure was presented to change previous methods of machine learning and probability forecasting, obtain readers' real internal reading rhythm and to synthesize voice with personalized rhythm. This research will enrich human-computer interactive form, and will be practical significance and application prospect in terms of

  5. Bona fide colour: DNA prediction of human eye and hair colour from ancient and contemporary skeletal remains

    PubMed Central

    2013-01-01

    Background DNA analysis of ancient skeletal remains is invaluable in evolutionary biology for exploring the history of species, including humans. Contemporary human bones and teeth, however, are relevant in forensic DNA analyses that deal with the identification of perpetrators, missing persons, disaster victims or family relationships. They may also provide useful information towards unravelling controversies that surround famous historical individuals. Retrieving information about a deceased person’s externally visible characteristics can be informative in both types of DNA analyses. Recently, we demonstrated that human eye and hair colour can be reliably predicted from DNA using the HIrisPlex system. Here we test the feasibility of the novel HIrisPlex system at establishing eye and hair colour of deceased individuals from skeletal remains of various post-mortem time ranges and storage conditions. Methods Twenty-one teeth between 1 and approximately 800 years of age and 5 contemporary bones were subjected to DNA extraction using standard organic protocol followed by analysis using the HIrisPlex system. Results Twenty-three out of 26 bone DNA extracts yielded the full 24 SNP HIrisPlex profile, therefore successfully allowing model-based eye and hair colour prediction. HIrisPlex analysis of a tooth from the Polish general Władysław Sikorski (1881 to 1943) revealed blue eye colour and blond hair colour, which was positively verified from reliable documentation. The partial profiles collected in the remaining three cases (two contemporary samples and a 14th century sample) were sufficient for eye colour prediction. Conclusions Overall, we demonstrate that the HIrisPlex system is suitable, sufficiently sensitive and robust to successfully predict eye and hair colour from ancient and contemporary skeletal remains. Our findings, therefore, highlight the HIrisPlex system as a promising tool in future routine forensic casework involving skeletal remains, including

  6. Ultrastructural changes in the melanocytes of aging human choroid.

    PubMed

    Nag, Tapas Chandra

    2015-12-01

    Retinal pigment epithelial cells as well as choroidal melanocytes (CM) possess melanin granules. The former show clear, age-related changes (formation of lipofuscin granules with a concomitant decrease in melanin content); however, data on changes in the CM with aging are fairly limited. We examined CM in human macular and mid-peripheral areas by light- and transmission electron microscopy in 50-94 year-old donor eyes (N=12). Unlike in the choroid of lower ages, the melanocytes from aging choroid (>75 years) showed partial fusion of about 8-15 melanosomes, forming rosettes-like structures. Besides, there was evidence of emptiness in cytoplasm caused by the loss of melanosomes in aged CM, as was confirmed by quantification in macular part of choroid. In advanced aged eyes (85-94-year-old), the CM possessed many lipid droplets as well as irregular lipofuscin granules, the latter had a tendency to fuse with melanosomes, as happens in aged retinal pigment epithelium. Macrophages in their cytoplasm contained abundant irregular as well as clumped melanosomes of variable size, suggesting that damaged granules/melanocytes are cleared by these phagocytes. These obvious changes in the CM are likely to make the choroid prone to damage by visible light.

  7. Loss of CD34 expression in aging human choriocapillaris endothelial cells.

    PubMed

    Sohn, Elliott H; Flamme-Wiese, Miles J; Whitmore, S Scott; Wang, Kai; Tucker, Budd A; Mullins, Robert F

    2014-01-01

    Structural and gene expression changes in the microvasculature of the human choroid occur during normal aging and age-related macular degeneration (AMD). In this study, we sought to determine the impact of aging and AMD on expression of the endothelial cell glycoprotein CD34. Sections from 58 human donor eyes were categorized as either young (under age 40), age-matched controls (> age 60 without AMD), or AMD affected (>age 60 with early AMD, geographic atrophy, or choroidal neovascularization). Dual labeling of sections with Ulex europaeus agglutinin-I lectin (UEA-I) and CD34 antibodies was performed, and the percentage of capillaries labeled with UEA-I but negative for anti-CD34 was determined. In addition, published databases of mouse and human retinal pigment epithelium-choroid were evaluated and CD34 expression compared between young and old eyes. Immunohistochemical studies revealed that while CD34 and UEA-I were colocalized in young eyes, there was variable loss of CD34 immunoreactivity in older donor eyes. While differences between normal aging and AMD were not significant, the percentage of CD34 negative capillaries in old eyes, compared to young eyes, was highly significant (p = 3.8×10(-6)). Endothelial cells in neovascular membranes were invariably CD34 positive. Published databases show either a significant decrease in Cd34 (mouse) or a trend toward decreased CD34 (human) in aging. These findings suggest that UEA-I and endogenous alkaline phosphatase activity are more consistent markers of aging endothelial cells in the choroid, and suggest a possible mechanism for the increased inflammatory milieu in the aging choroid.

  8. Loss of CD34 Expression in Aging Human Choriocapillaris Endothelial Cells

    PubMed Central

    Sohn, Elliott H.; Flamme-Wiese, Miles J.; Whitmore, S. Scott; Wang, Kai; Tucker, Budd A.; Mullins, Robert F.

    2014-01-01

    Structural and gene expression changes in the microvasculature of the human choroid occur during normal aging and age-related macular degeneration (AMD). In this study, we sought to determine the impact of aging and AMD on expression of the endothelial cell glycoprotein CD34. Sections from 58 human donor eyes were categorized as either young (under age 40), age-matched controls (> age 60 without AMD), or AMD affected (>age 60 with early AMD, geographic atrophy, or choroidal neovascularization). Dual labeling of sections with Ulex europaeus agglutinin-I lectin (UEA-I) and CD34 antibodies was performed, and the percentage of capillaries labeled with UEA-I but negative for anti-CD34 was determined. In addition, published databases of mouse and human retinal pigment epithelium-choroid were evaluated and CD34 expression compared between young and old eyes. Immunohistochemical studies revealed that while CD34 and UEA-I were colocalized in young eyes, there was variable loss of CD34 immunoreactivity in older donor eyes. While differences between normal aging and AMD were not significant, the percentage of CD34 negative capillaries in old eyes, compared to young eyes, was highly significant (p = 3.8×10−6). Endothelial cells in neovascular membranes were invariably CD34 positive. Published databases show either a significant decrease in Cd34 (mouse) or a trend toward decreased CD34 (human) in aging. These findings suggest that UEA-I and endogenous alkaline phosphatase activity are more consistent markers of aging endothelial cells in the choroid, and suggest a possible mechanism for the increased inflammatory milieu in the aging choroid. PMID:24466138

  9. Repeatability and reliability of human eye in visual shade selection.

    PubMed

    Özat, P B; Tuncel, İ; Eroğlu, E

    2013-12-01

    Deficiencies in the human visual percep-tion system have challenged the efficiency of the visual shade-matching protocol. The aim of this study was to evaluate the repeatability and reliability of human eye in visual shade selection. Fifty-four volunteering dentists were asked to match the shade of an upper right central incisor tooth of a single subject. The Vita 3D-Master shade guide was used for the protocol. Before each shade-matching procedure, the definitive codes of the shade tabs were hidden by an opaque strip and the shade tabs were placed into the guide randomly. The procedure was repeated 1 month later to ensure that visual memory did not affect the results. The L*, a* and b* values of the shade tabs were measured with a dental spectrophotometer (Vita Easyshade) to produce quantitative values to evaluate the protocol. The paired samples t-test and Pearson correlation test were used to compare the 1st and 2nd selections. The Yates-corrected chi-square test was use to compare qualitative values. Statistical significance was accepted at P < 0·05. Comparing baseline and 1st month records, statistical significance (P < 0·001) was found among qualitative data regarding repeatability on a yes/no (1/0) basis, revealing a very low percentage of repeatability (11·1%). Comparing baseline and 1st month records, statistical significance was not found (P = 0·000) among the L*, a*, b* and ΔE variables. These results indicate that dentists perform insufficiently regarding repeatability in visual shade matching, but they are able to select clinically acceptable shades.

  10. High rate internal pressurization of the human eye to determine dynamic rupture pressure.

    PubMed

    Bisplinghoff, Jill A; McNally, Craig; Yang, Siyang; Herring, Ian P; Brozoski, Fred T; Duma, Stefan M

    2008-01-01

    Over 1.9 million people suffer from eye injuries in the United States, occurring from automobile accidents, sports related impacts, and military combat. The purpose of the current study is to analyze the rupture pressure of human eyes using a high rate pressurization system. Internal pressure was dynamically induced into the eye with a drop tower pressurization system. The rupture pressure was measured with a small pressure sensor inserted into the optic nerve. A total of 10 human eye dynamic pressure tests were performed to determine rupture pressure and to compare the results with previous data. It was found that the average high rate rupture pressure of human eyes is 0.89+/- 0.25 MPa. In comparing these data with previous studies, it is concluded that as the loading rate increases the rupture pressure also increases.

  11. Computational Model-Based Prediction of Human Episodic Memory Performance Based on Eye Movements

    NASA Astrophysics Data System (ADS)

    Sato, Naoyuki; Yamaguchi, Yoko

    Subjects' episodic memory performance is not simply reflected by eye movements. We use a ‘theta phase coding’ model of the hippocampus to predict subjects' memory performance from their eye movements. Results demonstrate the ability of the model to predict subjects' memory performance. These studies provide a novel approach to computational modeling in the human-machine interface.

  12. Digital image database processing to simulate image formation in ideal lighting conditions of the human eye

    NASA Astrophysics Data System (ADS)

    Castañeda-Santos, Jessica; Santiago-Alvarado, Agustin; Cruz-Félix, Angel S.; Hernández-Méndez, Arturo

    2015-09-01

    The pupil size of the human eye has a large effect in the image quality due to inherent aberrations. Several studies have been performed to calculate its size relative to the luminance as well as considering other factors, i.e., age, size of the adapting field and mono and binocular vision. Moreover, ideal lighting conditions are known, but software suited to our specific requirements, low cost and low computational consumption, in order to simulate radiation adaptation and image formation in the retina with ideal lighting conditions has not yet been developed. In this work, a database is created consisting of 70 photographs corresponding to the same scene with a fixed target at different times of the day. By using this database, characteristics of the photographs are obtained by measuring the luminance average initial threshold value of each photograph by means of an image histogram. Also, we present the implementation of a digital filter for both, image processing on the threshold values of our database and generating output images with the threshold values reported for the human eye in ideal cases. Some potential applications for this kind of filters may be used in artificial vision systems.

  13. Choroid, Haller's, and Sattler's Layer Thickness in Intermediate Age-Related Macular Degeneration With and Without Fellow Neovascular Eyes

    PubMed Central

    Esmaeelpour, Marieh; Ansari-Shahrezaei, Siamak; Glittenberg, Carl; Nemetz, Susanne; Kraus, Martin F.; Hornegger, Joachim; Fujimoto, James G.; Drexler, Wolfgang; Binder, Susanne

    2014-01-01

    Purpose. To analyze choroidal, Sattler's, and Haller's layer thickness maps in age-related macular degeneration (AMD) patients having eyes with bilateral large drusen and pigment changes (intermediate AMD), in patients having intermediate AMD eyes with neovascular fellow eyes (nAMD), and in healthy subjects using three-dimensional (3D) 1060-nm optical coherence tomography (OCT). Methods. Automatically generated choroidal thickness (ChT), retinal thickness, and Sattler's and Haller's layer thickness maps were statistically analyzed in 67 subjects consisting of intermediate AMD (n = 21), intermediate AMD (n = 22) with fellow nAMD eyes (n = 22), and healthy eyes (n = 24) with no age and axial eye length difference between groups of eyes (P > 0.05, ANOVA). Eyes were imaged by a prototype high-speed (60,000 A-scans/s) spectral-domain 3D 1060-nm OCT over a 36° × 36° field of view. Results. The mean ± SD (μm) subfoveal ChT for healthy subjects and for bilateral intermediate AMD, unilateral intermediate AMD, and their nAMD fellow eyes was 259 ± 95 and 222 ± 98, 149 ± 60, and 171 ± 78, respectively. Choroidal thickness maps demonstrated significant submacular thinning in unilateral intermediate AMD in comparison to healthy and bilateral intermediate AMD eyes (P < 0.001, ANOVA, post hoc P < 0.001 and P < 0.05, respectively). Sattler's and Haller's layers were thinnest in intermediate AMDs that presented with nAMD fellow eyes (Kruskal-Wallis test P < 0.01). For the choroid and its sublayers, there was no difference between the intermediate AMD eyes and their fellow nAMD eyes (paired testing, P < 0.05). Conclusions. The 3D 1060-nm OCT choroidal imaging visualized significant changes in choroidal, Sattler's, and Haller's layer thickness in relation to the progression of AMD. This may be important for understanding the choroidopathy in the pathophysiology of AMD. PMID:25052997

  14. Efficient Avoidance of the Penalty Zone in Human Eye Movements

    PubMed Central

    Theeuwes, Jan

    2016-01-01

    People use eye movements extremely effectively to find objects of interest in a cluttered visual scene. Distracting, task-irrelevant attention capturing regions in the visual field should be avoided as they jeopardize the efficiency of search. In the current study, we used eye tracking to determine whether people are able to avoid making saccades to a predetermined visual area associated with a financial penalty, while making fast and accurate saccades towards stimuli placed near the penalty area. We found that in comparison to the same task without a penalty area, the introduction of a penalty area immediately affected eye movement behaviour: the proportion of saccades to the penalty area was immediately reduced. Also, saccadic latencies increased, but quite modestly, and mainly for saccades towards stimuli near the penalty area. We conclude that eye movement behaviour is under efficient cognitive control and thus quite flexible: it can immediately be adapted to changing environmental conditions to improve reward outcome. PMID:27930724

  15. Anticipatory Eye Movements in Interleaving Templates of Human Behavior

    NASA Technical Reports Server (NTRS)

    Matessa, Michael

    2004-01-01

    Performance modeling has been made easier by architectures which package psychological theory for reuse at useful levels of abstraction. CPM-GOMS uses templates of behavior to package at a task level (e.g., mouse move-click, typing) predictions of lower-level cognitive, perceptual, and motor resource use. CPM-GOMS also has a theory for interleaving resource use between templates. One example of interleaving is anticipatory eye movements. This paper describes the use of ACT-Stitch, a framework for translating CPM-GOMS templates and interleaving theory into ACT-R, to model anticipatory eye movements in skilled behavior. The anticipatory eye movements explain performance in a well-practiced perceptual/motor task, and the interleaving theory is supported with results from an eye-tracking experiment.

  16. Eye Detection and Tracking for Intelligent Human Computer Interaction

    DTIC Science & Technology

    2006-02-01

    image; (c) face image after Gaussian filter smoothing(filter size 15 × 15, σ =3.0); ( d ) terrain surface of the eye region of the smoothed image. 3...Figure 2: The topographic labels: The center pixel in each example carries the indicated label. (a) peak; (b) pit; (c) ridge; ( d ) ravine; (e) ridge...are shown in (c); (b) The non-eye samples used as a negative training set, whose corresponding terrain patches are shown in ( d

  17. The Importance of Mitochondria in Age-Related and Inherited Eye Disorders

    PubMed Central

    Jarrett, Stuart G.; Lewin, Alfred S.; Boulton, Michael E.

    2010-01-01

    Mitochondria are critical for ocular function as they represent the major source of a cell's supply of energy and play an important role in cell differentiation and survival. Mitochondrial dysfunction can occur as a result of inherited mitochondrial mutations (e.g. Leber's hereditary optic neuropathy and chronic progressive external ophthalmoplegia) or stochastic oxidative damage which leads to cumulative mitochondrial damage and is an important factor in age-related disorders (e.g. age-related macular degeneration, cataract and diabetic retinopathy). Mitochondrial DNA (mtDNA) instability is an important factor in mitochondrial impairment culminating in age-related changes and pathology, and in all regions of the eye mtDNA damage is increased as a consequence of aging and age-related disease. It is now apparent that the mitochondrial genome is a weak link in the defenses of ocular cells since it is susceptible to oxidative damage and it lacks some of the systems that protect the nuclear genome, such as nucleotide excision repair. Accumulation of mitochondrial mutations leads to cellular dysfunction and increased susceptibility to adverse events which contribute to the pathogenesis of numerous sporadic and chronic disorders in the eye. PMID:20829642

  18. Decreased Connectivity between the Thalamus and the Neocortex during Human Nonrapid Eye Movement Sleep

    PubMed Central

    Picchioni, Dante; Pixa, Morgan L.; Fukunaga, Masaki; Carr, Walter S.; Horovitz, Silvina G.; Braun, Allen R.; Duyn, Jeff H.

    2014-01-01

    Study Objectives: To determine whether thalamocortical signaling between the thalamus and the neocortex decreases from wakefulness to nonrapid eye movement (NREM) sleep. Design: Electroencephalography and functional magnetic resonance imaging data were collected simultaneously at 02:30 after 44 h of sleep deprivation. Setting: Clinical research hospital. Participants: There were six volunteers (mean age 24.2 y, one male) who yielded sufficient amounts of usable, artifact-free data. All were healthy, right-handed native English speakers who consumed less than 710 mL of caffeinated beverages per day. Psychiatric, neurological, circadian, and sleep disorders were ruled out by reviewing each patient's clinical history. A standard clinical nocturnal polysomnogram was negative for sleep disorders. Interventions: N/A. Measurements and Results: A functional connectivity analysis was performed using the centromedian nucleus as the seed region. We determined the statistical significance of the difference between correlations obtained during wakefulness and during slow wave sleep. Neocortical regions displaying decreased thalamic connectivity were all heteromodal regions (e.g., medial frontal gyrus and posterior cingulate/precuneus), whereas there was a complete absence of neocortical regions displaying increased thalamic connectivity. Although more clusters of significant decreases were observed in stage 2 sleep, these results were similar to the results for slow wave sleep. Conclusions: Results of this study provide evidence of a functional deafferentation of the neocortex during nonrapid eye movement (NREM) sleep in humans. This deafferentation likely accounts for increased sensory awareness thresholds during NREM sleep. Decreased thalamocortical connectivity in regions such as the posterior cingulate/precuneus also are observed in coma and general anesthesia, suggesting that changes in thalamocortical connectivity may act as a universal “control switch” for changes in

  19. Clinical significance of a new autoantibody against a human eye muscle soluble antigen, detected by immunofluorescence.

    PubMed Central

    Mengistu, M; Laryea, E; Miller, A; Wall, J R

    1986-01-01

    The clinical significance of a circulating autoantibody against a recently identified soluble human eye muscle-derived antigen was studied in patients with Graves' ophthalmopathy and autoimmune thyroid disorders. Tests were positive in 73% of patients with Graves' ophthalmopathy, including six of seven with no associated thyroid disease (euthyroid Graves' disease). Tests were also positive in 27% of patients with hyperthyroidism but no clinically apparent eye disease, in 13% of patients with Hashimoto's thyroiditis without eye disease, in two of 12 patients with subacute thyroiditis, in one of 20 patients with nonimmunological thyroid disorders but in none of 39 normal subjects. There were significant positive correlations between serum levels of the antibody (expressed as a titre) and the severity of the eye muscle component quantified as an index as well as the duration of the eye disease. Antibodies were detected in three of five patients with only lid lag and state who subsequently developed active ophthalmopathy, in six of nine patients who developed eye disease after treatment of their hyperthyroidism and in one of eight first degree relatives of patients with Graves' ophthalmopathy. In addition three of the 12 patients with autoimmune thyroid disease without apparent eye involvement, but positive antibody tests, have developed ophthalmopathy since the time of testing. These findings suggest that tests for antibodies against a soluble human eye muscle antigen may be useful clinically as a diagnostic test and to predict the onset of eye disease in predisposed patients and subjects. PMID:3539423

  20. Accommodative Movements of the Vitreous Membrane, Choroid, and Sclera in Young and Presbyopic Human and Nonhuman Primate Eyes

    PubMed Central

    Croft, Mary Ann; Nork, T. Michael; McDonald, Jared P.; Katz, Alexander; Lütjen-Drecoll, Elke; Kaufman, Paul L.

    2013-01-01

    Purpose. We report, for the first time to our knowledge, dynamic movements of the vitreous membrane and peripheral choroid during accommodation, and age-related changes in the anterior sclera. Methods. We studied 11 rhesus monkeys (ages 6–27 years) and 12 human subjects (ages 19–65 years). Accommodation was induced pharmacologically in human subjects and by central electrical stimulation in the monkeys. Ultrasound biomicroscopy, endoscopy, and contrast agents were used to image various intraocular structures. Results. In the monkey, the anterior hyaloid membrane bows backward during accommodation in proportion to accommodative amplitude and lens thickening. A cleft exists between the pars plicata region and the anterior hyaloid membrane, and the cleft width increases during accommodation from 0.79 ± 0.01 mm to 1.01 ± 0.02 mm in young eyes (n = 2, P < 0.005), as fluid from the anterior chamber flows around the lens equator toward the cleft. In the older eyes the cleft width was 0.30 ± 0.19 mm, which during accommodation increased to 0.45 ± 0.20 mm (n = 2). During accommodation the ciliary muscle moved forward by approximately 1.0 mm, pulling forward the choroid, retina, vitreous zonule, and the neighboring vitreous interconnected with the vitreous zonule. Among the humans, in the older eyes the scleral contour bowed inward in the region of the limbus, compared to the young eyes. Conclusions. The monkey anterior hyaloid bends posteriorly during accommodation in proportion to accommodative amplitude and the sclera bows inward with increasing age in both species. Future descriptions of the accommodative mechanism, and approaches to presbyopia therapy, may need to incorporate these findings. PMID:23745005

  1. Retinal images in the human eye with implanted intraocular lens

    NASA Astrophysics Data System (ADS)

    Zając, Marek; Siedlecki, Damian; Nowak, Jerzy

    2007-04-01

    A typical proceeding in cataract is based on the removal of opaque crystalline lens and inserting in its place the artificial intraocular lens (IOL). The quality of retinal image after such procedure depends, among others, on the parameters of the IOL, so the design of the implanted lens is of great importance. An appropriate choice of the IOL material, especially in relation to its biocompatibility, is often considered. However the parameter, which is often omitted during the IOL design is its chromatic aberration. In particular lack of its adequacy to the chromatic aberration of a crystalline lens may cause problems. In order to fit better chromatic aberration of the eye with implanted IOL to that of the healthy eye we propose a hybrid - refractive-diffractive IOL. It can be designed in such way that the total longitudinal chromatic aberration of an eye with implanted IOL equals the total longitudinal chromatic aberration of a healthy eye. In this study we compare the retinal image quality calculated numerically on the basis of the well known Liou-Brennan eye model with typical IOL implanted with that obtained if the IOL is done as hybrid (refractive-diffractive) design.

  2. Integrating the Advanced Human Eye Model (AHEM) and optical instrument models to model complete visual optical systems inclusive of the typical or atypical eye

    NASA Astrophysics Data System (ADS)

    Donnelly, William J., III

    2012-06-01

    PURPOSE: To present a commercially available optical modeling software tool to assist the development of optical instrumentation and systems that utilize and/or integrate with the human eye. METHODS: A commercially available flexible eye modeling system is presented, the Advanced Human Eye Model (AHEM). AHEM is a module that the engineer can use to perform rapid development and test scenarios on systems that integrate with the eye. Methods include merging modeled systems initially developed outside of AHEM and performing a series of wizard-type operations that relieve the user from requiring an optometric or ophthalmic background to produce a complete eye inclusive system. Scenarios consist of retinal imaging of targets and sources through integrated systems. Uses include, but are not limited to, optimization, telescopes, microscopes, spectacles, contact and intraocular lenses, ocular aberrations, cataract simulation and scattering, and twin eye model (binocular) systems. RESULTS: Metrics, graphical data, and exportable CAD geometry are generated from the various modeling scenarios.

  3. Measuring Human Performance in Simulated Nuclear Power Plant Control Rooms Using Eye Tracking

    SciTech Connect

    Kovesdi, Casey Robert; Rice, Brandon Charles; Bower, Gordon Ross; Spielman, Zachary Alexander; Hill, Rachael Ann; LeBlanc, Katya Lee

    2015-11-01

    Control room modernization will be an important part of life extension for the existing light water reactor fleet. As part of modernization efforts, personnel will need to gain a full understanding of how control room technologies affect performance of human operators. Recent advances in technology enables the use of eye tracking technology to continuously measure an operator’s eye movement, which correlates with a variety of human performance constructs such as situation awareness and workload. This report describes eye tracking metrics in the context of how they will be used in nuclear power plant control room simulator studies.

  4. [Experimental models of human skin aging].

    PubMed

    Nikolakis, G; Zoschke, C; Makrantonaki, E; Hausmann, C; Schäfer-Korting, M; Zouboulis, C C

    2016-02-01

    The skin is a representative model for the study of human aging. Despite the high regenerative capacity of the skin, skin physiology changes over the course of life. Medical and cosmetic research is trying to prevent aging, to slow, to stop, or to reverse it. Effects of age-related DNA damage and of changing skin structure on pharmacological parameters are largely unknown. This review article summarizes the state of scientific knowledge in the field of experimental models of human skin aging and shows approaches to improve organotypic skin models, to develop predictive models of aging, and improve aging research.

  5. The Optical Design of the Human Eye: a Critical Review

    PubMed Central

    Navarro, Rafael

    2010-01-01

    Cornea, lens and eye models are analyzed and compared to experimental findings to assess properties and eventually unveil optical design principles involved in the structure and function of the optical system of the eye. Models and data often show good match but also some paradoxes. The optical design seems to correspond to a wide angle lens. Compared to conventional optical systems, the eye presents a poor optical quality on axis, but a relatively good quality off-axis, thus yielding higher homogeneity for a wide visual field. This seems the result of an intriguing combination of the symmetry design principle with a total lack of rotational symmetry, decentrations and misalignments of the optical surfaces.

  6. Effects of age and communication level on eye contact in fragile X males and non-fragile X autistic males.

    PubMed

    Cohen, I L; Vietze, P M; Sudhalter, V; Jenkins, E C; Brown, W T

    1991-01-01

    Dyadic social gaze and eye contact were examined in fragile X [fra(X)] males and in non-fra(X) autistic males as a function of age and level of communicative ability. Lag sequential analysis showed that responsive eye contact was highly correlated with age and communicative ability in non-fra(X) autistic males but not in fra(X) males. Older, more communicative non-fra(X) autistic males exhibited more responsive eye contact than their fra(X) cohorts. Implications of these observations for theory and intervention are discussed.

  7. Human Commercial Models' Eye Colour Shows Negative Frequency-Dependent Selection.

    PubMed

    Forti, Isabela Rodrigues Nogueira; Young, Robert John

    2016-01-01

    In this study we investigated the eye colour of human commercial models registered in the UK (400 female and 400 male) and Brazil (400 female and 400 male) to test the hypothesis that model eye colour frequency was the result of negative frequency-dependent selection. The eye colours of the models were classified as: blue, brown or intermediate. Chi-square analyses of data for countries separated by sex showed that in the United Kingdom brown eyes and intermediate colours were significantly more frequent than expected in comparison to the general United Kingdom population (P<0.001). In Brazil, the most frequent eye colour brown was significantly less frequent than expected in comparison to the general Brazilian population. These results support the hypothesis that model eye colour is the result of negative frequency-dependent selection. This could be the result of people using eye colour as a marker of genetic diversity and finding rarer eye colours more attractive because of the potential advantage more genetically diverse offspring that could result from such a choice. Eye colour may be important because in comparison to many other physical traits (e.g., hair colour) it is hard to modify, hide or disguise, and it is highly polymorphic.

  8. Human Commercial Models’ Eye Colour Shows Negative Frequency-Dependent Selection

    PubMed Central

    2016-01-01

    In this study we investigated the eye colour of human commercial models registered in the UK (400 female and 400 male) and Brazil (400 female and 400 male) to test the hypothesis that model eye colour frequency was the result of negative frequency-dependent selection. The eye colours of the models were classified as: blue, brown or intermediate. Chi-square analyses of data for countries separated by sex showed that in the United Kingdom brown eyes and intermediate colours were significantly more frequent than expected in comparison to the general United Kingdom population (P<0.001). In Brazil, the most frequent eye colour brown was significantly less frequent than expected in comparison to the general Brazilian population. These results support the hypothesis that model eye colour is the result of negative frequency-dependent selection. This could be the result of people using eye colour as a marker of genetic diversity and finding rarer eye colours more attractive because of the potential advantage more genetically diverse offspring that could result from such a choice. Eye colour may be important because in comparison to many other physical traits (e.g., hair colour) it is hard to modify, hide or disguise, and it is highly polymorphic. PMID:28005995

  9. High-speed adaptive optics line scan confocal retinal imaging for human eye

    PubMed Central

    Wang, Xiaolin; Zhang, Yuhua

    2017-01-01

    Purpose Continuous and rapid eye movement causes significant intraframe distortion in adaptive optics high resolution retinal imaging. To minimize this artifact, we developed a high speed adaptive optics line scan confocal retinal imaging system. Methods A high speed line camera was employed to acquire retinal image and custom adaptive optics was developed to compensate the wave aberration of the human eye’s optics. The spatial resolution and signal to noise ratio were assessed in model eye and in living human eye. The improvement of imaging fidelity was estimated by reduction of intra-frame distortion of retinal images acquired in the living human eyes with frame rates at 30 frames/second (FPS), 100 FPS, and 200 FPS. Results The device produced retinal image with cellular level resolution at 200 FPS with a digitization of 512×512 pixels/frame in the living human eye. Cone photoreceptors in the central fovea and rod photoreceptors near the fovea were resolved in three human subjects in normal chorioretinal health. Compared with retinal images acquired at 30 FPS, the intra-frame distortion in images taken at 200 FPS was reduced by 50.9% to 79.7%. Conclusions We demonstrated the feasibility of acquiring high resolution retinal images in the living human eye at a speed that minimizes retinal motion artifact. This device may facilitate research involving subjects with nystagmus or unsteady fixation due to central vision loss. PMID:28257458

  10. Saccadic Eye Movements in Normal Children from 8 to 15 Years of Age: A Developmental Study of Visuospatial Attention.

    ERIC Educational Resources Information Center

    Ross, Randal G.; And Others

    1994-01-01

    This study used saccadic eye movements to assess visuospatial attention in 53 normal children (ages 8-15). Saccadic latency, the ability to suppress extraneous saccades during fixation, and the ability to inhibit task-provoked anticipatory saccades all improved with age. Developmental patterns varied by task. Analyses of age-related changes may be…

  11. Cell proliferation during the early stages of human eye development.

    PubMed

    Bozanić, Darka; Saraga-Babić, Mirna

    2004-08-01

    The distribution as well as the ultrastructural and biochemical characteristics of proliferating cells in the human eye were investigated in five conceptuses of 5-9 postovulatory weeks, using morphological techniques and Ki-67 immunostaining. The Ki-67 nuclear protein was used as a proliferation marker because of its expression in all phases of the cell cycle except the resting phase (G0). The labelling indices of Ki-67-positive cells were analysed by means of the Kruskal-Wallis ANOVA test and the Wilcoxon matched-pairs test. In the 5th week, mitotic cells were the most numerous between the two layers of the optic cup, the optic cup and stalk, and between the lens pit and the surface ectoderm. During the 6th week, cells were observed in the lens epithelium covering the whole cavity of the lens vesicle as well as in the neuroblast zone and the pigmented epithelium of the retina. At later stages (7th-9th weeks), Ki-67-positive cells were restricted to the anterior lens epithelium, the outer neuroblast zone, and the pigmented retina. Throughout all stages examined, mitotic figures were found lying exclusively adjacent to the intraretinal space. Early in the lens pit, they were confined to the free epithelial surface, and later were facing the cavity of the lens vesicle. The proliferative activity was the most intensive in the 6th week, whereas it decreased significantly in the later stages. Additionally, when proliferative activities were compared, the peripheral retina appeared to be less mature than the central before the 9th week. In the earliest analysed stage, cell proliferation might be associated with the sculpturing of the optic cup and stalk, the cornea, and the lens. In the 6th week, the most intensive proliferation seems to be involved not only in the further morphogenesis of the optic cup and the lens vesicle but also in the retinal neurogenesis. At later stages, the decreased proliferation might participate in the neurogenesis of the outer neuroblast zone

  12. Chromatic stability of acrylic resins of artificial eyes submitted to accelerated aging and polishing

    PubMed Central

    GOIATO, Marcelo Coelho; dos SANTOS, Daniela Micheline; SOUZA, Josiene Firmino; MORENO, Amália; PESQUEIRA, Aldiéris Alves

    2010-01-01

    Esthetics and durability of materials used to fabricate artificial eyes has been an important eissue since artificial eyes are essential to restore esthetics and function, protect the remaining tissues and help with patients' psychological therapy. However, these materials are submitted to degrading effects of environmental agents on the physical properties of the acrylic resin. Objective This study assessed the color stability of acrylic resins used to fabricate sclera in three basic shades (N1, N2 and N3) when subjected to accelerated aging, mechanical and chemical polishing. Material and methods Specimens of each resin were fabricated and submitted to mechanical and chemical polishing. Chromatic analysis was performed before and after accelerated aging through ultraviolet reflection spectrophotometry. Results All specimens revealed color alteration following polishing and accelerated aging. The resins presented statistically significant chromatic alteration (p<0.01) between the periods of 252 and 1008 h. Conclusions Both polishing methods presented no significant difference between the values of color derivatives of resins. PMID:21308298

  13. Human retinal development in an in situ whole eye culture system.

    PubMed

    Engelsberg, Karl; Ghosh, Fredrik

    2011-01-01

    Phenotypic characterization of human retinogenesis may be facilitated by use of the tissue culture system paradigm. Traditionally, most culture protocols involve isolation of retinal tissue and/or cells, imposing various degrees of trauma, which in many cases leads to abnormal development. In this paper, we present a novel culture technique using whole embryonic eyes to investigate whether the retina in situ can develop normally in vitro. All procedures were carried out in accordance with the Declaration of Helsinki. Human embryos were obtained from elective abortions with the informed consent of the women seeking abortion. A total of 19 eyes were enucleated. The ages of the embryonic retinas were 6-7.5 weeks. Eyecups from 2 eyes were fixed immediately, to be used as controls. The remaining 17 eyes were placed on culture plates and divided into 3 groups kept for 7 (n = 4), 14 (n = 7) and 28 (n = 6) days in vitro (DIV). After fixation, the specimens were processed for hematoxylin and eosin staining, immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). Antibodies against recoverin (rods and cones), protein kinase C (PKC; rod bipolar cells) and vimentin (Müller cells) were used. TUNEL was used to detect apoptotic cells. In hematoxylin- and eosin-stained sections, the control retinas displayed a neuroblast cell layer (NBL) and an inner marginal zone. Specimens kept 7-14 DIV had a similar appearance, while 28-day specimens consisted of an NBL with almost no marginal zone. Thirteen of the 17 cultured retinas displayed completely normal lamination without rosettes or double folds. Pyknotic cells were found at the inner margin of the retinas, and the proportion of these cells increased with time in vitro. TUNEL staining revealed a few scattered cells in 7-DIV specimens, and the amount of stained cells in the inner part of the retinas progressively increased in 14- and 28-DIV specimens. Vimentin labeling showed cells

  14. Rapid eye movement sleep behavior disorder in adults younger than 50 years of age.

    PubMed

    Ju, Yo-El S

    2013-08-01

    Rapid eye movement (REM) sleep behavior disorder (RBD) occurring prior to age 50 is termed early-onset RBD. Early-onset RBD comprises a substantial minority of cases, and demonstrates the differences in demographics, comorbidities, and clinical considerations from previously described typical RBD with onset >50years. The world literature on RBD is reviewed with specific focus on features that distinguish early-onset RBD, including more gender parity, increased proportion of idiopathic cases, increased proportion of cases associated with narcolepsy, parasomnia overlap disorder, antidepressants, and possibly autoimmune disorders, and clinical presentation.

  15. Concept of a human eye camera to assess laser dazzling interaction

    NASA Astrophysics Data System (ADS)

    Koerber, Michael; Eberle, Bernd

    2016-10-01

    The increase in availability and application of various laser sources poses an increasing threat to the human eye. Not only the actual damage dealt to the retina or other parts of the eye, but also dazzling during critical tasks has to be faced. However, experiments to verify the actual threat due to dazzling are quite critical, as it is almost never possible or even reasonable, to dazzle human observers. Based on this dilemma, we propose to construct a camera that mimics the perception of laser dazzle by the human eye as close as possible. The human eye camera consists of hardware and a software component, which perform the several tasks of the eye. The hardware controls the eye-movement (saccadic viewing), the adaption of the iris (irradiance control) and the projection of the image onto a sensor. The software receives the image taken by the sensor and includes the density of receptors, the retinal neural operations and a feedback to the hardware. The processed images by the virtual retina are meant to be used to evaluate the degree of dazzling, as it would occur to a human observer.

  16. Age-Related Differences in Vehicle Control and Eye Movement Patterns at Intersections: Older and Middle-Aged Drivers

    PubMed Central

    Yamani, Yusuke; Horrey, William J.; Liang, Yulan; Fisher, Donald L.

    2016-01-01

    Older drivers are at increased risk of intersection crashes. Previous work found that older drivers execute less frequent glances for detecting potential threats at intersections than middle-aged drivers. Yet, earlier work has also shown that an active training program doubled the frequency of these glances among older drivers, suggesting that these effects are not necessarily due to age-related functional declines. In light of findings, the current study sought to explore the ability of older drivers to coordinate their head and eye movements while simultaneously steering the vehicle as well as their glance behavior at intersections. In a driving simulator, older (M = 76 yrs) and middle-aged (M = 58 yrs) drivers completed different driving tasks: (1) travelling straight on a highway while scanning for peripheral information (a visual search task) and (2) navigating intersections with areas potential hazard. The results replicate that the older drivers did not execute glances for potential threats to the sides when turning at intersections as frequently as the middle-aged drivers. Furthermore, the results demonstrate costs of performing two concurrent tasks, highway driving and visual search task on the side displays: the older drivers performed more poorly on the visual search task and needed to correct their steering positions more compared to the middle-aged counterparts. The findings are consistent with the predictions and discussed in terms of a decoupling hypothesis, providing an account for the effects of the active training program. PMID:27736887

  17. Biomechanics of the Human Posterior Sclera: Age- and Glaucoma-Related Changes Measured Using Inflation Testing

    PubMed Central

    Coudrillier, Baptiste; Tian, Jing; Alexander, Stephen; Myers, Kristin M.; Quigley, Harry A.; Nguyen, Thao D.

    2012-01-01

    Purpose. The objective of this study was to measure the biomechanical response of the human posterior sclera in vitro and to estimate the effects of age and glaucoma. Methods. Scleral specimens from 22 donors with no history of glaucoma and 11 donors with a history of glaucoma were excised 3 mm posterior to the equator and affixed to an inflation chamber. Optic nerve cross-sections were graded to determine the presence of axon loss. The time-dependent inflation response was measured in a series of pressure-controlled load–unload tests to 30 mm Hg and creep tests to 15 and 30 mm Hg. Circumferential and meridional strains were computed from the digital image correlation displacements, and midposterior stresses were determined from pressure and deformed geometry. Results. Among normal specimens, older age was predictive of a stiffer response and a thinner sclera. In the age group 75 to 93, diagnosed glaucoma eyes with axon damage were thicker than normal eyes. Both damaged and undamaged glaucoma eyes had a different strain response in the peripapillary sclera characterized by a stiffer meridional response. Undamaged glaucoma eyes had slower circumferential creep rates in the peripapillary sclera than normal eyes. Glaucoma eyes were not different from normal eyes in stresses and strains in the midposterior sclera. Conclusions. The observed differences in the biomechanical response of normal and glaucoma sclera may represent baseline properties that contribute to axon damage, or may be characteristics that result from glaucomatous disease. PMID:22395883

  18. Endothelial glycocalyx layer in the aqueous outflow pathway of bovine and human eyes.

    PubMed

    Yang, Chen-Yuan Charlie; Huynh, Tiffany; Johnson, Mark; Gong, Haiyan

    2014-11-01

    The glycocalyx layer on the vascular endothelium is known to have an important role as a transport barrier and in the mechanotransduction of fluid shear stress. The detailed structure and distribution of the glycocalyx in the bovine and human aqueous humor outflow pathways has not yet been reported. The purpose of this study was to determine whether this layer exists in the bovine and human aqueous outflow pathways and to compare the distribution and thickness therein. Enucleated bovine (N = 4) and human (N = 4) eyes were fixed using Alcian Blue to preserve the glycocalyx. The glycocalyx distribution and thickness (in regions where it was seen) were measured on the trabecular beams (TM), Schlemm's canal (SC)/aqueous plexus (AP), and collector channels (CC). The glycocalyx, which appears as a layer of hair-like brushes, coats the surface of the endothelium non-uniformly in the bovine and human aqueous outflow pathways with a thickness in bovine eyes of 68-122 nm and in human eyes of 52-166 nm (25th to 75th percentiles). The distribution of the glycocalyx in different regions of the outflow pathway is not the same between bovine and human eyes. In both species, the glycocalyx was most uniform in the CCs. Less coverage of glycocalyx was found in the AP than the TM in bovine eyes, while more coverage was found in SC than the TM in human eyes. Most interestingly, glycocalyx was also found filling most pores of the endothelium of AP/SC in both bovine and human eyes. Glycocalyx was usually not found coating the inner membranes of the giant vacuoles (GVs); however, in GVs with a visible pore, glycocalyx was frequently observed on the inner membranes of the GVs. Based on our findings and those from the vascular endothelium, it is likely that the glycocalyx in SC plays a role in transduction of shear stress and perhaps regulation of outflow resistance.

  19. Endothelial Glycocalyx Layer in the Aqueous Outflow Pathway of Bovine and Human Eyes

    PubMed Central

    Yang, Chen-Yuan Charlie; Huynh, Tiffany; Johnson, Mark; Gong, Haiyan

    2014-01-01

    The glycocalyx layer on the vascular endothelium is known to have an important role as a transport barrier and in the mechanotransduction of fluid shear stress. The detailed structure and distribution of the glycocalyx in the bovine and human aqueous humor outflow pathways has not yet been reported. The purpose of this study was to determine whether this layer exists in the bovine and human aqueous outflow pathways and to compare the distribution and thickness therein. Enucleated bovine (N=4) and human (N=4) eyes were fixed using Alcian Blue to preserve the glycocalyx. The glycocalyx distribution and thickness (in regions where it was seen) were measured on the trabecular beams (TM), Schlemm’s canal (SC)/aqueous plexus (AP), and collector channels (CC). The glycocalyx, which appears as a layer of hair-like brushes, coats the surface of the endothelium non-uniformly in the bovine and human aqueous outflow pathways with a thickness in bovine eyes of 68–122 nm and in human eyes of 52–166 nm (25th to 75th percentiles). The distribution of the glycocalyx in different regions of the outflow pathway is not the same between bovine and human eyes. In both species, the glycocalyx was most uniform in the CCs. Less coverage of glycocalyx was found in the AP than the TM in bovine eyes, while more coverage was found in SC than the TM in human eyes. Most interestingly, glycocalyx was also found filling most pores of the endothelium of AP/SC in both bovine and human eyes. Glycocalyx was usually not found coating the inner membranes of the giant vacuoles (GVs); however, in GVs with a visible pore, glycocalyx was frequently observed on the inner membranes of the GVs. Based on our findings and those from the vascular endothelium, it is likely that the glycocalyx in SC plays a role in transduction of shear stress and perhaps regulation of outflow resistance. PMID:25217864

  20. Effect of age and sex on retinal layer thickness and volume in normal eyes

    PubMed Central

    Won, Jae Yon; Kim, Sung Eun; Park, Young-Hoon

    2016-01-01

    Abstract The aim of the study was to evaluate the effect of sex and age on the thickness of the retinal layer in normal eyes using spectral-domain optical coherence tomography (SD-OCT). Fifty healthy subjects between the ages of 20 and 80 had their retinal layers measured using SD-OCT at Seoul St. Mary's Hospital. Mean thickness and volume were measured for 9 retinal layers in the fovea, the pericentral ring, and the peripheral ring. The differences of sex- and age-related thickness and volume in each retinal layer were analyzed. The retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), and outer plexiform layer (OPL) were thinnest in the fovea area, whereas the outer nuclear layer (ONL), photoreceptor layer (PHL), and retinal pigment epithelium (RPE) were thickest at similar locations. Mean thickness of the RNFL, GCL, IPL, and OPL was significantly greater in men than women. However, mean thickness of the ONL was greater in women than in men. When compared between patients < 30 years and > 60 years of age, the thickness and volume of peripheral RNFL, GCL, and pericentral and peripheral IPL were significantly larger in the younger group than the older group. Conversely, the thickness and volume of foveal INL and IR were larger in the older group than in the younger group. The thickness and volume of the retinal layer in normal eyes significantly vary depending on age and sex. These results should be considered when evaluating layer analysis in retinal disease. PMID:27861391

  1. Effect of tissue and atmosphere's parameters on human eye temperature distribution.

    PubMed

    Firoozan, Mohammad Sadegh; Porkhial, Soheil; Nejad, Ali Salmani

    2015-01-01

    A three dimensional finite element method analysis was employed to investigate the effect of tissue and atmosphere parameters namely, ambient temperature, ambient convection coefficient, local blood temperature, and blood convection coefficient upon temperature distribution of human eyes. As a matter of simplification, only eye ball and skull bone are considered as the system of eye modeling. Decreasing the local blood temperature and keeping it cool is one of the most important ways to control bleeding during surgeries. By lower temperature of body organs such as the eye, the need for oxygenated blood is reduced, allowing for an extension in time for surgery. With this in mind, this study is done to see which one of parameters, such as ambient temperature, ambient convection coefficient, local blood temperature, and blood convection coefficient, has an effective role in decreasing the temperature of the eye. To this end, 3 different paths were employed to find out about the temperature distribution through the eye. The analysis of the three paths demonstrates the interaction of ambient and blood temperature in modeling temperature changes in specific locations of the eye. These data will be important in applications such as eye surgery, relaxation, and sleep therapy.

  2. Identification of hydroxyapatite spherules provides new insight into subretinal pigment epithelial deposit formation in the aging eye

    PubMed Central

    Thompson, Richard B.; Reffatto, Valentina; Bundy, Jacob G.; Kortvely, Elod; Flinn, Jane M.; Lanzirotti, Antonio; Jones, Emrys A.; McPhail, David S.; Fearn, Sarah; Boldt, Karsten; Ueffing, Marius; Ratu, Savanjeet Guy Singh; Pauleikhoff, Laurenz; Bird, Alan C.; Lengyel, Imre

    2015-01-01

    Accumulation of protein- and lipid-containing deposits external to the retinal pigment epithelium (RPE) is common in the aging eye, and has long been viewed as the hallmark of age-related macular degeneration (AMD). The cause for the accumulation and retention of molecules in the sub-RPE space, however, remains an enigma. Here, we present fluorescence microscopy and X-ray diffraction evidence for the formation of small (0.5–20 μm in diameter), hollow, hydroxyapatite (HAP) spherules in Bruch’s membrane in human eyes. These spherules are distinct in form, placement, and staining from the well-known calcification of the elastin layer of the aging Bruch’s membrane. Secondary ion mass spectrometry (SIMS) imaging confirmed the presence of calcium phosphate in the spherules and identified cholesterol enrichment in their core. Using HAP-selective fluorescent dyes, we show that all types of sub-RPE deposits in the macula, as well as in the periphery, contain numerous HAP spherules. Immunohistochemical labeling for proteins characteristic of sub-RPE deposits, such as complement factor H, vitronectin, and amyloid beta, revealed that HAP spherules were coated with these proteins. HAP spherules were also found outside the sub-RPE deposits, ready to bind proteins at the RPE/choroid interface. Based on these results, we propose a novel mechanism for the growth, and possibly even the formation, of sub-RPE deposits, namely, that the deposit growth and formation begin with the deposition of insoluble HAP shells around naturally occurring, cholesterol-containing extracellular lipid droplets at the RPE/choroid interface; proteins and lipids then attach to these shells, initiating or supporting the growth of sub-RPE deposits. PMID:25605911

  3. Activation of neural progenitor cells in human eyes with proliferative vitreoretinopathy.

    PubMed

    Johnsen, Erik O; Frøen, Rebecca C; Albert, Réka; Omdal, Bente K; Sarang, Zsolt; Berta, András; Nicolaissen, Bjørn; Petrovski, Goran; Moe, Morten C

    2012-05-01

    In addition to the ability for self-renewal and functional differentiation, neural stem/progenitor cells (NSCs) can respond to CNS injuries by targeted migration. In lower vertebrates, retinal injury is known to activate NSCs in the ciliary marginal zone (CMZ). Cells expressing markers of NSCs are also present in the ciliary body epithelium (CE) and in Müller glia in the peripheral retina (PR) of the adult human eye. However, these cells seem to be quiescent in the adult human eye and recent reports have shown that CE cells have limited properties of NSCs. In order to further clarify whether NSCs exist in the adult human eye, we tested whether NSC-like cells could be activated in eyes with proliferative vitreoretinopathy (PVR). The PR and CE were studied for NSC-associated markers in human enucleated control eyes and eyes with confirmed PVR, as well as in a mouse model of PVR. Furthermore, cells isolated from vitreous samples obtained during vitrectomies for retinal detachment were directly fixed or cultured in a stem cell-promoting medium and compared to cells cultured from the post-mortem retina and CE. In situ characterization of the normal eyes revealed robust expression of markers present in NSCs (Nestin, Sox2, Pax6) only around peripheral cysts of the proximal pars plana region and the PR, the latter population also staining for the glial marker GFAP. Although there were higher numbers of dividing cells in the CE of PVR eyes than in controls, we did not detect NSC-associated markers in the CE except around the proximal pars plana cysts. In the mice PVR eyes, Nestin activation was also found in the CE. In human PVR eyes, proliferation of both non-glial and glial cells co-staining NSC-associated markers was evident around the ora serrata region. Spheres formed in 7/10 vitreous samples from patients with PVR compared to 2/15 samples from patients with no known PVR, and expressed glial - and NSC-associated markers both after direct fixation and repetitive

  4. Intraocular Penetration of Intravenous Micafungin in Inflamed Human Eyes

    PubMed Central

    Sawada, Akira; Suemori, Shinsuke; Kawakami, Hideaki; Niwa, Yoshiaki; Kondo, Yuji; Ohkusu, Kiyofumi; Yamada, Noriaki; Ogura, Shinji; Yaguchi, Takashi; Nishimura, Kazuko; Kishino, Satoshi

    2013-01-01

    Eight eyes of 7 patients with fungal disease received intravenous injections of 150 to 300 mg micafungin, and samples of blood, cornea, retina-choroid, aqueous humor, and vitreous humor were collected. The micafungin levels in all collected samples exceeded the MICs; however, the levels in the vitreous and aqueous humors were lower. Our findings suggest that intravenous micafungin should be given in combination with intravitreal antifungal agents after vitrectomy in severe cases of intraocular fungal diseases. PMID:23689706

  5. Measurement of parameters of polarization in the living human eye using imaging polarimetry.

    PubMed

    Bueno, J M

    2000-01-01

    An imaging polarimeter using liquid-crystal variable retarders (Bueno, J. M., Artal, P. (1999). Double-pass imaging polarimetry in the human eye. Optics Letters, 24, 64-66) has been used to study the parameters of polarization in the living human eye. Retardation introduced by birefringent structures of the eye has been calculated by using a spatially resolved collection of Mueller matrices obtained from series of 16 double-pass retinal images. Results for images with a 2-mm pupil diameter show that although the retardation introduced by the eye in a double-pass varies among individuals, at the central cornea the slow axis is directed along the upper-temporal to lower-nasal line and the ellipticity is close to zero, which indicates the presence of linear birefringence. As pupil size increased, the measured retardation also increased, while ocular birefringence remained linear and azimuthal angle changed without a clear tendency.

  6. Age-related deficits in voluntary control over saccadic eye movements: consideration of electrical brain stimulation as a therapeutic strategy.

    PubMed

    Chen, Po Ling; Machado, Liana

    2016-05-01

    Sudden changes in our visual environment trigger reflexive eye movements, so automatically they often go unnoticed. Consequently, voluntary control over reflexive eye movements entails considerable effort. In relation to frontal-lobe deterioration, adult aging adversely impacts voluntary saccadic eye movement control in particular, which compromises effective performance of daily activities. Here, we review the nature of age-related changes in saccadic control, focusing primarily on the antisaccade task because of its assessment of 2 key age-sensitive control functions: reflexive saccade inhibition and voluntary saccade generation. With an ultimate view toward facilitating development of therapeutic strategies, we systematically review the neuroanatomy underpinning voluntary control over saccadic eye movements and natural mechanisms that kick in to compensate for age-related declines. We then explore the potential of noninvasive electrical brain stimulation to counteract aging deficits. Based on evidence that anodal transcranial direct current stimulation can confer a range of benefits specifically relevant to aging brains, we put forward this neuromodulation technique as a therapeutic strategy for improving voluntary saccadic eye movement control in older adults.

  7. Peripapillary Choroidal Thickness Variation With Age and Race in Normal Eyes

    PubMed Central

    Rhodes, Lindsay A.; Huisingh, Carrie; Johnstone, John; Fazio, Massimo A.; Smith, Brandon; Wang, Lan; Clark, Mark; Downs, J. Crawford; Owsley, Cynthia; Girard, Michael J. A.; Mari, Jean Martial; Girkin, Christopher A.

    2015-01-01

    Purpose. This study examined the association between peripapillary choroidal thickness (PCT) with age and race in a group of African descent (AD) and European descent (ED) subjects with normal eyes. Methods. Optic nerve head images from enhanced depth imaging spectral-domain optical coherence tomography of 166 normal eyes from 84 subjects of AD and ED were manually delineated to identify the principal surfaces of Bruch's membrane (BM), Bruch's membrane opening (BMO), and anterior sclera (AS). Peripapillary choroidal thickness was measured between BM and AS at increasing distance away from BMO. The mean PCT was compared between AD and ED subjects and generalized estimating equation (GEE) regression analysis was used to examine the association between race and PCT overall, in each quadrant, and by distance from BMO. Models were adjusted for age, BMO area, and axial length in the regression analysis. Results. Overall, the mean PCT increased from 63.9 μm ± 18.1 at 0 to 250 μm to 170.3 μm ± 56.7 at 1500 to 2000 μm from BMO. Individuals of AD had a greater mean PCT than those of ED at all distances from BMO (P < 0.05 at each distance) and in each quadrant (P < 0.05 in each quadrant). Results from multivariate regression indicate that ED subjects had significantly lower PCT compared to AD overall and in all quadrants and distances from BMO. Increasing age was also significantly associated with a lower PCT in both ED and AD participants. Conclusions. Peripapillary choroidal thickness varies with race and age, as individuals of AD have a thicker peripapillary choroid than those of ED. (ClinicalTrials.gov number, NCT00221923.) PMID:25711640

  8. Calorie restriction: A new therapeutic intervention for age-related dry eye disease in rats

    SciTech Connect

    Kawashima, Motoko; Kawakita, Tetsuya; Okada, Naoko; Ogawa, Yoko; Murat, Dogru; Nakamura, Shigeru; Nakashima, Hideo; Shimmura, Shigeto; Shinmura, Ken; Tsubota, Kazuo

    2010-07-09

    A decrease in lacrimal gland secretory function is closely related to aging and leads to an increased prevalence of dry eye syndrome. Since calorie restriction (CR) is considered to prevent functional decline of various organs due to aging, we hypothesized that CR could prevent age-related lacrimal dysfunction. Six-month-old male Fischer 344 rats were randomly divided into ad libitum (AL) and CR (-35%) groups. After 6 months of CR, tear function was examined under conscious state. After euthanasia, lacrimal glands were subjected to histological examination, tear protein secretion stimulation test with Carbachol, and assessment of oxidative stress with 8-hydroxy-2 deoxyguanosine (8-OHdG) and 4-hydroxynonenal (HNE) antibodies. CR significantly improved tear volume and tended to increase tear protein secretion volume after stimulation with Carbachol compared to AL. The acinar unit density was significantly higher in the CR rats compared to AL rats. Lacrimal glands in the CR rats showed a lesser degree of interstitial fibrosis. CR reduced the concentration of 8-OHdG and the extent of staining with HNE in the lacrimal gland, compared to AL. Furthermore, our electron microscopic observations showed that mitochondrial structure of the lacrimal gland obtained from the middle-aged CR rats was preserved in comparison to the AL rats. Collectively, these results demonstrate for the first time that CR may attenuate oxidative stress related damage in the lacrimal gland with preservation of lacrimal gland functions. Although molecular mechanism(s) by which CR maintains lacrimal gland function remains to be resolved, CR might provide a novel therapeutic strategy for treating dry eye syndrome.

  9. Optical imaging of the chorioretinal vasculature in the living human eye.

    PubMed

    Kim, Dae Yu; Fingler, Jeff; Zawadzki, Robert J; Park, Susanna S; Morse, Lawrence S; Schwartz, Daniel M; Fraser, Scott E; Werner, John S

    2013-08-27

    Detailed visualization of microvascular changes in the human retina is clinically limited by the capabilities of angiography imaging, a 2D fundus photograph that requires an intravenous injection of fluorescent dye. Whereas current angiography methods enable visualization of some retinal capillary detail, they do not adequately reveal the choriocapillaris or other microvascular features beneath the retina. We have developed a noninvasive microvascular imaging technique called phase-variance optical coherence tomography (pvOCT), which identifies vasculature three dimensionally through analysis of data acquired with OCT systems. The pvOCT imaging method is not only capable of generating capillary perfusion maps for the retina, but it can also use the 3D capabilities to segment the data in depth to isolate vasculature in different layers of the retina and choroid. This paper demonstrates some of the capabilities of pvOCT imaging of the anterior layers of choroidal vasculature of a healthy normal eye as well as of eyes with geographic atrophy (GA) secondary to age-related macular degeneration. The pvOCT data presented permit digital segmentation to produce 2D depth-resolved images of the retinal vasculature, the choriocapillaris, and the vessels in Sattler's and Haller's layers. Comparisons are presented between en face projections of pvOCT data within the superficial choroid and clinical angiography images for regions of GA. Abnormalities and vascular dropout observed within the choriocapillaris for pvOCT are compared with regional GA progression. The capability of pvOCT imaging of the microvasculature of the choriocapillaris and the anterior choroidal vasculature has the potential to become a unique tool to evaluate therapies and understand the underlying mechanisms of age-related macular degeneration progression.

  10. Ageing of the human hypothalamus.

    PubMed

    Swaab, D F

    1995-01-01

    The various hypothalamic nuclei show very different patterns of change in ageing. These patterns are a basis for changes in biological rhythms, hormones, autonomous functions or behavior. The suprachiasmatic nucleus (SCN) coordinates circadian and circannual rhythms. A marked seasonal and circadian variation in the vasopressin (AVP) cell number of the SCN was observed in relation to the variation in photoperiod. During normal ageing, the circadian variation and number of AVP-expressing neurons in the SCN decreases. The sexually dimorphic nucleus (SDN), intermediate nucleus or INAH-1 is localized between the supraoptic and paraventricular nucleus (PVN). In adult men the SDN is twice as large as in adult women. In girls, the SDN shows a first period of decreasing cell numbers during prepubertal development, leading to sexual dimorphism. During ageing a decrease in cell number is found in both sexes. The cells of the supraoptic nucleus and PVN produce AVP or oxytocin and coexpress tyrosine hydroxylase. These nuclei are examples of neuron populations that seem to stay perfectly intact in ageing. Parvicellular corticotropin-releasing-hormone (CRH)-containing neurons are found throughout the PVN. CRH neurons in the PVN are activated in the course of ageing, as indicated by their increase in number and AVP coexpression. Part of the infundibular (or arcuate) nucleus, the subventricular nucleus, contains hypertrophic neurons in postmenopausal women. The hypertrophied neurons contain neurokinin-B (NKB), substance P and estrogen receptors and probably act on LHRH neurons as interneurons. The NKB neurons may also be involved in the initiation of menopausal flushes. The nucleus tuberalis lateralis might be involved in feeding behavior and metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Longitudinal patterns of change in eye-hand coordination in children aged 8-16 years.

    PubMed

    Wicks, Lennon J; Telford, Rohan M; Cunningham, Ross B; Semple, Stuart J; Telford, Richard D

    2015-10-01

    Enhanced eye-hand coordination (EHC) is associated with greater participation in physical activity. No longitudinal studies have examined the change in throw-catch EHC from childhood to mid-adolescence. We investigated the development of EHC with an object control test from childhood to mid-adolescence in boys and girls. Evaluated at age 8, 10, 12 and 16 years, EHC was measured as the aggregate success rate of a throw and wall-rebound catch test. The test involved 40 attempts of progressive increasing difficulty, as determined by increased distances from a wall and transitions from two-handed to one-handed catches. Outcomes were treated as quasi-binomial and modelled by generalised linear mixed logistic regression analysis. EHC improved with age from childhood to mid-adolescence, although boys were more adept at each age (p<0.001). The patterns of change in EHC with increasing age varied according to the degree of difficulty of the task (p<0.001); throw and two-handed catch proficiency developing earlier than throw and one-handed catch in both sexes. Boys' EHC was better than girls' as early as age 8 years and male proficiency was maintained through to mid-adolescence. The proficiency of throw and two-handed catch rates developed faster than throw and one-handed catch rates for both sexes.

  12. Assessment of Choroidal Microstructure and Subfoveal Thickness Change in Eyes With Different Stages of Age-Related Macular Degeneration

    PubMed Central

    Lu, Linna; Xu, Shiqiong; He, Fangling; Liu, Yan; Zhang, Yidan; Wang, Jing; Wang, Zhiliang; Fan, Xianqun

    2016-01-01

    Abstract Age-related macular degeneration (AMD) is a major cause of irreversible blindness. Choroidal structural changes seem to be inevitable in AMD pathogenesis. Our study revealed associated choroidal microstructural changes in AMD eyes. The aim of the study was to compare choroidal microstructural changes in eyes with AMD of different stages. The study was a retrospective, cross-sectional case series. The participants comprised of 32 age-matched normal eyes as controls, and 26 fellow uninvolved eyes of intermediate/late AMD, 29 of early AMD, 28 of intermediate AMD, and 39 of late AMD. All subjects underwent comprehensive ophthalmologic examination. The choroid images, including subfoveal choroidal thickness, percentage of Sattler layer area, and en face images of the choroid, were obtained using spectral-domain optical coherence tomography. The main outcome measures were subfoveal choroidal thickness changes, percentage of Sattler layer area changes, and en face images of the choroid in AMD eyes. One hundred fifty-four eyes of 96 individuals with mean age of 67.1±9.2 years were included. The mean subfoveal choroidal thickness was 295.4 ± 56.8 μm in age-matched normal eyes, 306.7 ± 68.4 μm in fellow uninvolved eyes with AMD, 293.8 ± 80.4 μm in early AMD, 215.6 ± 80.4 μm in intermediate AMD, and 200.4 ± 66.6 μm in late AMD (F = 14.2, all P < 0.001). Choroidal thickness was greater in early AMD eyes than in intermediate/late AMD eyes (P < 0.001). Mean percentage of Sattler layer area in each group showed a similar tendency. Microstructure of the choroid showed reduced vascular density of Sattler layer areas in late AMD eyes compared with normal eyes. Decreasing subfoveal choroidal thickness and percentage of Sattler layer area were demonstrated in the progression of AMD. The choroidal change was related to atrophy of the microstructural changes of underlying capillaries and medium-sized vessels. PMID:26962799

  13. Looking at human eyes affects contralesional stimulus processing after right hemispheric stroke.

    PubMed

    Maravita, A; Posteraro, L; Husain, M; Vuilleumier, P; Schwartz, S; Driver, J

    2007-10-16

    Human eyes are a powerful social cue that may automatically attract the attention of an observer. Here we tested whether looking toward open human eyes, as often arises in standard clinical "confrontation" tests, may affect contralesional errors in a group of right brain-damaged patients showing visual extinction. Patients were requested to discriminate peripheral shape-targets presented on the left, right, or bilaterally. On each trial they also saw a central task-irrelevant stimulus, comprising an image of the eye sector of a human face, with those seen eyes open or closed. The conditions with central eye stimuli open (vs closed) induced more errors for contralesional peripheral targets, particularly for bilateral trials. These results suggest that seeing open eyes in central vision may attract attentional resources there, reducing attention to the periphery, particularly for the affected contralesional side. The seen gaze of the examiner may thus need to be considered during confrontation testing and may contribute to the effectiveness of that clinical procedure.

  14. Does direct human eye contact function as a warning cue for domestic sheep (Ovis aries)?

    PubMed

    Beausoleil, Ngaio J; Stafford, Kevin J; Mellor, David J

    2006-08-01

    Direct eye contact may function as a warning cue during interspecific interactions, and human staring has been shown to influence the behavior of many species. The authors used an arena test to assess whether human staring altered the behavior of domestic sheep (Ovis aries) compared with no human eye contact. Sheep glanced at the staring human's face more often in the first 2 min of the test, indicating that they perceived a difference between the human stimuli. Staring also elicited more locomotor activity and urination than averted gaze. However, there were no differences in fear-related behaviors, suggesting that a staring human did not represent a greater immediate threat than a nonwatching human. These results imply that human staring is a warning cue for domestic sheep, but no more. Without further reinforcement, sheep quickly habituated to the warning cue.

  15. Development of a novel pink-eyed dilution mouse model showing progressive darkening of the eyes and coat hair with aging

    PubMed Central

    ISHIKAWA, Akira; SUGIYAMA, Makoto; HONDO, Eiichi; KINOSHITA, Keiji; YAMAGISHI, Yuki

    2015-01-01

    Oca2p-cas (oculocutaneous albinism II; pink-eyed dilution castaneus) is a coat color mutant gene on mouse chromosome 7 that arose spontaneously in wild Mus musculus castaneus mice. Mice homozygous for Oca2p-cas usually exhibit pink eyes and gray coat hair on the non-agouti genetic background, and this ordinary phenotype remains unchanged throughout life. During breeding of a mixed strain carrying this gene on the C57BL/6J background, we discovered a novel spontaneous mutation that causes darkening of the eyes and coat hair with aging. In this study, we developed a novel mouse model showing this unique phenotype. Gross observations revealed that the pink eyes and gray coat hair of the novel mutant young mice became progressively darker in color by approximately 3 months after birth. Light and transmission-electron microscopic observations revealed a marked increase in melanin pigmentation of coat hair shafts and choroid of the eye in the novel mice compared to that in the ordinary mice. Sequence analysis of Oca2p-cas revealed a 4.1-kb deletion involving exons 15 and 16 of its wild-type gene. However, there was no sequence difference between the two types of mutant mice. Mating experiments suggested that the novel mutant phenotype was not inherited in a simple fashion, due to incomplete penetrance. The novel spontaneous mutant mouse is the first example of progressive hair darkening animals and is an essential animal model for understanding of the regulation mechanisms of melanin biosynthesis with aging. PMID:25739360

  16. Development of a novel pink-eyed dilution mouse model showing progressive darkening of the eyes and coat hair with aging.

    PubMed

    Ishikawa, Akira; Sugiyama, Makoto; Hondo, Eiichi; Kinoshita, Keiji; Yamagishi, Yuki

    2015-01-01

    Oca2(p-cas) (oculocutaneous albinism II; pink-eyed dilution castaneus) is a coat color mutant gene on mouse chromosome 7 that arose spontaneously in wild Mus musculus castaneus mice. Mice homozygous for Oca2(p-cas) usually exhibit pink eyes and gray coat hair on the non-agouti genetic background, and this ordinary phenotype remains unchanged throughout life. During breeding of a mixed strain carrying this gene on the C57BL/6J background, we discovered a novel spontaneous mutation that causes darkening of the eyes and coat hair with aging. In this study, we developed a novel mouse model showing this unique phenotype. Gross observations revealed that the pink eyes and gray coat hair of the novel mutant young mice became progressively darker in color by approximately 3 months after birth. Light and transmission-electron microscopic observations revealed a marked increase in melanin pigmentation of coat hair shafts and choroid of the eye in the novel mice compared to that in the ordinary mice. Sequence analysis of Oca2(p-cas) revealed a 4.1-kb deletion involving exons 15 and 16 of its wild-type gene. However, there was no sequence difference between the two types of mutant mice. Mating experiments suggested that the novel mutant phenotype was not inherited in a simple fashion, due to incomplete penetrance. The novel spontaneous mutant mouse is the first example of progressive hair darkening animals and is an essential animal model for understanding of the regulation mechanisms of melanin biosynthesis with aging.

  17. Does eating particular diets alter risk of age-related macular degeneration in users of the Age-Related Eye Disease Study supplements?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Recent information suggests that the Age-Related Eye Disease Study (AREDS) supplement, enhanced intake of omega-3 fatty acids, and diminishing dietary glycemic index (dGI) are protective against advanced age-related macular degeneration (AMD). Methods: Dietary information was collected a...

  18. Barriers to eye care among people aged 40 years and older with diagnosed diabetes, 2006-2010.

    PubMed

    Chou, Chiu-Fang; Sherrod, Cheryl E; Zhang, Xinzhi; Barker, Lawrence E; Bullard, Kai McKeever; Crews, John E; Saaddine, Jinan B

    2014-01-01

    OBJECTIVE We examine barriers to receiving recommended eye care among people aged ≥40 years with diagnosed diabetes. RESEARCH DESIGN AND METHODS We analyzed 2006-2010 Behavioral Risk Factor Surveillance System data from 22 states (n = 27,699). Respondents who had not sought eye care in the preceding 12 months were asked the main reason why. We categorized the reasons as cost/lack of insurance, no need, no eye doctor/travel/appointment, and other (meaning everything else). We used multinomial logistic regression to control for race/ethnicity, education, income, and other selected covariates. RESULTS Among adults with diagnosed diabetes, nonadherence to the recommended annual eye examinations was 23.5%. The most commonly reported reasons for not receiving eye care in the preceding 12 months were "no need" and "cost or lack of insurance" (39.7 and 32.3%, respectively). Other reasons were "no eye doctor," "no transportation" or "could not get appointment" (6.4%), and "other" (21.5%). After controlling for covariates, adults aged 40-64 years were more likely than those aged ≥65 years (relative risk ratio [RRR] = 2.79; 95% CI 2.01-3.89) and women were more likely than men (RRR = 2.33; 95% CI 1.75-3.14) to report "cost or lack of insurance" as their main reason. However, people aged 40-64 years were less likely than those aged ≥65 years to report "no need" (RRR = 0.51; 95% CI 0.39-0.67) as their main reason. CONCLUSIONS Addressing concerns about "cost or lack of insurance" for adults under 65 years and "no perceived need" among those 65 years and older could help improve eye care service utilization among people with diabetes.

  19. Barriers to Eye Care Among People Aged 40 Years and Older With Diagnosed Diabetes, 2006–2010

    PubMed Central

    Chou, Chiu-Fang; Sherrod, Cheryl E.; Zhang, Xinzhi; Barker, Lawrence E.; Bullard, Kai McKeever; Crews, John E.; Saaddine, Jinan B.

    2016-01-01

    OBJECTIVE We examine barriers to receiving recommended eye care among people aged ≥40 years with diagnosed diabetes. RESEARCH DESIGN AND METHODS We analyzed 2006–2010 Behavioral Risk Factor Surveillance System data from 22 states (n = 27,699). Respondents who had not sought eye care in the preceding 12 months were asked the main reason why. We categorized the reasons as cost/lack of insurance, no need, no eye doctor/travel/appointment, and other (meaning everything else). We used multinomial logistic regression to control for race/ethnicity, education, income, and other selected covariates. RESULTS Among adults with diagnosed diabetes, nonadherence to the recommended annual eye examinations was 23.5%. The most commonly reported reasons for not receiving eye care in the preceding 12 months were “no need” and “cost or lack of insurance” (39.7 and 32.3%, respectively). Other reasons were “no eye doctor,” “no transportation” or “could not get appointment” (6.4%), and “other” (21.5%). After controlling for covariates, adults aged 40–64 years were more likely than those aged ≥65 years (relative risk ratio [RRR] = 2.79; 95% CI 2.01–3.89) and women were more likely than men (RRR = 2.33; 95% CI 1.75–3.14) to report “cost or lack of insurance” as their main reason. However, people aged 40–64 years were less likely than those aged ≥65 years to report “no need” (RRR = 0.51; 95% CI 0.39–0.67) as their main reason. CONCLUSIONS Addressing concerns about “cost or lack of insurance” for adults under 65 years and “no perceived need” among those 65 years and older could help improve eye care service utilization among people with diabetes. PMID:24009300

  20. The Impact of Aging on Human Sexuality.

    ERIC Educational Resources Information Center

    Rienzo, Barbara A.

    1985-01-01

    Lay persons and professionals need to be educated on the effects of aging on human sexuality. Effective communication techniques and accurate sexuality information can lead to prevention of psychosocial problems and sexual dysfunction. (Author/DF)

  1. Characterization of Choroidal Layers in Normal Aging Eyes Using Enface Swept-Source Optical Coherence Tomography

    PubMed Central

    Mullins, Robert F.; Baumal, Caroline R.; Mohler, Kathrin J.; Kraus, Martin F.; Liu, Jonathan; Badaro, Emmerson; Alasil, Tarek; Hornegger, Joachim; Fujimoto, James G.; Duker, Jay S.; Waheed, Nadia K.

    2015-01-01

    Purpose To characterize qualitative and quantitative features of the choroid in normal eyes using enface swept-source optical coherence tomography (SS-OCT). Methods Fifty-two eyes of 26 consecutive normal subjects were prospectively recruited to obtain multiple three-dimensional 12x12mm volumetric scans using a long-wavelength high-speed SS-OCT prototype. A motion-correction algorithm merged multiple SS-OCT volumes to improve signal. Retinal pigment epithelium (RPE) was segmented as the reference and enface images were extracted at varying depths every 4.13μm intervals. Systematic analysis of the choroid at different depths was performed to qualitatively assess the morphology of the choroid and quantify the absolute thicknesses as well as the relative thicknesses of the choroidal vascular layers including the choroidal microvasculature (choriocapillaris, terminal arterioles and venules; CC) and choroidal vessels (CV) with respect to the subfoveal total choroidal thickness (TC). Subjects were divided into two age groups: younger (<40 years) and older (≥40 years). Results Mean age of subjects was 41.92 (24-66) years. Enface images at the level of the RPE, CC, CV, and choroidal-scleral interface were used to assess specific qualitative features. In the younger age group, the mean absolute thicknesses were: TC 379.4μm (SD±75.7μm), CC 81.3μm (SD±21.2μm) and CV 298.1μm (SD±63.7μm). In the older group, the mean absolute thicknesses were: TC 305.0μm (SD±50.9μm), CC 56.4μm (SD±12.1μm) and CV 248.6μm (SD±49.7μm). In the younger group, the relative thicknesses of the individual choroidal layers were: CC 21.5% (SD±4.0%) and CV 78.4% (SD±4.0%). In the older group, the relative thicknesses were: CC 18.9% (SD±4.5%) and CV 81.1% (SD±4.5%). The absolute thicknesses were smaller in the older age group for all choroidal layers (TC p=0.006, CC p=0.0003, CV p=0.03) while the relative thickness was smaller only for the CC (p=0.04). Conclusions Enface SS-OCT at

  2. Intravitreal aflibercept treatment in eyes with exudative age-related macular degeneration following prior treatment with intravitreal ranibizumab

    PubMed Central

    Narayan, Daniel Sanju; Muecke, James

    2015-01-01

    Background: To investigate visual and anatomical outcomes in eyes with exudative age-related macular degeneration treated with intravitreal aflibercept following prior treatment with intravitreal ranibizumab. Materials and Methods: Retrospective, single-center study of 192 eyes treated with 0.5 mg intravitreal ranibizumab every 4 weeks for three consecutive doses followed by a variable dose schedule. After more than 12 months of ranibizumab treatment, eyes that required ranibizumab injections at 4-week or 6-week intervals were switched to aflibercept therapy. Results: After 12–69 months (42 months ± 18 months, mean ± standard deviation [SD]) of treatment with intravitreal ranibizumab, 80 eyes were changed to 2 mg intravitreal aflibercept treatment with follow-up after 12–18 months (16 months ± 1 month, mean ± SD). Thirty-nine eyes had persistent macular fluid after treatment with ranibizumab. Mean logMAR visual acuity (VA) in eyes treated with ranibizumab changed by − 0.089 ± 0.310 (mean ± SD; P = 0.0003), which correlates to an approximate gain of 4.5 letters. The number of eyes with macular fluid decreased from 39 to 23 after aflibercept treatment. Mean logMAR VA in eyes with intraretinal macular fluid treated with aflibercept changed by −0.079 ± 0.134 (mean ± SD; P = 0.006), which correlates to an approximate gain of 4 letters. Mean logMAR VA in eyes with submacular fluid was not significantly different after aflibercept treatment. Conclusion: Eyes with persistent intraretinal macular fluid had visual and anatomic response after changing from ranibizumab to aflibercept treatment. PMID:26669334

  3. Curvature sensor for the measurement of the static corneal topography and the dynamic tear film topography in the human eye

    NASA Astrophysics Data System (ADS)

    Gruppetta, Steve; Koechlin, Laurent; Lacombe, François; Puget, Pascal

    2005-10-01

    A system to measure the topography of the first optical surface of the human eye noninvasively by using a curvature sensor is described. The static corneal topography and the dynamic topography of the tear film can both be measured, and the topographies obtained are presented. The system makes possible the study of the dynamic aberrations introduced by the tear film to determine their contribution to the overall ocular aberrations in healthy eyes, eyes with corneal pathologies, and eyes wearing contact lenses.

  4. Ocular penetration of cyclosporin A. III: The human eye.

    PubMed Central

    BenEzra, D; Maftzir, G; de Courten, C; Timonen, P

    1990-01-01

    The distribution of cyclosporin A (CsA) in the blood, saliva, tears, aqueous humour, vitreous, and cerebrospinal fluid has been studied after oral treatment with 5 mg/kg/day of CsA or application of 2% CsA eye drops in olive oil solution. After oral treatment all patients had high CsA levels in blood. Measurable levels of CsA were also found in the saliva and tears. Patients without any intraocular inflammation or patients with mild uveitis did not have any detectable CsA in the aqueous humour. However, patients with severe uveitis had significant levels of CsA in the aqueous humour and in the vitreous. No CsA was found in the cerebrospinal fluid of two patients with central nervous system manifestations of Behçet's disease. After local treatment with 2% CsA eye drops no detectable levels of CsA were found in the blood, the saliva, the aqueous humour, or the vitreous even in patients with severe uveitis. PMID:2378841

  5. Versatile optical coherence tomography for imaging the human eye.

    PubMed

    Tao, Aizhu; Shao, Yilei; Zhong, Jianguang; Jiang, Hong; Shen, Meixiao; Wang, Jianhua

    2013-07-01

    We demonstrated the feasibility of a CMOS-based spectral domain OCT (SD-OCT) for versatile ophthalmic applications of imaging the corneal epithelium, limbus, ocular surface, contact lens, crystalline lens, retina, and full eye in vivo. The system was based on a single spectrometer and an alternating reference arm with four mirrors. A galvanometer scanner was used to switch the reference beam among the four mirrors, depending on the imaging application. An axial resolution of 7.7 μm in air, a scan depth of up to 37.7 mm in air, and a scan speed of up to 70,000 A-lines per second were achieved. The approach has the capability to provide high-resolution imaging of the corneal epithelium, contact lens, ocular surface, and tear meniscus. Using two reference mirrors, the zero delay lines were alternatively placed on the front cornea or on the back lens. The entire ocular anterior segment was imaged by registering and overlapping the two images. The full eye through the pupil was measured when the reference arm was switched among the four reference mirrors. After mounting a 60 D lens in the sample arm, this SD-OCT was used to image the retina, including the macula and optical nerve head. This system demonstrates versatility and simplicity for multi-purpose ophthalmic applications.

  6. Eye tracking using artificial neural networks for human computer interaction.

    PubMed

    Demjén, E; Aboši, V; Tomori, Z

    2011-01-01

    This paper describes an ongoing project that has the aim to develop a low cost application to replace a computer mouse for people with physical impairment. The application is based on an eye tracking algorithm and assumes that the camera and the head position are fixed. Color tracking and template matching methods are used for pupil detection. Calibration is provided by neural networks as well as by parametric interpolation methods. Neural networks use back-propagation for learning and bipolar sigmoid function is chosen as the activation function. The user's eye is scanned with a simple web camera with backlight compensation which is attached to a head fixation device. Neural networks significantly outperform parametric interpolation techniques: 1) the calibration procedure is faster as they require less calibration marks and 2) cursor control is more precise. The system in its current stage of development is able to distinguish regions at least on the level of desktop icons. The main limitation of the proposed method is the lack of head-pose invariance and its relative sensitivity to illumination (especially to incidental pupil reflections).

  7. Versatile optical coherence tomography for imaging the human eye

    PubMed Central

    Tao, Aizhu; Shao, Yilei; Zhong, Jianguang; Jiang, Hong; Shen, Meixiao; Wang, Jianhua

    2013-01-01

    We demonstrated the feasibility of a CMOS-based spectral domain OCT (SD-OCT) for versatile ophthalmic applications of imaging the corneal epithelium, limbus, ocular surface, contact lens, crystalline lens, retina, and full eye in vivo. The system was based on a single spectrometer and an alternating reference arm with four mirrors. A galvanometer scanner was used to switch the reference beam among the four mirrors, depending on the imaging application. An axial resolution of 7.7 μm in air, a scan depth of up to 37.7 mm in air, and a scan speed of up to 70,000 A-lines per second were achieved. The approach has the capability to provide high-resolution imaging of the corneal epithelium, contact lens, ocular surface, and tear meniscus. Using two reference mirrors, the zero delay lines were alternatively placed on the front cornea or on the back lens. The entire ocular anterior segment was imaged by registering and overlapping the two images. The full eye through the pupil was measured when the reference arm was switched among the four reference mirrors. After mounting a 60 D lens in the sample arm, this SD-OCT was used to image the retina, including the macula and optical nerve head. This system demonstrates versatility and simplicity for multi-purpose ophthalmic applications. PMID:23847729

  8. Switchable liquid crystal contact lenses: dynamic vision for the ageing eye

    NASA Astrophysics Data System (ADS)

    Milton, Harry E.; Gleeson, Helen F.; Morgan, Philip B.; Goodby, John W.; Cowling, Stephen; Clamp, John H.

    2014-02-01

    The inability of the eye to focus on nearby objects, presbyopia, is suffered by ~100% of people over the age of 50. Liquid crystal (LC) spectacle lenses have shown great potential for correcting presbyopia. However, correcting presbyopia in contact lens users has proven elusive and existing commercial options suffer significant compromises in vision and comfort. We describe a novel contact lens that includes a liquid crystal element that offers to correct presbyopia without the compromises associated with other technologies. We fabricated variable focus lenses using a balanced optical system, providing the additional optical power presbyopes require for near vision (typically +1.00 D to +2.00 D). The system uses positive optical power from the two substrates and variable negative optical power from the LC layer to form a balanced optical system which, when unpowered, corrects distance vision. Upon voltage application, the liquid crystal layer decreases in refractive index, resulting in additional optical power in the system, offering correction equivalent to reading glasses. Our new technology is based on a traditional contact lens material which could be placed directly on the eye. The liquid crystal lens employed is well suited to the small optical areas associated with contact lenses. We compare several different LC materials and geometries which are suitable for our application, and discuss the influence of material and geometry on switching times, optical quality and operating voltage. Our contact lenses typically switch +/-2.00D in response to < 10 Vrms with response times of the order of a second.

  9. Novel quantitative pigmentation phenotyping enhances genetic association, epistasis, and prediction of human eye colour

    PubMed Central

    Wollstein, Andreas; Walsh, Susan; Liu, Fan; Chakravarthy, Usha; Rahu, Mati; Seland, Johan H.; Soubrane, Gisèle; Tomazzoli, Laura; Topouzis, Fotis; Vingerling, Johannes R.; Vioque, Jesus; Böhringer, Stefan; Fletcher, Astrid E.; Kayser, Manfred

    2017-01-01

    Success of genetic association and the prediction of phenotypic traits from DNA are known to depend on the accuracy of phenotype characterization, amongst other parameters. To overcome limitations in the characterization of human iris pigmentation, we introduce a fully automated approach that specifies the areal proportions proposed to represent differing pigmentation types, such as pheomelanin, eumelanin, and non-pigmented areas within the iris. We demonstrate the utility of this approach using high-resolution digital eye imagery and genotype data from 12 selected SNPs from over 3000 European samples of seven populations that are part of the EUREYE study. In comparison to previous quantification approaches, (1) we achieved an overall improvement in eye colour phenotyping, which provides a better separation of manually defined eye colour categories. (2) Single nucleotide polymorphisms (SNPs) known to be involved in human eye colour variation showed stronger associations with our approach. (3) We found new and confirmed previously noted SNP-SNP interactions. (4) We increased SNP-based prediction accuracy of quantitative eye colour. Our findings exemplify that precise quantification using the perceived biological basis of pigmentation leads to enhanced genetic association and prediction of eye colour. We expect our approach to deliver new pigmentation genes when applied to genome-wide association testing. PMID:28240252

  10. Eye coding mechanisms in early human face event-related potentials.

    PubMed

    Rousselet, Guillaume A; Ince, Robin A A; van Rijsbergen, Nicola J; Schyns, Philippe G

    2014-11-10

    In humans, the N170 event-related potential (ERP) is an integrated measure of cortical activity that varies in amplitude and latency across trials. Researchers often conjecture that N170 variations reflect cortical mechanisms of stimulus coding for recognition. Here, to settle the conjecture and understand cortical information processing mechanisms, we unraveled the coding function of N170 latency and amplitude variations in possibly the simplest socially important natural visual task: face detection. On each experimental trial, 16 observers saw face and noise pictures sparsely sampled with small Gaussian apertures. Reverse-correlation methods coupled with information theory revealed that the presence of the eye specifically covaries with behavioral and neural measurements: the left eye strongly modulates reaction times and lateral electrodes represent mainly the presence of the contralateral eye during the rising part of the N170, with maximum sensitivity before the N170 peak. Furthermore, single-trial N170 latencies code more about the presence of the contralateral eye than N170 amplitudes and early latencies are associated with faster reaction times. The absence of these effects in control images that did not contain a face refutes alternative accounts based on retinal biases or allocation of attention to the eye location on the face. We conclude that the rising part of the N170, roughly 120-170 ms post-stimulus, is a critical time-window in human face processing mechanisms, reflecting predominantly, in a face detection task, the encoding of a single feature: the contralateral eye.

  11. Novel quantitative pigmentation phenotyping enhances genetic association, epistasis, and prediction of human eye colour.

    PubMed

    Wollstein, Andreas; Walsh, Susan; Liu, Fan; Chakravarthy, Usha; Rahu, Mati; Seland, Johan H; Soubrane, Gisèle; Tomazzoli, Laura; Topouzis, Fotis; Vingerling, Johannes R; Vioque, Jesus; Böhringer, Stefan; Fletcher, Astrid E; Kayser, Manfred

    2017-02-27

    Success of genetic association and the prediction of phenotypic traits from DNA are known to depend on the accuracy of phenotype characterization, amongst other parameters. To overcome limitations in the characterization of human iris pigmentation, we introduce a fully automated approach that specifies the areal proportions proposed to represent differing pigmentation types, such as pheomelanin, eumelanin, and non-pigmented areas within the iris. We demonstrate the utility of this approach using high-resolution digital eye imagery and genotype data from 12 selected SNPs from over 3000 European samples of seven populations that are part of the EUREYE study. In comparison to previous quantification approaches, (1) we achieved an overall improvement in eye colour phenotyping, which provides a better separation of manually defined eye colour categories. (2) Single nucleotide polymorphisms (SNPs) known to be involved in human eye colour variation showed stronger associations with our approach. (3) We found new and confirmed previously noted SNP-SNP interactions. (4) We increased SNP-based prediction accuracy of quantitative eye colour. Our findings exemplify that precise quantification using the perceived biological basis of pigmentation leads to enhanced genetic association and prediction of eye colour. We expect our approach to deliver new pigmentation genes when applied to genome-wide association testing.

  12. Goat's eye integrated with a human cataractous lens: A training model for phacoemulsification

    PubMed Central

    Sengupta, Sabyasachi; Dhanapal, Praveen; Nath, Manas; Haripriya, Aravind; Venkatesh, Rengaraj

    2015-01-01

    A relatively simple and inexpensive technique to train surgeons in phacoemulsification using a goat's eye integrated with a human cataractous nucleus is described. The goat's eye is placed on a bed of cotton within the lumen of a cylindrical container. This is then mounted on a rectangular thermocol so that the limbus is presented at the surgical field. After making a clear corneal entry with a keratome, the trainer makes a 5–5.5 mm continuous curvilinear capsulorhexis in the anterior lens capsule, creates a crater of adequate depth in the cortex and inserts the human nucleus within this crater in the goat's capsular bag. The surgical wound is sutured, and the goat's eye is ready for training. Creating the capsulorhexis with precision and making the crater of adequate depth to snugly accommodate the human nucleus are the most important steps to prevent excessive wobbling of the nucleus while training. PMID:25971179

  13. Identification of lymphatics in the ciliary body of the human eye: a novel "uveolymphatic" outflow pathway.

    PubMed

    Yücel, Yeni H; Johnston, Miles G; Ly, Tina; Patel, Manoj; Drake, Brian; Gümüş, Ersin; Fraenkl, Stephan A; Moore, Sara; Tobbia, Dalia; Armstrong, Dianna; Horvath, Eva; Gupta, Neeru

    2009-11-01

    Impaired aqueous humor flow from the eye may lead to elevated intraocular pressure and glaucoma. Drainage of aqueous fluid from the eye occurs through established routes that include conventional outflow via the trabecular meshwork, and an unconventional or uveoscleral outflow pathway involving the ciliary body. Based on the assumption that the eye lacks a lymphatic circulation, the possible role of lymphatics in the less well defined uveoscleral pathway has been largely ignored. Advances in lymphatic research have identified specific lymphatic markers such as podoplanin, a transmembrane mucin-type glycoprotein, and lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1). Lymphatic channels were identified in the human ciliary body using immunofluorescence with D2-40 antibody for podoplanin, and LYVE-1 antibody. In keeping with the criteria for lymphatic vessels in conjunctiva used as positive control, D2-40 and LYVE-1-positive lymphatic channels in the ciliary body had a distinct lumen, were negative for blood vessel endothelial cell marker CD34, and were surrounded by either discontinuous or no collagen IV-positive basement membrane. Cryo-immunogold electron microscopy confirmed the presence D2-40-immunoreactivity in lymphatic endothelium in the human ciliary body. Fluorescent nanospheres injected into the anterior chamber of the sheep eye were detected in LYVE-1-positive channels of the ciliary body 15, 30, and 45 min following injection. Four hours following intracameral injection, Iodine-125 radio-labeled human serum albumin injected into the sheep eye (n = 5) was drained preferentially into cervical, retropharyngeal, submandibular and preauricular lymph nodes in the head and neck region compared to reference popliteal lymph nodes (P < 0.05). These findings collectively indicate the presence of distinct lymphatic channels in the human ciliary body, and that fluid and solutes flow at least partially through this system. The discovery of a uveolymphatic

  14. Lipid-protein interactions in plasma membranes of fiber cells isolated from the human eye lens.

    PubMed

    Raguz, Marija; Mainali, Laxman; O'Brien, William J; Subczynski, Witold K

    2014-03-01

    The protein content in human lens membranes is extremely high, increases with age, and is higher in the nucleus as compared with the cortex, which should strongly affect the organization and properties of the lipid bilayer portion of intact membranes. To assess these effects, the intact cortical and nuclear fiber cell plasma membranes isolated from human lenses from 41- to 60-year-old donors were studied using electron paramagnetic resonance spin-labeling methods. Results were compared with those obtained for lens lipid membranes prepared from total lipid extracts from human eyes of the same age group [Mainali, L., Raguz, M., O'Brien, W. J., and Subczynski, W. K. (2013) Biochim. Biophys. Acta]. Differences were considered to be mainly due to the effect of membrane proteins. The lipid-bilayer portions of intact membranes were significantly less fluid than lipid bilayers of lens lipid membranes, prepared without proteins. The intact membranes were found to contain three distinct lipid environments termed the bulk lipid domain, boundary lipid domain, and trapped lipid domain. However, the cholesterol bilayer domain, which was detected in cortical and nuclear lens lipid membranes, was not detected in intact membranes. The relative amounts of bulk and trapped lipids were evaluated. The amount of lipids in domains uniquely formed due to the presence of membrane proteins was greater in nuclear membranes than in cortical membranes. Thus, it is evident that the rigidity of nuclear membranes is greater than that of cortical membranes. Also the permeability coefficients for oxygen measured in domains of nuclear membranes were significantly lower than appropriate coefficients measured in cortical membranes. Relationships between the organization of lipids into lipid domains in fiber cells plasma membranes and the organization of membrane proteins are discussed.

  15. Lipid-Protein Interactions in Plasma Membranes of Fiber Cells Isolated from the Human Eye Lens

    PubMed Central

    Raguz, Marija; Mainali, Laxman; O’Brien, William J.; Subczynski, Witold K.

    2014-01-01

    The protein content in human lens membranes is extremely high, increases with age, and is higher in the nucleus as compared with the cortex, which should strongly affect the organization and properties of the lipid bilayer portion of intact membranes. To assess these effects, the intact cortical and nuclear fiber cell plasma membranes isolated from human lenses from 41- to 60-year-old donors were studied using electron paramagnetic resonance spin-labeling methods. Results were compared with those obtained for lens lipid membranes prepared from total lipid extracts from human eyes of the same age group [Mainali,L., Raguz, M., O’Brien, W. J., and Subczynski, W. K. (2013) Biochim. Biophys. Acta]. Differences were considered to be mainly due to the effect of membrane proteins. The lipid-bilayer portions of intact membranes were significantly less fluid than lipid bilayers of lens lipid membranes, prepared without proteins. The intact membranes were found to contain three distinct lipid environments termed the bulk lipid domain, boundary lipid domain, and trapped lipid domain. However, the cholesterol bilayer domain, which was detected in cortical and nuclear lens lipid membranes, was not detected in intact membranes. The relative amounts of bulk and trapped lipids were evaluated. The amount of lipids in domains uniquely formed due to the presence of membrane proteins was greater in nuclear membranes than in cortical membranes. Thus, it is evident that the rigidity of nuclear membranes is greater than that of cortical membranes. Also the permeability coefficients for oxygen measured in domains of nuclear membranes were significantly lower than appropriate coefficients measured in cortical membranes. Relationships between the organization of lipids into lipid domains in fiber cells plasma membranes and the organization of membrane proteins are discussed. PMID:24486794

  16. Age Differences in Online Processing of Video: An Eye Movement Study

    PubMed Central

    Kirkorian, Heather L.; Anderson, Daniel R.; Keen, Rachel

    2011-01-01

    Eye movements were recorded while 62 one-year-olds, four-year-olds, and adults watched television. Of interest was the extent to which viewers looked at the same place at the same time as their peers because high similarity across viewers suggests systematic viewing driven by comprehension processes. Similarity of gaze location increased with age. This was particularly true immediately following a cut to a new scene, partly because older viewers (but not infants) tended to fixate the center of the screen following a cut. Conversely, infants appear to require several seconds to orient to a new scene. Results are interpreted in the context of developing attention skills. Findings have implications for the extent to which infants comprehend and learn from commercial video. PMID:22288510

  17. Statistical characteristics of aberrations of human eyes after small incision lenticule extraction surgery and analysis of visual performance with individual eye model.

    PubMed

    Lou, Qiqi; Wang, Yan; Wang, Zhaoqi; Liu, Yongji; Zhang, Lin; Fang, Hui

    2015-09-01

    Preoperative and postoperative wavefront aberrations of 73 myopic eyes with small incision lenticule extraction surgery are analyzed in this paper. Twenty-eight postoperative individual eye models are constructed to investigate the visual acuity (VA) of human eyes. Results show that in photopic condition, residual defocus, residual astigmatism, and higher-order aberrations are relatively small. 100% of eyes reach a VA of 0.8 or better, and 89.3% of eyes reach a VA of 1.0 or better. In scotopic condition, the residual defocus and the higher-order aberrations are, respectively, 1.9 and 8.5 times the amount of that in photopic condition, and the defocus becomes the main factor attenuating visual performance.

  18. Incidence of Choroidal Neovascularization in the Fellow Eye in the Comparison of Age-related Macular Degeneration Treatments Trials

    PubMed Central

    Maguire, Maureen G.; Daniel, Ebenezer; Shah, Ankoor R.; Grunwald, Juan E.; Hagstrom, Stephanie A.; Avery, Robert L.; Huang, Jiayan; Martin, Revell W.; Roth, Daniel B.; Castellarin, Alessandro A.; Bakri, Sophie J.; Fine, Stuart L.; Martin, Daniel F.

    2013-01-01

    Objective To assess the influence of drug, dosing regimen, and traditional, non-traditional, and genetic risk factors on the incidence of choroidal neovascularization (CNV) in the fellow eye of patients treated for CNV with ranibizumab or bevacizumab. Design Cohort study of patients enrolled in a multicenter randomized clinical trial. Participants Patients with no CNV in the fellow eye at the time of enrollment in the Comparison of Age-related Macular Degeneration Treatments Trials (CATT). Methods Eligibility criteria for the clinical trial required that study eyes have evidence on fluorescein angiography and optical coherence tomography (OCT) of CNV secondary to age-related macular degeneration (AMD) and visual acuity between 20/25 and 20/320. Treatment for the study eye was assigned randomly to either ranibizumab or bevacizumab and to three different regimens for dosing over a two-year period. The genotypes for four single nucleotide polymorphisms (SNPS) associated with risk of AMD were determined. Only patients without CNV in the fellow eye at baseline were considered at risk. CATT ophthalmologists examined patients every four weeks through two years and recorded treatment for CNV in the fellow eye. Main Outcome Measures Development of CNV in the fellow eye. Results Among 1185 CATT participants, 727 (61%) had no CNV in the fellow eye at enrollment. At two years, CNV had developed in 75 (20.6%) of 365 patients treated with ranibizumab and 60 (16.6%) of 362 patients treated with bevacizumab (absolute difference 4.0%, 95% confidence interval (−1.7%, 9.6%); p=0.17). The risk ratio for pro re nata (PRN) dosing relative to monthly dosing was 1.1 (95% confidence interval (0.8, 1.6)). Greater elevation of the retinal pigment epithelium and fluid in the foveal center of the study eye were associated with increased incidence of CNV in the fellow eye. Incidence was not associated with genotype on rs1061170 (CFH), rs10490924 (ARMS2), rs11200638 (HTRA1), and rs2230199 (C3

  19. Category Processing and the human likeness dimension of the Uncanny Valley Hypothesis: Eye-Tracking Data.

    PubMed

    Cheetham, Marcus; Pavlovic, Ivana; Jordan, Nicola; Suter, Pascal; Jancke, Lutz

    2013-01-01

    The Uncanny Valley Hypothesis (Mori, 1970) predicts that perceptual difficulty distinguishing between a humanlike object (e.g., lifelike prosthetic hand, mannequin) and its human counterpart evokes negative affect. Research has focused on affect, with inconsistent results, but little is known about how objects along the hypothesis' dimension of human likeness (DHL) are actually perceived. This study used morph continua based on human and highly realistic computer-generated (avatar) faces to represent the DHL. Total number and dwell time of fixations to facial features were recorded while participants (N = 60) judged avatar versus human category membership of the faces in a forced choice categorization task. Fixation and dwell data confirmed the face feature hierarchy (eyes, nose, and mouth in this order of importance) across the DHL. There were no further findings for fixation. A change in the relative importance of these features was found for dwell time, with greater preferential processing of eyes and mouth of categorically ambiguous faces compared with unambiguous avatar faces. There were no significant differences between ambiguous and human faces. These findings applied for men and women, though women generally dwelled more on the eyes to the disadvantage of the nose. The mouth was unaffected by gender. In summary, the relative importance of facial features changed on the DHL's non-human side as a function of categorization ambiguity. This change was indicated by dwell time only, suggesting greater depth of perceptual processing of the eyes and mouth of ambiguous faces compared with these features in unambiguous avatar faces.

  20. Towards Quantum Experiments with Human Eye Detectors Based on Cloning via Stimulated Emission ?

    NASA Astrophysics Data System (ADS)

    De Martini, Francesco

    2010-05-01

    In a recent theoretical paper published in Physical Review Letters, Sekatsky, Brunner, Branciard, Gisin, Simon report an extended investigation on some properties of the human eye that affect its behavior as a quantum detector. We believe that the content of this work, albeit appealing at fist sight, is highly questionable simply because the human eye cannot be adopted as a sensing device within any quantum measurement apparatus. Furthermore, the criticism raised by these Authors against a real experiment on Micro—Macro entanglement recently published in Physical Review Letters (100, 253601, 2008) is found misleading and misses its target.

  1. Simulation of the optical performance of refractive elements to mimic the human eye focusing

    NASA Astrophysics Data System (ADS)

    Diaz-Gonzalez, G.; Santiago-Alvarado, Agustín.; Cruz-Félix, Ángel S.

    2015-09-01

    Refractive optics has evolved and incorporated new elements in optical systems every day, such as conventional lenses, tunable lenses, GRIN lenses, diffractive lenses, intraocular lenses, etc. Some of these elements are reported in the literature together with different proposed models of the human eye. In this work, optical properties of some of these lenses will be studied, and simulations of their behavior will be done in order to analyze which one is better for imaging process. Such lenses will be incorporated in an optical system that mimics the human eye behavior. Analysis and obtained results are reported, as well as the proposed optical system. Finally, we present the conclusions of the work.

  2. Color vision deficiency in a middle-aged population: the Shahroud Eye Study.

    PubMed

    Jafarzadehpur, Ebrahim; Hashemi, Hassan; Emamian, Mohammad Hassan; Khabazkhoob, Mehdi; Mehravaran, Shiva; Shariati, Mohammad; Fotouhi, Akbar

    2014-10-01

    The aim of this study was to determine the prevalence of color vision defects in the middle-age population of Shahroud, Iran. We selected 6,311 people from the 40- to 64-year-old population through random cluster sampling. Color vision testing was performed with the Farnsworth D-15. Cases with similar and symmetric results in both eyes were classified as hereditary, and those with asymmetric results were considered acquired. Cases that did not conform to standard patterns were classified as unknown category. Of 5,190 respondents (response rate 82.2 %), 5,102 participants underwent the color vision test. Of these, 14.7 % (95 % confidence interval 13.7-15.6) had some type of color vision deficiency. Of the 2,157 male participants, 6.2 % were hereditary and 10.2 % were acquired and of the 2,945 female participants, 3.1 % were hereditary and 10 % were acquired. Hereditary color deficiencies were mostly of the deutan form (63.8 %), and acquired deficiencies were mostly tritan (66.1 %). The prevalence of hereditary and acquired color vision deficiency, as well as different types of red-green and blue-yellow color vision defects significantly increased with age (p < 0.001). In conclusion, the pattern of color vision defects among the middle-aged population of Shahroud was significantly different from that seen in the younger population. This could be due to changes associated with age, gender, medical and ocular conditions, and differences in race and environment. Thus, results of previous examinations and the overall health status should be considered before making any judgment about the status of color vision in middle-aged people.

  3. A Mesolithic (Middle Stone Age!) Spanish artificial eye: please realize this technology is circa 7000-years-old!

    PubMed

    Enoch, Jay M

    2009-04-01

    In 2008, the author presented a paper at the Cogan Society which addressed an amazing ancient artificial eye recently found in Iran. That artificial eye is about 5000-years-old. A kind reader of some of JME's writings [who lives in Spain] noted this report, and called his attention to yet another artificial eye of a similar sort, but it was 2000 years older! It is dated ca. 7000 years BP [before the present] during the Mesolithic Time Period, i.e., the Middle Stone Age(!), and was unearthed in modern Spain. This artificial eye was found in situ in the right orbit of the scull of a man who died at 40-45 years of age. The man was tall, and was apparently relatively well-to-do (JME assumes this is based upon items found in the grave). The artificial eye was made of ocher (or ochre). In the artificial eye, an incised cornea (and possibly a pupil) can be identified. This prosthesis may have been inserted backwards into the orbit at the time of burial. This artificial eye was much more primitive in both shape and design than the later one discovered at "The Bumt City" in Eastern Iran. The man's body (containing the artificial eye) was found at an archaeological site in Spain called Cingle del Mas Nou i Cava Fosca, Ares del Maestro, Castellón Province. This particular body was exhumed at Cingle del Mas Nou by Profa. Dr. Carme Olària Puyoles and her team.

  4. Dose conversion coefficients for neutron exposure to the lens of the human eye

    SciTech Connect

    Manger, Ryan P; Bellamy, Michael B; Eckerman, Keith F

    2011-01-01

    Dose conversion coefficients for the lens of the human eye have been calculated for neutron exposure at energies from 1 x 10{sup -9} to 20 MeV and several standard orientations: anterior-to-posterior, rotational and right lateral. MCNPX version 2.6.0, a Monte Carlo-based particle transport package, was used to determine the energy deposited in the lens of the eye. The human eyeball model was updated by partitioning the lens into sensitive and insensitive volumes as the anterior portion (sensitive volume) of the lens being more radiosensitive and prone to cataract formation. The updated eye model was used with the adult UF-ORNL mathematical phantom in the MCNPX transport calculations.

  5. Eye center localization and gaze gesture recognition for human-computer interaction.

    PubMed

    Zhang, Wenhao; Smith, Melvyn L; Smith, Lyndon N; Farooq, Abdul

    2016-03-01

    This paper introduces an unsupervised modular approach for accurate and real-time eye center localization in images and videos, thus allowing a coarse-to-fine, global-to-regional scheme. The trajectories of eye centers in consecutive frames, i.e., gaze gestures, are further analyzed, recognized, and employed to boost the human-computer interaction (HCI) experience. This modular approach makes use of isophote and gradient features to estimate the eye center locations. A selective oriented gradient filter has been specifically designed to remove strong gradients from eyebrows, eye corners, and shadows, which sabotage most eye center localization methods. A real-world implementation utilizing these algorithms has been designed in the form of an interactive advertising billboard to demonstrate the effectiveness of our method for HCI. The eye center localization algorithm has been compared with 10 other algorithms on the BioID database and six other algorithms on the GI4E database. It outperforms all the other algorithms in comparison in terms of localization accuracy. Further tests on the extended Yale Face Database b and self-collected data have proved this algorithm to be robust against moderate head poses and poor illumination conditions. The interactive advertising billboard has manifested outstanding usability and effectiveness in our tests and shows great potential for benefiting a wide range of real-world HCI applications.

  6. Histopathological Studies on Rabbits Infected by Bacteria Causing Infectious Keratitis in Human through Eye Inoculation

    PubMed Central

    Aldebasi, Yousef H.; Mohamed, Hala A.; Aly, Salah M.

    2014-01-01

    Aim This study aimed to investigate the pathogenic effect of bacteria causing infectious keratitis among patients through experimental study conducted on rabbits’ eyes with the aid of histopathology as eye infection is a common disease in developing countries that may complicate to loss of vision. Methodology 100 swab samples were collected from human infected eyes, at Qassim region during 2012, for the isolation of Pseudomonas aeruginosa and Staphylococcus aureus. The isolated pathogenic bacteria were tested to various antibiotics using some selected antibiotics discs through agar-well diffusion method. Then, experimental study conducted on 27 rabbits. The rabbits were divided randomly into three equal groups, each containing 9 rabbits. Rabbits of group (1) served as control group (Negative Control) and their eyes were inoculated with the buffer only. Rabbits of group (2) were inoculated through eyes with the isolated Pseudomonas aeruginosa. Rabbits of group (3) were inoculated through eyes with the isolated Staphylococcus aureus. Results Out of 100 collected swab samples from human infected eyes, Pseudomonas aeruginosa and Staphylococcus aureus were isolated with a total percentage of 25.21% and 15.65%; respectively and used in this study. Both bacterial isolates were sensitive to Gentamicin and Cefuroxime. Clinically, experimentally infected rabbits by Pseudomonas aeruginosa, revealed varying degree corneal abrasions, corneal abscess and dense corneal opacity. Histopathologically, at 3rd day post-infection (PI), the cornea revealed polymorpho-nuclear cells infiltration with loss of the outer epithelial lining. At 7th day PI, neutrophils were seen in the stroma. At 15th day PI, proliferation of fibroblasts and new vascularisation were seen in the stroma. Clinically, rabbits experimentally infected with Staphylococcus aureus, revealed corneal ulcers and focal abscesses. Histopathologically, at 3rd and 7th day PI, the cornea revealed edema and infiltration of

  7. The effect of human image in B2C website design: an eye-tracking study

    NASA Astrophysics Data System (ADS)

    Wang, Qiuzhen; Yang, Yi; Wang, Qi; Ma, Qingguo

    2014-09-01

    On B2C shopping websites, effective visual designs can bring about consumers' positive emotional experience. From this perspective, this article developed a research model to explore the impact of human image as a visual element on consumers' online shopping emotions and subsequent attitudes towards websites. This study conducted an eye-tracking experiment to collect both eye movement data and questionnaire data to test the research model. Questionnaire data analysis showed that product pictures combined with human image induced positive emotions among participants, thus promoting their attitudes towards online shopping websites. Specifically, product pictures with human image first produced higher levels of image appeal and perceived social presence, thus stimulating higher levels of enjoyment and subsequent positive attitudes towards the websites. Moreover, a moderating effect of product type was demonstrated on the relationship between the presence of human image and the level of image appeal. Specifically, human image significantly increased the level of image appeal when integrated in entertainment product pictures while this relationship was not significant in terms of utilitarian products. Eye-tracking data analysis further supported these results and provided plausible explanations. The presence of human image significantly increased the pupil size of participants regardless of product types. For entertainment products, participants paid more attention to product pictures integrated with human image whereas for utilitarian products more attention was paid to functional information of products than to product pictures no matter whether or not integrated with human image.

  8. [Physiological features of skin ageing in human].

    PubMed

    Tikhonova, I V; Tankanag, A V; Chemeris, N K

    2013-01-01

    The issue deals with the actual problem of gerontology, notably physiological features of human skin ageing. In the present review the authors have considered the kinds of ageing, central factors, affected on the ageing process (ultraviolet radiation and oxidation stress), as well as the research guidelines of the ageing changes in the skin structure and fuctions: study of mechanical properties, microcirculation, pH and skin thickness. The special attention has been payed to the methods of assessment of skin blood flow, and to results of investigations of age features of peripheral microhemodynamics. The laser Doppler flowmetry technique - one of the modern, noninvasive and extensively used methods for the assessmant of skin blood flow microcirculation system has been expanded in the review. The main results of the study of the ageing changes of skin blood perfusion using this method has been also presented.

  9. [Age and aging as incomplete architecture of human ontogenesis].

    PubMed

    Baltes, P B

    1999-12-01

    The focus is on the basic biological-genetic and social-cultural architecture of human development across the life span. The starting point is the frame provided by past evolutionary forces. A first conclusion is that for modern times and the relative brevity of the time windows involved in modernity, further change in human functioning is primarily dependent on the evolution of new cultural forms of knowledge rather than evolution-based changes in the human genome. A second conclusion concerns the general architecture of the life course. Three governing lifespan developmental principles coexist. First, because long-term evolutionary selection evince a negative age correlation, genome-based plasticity and biological potential decrease with age. Second, for growth aspects of human development to extend further into the life span, culture-based resources are required at ever increasing levels. Third, because of age-related losses in biological plasticity and negative effects associated with some principles of learning (e.g., negative transfer), the efficiency of culture is reduced as lifespan development unfolds. Joint application of these principles suggests that the lifespan architecture becomes more and more incomplete with age. Three examples are given to illustrate the implications of the lifespan architecture outlined. The first is a general theory of development involving the orchestration of three component processes and their age-related dynamics: Selection, optimization, and compensation. The second example is theory and research on lifespan intelligence that distinguishes between the biology-based mechanics and culture-based pragmatics of intelligence and specifies distinct age gradients for the two categories of intellectual functioning. The third example considers the goal of evolving a positive biological and cultural scenario for the last phase of life (fourth age). Because of the general lifespan architecture outlined, this objective becomes

  10. Visual Acuity after Cataract Surgery in Patients with Age-Related Macular Degeneration. Age-Related Eye Disease Study 2 Report No. 5

    PubMed Central

    Huynh, Nancy; Nicholson, Benjamin P.; Agrón, Elvira; Clemons, Traci E.; Bressler, Susan B.; Rosenfeld, Philip J.; Chew, Emily Y.

    2014-01-01

    Objective To evaluate visual acuity outcomes after cataract surgery in persons with varying severity of age-related macular degeneration (AMD). Design Cohort study. Participants A total of 1232 eyes of 793 participants who underwent cataract surgery during the Age-Related Eye Disease Study 2 (AREDS2), a prospective, multicenter, randomized controlled trial of nutritional supplements for treatment of AMD. Methods Preoperative and postoperative characteristics of participants who underwent cataract extraction during the 5 year trial were analyzed. Both clinical data and standardized red-reflex lens and fundus photographs were obtained at baseline and annually. Photographs were graded by a centralized reading center for cortical and posterior subcapsular lens opacities and for AMD severity. Cataract surgery was documented at annual study visits or by history during the 6 month telephone calls. Analyses were conducted using multivariate repeated-measures regression. Main Outcome Measures Change in best-corrected visual acuity (BCVA) after cataract surgery compared with preoperative BCVA. Results Adjusting for age at time of surgery, gender, interval between preoperative and postoperative visits, and type and severity of cataract, the mean changes in visual acuity were as follows: eyes with mild AMD (n=30) gained 11.2 letters (95% confidence interval (CI), 6.9-15.5), eyes with moderate AMD (n=346) gained 11.1 letters (95% CI, 9.1-13.2), eyes with severe AMD (n=462) gained 8.7 letters (95% CI, 6.7-10.7), eyes with non-central geographic atrophy (n=70) gained 8.9 letters (95% CI, 5.8-12.1), and eyes with advanced AMD (central geographic atrophy and/or neovascular) AMD (n=324) gained 6.8 letters (95% CI, 4.9-8.8). The visual acuity gain across all AMD severity groups was statistically significant from pre-operative state (P<0.0001). Conclusions Mean visual acuities improved significantly after cataract surgery across varying degrees of AMD severity. PMID:24613825

  11. Evolutionary adaptive eye tracking for low-cost human computer interaction applications

    NASA Astrophysics Data System (ADS)

    Shen, Yan; Shin, Hak Chul; Sung, Won Jun; Khim, Sarang; Kim, Honglak; Rhee, Phill Kyu

    2013-01-01

    We present an evolutionary adaptive eye-tracking framework aiming for low-cost human computer interaction. The main focus is to guarantee eye-tracking performance without using high-cost devices and strongly controlled situations. The performance optimization of eye tracking is formulated into the dynamic control problem of deciding on an eye tracking algorithm structure and associated thresholds/parameters, where the dynamic control space is denoted by genotype and phenotype spaces. The evolutionary algorithm is responsible for exploring the genotype control space, and the reinforcement learning algorithm organizes the evolved genotype into a reactive phenotype. The evolutionary algorithm encodes an eye-tracking scheme as a genetic code based on image variation analysis. Then, the reinforcement learning algorithm defines internal states in a phenotype control space limited by the perceived genetic code and carries out interactive adaptations. The proposed method can achieve optimal performance by compromising the difficulty in the real-time performance of the evolutionary algorithm and the drawback of the huge search space of the reinforcement learning algorithm. Extensive experiments were carried out using webcam image sequences and yielded very encouraging results. The framework can be readily applied to other low-cost vision-based human computer interactions in solving their intrinsic brittleness in unstable operational environments.

  12. Aging of the human ovary and testis.

    PubMed

    Perheentupa, Antti; Huhtaniemi, Ilpo

    2009-02-05

    Aging is associated with structural and functional alterations in all organs of the human body. The aging of gonads represents in this respect a special case, because these organs are not functional for the whole lifespan of an individual and their normal function is not indispensable for functions of the rest of the body. Ovarian function lasts for the reproductive life of a woman, i.e., from menarche until menopause. The testicular endocrine function, in contrast, begins already in utero, is interrupted between neonatal life and puberty, and continues thereafter along with spermatogenesis, with only slight decline, until old age. The aging processes of the ovary and testis are therefore very different. We describe in this review the structural and functional alterations in the human ovary and testis upon aging. Special emphasis will be given to clinically significant alterations, which in women concern the causes and consequences of the individual variability of fertility during the latter part of the reproductive age. The clinically important aspect of testicular aging entails the decline of androgen production in aging men.

  13. What Do the Prospective Science Teachers Know about the Human Eye?

    ERIC Educational Resources Information Center

    Sahin, Çigdem

    2014-01-01

    In this study, the views of the Prospective Science Teacher (PST)s about the human eye were examined. The following data collection tools were used: the Word Association Test (WAT), open ended questions, drawing technique, two tiered question item and an interview about concepts. The data of the study whose sample consisted of 34 PSTs were…

  14. A Simple Model of the Accommodating Lens of the Human Eye

    ERIC Educational Resources Information Center

    Oommen, Vinay; Kanthakumar, Praghalathan

    2014-01-01

    The human eye is often discussed as optically equivalent to a photographic camera. The iris is compared with the shutter, the pupil to the aperture, and the retina to the film, and both have lens systems to focus rays of light. Although many similarities exist, a major difference between the two systems is the mechanism involved in focusing an…

  15. The impact of aging on human sexuality.

    PubMed

    Rienzo, B A

    1985-02-01

    Review of gerontological and medical literature reveals the need for education for lay persons and professionals about the effects of the aging process on human sexuality. Primary prevention of psychosocial problems and sexual dysfunction could be abated by including accurate information about sexuality and aging and effective communication techniques in sexuality education programs, including those with young adults. In addition, professional preparation of health educators must include the skills and knowledge needed in this area.

  16. Ocular Risk Factors for Age-related Macular Degeneration: The Los Angeles Latino Eye Study (LALES)

    PubMed Central

    Fraser-Bell, Samantha; Choudhury, Farzana; Klein, Ronald; Azen, Stanley; Varma, Rohit

    2010-01-01

    Purpose To assess the association of ocular factors and age-related macular degeneration (AMD) in Latinos. Design Population-based, cross-sectional study of 6357 self-identified Latinos aged 40 years and older. Methods Ophthalmic examination included subjective refraction, measurement of axial length, evaluation of iris color, Lens Opacities Classification System II (LOCS II) grading of cataracts, and stereoscopic macular photographs for AMD lesions. Generalized estimating equation analysis incorporated data from both eyes to estimate odds ratios adjusted for covariates. Results After controlling for confounders (age, gender and smoking), prior cataract surgery was associated with advanced AMD (OR: 2.8, 95% CI 1.0, 7.8), increased retinal pigment (OR: 1.6, 95% CI 1.0, 1.5) and retinal pigment epithelial depigmentation (OR: 2.2, 95% CI 1.1, 4.4). The presence of any lens opacity was associated with soft drusen (OR: 1.2; 95% CI 1.0, 1.5). Longer axial length (per mm) was associated with a decreased odds of soft drusen, increased retinal pigment, and geographic atrophy (GA) (ORs: 0.8 [95% CI 0.7, 0.9], 0.8 [95% CI 0.7, 0.9], 0.7 [95% CI 0.5, 0.9], respectively. Myopia was inversely associated with soft drusen (OR: 0.8; 95% CI 0.7, 1.0). Lighter colored irises were associated with GA (OR: 5.0; 95% CI 1.0, 25.3). Conclusions Cross-sectional associations of ocular factors such as cataract, cataract surgery, and refractive errors with early AMD lesions found in Latinos were consistent with those in whites. Additionally, prior cataract surgery was associated with advanced AMD. PMID:20138605

  17. [THE STRUCTURE OF LYMPHATIC CAPILLARIES OF THE CILIARY BODY OF THE HUMAN EYE].

    PubMed

    Borodin, Yu I; Bgatova, N P; Chernykh, V V; Trunov, A N; Pozhidayeva, A A; Konenkov, V I

    2015-01-01

    Using light microscopy, immunohistochemistry and electron microscopy, the structural organization of interstitial spaces and vessels of the ciliary body of the human eye (n = 5) were studied. The ciliary body was found to contain wide interstitial spaces--tissue clefts bound by collagen fibers and fibroblasts. Organ-specific lymphatic capillaries were also demonstrated in the ciliary body. According to the present findings and the lymphatic region concept, the first 2 elements of the lymphatic region of the eye were described: tissue clefts--prelymphatics and lymphatic capillaries of the ciliary body. The third element of the lymphatic region are the lymph nodes of the head and neck.

  18. Relative size of the eye and orbit: an evolutionary and craniofacial constraint model for examining the etiology and disparate incidence of juvenile-onset myopia in humans.

    PubMed

    Masters, Michael P

    2012-05-01

    The principal aim of this research is to provide a new model for investigating myopia in humans, and contribute to an understanding of the degree to which modern variation and evolutionary change in orbital and overall craniofacial morphology may help explain the common eye form association with this condition. Recent research into long and short-term evolution of the human orbit reveals a number of changes in this feature, and particularly since the Upper Paleolithic. These include a reduction in orbital depth, a decrease in anterior projection of the upper and lower orbital margins, and most notably, a reduction in orbital volume since the Holocene in East Asia. Reduced orbital volume in this geographic region could exacerbate an existing trend in recent hominin evolution toward larger eyes in smaller orbits, and may help explain the unusually high frequency of myopia in East Asian populations. The objective of the current study is to test a null hypothesis of no relationship between a ratio of orbit to eye volume and spherical equivalent refractive error (SER) in a sample of Chinese adults, and examine how relative size of the eye within the orbit relates to SER between the sexes and across the sample population. Analysis of the orbit, eye, and SER reveals a strong relationship between relative size of the eye within the orbit and the severity of myopic refractive error. An orbit/eye ratio of 3 for females and 3.5 for males (or an eye that occupies approximately 34% and 29% of the orbit, respectively), designates a clear threshold at which myopia develops, and becomes progressively worse as the eye continues to occupy a greater proportion of the orbital cavity. These results indicate that relative size of the eye within the orbit is an important factor in the development of myopia, and suggests that individuals with large eyes in small orbits lack space for adequate development of ocular tissues, leading to compression and distortion of the lithesome globe

  19. [Detection of carotenoids in the vitreous body of the human eye during prenatal development].

    PubMed

    Iakovleva, M A; Panova, I G; Fel'dman, T B; Zak, P P; Tatikolov, A S; Sukhikh, G T; Ostrovskiĭ, M A

    2007-01-01

    Carotenoids were found for the first time in the vitreous body of human eye during the fetal period from week 15 until week 28. Their maximum content was timed to week 16-22. No carotenoids were found the vitreous body of 31-week fetuses, as well as adult humans, which corresponds to the published data. It was shown using HPLC that chromatographic characteristics of these carotenoids correspond to those of lutein and zeaxanthin, characteristic pigments of the retinal yellow macula.

  20. Potentiation of intraocular absorption and drug metabolism of N-acetylcarnosine lubricant eye drops: drug interaction with sight threatening lipid peroxides in the treatment for age-related eye diseases.

    PubMed

    Babizhayev, Mark A

    2009-01-01

    Cataract is the dominant cause of blindness worldwide. Studies of the morphological structure and biophysical changes of the lens in human senile cataracts have demonstrated the disappearance of normal fiber structure in the opaque region of the lens and the disintegration of the lens fiber plasma membrane in the lens tissue. Morphological and biochemical techniques have revealed the regions in human cataractous lenses in which the plasma membrane derangement occurs as the primary light scattering centers which cause the observed lens opacity. Human cataract formation is mostly considered to be a multifactorial disease; however, oxidative stress might be one of the leading causes for both nuclear and cortical cataract. Phospholipid molecules modified with oxygen, accumulating in the lipid bilayer, change its geometry and impair lipid-lipid and protein-lipid interactions in lenticular fiber membranes. Electron microscopy data of human lenses at various stages of age-related cataract document that these disruptions were globules, vacuoles, multilamellar membranes, and clusters of highly undulating membranes. The opaque shades of cortical cataracts represent cohorts of locally affected fibres segregated from unaffected neighbouring fibres by plasma membranes. Other potential scattering centers found throughout the mature cataract nucleus included variations in staining density between adjacent cells, enlarged extracellular spaces between undulating membrane pairs, and protein-like deposits in the extracellular space. These affected parts had membranes with a fine globular aspect and in cross-section proved to be filled with medium to large globular elements. Lipid peroxidation (LPO) is a pathogenetic and causative factor of cataract. Increased concentrations of primary molecular LPO products (diene conjugates, lipid hydroperoxides, fatty acid oxy-derivatives) and end fluorescent LPO products were detected in the lipid moieties of the aqueous humor samples and human

  1. Physical human model eye and methods of its use to analyse optical performance of soft contact lenses.

    PubMed

    Bakaraju, Ravi C; Ehrmann, Klaus; Falk, Darrin; Ho, Arthur; Papas, Eric

    2010-08-02

    A bench-top physical model eye that closely replicates both anatomical and optical properties of an average human eye was designed and constructed. The cornea was sourced from a flouro-polymer with refractive index (RI) of 1.376 and crystalline lenses were made of Boston RGP polymers, EO and Equalens II, with an equivalent RI of 1.429 and 1.423 respectively. These materials served to make crystalline lens components of different age groups and accommodative states. De-Ionized water, with RI of 1.334 represented both aqueous and vitreous humor. The complementary metal-oxide sensor of a PixelLink digital camera with a resolution of 5MP and a 2.2 microm pixel pitch, hosted on a motor-base, served as the 'acting' retina. The translation and rotary functions of the motor-base facilitated the simulation of different states of ametropia and assessment of peripheral visual function, respectively. We validated one of its configurations to suit normal viewing conditions and results from the on and off-axis optical quality measurements are presented. As a demonstration of potential practical uses, several corrective soft contact lenses were placed on the model eye and their optical performance evaluated.

  2. Course for undergraduate students: analysis of the retinal image quality of a human eye model

    NASA Astrophysics Data System (ADS)

    del Mar Pérez, Maria; Yebra, Ana; Fernández-Oliveras, Alicia; Ghinea, Razvan; Ionescu, Ana M.; Cardona, Juan C.

    2014-07-01

    In teaching of Vision Physics or Physiological Optics, the knowledge and analysis of the aberration that the human eye presents are of great interest, since this information allows a proper evaluation of the quality of the retinal image. The objective of the present work is that the students acquire the required competencies which will allow them to evaluate the optical quality of the human visual system for emmetropic and ammetropic eye, both with and without the optical compensation. For this purpose, an optical system corresponding to the Navarro-Escudero eye model, which allows calculating and evaluating the aberration of this eye model in different ammetropic conditions, was developed employing the OSLO LT software. The optical quality of the visual system will be assessed through determinations of the third and fifth order aberration coefficients, the impact diagram, wavefront analysis, calculation of the Point Spread Function and the Modulation Transfer Function for ammetropic individuals, with myopia or hyperopia, both with or without the optical compensation. This course is expected to be of great interest for student of Optics and Optometry Sciences, last courses of Physics or medical sciences related with human vision.

  3. Lipofuscin Redistribution and Loss Accompanied by Cytoskeletal Stress in Retinal Pigment Epithelium of Eyes With Age-Related Macular Degeneration

    PubMed Central

    Ach, Thomas; Tolstik, Elen; Messinger, Jeffrey D.; Zarubina, Anna V.; Heintzmann, Rainer; Curcio, Christine A.

    2015-01-01

    Purpose. Lipofuscin (LF) and melanolipofuscin (MLF) of the retinal pigment epithelium (RPE) are the principal sources of autofluorescence (AF) signals in clinical fundus–AF imaging. Few details about the subcellular distribution of AF organelles in AMD are available. We describe the impact of aging and AMD on RPE morphology revealed by the distribution of AF LF/MLF granules and actin cytoskeleton in human tissues. Methods. Thirty-five RPE-Bruch's membrane flatmounts from 35 donors were prepared (postmortem: ≤4 hours). Ex vivo fundus examination at the time of accession revealed either absence of chorioretinal pathologies (10 tissues; mean age: 83.0 ± 2.6 years) or stages of AMD (25 tissues; 85.0 ± 5.8 years): early AMD, geographic atrophy, and late exudative AMD. Retinal pigment epithelium cytoskeleton was labeled with AlexaFluor647-Phalloidin. Tissues were imaged on a spinning-disk fluorescence microscope and a high-resolution structured illumination microscope. Results. Age-related macular degeneration impacts individual RPE cells by (1) lipofuscin redistribution by (i) degranulation (granule-by-granule loss) and/or (ii) aggregation and apparent shedding into the extracellular space; (2) enlarged RPE cell area and conversion from convex to irregular and sometimes concave polygons; and (3) cytoskeleton derangement including separations and breaks around subretinal deposits, thickening, and stress fibers. Conclusions. We report an extensive and systematic en face analysis of LF/MLF-AF in AMD eyes. Redistribution and loss of AF granules are among the earliest AMD changes and could reduce fundus AF signal attributable to RPE at these locations. Data can enhance the interpretation of clinical fundus–AF and provide a basis for future quantitative studies. PMID:25758814

  4. Combined Effect of Irradiation and Ageing Condition on Physicochemical and Microbial Quality of Hanwoo Eye of Round

    PubMed Central

    Yim, Dong-Gyun; Jo, Cheorun; Kim, Hyun-Joo

    2015-01-01

    The combined effects of electron-beam irradiation and ageing of beef were examined. The irradiated samples at dose of 0 or 2 kGy were kept and analyzed for the microbial growth, shear values, meat color, and nucleotide-related flavor compounds at different ageing temperatures (2, 10, or 25℃) for 8 d. The irradiation effect on inactivation of foodborne pathogens was also investigated. The population of Listeria monocytogenes and E. coli O157:H7 inoculated in beef samples decreased in proportion to the irradiation dose, showing D10 values of 0.66 and 0.65 kGy respectively. The irradiated beef eye of round had lower number of total aerobic bacteria (TAB) than non-irradiated one during the storage, but the TAB increased with higher ageing temperature (p<0.05). Especially, TAB increased sharply in non-irradiated samples aged at 25℃ after 4 d (p<0.05). With increasing ageing temperature and ageing time, shear force values decreased (p<0.05). The color a* values of the irradiated beef were lower than those of the non-irradiated throughout the ageing period (p<0.05). As ageing time and temperature increased, the amounts of inosine monophosphate decreased and the hypoxanthine increased (p<0.05). Relatively high ageing temperature could be used at irradiated beef eye of round to shorten the ageing time. PMID:26761855

  5. Ultrasonographic and macroscopic anatomy of the enucleated eyes of the buffalo (Bos bubalis) and the one-humped camel (Camelus dromedarius) of different ages.

    PubMed

    Kassab, A

    2012-02-01

    The ultrasonographic appearance and measurements of the normal buffalo and camel eye globes were described in 60 buffaloes (Bos bubalis) aged 1 year (28 eyes) and 10 years (32 eyes), and in 51 humped camels (Camelus dromedarius) aged 1 year (26 eyes) and 10 years (24 eyes). Ocular measurements were recorded by A- and B-scan ultrasonographic examination of 40 buffalo eyes (18 young and 22 adult eyes) and 34 camel eyes (14 young and 20 adult eyes) using a KANGH ultrasound scanner equipped with 10 MHz probe. For gross measurements, 20 buffalo and 16 camel eye globes were frozen and dissected and the same measurements were made using fine callipers macroscopically. The aqueous and vitreous humour of the buffalo and camel eyes appeared anechoic. The cornea, anterior and posterior lens capsule and iris appeared hyperechoic. The ocular measurements for the axial length, vitreous chamber depth (VCD), corneal thickness, lens thickness and scleroretinal rim thickness increase with the advance of age in both buffaloes and camels. Except for the anterior chamber depth, VCD and lens thickness, which were larger in adult camels than in adult buffaloes, no other differences between ocular dimensions were observed in both species. The results of this study are valuable for comparative ocular anatomy and will be useful for ultrasonographic evaluation of ocular diseases in buffaloes and camels.

  6. Hypothesis on human eye perceiving optical spectrum rather than an image

    NASA Astrophysics Data System (ADS)

    Zheng, Yufeng; Szu, Harold

    2015-05-01

    It is a common knowledge that we see the world because our eyes can perceive an optical image. A digital camera seems a good example of simulating the eye imaging system. However, the signal sensing and imaging on human retina is very complicated. There are at least five layers (of neurons) along the signal pathway: photoreceptors (cones and rods), bipolar, horizontal, amacrine and ganglion cells. To sense an optical image, it seems that photoreceptors (as sensors) plus ganglion cells (converting to electrical signals for transmission) are good enough. Image sensing does not require ununiformed distribution of photoreceptors like fovea. There are some challenging questions, for example, why don't we feel the "blind spots" (never fibers exiting the eyes)? Similar situation happens to glaucoma patients who do not feel their vision loss until 50% or more nerves died. Now our hypothesis is that human retina initially senses optical (i.e., Fourier) spectrum rather than optical image. Due to the symmetric property of Fourier spectrum the signal loss from a blind spot or the dead nerves (for glaucoma patients) can be recovered. Eye logarithmic response to input light intensity much likes displaying Fourier magnitude. The optics and structures of human eyes satisfy the needs of optical Fourier spectrum sampling. It is unsure that where and how inverse Fourier transform is performed in human vision system to obtain an optical image. Phase retrieval technique in compressive sensing domain enables image reconstruction even without phase inputs. The spectrum-based imaging system can potentially tolerate up to 50% of bad sensors (pixels), adapt to large dynamic range (with logarithmic response), etc.

  7. Gene-gene interactions contribute to eye colour variation in humans.

    PubMed

    Pośpiech, Ewelina; Draus-Barini, Jolanta; Kupiec, Tomasz; Wojas-Pelc, Anna; Branicki, Wojciech

    2011-06-01

    Prediction of phenotypes from genetic data is considered to be the first practical application of data gained from association studies, with potential importance for medicine and the forensic sciences. Multiple genes and polymorphisms have been found to be associated with variation in human pigmentation. Their analysis enables prediction of blue and brown eye colour with a reasonably high accuracy. More accurate prediction, especially in the case of intermediate eye colours, may require better understanding of gene-gene interactions affecting this polygenic trait. Using multifactor dimensionality reduction and logistic regression methods, a study of gene-gene interactions was conducted based on variation in 11 known pigmentation genes examined in a cohort of 718 individuals of European descent. The study revealed significant interactions of a redundant character between the HERC2 and OCA2 genes affecting determination of hazel eye colour and between HERC2 and SLC24A4 affecting determination of blue eye colour. Our research indicates interactive effects of a synergistic character between HERC2 and OCA2, and also provides evidence for a novel strong synergistic interaction between HERC2 and TYRP1, both affecting determination of green eye colour.

  8. Laser Ray Tracing versus Hartmann-Shack sensor for measuring optical aberrations in the human eye.

    PubMed

    Moreno-Barriuso, E; Navarro, R

    2000-06-01

    A comparison and validation study of Laser Ray Tracing (LRT) and Hartmann-Shack wave-front-sensor (to be referred to as H-S) methods was carried out on both artificial and human eyes. The aim of this work was double. First, we wanted to verify experimentally the equivalence of single- and double-pass measurements for both H-S and LRT. This interest is due to the impossibility of making single-pass measurements in human eyes. In addition, we wanted to validate the LRT technique by comparing it with the H-S wave-front sensor, currently used in many physiological optics laboratories. Comparison of the different methods and configurations carried out in the artificial eye yielded basically the same results in all cases, which means a reciprocal validation of both LRT and H-S, in either single- or double-pass configurations. Other aspects, such as robustness against speckle noise or the influence of the size of the entrance (H-S) or exit (LRT) pupil were studied as well. As a global reference, the point-spread function (PSF) of the artificial eye was recorded directly on a CCD camera and compared with simulated PSF's computed from the experimental aberration data. We also applied these two methods to real eyes (double pass), finding again a close match between the resulting aberration coefficients and also between the standard errors for two normal subjects. However, for one myopic eye with an especially low optical quality (RMS wave-front error >2 microm) and asymmetric aberrations, the array of spots recorded with the H-S sensor was highly distorted and too difficult to analyze.

  9. Accelerated aging syndromes, are they relevant to normal human aging?

    PubMed

    Dreesen, Oliver; Stewart, Colin L

    2011-09-01

    Hutchinson-Gilford Progeria (HGPS) and Werner syndromes are diseases that clinically resemble some aspects of accelerated aging. HGPS is caused by mutations in theLMNA gene resulting in post-translational processing defects that trigger Progeria in children. Werner syndrome, arising from mutations in the WRN helicase gene, causes premature aging in young adults. What are the molecular mechanism(s) underlying these disorders and what aspects of the diseases resemble physiological human aging? Much of what we know stems from the study of patient derived fibroblasts with both mutations resulting in increased DNA damage, primarily at telomeres. However, in vivo patients with Werner's develop arteriosclerosis, among other pathologies. In HGPS patients, including iPS derived cells from HGPS patients, as well as some mouse models for Progeria, vascular smooth muscle (VSM) appears to be among the most severely affected tissues. Defective Lamin processing, associated with DNA damage, is present in VSM from old individuals, indicating processing defects may be a factor in normal aging. Whether persistent DNA damage, particularly at telomeres, is the root cause for these pathologies remains to be established, since not all progeroid Lmna mutations result in DNA damage and genome instability.

  10. DNA methylation and healthy human aging.

    PubMed

    Jones, Meaghan J; Goodman, Sarah J; Kobor, Michael S

    2015-12-01

    The process of aging results in a host of changes at the cellular and molecular levels, which include senescence, telomere shortening, and changes in gene expression. Epigenetic patterns also change over the lifespan, suggesting that epigenetic changes may constitute an important component of the aging process. The epigenetic mark that has been most highly studied is DNA methylation, the presence of methyl groups at CpG dinucleotides. These dinucleotides are often located near gene promoters and associate with gene expression levels. Early studies indicated that global levels of DNA methylation increase over the first few years of life and then decrease beginning in late adulthood. Recently, with the advent of microarray and next-generation sequencing technologies, increases in variability of DNA methylation with age have been observed, and a number of site-specific patterns have been identified. It has also been shown that certain CpG sites are highly associated with age, to the extent that prediction models using a small number of these sites can accurately predict the chronological age of the donor. Together, these observations point to the existence of two phenomena that both contribute to age-related DNA methylation changes: epigenetic drift and the epigenetic clock. In this review, we focus on healthy human aging throughout the lifetime and discuss the dynamics of DNA methylation as well as how interactions between the genome, environment, and the epigenome influence aging rates. We also discuss the impact of determining 'epigenetic age' for human health and outline some important caveats to existing and future studies.

  11. Aging-associated changes in human brain.

    PubMed

    Mrak, R E; Griffin, S T; Graham, D I

    1997-12-01

    A wide variety of anatomic and histological alterations are common in brains of aged individuals. However, identification of intrinsic aging changes--as distinct from changes resulting from cumulative environmental insult--is problematic. Some degree of neuronal and volume loss would appear to be inevitable, but recent studies have suggested that the magnitudes of such changes are much less than previously thought, and studies of dendritic complexity in cognitively intact individuals suggest continuing neuronal plasticity into the eighth decade. A number of vascular changes become more frequent with age, many attributable to systemic conditions such as hypertension and atherosclerosis. Age-associated vascular changes not clearly linked to such conditions include hyaline arteriosclerotic changes with formation of arterial tortuosities in small intracranial vessels and the radiographic changes in deep cerebral white matter known as "leukoaraiosis." Aging is accompanied by increases in glial cell activation, in oxidative damage to proteins and lipids, in irreversible protein glycation, and in damage to DNA, and such changes may underlie in part the age-associated increasing incidence of "degenerative" conditions such as Alzheimer disease and Parkinson disease. A small number of histological changes appear to be universal in aged human brains. These include increasing numbers of corpora amylacea within astrocytic processes near blood-brain or cerebrospinal fluid-brain interfaces, accumulation of the "aging" pigment lipofuscin in all brain regions, and appearance of Alzheimer-type neurofibrillary tangles (but not necessarily amyloid plaques) in mesial temporal structures.

  12. Obesity accelerates epigenetic aging of human liver.

    PubMed

    Horvath, Steve; Erhart, Wiebke; Brosch, Mario; Ammerpohl, Ole; von Schönfels, Witigo; Ahrens, Markus; Heits, Nils; Bell, Jordana T; Tsai, Pei-Chien; Spector, Tim D; Deloukas, Panos; Siebert, Reiner; Sipos, Bence; Becker, Thomas; Röcken, Christoph; Schafmayer, Clemens; Hampe, Jochen

    2014-10-28

    Because of the dearth of biomarkers of aging, it has been difficult to test the hypothesis that obesity increases tissue age. Here we use a novel epigenetic biomarker of aging (referred to as an "epigenetic clock") to study the relationship between high body mass index (BMI) and the DNA methylation ages of human blood, liver, muscle, and adipose tissue. A significant correlation between BMI and epigenetic age acceleration could only be observed for liver (r = 0.42, P = 6.8 × 10(-4) in dataset 1 and r = 0.42, P = 1.2 × 10(-4) in dataset 2). On average, epigenetic age increased by 3.3 y for each 10 BMI units. The detected age acceleration in liver is not associated with the Nonalcoholic Fatty Liver Disease Activity Score or any of its component traits after adjustment for BMI. The 279 genes that are underexpressed in older liver samples are highly enriched (1.2 × 10(-9)) with nuclear mitochondrial genes that play a role in oxidative phosphorylation and electron transport. The epigenetic age acceleration, which is not reversible in the short term after rapid weight loss induced by bariatric surgery, may play a role in liver-related comorbidities of obesity, such as insulin resistance and liver cancer.

  13. Thermal behavior of human eye in relation with change in blood perfusion, porosity, evaporation and ambient temperature.

    PubMed

    Rafiq, Aasma; Khanday, M A

    2016-12-01

    Extreme environmental and physiological conditions present challenges for thermal processes in body tissues including multi-layered human eye. A mathematical model has been formulated in this direction to study the thermal behavior of the human eye in relation with the change in blood perfusion, porosity, evaporation and environmental temperatures. In this study, a comprehensive thermal analysis has been performed on the multi-layered eye using Pennes' bio-heat equation with appropriate boundary and interface conditions. The variational finite element method and MATLAB software were used for the solution purpose and simulation of the results. The thermoregulatory effect due to blood perfusion rate, porosity, ambient temperature and evaporation at various regions of human eye was illustrated mathematically and graphically. The main applications of this model are associated with the medical sciences while performing laser therapy and other thermoregulatory investigation on human eye.

  14. Exploring the Human Fabric through an Analyst's Eyes

    NASA Astrophysics Data System (ADS)

    Belov, Nadya; Patti, Jeff; Wilcox, Saki; Almanzar, Rafael; Kim, Janet; Kellogg, Jennifer; Dang, Steven

    The nature and type of conflicts drastically changed in the last half of the twentieth century. Wars are no longer limited to the field; they are supplemented with guerrilla warfare and other asymmetric warfare tactics including domestic terrorism. Domestic terrorism has demonstrated a need for improved homeland security capabilities. Establishing and maintaining the understanding of the key players and the underlying social networks is essential to combating asynchronous warfare tactics. Herein, we identify the key challenges addressed by our Collection/Exploitation Decision System (CEDS) that assist analysts in maintaining an up-to-date understanding of dynamic human networks.

  15. Category Processing and the human likeness dimension of the Uncanny Valley Hypothesis: Eye-Tracking Data

    PubMed Central

    Cheetham, Marcus; Pavlovic, Ivana; Jordan, Nicola; Suter, Pascal; Jancke, Lutz

    2013-01-01

    The Uncanny Valley Hypothesis (Mori, 1970) predicts that perceptual difficulty distinguishing between a humanlike object (e.g., lifelike prosthetic hand, mannequin) and its human counterpart evokes negative affect. Research has focused on affect, with inconsistent results, but little is known about how objects along the hypothesis’ dimension of human likeness (DHL) are actually perceived. This study used morph continua based on human and highly realistic computer-generated (avatar) faces to represent the DHL. Total number and dwell time of fixations to facial features were recorded while participants (N = 60) judged avatar versus human category membership of the faces in a forced choice categorization task. Fixation and dwell data confirmed the face feature hierarchy (eyes, nose, and mouth in this order of importance) across the DHL. There were no further findings for fixation. A change in the relative importance of these features was found for dwell time, with greater preferential processing of eyes and mouth of categorically ambiguous faces compared with unambiguous avatar faces. There were no significant differences between ambiguous and human faces. These findings applied for men and women, though women generally dwelled more on the eyes to the disadvantage of the nose. The mouth was unaffected by gender. In summary, the relative importance of facial features changed on the DHL’s non-human side as a function of categorization ambiguity. This change was indicated by dwell time only, suggesting greater depth of perceptual processing of the eyes and mouth of ambiguous faces compared with these features in unambiguous avatar faces. PMID:23471214

  16. A Bird’s Eye View of Human Language Evolution

    PubMed Central

    Berwick, Robert C.; Beckers, Gabriël J. L.; Okanoya, Kazuo; Bolhuis, Johan J.

    2012-01-01

    Comparative studies of linguistic faculties in animals pose an evolutionary paradox: language involves certain perceptual and motor abilities, but it is not clear that this serves as more than an input–output channel for the externalization of language proper. Strikingly, the capability for auditory–vocal learning is not shared with our closest relatives, the apes, but is present in such remotely related groups as songbirds and marine mammals. There is increasing evidence for behavioral, neural, and genetic similarities between speech acquisition and birdsong learning. At the same time, researchers have applied formal linguistic analysis to the vocalizations of both primates and songbirds. What have all these studies taught us about the evolution of language? Is the comparative study of an apparently species-specific trait like language feasible? We argue that comparative analysis remains an important method for the evolutionary reconstruction and causal analysis of the mechanisms underlying language. On the one hand, common descent has been important in the evolution of the brain, such that avian and mammalian brains may be largely homologous, particularly in the case of brain regions involved in auditory perception, vocalization, and auditory memory. On the other hand, there has been convergent evolution of the capacity for auditory–vocal learning, and possibly for structuring of external vocalizations, such that apes lack the abilities that are shared between songbirds and humans. However, significant limitations to this comparative analysis remain. While all birdsong may be classified in terms of a particularly simple kind of concatenation system, the regular languages, there is no compelling evidence to date that birdsong matches the characteristic syntactic complexity of human language, arising from the composition of smaller forms like words and phrases into larger ones. PMID:22518103

  17. Human stereopsis is not limited by the optics of the well-focused eye.

    PubMed

    Vlaskamp, Björn N S; Yoon, Geunyoung; Banks, Martin S

    2011-07-06

    Human stereopsis, the perception of depth from differences in the two eyes' images, is very precise: image differences smaller than a single photoreceptor can be converted into a perceived difference in depth. To better understand what determines this precision, we examined how the eyes' optics affects stereo resolution. We did this by comparing performance with normal, well-focused optics and with optics improved by eliminating chromatic aberration and correcting higher-order aberrations. We first measured luminance contrast sensitivity in both eyes and showed that we had indeed improved optical quality significantly. We then measured stereo resolution in two ways: by finding the finest corrugation in depth that one can perceive, and by finding the smallest disparity one can perceive as different from zero. Our optical manipulation had no effect on stereo performance. We checked this by redoing the experiments at low contrast and again found no effect of improving optical quality. Thus, the resolution of human stereopsis is not limited by the optics of the well-focused eye. We discuss the implications of this remarkable finding.

  18. Transverse chromatic aberration across the visual field of the human eye

    PubMed Central

    Winter, Simon; Sabesan, Ramkumar; Tiruveedhula, Pavan; Privitera, Claudio; Unsbo, Peter; Lundström, Linda; Roorda, Austin

    2016-01-01

    The purpose of this study was to measure the transverse chromatic aberration (TCA) across the visual field of the human eye objectively. TCA was measured at horizontal and vertical field angles out to ±15° from foveal fixation in the right eye of four subjects. Interleaved retinal images were taken at wavelengths 543 nm and 842 nm in an adaptive optics scanning laser ophthalmoscope (AOSLO). To obtain true measures of the human eye's TCA, the contributions of the AOSLO system's TCA were measured using an on-axis aligned model eye and subtracted from the ocular data. The increase in TCA was found to be linear with eccentricity, with an average slope of 0.21 arcmin/degree of visual field angle (corresponding to 0.41 arcmin/degree for 430 nm to 770 nm). The absolute magnitude of ocular TCA varied between subjects, but was similar to the resolution acuity at 10° in the nasal visual field, encompassing three to four cones. Therefore, TCA can be visually significant. Furthermore, for high-resolution imaging applications, whether visualizing or stimulating cellular features in the retina, it is important to consider the lateral displacements between wavelengths and the variation in blur over the visual field. PMID:27832270

  19. Transverse chromatic aberration across the visual field of the human eye.

    PubMed

    Winter, Simon; Sabesan, Ramkumar; Tiruveedhula, Pavan; Privitera, Claudio; Unsbo, Peter; Lundström, Linda; Roorda, Austin

    2016-11-01

    The purpose of this study was to measure the transverse chromatic aberration (TCA) across the visual field of the human eye objectively. TCA was measured at horizontal and vertical field angles out to ±15° from foveal fixation in the right eye of four subjects. Interleaved retinal images were taken at wavelengths 543 nm and 842 nm in an adaptive optics scanning laser ophthalmoscope (AOSLO). To obtain true measures of the human eye's TCA, the contributions of the AOSLO system's TCA were measured using an on-axis aligned model eye and subtracted from the ocular data. The increase in TCA was found to be linear with eccentricity, with an average slope of 0.21 arcmin/degree of visual field angle (corresponding to 0.41 arcmin/degree for 430 nm to 770 nm). The absolute magnitude of ocular TCA varied between subjects, but was similar to the resolution acuity at 10° in the nasal visual field, encompassing three to four cones. Therefore, TCA can be visually significant. Furthermore, for high-resolution imaging applications, whether visualizing or stimulating cellular features in the retina, it is important to consider the lateral displacements between wavelengths and the variation in blur over the visual field.

  20. Aged Garlic Extract Modifies Human Immunity.

    PubMed

    Percival, Susan S

    2016-02-01

    Garlic contains numerous compounds that have the potential to influence immunity. Immune cells, especially innate immune cells, are responsible for the inflammation necessary to kill pathogens. Two innate lymphocytes, γδ-T and natural killer (NK) cells, appear to be susceptible to diet modification. The purpose of this review was to summarize the influence of aged garlic extract (AGE) on the immune system. The author's laboratory is interested in AGE's effects on cell proliferation and activation and inflammation and to learn whether those changes might affect the occurrence and severity of colds and flu. Healthy human participants (n = 120), between 21 and 50 y of age, were recruited for a randomized, double-blind, placebo-controlled parallel-intervention study to consume 2.56 g AGE/d or placebo supplements for 90 d during the cold and flu season. Peripheral blood mononuclear cells were isolated before and after consumption, and γδ-T and NK cell function was assessed by flow cytometry. The effect on cold and flu symptoms was determined by using daily diary records of self-reported illnesses. After 45 d of AGE consumption, γδ-T and NK cells proliferated better and were more activated than cells from the placebo group. After 90 d, although the number of illnesses was not significantly different, the AGE group showed reduced cold and flu severity, with a reduction in the number of symptoms, the number of days participants functioned suboptimally, and the number of work/school days missed. These results suggest that AGE supplementation may enhance immune cell function and may be partly responsible for the reduced severity of colds and flu reported. The results also suggest that the immune system functions well with AGE supplementation, perhaps with less accompanying inflammation. This trial was registered at clinicaltrials.gov as NCT01390116.

  1. Machine vision based on the concept of contrast sensitivity of the human eye

    NASA Astrophysics Data System (ADS)

    Bezzubik, Vitali; Belashenkov, Nikolai; Vdovin, Gleb

    2014-09-01

    The model of contrast sensitivity function (CSF) of machine vision system, based on the CSF of the human visual system is proposed. By analogy with the human eye, we employ the concept of ganglion cell receptive field to the artificial light-sensitive elements. By further following this concept, we introduced quantative metrics of local and global contrast of digital image. We suggested that the contrast sensitivity threshold forms an iso-line in the parameter space contrast - spatial frequency. The model, implemented in a computer vision system, has been compared to the results of contrast sensitivity research, conducted directly with the human visual system, and demonstrated a good match.

  2. Dose conversion coefficients for photon exposure of the human eye lens

    NASA Astrophysics Data System (ADS)

    Behrens, R.; Dietze, G.

    2011-01-01

    In recent years, several papers dealing with the eye lens dose have been published, because epidemiological studies implied that the induction of cataracts occurs even at eye lens doses of less than 500 mGy. Different questions were addressed: Which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens? Is a new definition of the dose quantity Hp(3) based on a cylinder phantom to represent the human head necessary? Are current conversion coefficients from fluence to equivalent dose to the lens sufficiently accurate? To investigate the latter question, a realistic model of the eye including the inner structure of the lens was developed. Using this eye model, conversion coefficients for electrons have already been presented. In this paper, the same eye model—with the addition of the whole body—was used to calculate conversion coefficients from fluence (and air kerma) to equivalent dose to the lens for photon radiation from 5 keV to 10 MeV. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are similar between 40 keV and 1 MeV and lower by up to a factor of 5 and 7 for photon energies at about 10 keV and 10 MeV, respectively. Above 1 MeV, the new values (calculated without kerma approximation) should be applied in pure photon radiation fields, while the values adopted by the ICRP in 1996 (calculated with kerma approximation) should be applied in case a significant contribution from secondary electrons originating outside the body is present.

  3. A Novel Fluorescent Lipid Probe for Dry Eye: Retrieval by Tear Lipocalin in Humans

    PubMed Central

    Yeh, Po-Ting; Casey, Richard; Glasgow, Ben J.

    2013-01-01

    Purpose. A fluorescent probe was used to identify mucin-depleted areas on the ocular surface and to test the hypothesis that tear lipocalin retrieves lipids from the eyes of normal and dry eye subjects. Methods. Fluorescein-labeled octadecyl ester, FODE, was characterized by mass spectrometry and absorbance spectrophotometry. The use of FODE to define mucin defects was studied with impression membranes under conditions that selectively deplete mucin. The kinetics of FODE removal from the ocular surface were analyzed by sampling tears from control and dry eye patients at various times. The tear protein–FODE complexes were isolated by gel filtration and ion exchange chromatographies, monitored with absorption and fluorescent spectroscopies, and analyzed by gel electrophoresis. Immunoprecipitation verified FODE complexed to tear lipocalin in tears. Results. FODE exhibits an isosbestic point at 473 nm, pKa of 7.5, and red shift relative to fluorescein. The low solubility of FODE in buffer is enhanced with 1% Tween 80 and ethanol. FODE adheres to the ocular surface of dry eye patients. FODE produces visible staining at the contact sites of membranes, which correlates with removal of mucin. Despite the fact that tear lipocalin is reduced in dry eye patients, FODE removal follows similar rapid exponential decay functions for all subjects. FODE is bound to tear lipocalin in tears. Conclusions. Tear lipocalin retrieves lipid rapidly from the human ocular surface in mild to moderate dry eye disease and controls. With improvements in solubility, FODE may have potential as a fluorescent probe to identify mucin-depleted areas. PMID:23361507

  4. Effect of human milk as a treatment for dry eye syndrome in a mouse model

    PubMed Central

    Diego, Jose L.; Bidikov, Luke; Pedler, Michelle G.; Kennedy, Jeffrey B.; Quiroz-Mercado, Hugo; Gregory, Darren G.; Petrash, J. Mark

    2016-01-01

    Purpose Dry eye syndrome (DES) affects millions of people worldwide. Homeopathic remedies to treat a wide variety of ocular diseases have previously been documented in the literature, but little systematic work has been performed to validate the remedies’ efficacy using accepted laboratory models of disease. The purpose of this study was to evaluate the efficacy of human milk and nopal cactus (prickly pear), two widely used homeopathic remedies, as agents to reduce pathological markers of DES. Methods The previously described benzalkonium chloride (BAK) dry eye mouse model was used to study the efficacy of human milk and nopal cactus (prickly pear). BAK (0.2%) was applied to the mouse ocular surface twice daily to induce dry eye pathology. Fluorescein staining was used to verify that the animals had characteristic signs of DES. After induction of DES, the animals were treated with human milk (whole and fat-reduced), nopal, nopal extract derivatives, or cyclosporine four times daily for 7 days. Punctate staining and preservation of corneal epithelial thickness, measured histologically at the end of treatment, were used as indices of therapeutic efficacy. Results Treatment with BAK reduced the mean corneal epithelial thickness from 36.77±0.64 μm in the control mice to 21.29±3.2 μm. Reduction in corneal epithelial thickness was largely prevented by administration of whole milk (33.2±2.5 μm) or fat-reduced milk (36.1±1.58 μm), outcomes that were similar to treatment with cyclosporine (38.52±2.47 μm), a standard in current dry eye therapy. In contrast, crude or filtered nopal extracts were ineffective at preventing BAK-induced loss of corneal epithelial thickness (24.76±1.78 μm and 27.99±2.75 μm, respectively), as were solvents used in the extraction of nopal materials (26.53±1.46 μm for ethyl acetate, 21.59±5.87 μm for methanol). Epithelial damage, as reflected in the punctate scores, decreased over 4 days of treatment with whole and fat

  5. FOUR-YEAR INCIDENCE AND PROGRESSION OF AGE-RELATED MACULAR DEGENERATION: THE LOS ANGELES LATINO EYE STUDY

    PubMed Central

    Varma, Rohit; Foong, Athena W.P.; Lai, Mei-Ying; Choudhury, Farzana; Klein, Ronald; Azen, Stanley P.

    2011-01-01

    Purpose To estimate 4-year incidence and progression of early and advanced age-related macular degeneration (AMD). Design Population-based cohort study. Methods A comprehensive ophthalmologic examination including stereoscopic fundus photography was performed on adult Latinos at baseline and follow-up. Photographs were graded using a modified Wisconsin Age-Related Maculopathy Grading System. For estimations of incidence and progression of AMD, the Age Related Eye Disease Study Scale was used. Main outcome measures are incidence and progression of early AMD (drusen type, drusen size, and retinal pigmentary abnormalities) and advanced AMD (exudative AMD and geographic atrophy). Results 4,658/6100 (76%) completed the follow-up examination. The 4-year incidence of early AMD was 7.5% (95%CI:6.6,8.4) and advanced AMD was 0.2% (95%CI:0.1,0.4). Progression of any AMD occurred in 9.3% (95%CI:8.4,10.3) of at-risk participants. Incidence and progression increased with age. Incidence of early AMD in the second eye (10.8%) was higher than incidence in the first eye (6.9%). Baseline presence of soft indistinct large drusen≥250μm in diameter was more likely to predict the 4-year incidence of pigmentary abnormalities, geographic atrophy, and exudative AMD than smaller or hard or soft distinct drusen. Conclusions Age-specific incidence and progression of AMD in Latinos are lower than in non-Hispanic whites. While incident early AMD is more often unilateral, the risk of its development in the second is higher than in the first eye. Older persons and those with soft indistinct large drusen had a higher risk of developing advanced AMD compared to those who were younger and did not have soft indistinct large drusen. PMID:20399926

  6. Age-dependent increase in miRNA-34a expression in the posterior pole of the mouse eye

    PubMed Central

    Forward, Krisztina I.; Nguyen, Anthony T.; Bordbari, Matthew H.; Oltjen, Sharon L.; Hjelmeland, Leonard M.

    2014-01-01

    Purpose MicroRNA-34a (miR-34a) has been implicated in neurodegeneration. MiR-34a belongs to a signaling network involving p53 and Sirt-1. This network responds to DNA damage with further downstream signals that induce senescence or apoptosis. Our goal was to measure the expression level of miR-34a in the mouse retina and RPE as a function of age. Methods The age-dependent change in miR-34a expression was quantified using a real-time PCR (RT-PCR) assay on microRNA isolates from eye tissue: the retina and RPE/choroid (4, 18, 24, and 32 months of age). Tissue localization of miR-34a was determined by in situ hybridization (ISH) for a series of time points. Expression of the miR-34a target gene Sirt1 was analyzed using RT-PCR and immunohistochemistry. Results MiR-34a examined with real-time PCR showed a linear increase in expression with age when compared to that of 4-month-old mice. However, the level of expression between the 24 and 32-month-old animals showed mild downregulation. An age-related increase in miR-34a expression was confirmed in the mouse eye using in situ hybridization. An inverse relationship between the levels of expression of miR-34a and its target Sirt1 mRNA was found at 18 and 24 months of age. Conclusions Our data showed that miR-34a expression increased in the retina and RPE with age. The level of DNA damage in mitochondria in the retina and RPE followed a similar time course. This suggests that miR-34a may play a role in the senescence and apoptosis of the retina and RPE cells in the aging eye. PMID:25489229

  7. The effects of metamaterial on electromagnetic fields absorption characteristics of human eye tissues.

    PubMed

    Gasmelseed, Akram; Yunus, Jasmy

    2014-01-01

    The interaction of a dipole antenna with a human eye model in the presence of a metamaterial is investigated in this paper. The finite difference time domain (FDTD) method with convolutional perfectly matched layer (CPML) formulation have been used. A three-dimensional anatomical model of the human eye with resolution of 1.25 mm × 1.25 mm × 1.25 mm was used in this study. The dipole antenna was driven by modulated Gaussian pulse and the numerical study is performed with dipole operating at 900 MHz. The analysis has been done by varying the size and value of electric permittivity of the metamaterial. By normalizing the peak SAR (1 g and 10 g) to 1 W for all examined cases, we observed how the SAR values are not affected by the different permittivity values with the size of the metamaterial kept fixed.

  8. Distribution of the neuro-regulatory peptide galanin in the human eye.

    PubMed

    Kaser-Eichberger, Alexandra; Trost, Andrea; Strohmaier, Clemens; Bogner, Barbara; Runge, Christian; Bruckner, Daniela; Hohberger, Bettina; Jünemann, Anselm; Kofler, Barbara; Reitsamer, Herbert A; Schrödl, Falk

    2016-11-25

    Galanin (GAL) is a neuro-regulatory peptide involved in many physiological and pathophysiological processes. While data of GAL origin/distribution in the human eye are rather fragmentary and since recently the presence of GAL-receptors in the normal human eye has been reported, we here systematically search for sources of ocular GAL in the human eye. Human eyes (n=14) were prepared for single- and double-immunohistochemistry of GAL and neurofilaments (NF). Cross- and flat-mount sections were achieved; confocal laser-scanning microscopy was used for documentation. In the anterior eye, GAL-immunoreactivity (GAL-IR) was detected in basal layers of corneal epithelium, endothelium, and in nerve fibers and keratinocytes of the corneal stroma. In the conjunctiva, GAL-IR was seen throughout all epithelial cell layers. In the iris, sphincter and dilator muscle and endothelium of iris vessels displayed GAL-IR. It was also detected in stromal cells containing melanin granules, while these were absent in others. In the ciliary body, ciliary muscle and pigmented as well as non-pigmented ciliary epithelium displayed GAL-IR. In the retina, GAL-IR was detected in cells associated with the ganglion cell layer, and in endothelial cells of retinal blood vessels. In the choroid, nerve fibers of the choroidal stroma as well as fibers forming boutons and surrounding choroidal blood vessels displayed GAL-IR. Further, the majority of intrinsic choroidal neurons were GAL-positive, as revealed by co-localization-experiments with NF, while a minority displayed NF- or GAL-IR only. GAL-IR was also detected in choroidal melanocytes, as identified by the presence of intracellular melanin-granules, as well as in cells lacking melanin-granules, most likely representing macrophages. GAL-IR was detected in numerous cells and tissues throughout the anterior and posterior eye and might therefore be an important regulatory peptide for many aspects of ocular control. Upcoming studies in diseased tissue

  9. Immunolocalization of CYP1B1 in normal, human, fetal and adult eyes.

    PubMed

    Doshi, Manali; Marcus, Craig; Bejjani, Bassem A; Edward, Deepak P

    2006-01-01

    CYP1B1 is a cytochrome P450 enzyme implicated in autosomal recessive primary congenital glaucoma (PCG). The mechanism and function of CYP1B1 in the development of the PCG phenotype is unknown. Previously, investigators have reported detection of Cyp1b1 mRNA in the ciliary body and epithelium and neuroepithelium in the developing mouse eye, employing in situ hybridization techniques. Similarly, additional investigators have detected CYP1B1 mRNA in the iris, ciliary body, non-pigmented ciliary epithelial line, cornea, retinal-pigment epithelium, and retina in the human adult eye, using Northern blotting. This study was designed to immunolocalize CYP1B1 protein in the various ocular structures of normal, human fetal and adult eyes. Normal fetal and adult eyes were immunolabeled with a polyclonal antibody against human CYP1B1 using indirect immunofluorescence, and then compared with appropriate controls. The intensity of immunolabeling of the various ocular structures was assessed by qualitative and semi-quantitative techniques. In the anterior segment anti-CYP1B1 immunoreactivity (IR) was detected early in fetal development in the primitive ciliary epithelium. As well, the most intense CYP1B1 IR was in the non-pigmented ciliary epithelium. In addition, CYP1B1 IR was also present in the corneal epithelium and keratocytes, both layers of the iris pigmented epithelium, and retina. However, CYP1B1 IR was absent in the trabecular meshwork in all of the samples. In general, CYP1B1 immunolabeling in the human fetal eyes was more intense when compared to adult eyes. CYP1B1 IR was primarily immunolocalized to the non-pigmented ciliary epithelium and early in fetal development. In addition, CYP1B1 IR was not detected in the trabecular meshwork. These findings suggest that the abnormalities in the development of the trabecular meshwork in PCG may result from diminished or absent metabolism of important endogenous substrates in the ciliary epithelium due to non-functional CYP1B1

  10. Human serum metabolic profiles are age dependent

    PubMed Central

    Yu, Zhonghao; Zhai, Guangju; Singmann, Paula; He, Ying; Xu, Tao; Prehn, Cornelia; Römisch-Margl, Werner; Lattka, Eva; Gieger, Christian; Soranzo, Nicole; Heinrich, Joachim; Standl, Marie; Thiering, Elisabeth; Mittelstraß, Kirstin; Wichmann, Heinz-Erich; Peters, Annette; Suhre, Karsten; Li, Yixue; Adamski, Jerzy; Spector, Tim D; Illig, Thomas; Wang-Sattler, Rui

    2012-01-01

    Understanding the complexity of aging is of utmost importance. This can now be addressed by the novel and powerful approach of metabolomics. However, to date, only a few metabolic studies based on large samples are available. Here, we provide novel and specific information on age-related metabolite concentration changes in human homeostasis. We report results from two population-based studies: the KORA F4 study from Germany as a discovery cohort, with 1038 female and 1124 male participants (32–81 years), and the TwinsUK study as replication, with 724 female participants. Targeted metabolomics of fasting serum samples quantified 131 metabolites by FIA-MS/MS. Among these, 71/34 metabolites were significantly associated with age in women/men (BMI adjusted). We further identified a set of 13 independent metabolites in women (with P values ranging from 4.6 × 10−04 to 7.8 × 10−42, αcorr = 0.004). Eleven of these 13 metabolites were replicated in the TwinsUK study, including seven metabolite concentrations that increased with age (C0, C10:1, C12:1, C18:1, SM C16:1, SM C18:1, and PC aa C28:1), while histidine decreased. These results indicate that metabolic profiles are age dependent and might reflect different aging processes, such as incomplete mitochondrial fatty acid oxidation. The use of metabolomics will increase our understanding of aging networks and may lead to discoveries that help enhance healthy aging. PMID:22834969

  11. Photodetection and computer analysis of a human eye retina image influenced by glaucoma

    NASA Astrophysics Data System (ADS)

    Pluhacek, Frantisek; Pospisil, Jaroslav

    2003-07-01

    This paper deals with some present methods of the photodetection of a human eye retina image and the following computer analysis of the obtained image dates. There are considered the detection and the computer quantitative evaluations of characteristic symptoms of glaucoma on the human eye retina. These symptoms and their numerical parameters, that are usually used, are shortly described. The main part of this paper describes the methods of the creation and the computer analysis of a three-dimensional map of the blind spot of the human eye retina (papila) and the adjacent area of the retina. The changes important for diagnostics of the above mentioned three-dimensional map are then detected through the computer analysis. Specially, the methods of scanning laser tomography and stereophotographic measurement of the mentioned part of retina are considered. Some concrete results ascertained by the mentioned methods are also shown. Lastly, our suggestions of methods of analyzing two-dimensional images of retina obtained by the colour fundus camera are shown.

  12. Visual exploration patterns of human figures in action: an eye tracker study with art paintings

    PubMed Central

    Villani, Daniela; Morganti, Francesca; Cipresso, Pietro; Ruggi, Simona; Riva, Giuseppe; Gilli, Gabriella

    2015-01-01

    Art exploration is a complex process conditioned by factors at different levels and includes both basic visual principles and complex cognitive factors. The human figure is considered a critical factor attracting the attention in art painting. Using an eye-tracking methodology, the goal of this study was to explore different elements of the human figure performing an action (face and body parts in action) in complex social scenes characterized by different levels of social interaction between agents depicted in scenes (individual vs. social). The sample included 44 laypersons, and the stimuli consisted of 10 fine art paintings representing the figurative style of classical art. The results revealed different scanning patterns of the human figure elements related to the level of social interaction of agents depicted in the scene. The agents’ face attracted eye movements in social interaction scenes while the agents’ body parts attracted eye movements only when the agents were involved in individual actions. These processes were confirmed specifically in participants with high empathic abilities who became immediately fixated on faces to develop a mimetic engagement with other agents. Future studies integrating other measures would help confirm the results obtained and strengthen their implication for embodiment processes. PMID:26579021

  13. Biobanking of Human Retinas: The Next Big Leap for Eye Banks?

    PubMed

    Lužnik, Zala; Parekh, Mohit; Bertolin, Marina; Griffoni, Carlo; Ponzin, Diego; Ferrari, Stefano

    2015-08-01

    Retinal degenerative diseases are one of the main clinical causes of incurable and severe visional impairment. Thus, extensive research effort is put into the development of new causal therapeutic options. Promisingly, a number of studies showed regenerative capacity in specific retinal regions (the ciliary epithelium, retinal pigmented epithelium, iris, and Müller glia cells). However, most recent research studies are based on animal models or in vitro cultured cells, probably because of the limited availability of human posterior eye tissues (vitreous, retina, and choroid). To address this, we showed in our previous reports that eye banks with large numbers of globes collected yearly could set up biorepositories/biobanks where these precious tissues are isolated, quality controlled, and finally stored for scientists and clinicians wanting to access human tissues and test their own hypotheses. These precious human posterior eye tissues could be used for further research purposes, epidemiological studies, and target validation of newly developed drugs. In addition, this could be a promising and challenging option to retrieve potential retinal stem and progenitor cells from different parts of the retina and could be a breakthrough in the future delivery of ex vivo prepared customized (histocompatible) retinal tissue on scaffolds for transplantation purposes. In this Perspective, we will consider how the biorepositories could influence the future strategies for retinal stem cell therapies.

  14. Visual disruption using the thermal lensing effect in the human eye: pilot study.

    PubMed

    Towle, Erica L; Garcia, Paul V; Smith, Peter A; Thomas, Robert J; Dunn, Andrew K; Welch, Ashley J; Foutch, Brian K

    2012-10-01

    At select wavelengths, near infrared (IR) light is absorbed in the preretinal media of the eye. This produces small transient increases in temperature that temporarily alter the local index of refraction. If the IR exposure is sufficiently high, a momentary reduction in the focusing power of the eye can be induced through an effect known as thermal lensing. Fundamental optical interaction and safety aspects of this phenomenon have been demonstrated previously in animal and artificial eye models. However, whether the effect will induce an observable visual change in human subjects has not been explored. Here, results of a pilot study are shown where eight human subjects were exposed to an IR laser at levels that were below the safe exposure limit. The exposures did induce a transient visual distortion if sufficiently high levels were used. While the description of the visual change varied between subjects, this experiment was able to determine a general guideline for power needed to induce significant effects in human subjects.

  15. Simplifying numerical ray tracing for two-dimensional non circularly symmetric models of the human eye.

    PubMed

    Jesus, Danilo A; Iskander, D Robert

    2015-12-01

    Ray tracing is a powerful technique to understand the light behavior through an intricate optical system such as that of a human eye. The prediction of visual acuity can be achieved through characteristics of an optical system such as the geometrical point spread function. In general, its precision depends on the number of discrete rays and the accurate surface representation of each eye's components. Recently, a method that simplifies calculation of the geometrical point spread function has been proposed for circularly symmetric systems [Appl. Opt.53, 4784 (2014)]. An extension of this method to 2D noncircularly symmetric systems is proposed. In this method, a two-dimensional ray tracing procedure for an arbitrary number of surfaces and arbitrary surface shapes has been developed where surfaces, rays, and refractive indices are all represented in functional forms being approximated by Chebyshev polynomials. The Liou and Brennan anatomically accurate eye model has been adapted and used for evaluating the method. Further, real measurements of the anterior corneal surface of normal, astigmatic, and keratoconic eyes were substituted for the first surface in the model. The results have shown that performing ray tracing, utilizing the two-dimensional Chebyshev function approximation, is possible for noncircularly symmetric models, and that such calculation can be performed with a newly created Chebfun toolbox.

  16. Age-related changes in human posture control: Sensory organization tests

    NASA Technical Reports Server (NTRS)

    Peterka, R. J.; Black, F. O.

    1989-01-01

    Postural control was measured in 214 human subjects ranging in age from 7 to 81 years. Sensory organization tests measured the magnitude of anterior-posterior body sway during six 21 s trials in which visual and somatosensory orientation cues were altered (by rotating the visual surround and support surface in proportion to the subject's sway) or vision eliminated (eyes closed) in various combinations. No age-related increase in postural sway was found for subjects standing on a fixed support surface with eyes open or closed. However, age-related increases in sway were found for conditions involving altered visual or somatosensory cues. Subjects older than about 55 years showed the largest sway increases. Subjects younger than about 15 years were also sensitive to alteration of sensory cues. On average, the older subjects were more affected by altered visual cues whereas younger subjects had more difficulty with altered somatosensory cues.

  17. The Age of Human Cerebral Cortex Neurons

    SciTech Connect

    Bhardwaj, R D; Curtis, M A; Spalding, K L; Buchholz, B A; Fink, D; Bjork-Eriksson, T; Nordborg, C; Gage, F H; Druid, H; Eriksson, P S; Frisen, J

    2006-04-06

    The traditional static view of the adult mammalian brain has been challenged by the realization of continuous generation of neurons from stem cells. Based mainly on studies in experimental animals, adult neurogenesis may contribute to recovery after brain insults and decreased neurogenesis has been implicated in the pathogenesis of neurological and psychiatric diseases in man. The extent of neurogenesis in the adult human brain has, however, been difficult to establish. We have taken advantage of the integration of {sup 14}C, generated by nuclear bomb tests during the Cold War, in DNA to establish the age of neurons in the major areas of the human cerebral cortex. Together with the analysis of the cortex from patients who received BrdU, which integrates in the DNA of dividing cells, our results demonstrate that whereas non-neuronal cells turn over, neurons in the human cerebral cortex are not generated postnatally at detectable levels, but are as old as the individual.

  18. Judgment of the Humanness of an Interlocutor Is in the Eye of the Beholder

    PubMed Central

    Lortie, Catherine L.; Guitton, Matthieu J.

    2011-01-01

    Despite tremendous advances in artificial language synthesis, no machine has so far succeeded in deceiving a human. Most research focused on analyzing the behavior of “good” machine. We here choose an opposite strategy, by analyzing the behavior of “bad” humans, i.e., humans perceived as machine. The Loebner Prize in Artificial Intelligence features humans and artificial agents trying to convince judges on their humanness via computer-mediated communication. Using this setting as a model, we investigated here whether the linguistic behavior of human subjects perceived as non-human would enable us to identify some of the core parameters involved in the judgment of an agents' humanness. We analyzed descriptive and semantic aspects of dialogues in which subjects succeeded or failed to convince judges of their humanness. Using cognitive and emotional dimensions in a global behavioral characterization, we demonstrate important differences in the patterns of behavioral expressiveness of the judges whether they perceived their interlocutor as being human or machine. Furthermore, the indicators of interest displayed by the judges were predictive of the final judgment of humanness. Thus, we show that the judgment of an interlocutor's humanness during a social interaction depends not only on his behavior, but also on the judge himself. Our results thus demonstrate that the judgment of humanness is in the eye of the beholder. PMID:21966420

  19. Dry Eye

    MedlinePlus

    ... Courier services use: Rockville, MD 20852) 301-451-2020 Research at NEI Office of the Scientific Director ... Eye Disease Education Program Glaucoma Education Program Low Vision Education Program Hispanic/Latino Program Vision and Aging ...

  20. Comparing the accuracy of video-oculography and the scleral search coil system in human eye movement analysis.

    PubMed

    Imai, Takao; Sekine, Kazunori; Hattori, Kousuke; Takeda, Noriaki; Koizuka, Izumi; Nakamae, Koji; Miura, Katsuyoshi; Fujioka, Hiromu; Kubo, Takeshi

    2005-03-01

    The measurement of eye movements in three dimensions is an important tool to investigate the human vestibular and oculomotor system. The primary methods for three dimensional eye movement measurement are the scleral search coil system (SSCS) and video-oculography (VOG). In the present study, we compare the accuracy of VOG with that of SSCS using an artificial eye. We then analyzed the Y (pitch) and Z (yaw) component of human eye movements during saccades, smooth pursuit and optokinetic nystagmus, and the X (roll) component of human eye movement during the torsional vestibulo-ocular reflex induced by rotation in normal subjects, using simultaneous VOG and SSCS measures. The coefficients of the linear relationship between the angle of a simulated eyeball and the angle measured by both VOG and SSCS was almost unity with y-intercepts close to zero for torsional (X), vertical (Y) and horizontal (Z) movements, indicating that the in vitro accuracy of VOG was similar to that of SSCS. The average difference between VOG and SSCS was 0.56 degrees , 0.78 degrees and 0.18 degrees for the X, Y and Z components of human eye movements, respectively. Both the in vitro and in vivo comparisons demonstrate that VOG has accuracy comparable to SSCS, and is a reliable method for measurement of three dimensions (3D) human eye movements.

  1. Biobanking of Human Retinas: The Next Big Leap for Eye Banks?

    PubMed Central

    Lužnik, Zala; Parekh, Mohit; Bertolin, Marina; Griffoni, Carlo; Ponzin, Diego

    2015-01-01

    Summary Retinal degenerative diseases are one of the main clinical causes of incurable and severe visional impairment. Thus, extensive research effort is put into the development of new causal therapeutic options. Promisingly, a number of studies showed regenerative capacity in specific retinal regions (the ciliary epithelium, retinal pigmented epithelium, iris, and Müller glia cells). However, most recent research studies are based on animal models or in vitro cultured cells, probably because of the limited availability of human posterior eye tissues (vitreous, retina, and choroid). To address this, we showed in our previous reports that eye banks with large numbers of globes collected yearly could set up biorepositories/biobanks where these precious tissues are isolated, quality controlled, and finally stored for scientists and clinicians wanting to access human tissues and test their own hypotheses. These precious human posterior eye tissues could be used for further research purposes, epidemiological studies, and target validation of newly developed drugs. In addition, this could be a promising and challenging option to retrieve potential retinal stem and progenitor cells from different parts of the retina and could be a breakthrough in the future delivery of ex vivo prepared customized (histocompatible) retinal tissue on scaffolds for transplantation purposes. In this Perspective, we will consider how the biorepositories could influence the future strategies for retinal stem cell therapies. Significance Retinal degenerative diseases are one of the main causes of severe vision impairment and regenerative medicine is attracting much attention as a potential therapy. Although highly desirable, the reactivation and proliferation of endogenous stem cells in vivo is not sufficient to generate enough cells to restore visual function after retinal injury. Thus, the replacement of exogenously derived normal donor cells is a promising solution. The challenge is to

  2. Quantitative Classification of Eyes with and without Intermediate Age-related Macular Degeneration Using Optical Coherence Tomography

    PubMed Central

    Farsiu, Sina; Chiu, Stephanie J.; O'Connell, Rachelle V.; Folgar, Francisco A.; Yuan, Eric; Izatt, Joseph A.; Toth, Cynthia A.

    2013-01-01

    Objective To define quantitative indicators for the presence of intermediate age-related macular degeneration (AMD) via spectral-domain optical coherence tomography (SD-OCT) imaging of older adults. Design Evaluation of diagnostic test and technology. Participants and Controls One eye from 115 elderly subjects without AMD and 269 subjects with intermediate AMD from the Age-Related Eye Disease Study 2 (AREDS2) Ancillary SD-OCT Study. Methods We semiautomatically delineated the retinal pigment epithelium (RPE) and RPE drusen complex (RPEDC, the axial distance from the apex of the drusen and RPE layer to Bruch's membrane) and total retina (TR, the axial distance between the inner limiting and Bruch's membranes) boundaries. We registered and averaged the thickness maps from control subjects to generate a map of “normal” non-AMD thickness. We considered RPEDC thicknesses larger or smaller than 3 standard deviations from the mean as abnormal, indicating drusen or geographic atrophy (GA), respectively. We measured TR volumes, RPEDC volumes, and abnormal RPEDC thickening and thinning volumes for each subject. By using different combinations of these 4 disease indicators, we designed 5 automated classifiers for the presence of AMD on the basis of the generalized linear model regression framework. We trained and evaluated the performance of these classifiers using the leave-one-out method. Main Outcome Measures The range and topographic distribution of the RPEDC and TR thicknesses in a 5-mm diameter cylinder centered at the fovea. Results The most efficient method for separating AMD and control eyes required all 4 disease indicators. The area under the curve (AUC) of the receiver operating characteristic (ROC) for this classifier was >0.99. Overall neurosensory retinal thickening in eyes with AMD versus control eyes in our study contrasts with previous smaller studies. Conclusions We identified and validated efficient biometrics to distinguish AMD from normal eyes by

  3. Parainflammation associated with advanced glycation endproduct stimulation of RPE in vitro: implications for age-related degenerative diseases of the eye.

    PubMed

    Lin, Tony; Walker, Gregory Brett; Kurji, Khaliq; Fang, Edward; Law, Geoffrey; Prasad, Shiv S; Kojic, Luba; Cao, Sijia; White, Valerie; Cui, Jing Z; Matsubara, Joanne A

    2013-06-01

    Age related macular degeneration (AMD) is one of the leading causes of blindness in Western society. A hallmark of early stage AMD are drusen, extracellular deposits that accumulate in the outer retina. Advanced glycation endproducts (AGE) accumulate with aging and are linked to several age-related diseases such as Alzheimer's disease, osteoarthritis, atherosclerosis and AMD. AGE deposits are found in drusen and in Bruch's membrane of the eye and several studies have suggested its role in promoting oxidative stress, apoptosis and lipofuscin accumulation. Recently, complement activation and chronic inflammation have been implicated in the pathogenesis of AMD. While AGEs have been shown to promote inflammation in other diseases, whether it plays a similar role in AMD is not known. This study investigates the effects of AGE stimulation on pro- and anti-inflammatory pathways in primary culture of human retinal pigment epithelial cells (RPE). Differential gene expression studies revealed a total of 41 up- and 18 down-regulated RPE genes in response to AGE stimulation. These genes fell into three categories as assessed by gene set enrichment analysis (GSEA). The main categories were inflammation (interferon-induced, immune response) and proteasome degradation, followed by caspase signaling. Using suspension array technology, protein levels of secreted cytokines and growth factors were also examined. Anti-inflammatory cytokines including IL10, IL1ra and IL9 were all overexpressed. Pro-inflammatory cytokines including IL4, IL15 and IFN-γ were overexpressed, while other pro-inflammatory cytokines including IL8, MCP1, IP10 were underexpressed after AGE stimulation, suggesting a para-inflammation state of the RPE under these conditions. Levels of mRNA of chemokine, CXCL11, and viperin, RSAD2, were up-regulated and may play a role in driving the inflammatory response via the NF-kB and JAK-STAT pathways. CXCL11 was strongly immunoreactive and associated with drusen in the AMD

  4. Bitter Taste Receptor Polymorphisms and Human Aging

    PubMed Central

    Carrai, Maura; Crocco, Paolina; Montesanto, Alberto; Canzian, Federico; Rose, Giuseppina; Rizzato, Cosmeri

    2012-01-01

    Several studies have shown that genetic factors account for 25% of the variation in human life span. On the basis of published molecular, genetic and epidemiological data, we hypothesized that genetic polymorphisms of taste receptors, which modulate food preferences but are also expressed in a number of organs and regulate food absorption processing and metabolism, could modulate the aging process. Using a tagging approach, we investigated the possible associations between longevity and the common genetic variation at the three bitter taste receptor gene clusters on chromosomes 5, 7 and 12 in a population of 941 individuals ranging in age from 20 to 106 years from the South of Italy. We found that one polymorphism, rs978739, situated 212 bp upstream of the TAS2R16 gene, shows a statistically significant association (p = 0.001) with longevity. In particular, the frequency of A/A homozygotes increases gradually from 35% in subjects aged 20 to 70 up to 55% in centenarians. These data provide suggestive evidence on the possible correlation between human longevity and taste genetics. PMID:23133589

  5. An eye-tracking investigation of developmental changes in infants’ exploration of upright and inverted human faces

    PubMed Central

    Oakes, Lisa M.; Ellis, Ann E.

    2011-01-01

    We used eye-tracking to examine 4.5- to 12.5-month-old infants’ (N = 92) eye-movements during 3-s presentations of upright and inverted faces. Scanning of inverted faces was statistically indistinguishable at 4.5, 6.5, 8, and 12.5 months of age; at each of these ages infants disproportionately scanned the region containing the eyes. Scanning of upright faces changed over this age range. When viewing upright faces, 4.5-month-old and 6.5-month-old infants focused disproportionately on the region containing the eyes, whereas 12.5-month-old and 8-month-old infants distributed looking more broadly, scanning more of the internal area of the faces. These results are consistent with other observed developmental differences in face processing, and provide insight into how moment-to-moment face processing changes during infancy. PMID:23525142

  6. Screening for potential hazard effects from four nitramines on human eye and skin.

    PubMed

    Fjellsbø, Lise Marie; Van Rompay, An R; Hooyberghs, Jef; Nelissen, Inge; Dusinska, Maria

    2013-06-01

    Amines have potential to be used in CO2 capture and storage (CCS) technology, but as they can be released into the environment and be degraded into more toxic compounds, such as nitrosamines and nitramines, there have been concerns about their negative impact on human health. We investigated the potential toxic effects from acute exposure to dimethylnitramine (DMA-NO2), methylnitramine (MA-NO2), ethanolnitramine (MEA-NO2) and 2-methyl-2-(nitroamino)-1-propanol (AMP-NO2). The eye irritation, and skin sensitization, irritation and corrosion potential of these substances have been evaluated in vitro using the Bovine Corneal Opacity and Permeability (BCOP) assay, VITOSENS® assay, Reconstructed Human Epidermis (RHE) skin irritation test and Corrositex Skin corrosion test, respectively. Exposure to DMA-NO2 induced a mild eye irritation response, while MA-NO2, MEA-NO2 and AMP-NO2 were shown to be very severe eye irritants. MA-NO2 and MEA-NO2 were tested for skin sensitization and found to be non-sensitizers to the skin. In addition, none of the four test substances was irritant or corrosive to the skin.

  7. Chromatic aberration correction of the human eye for retinal imaging in the near infrared

    NASA Astrophysics Data System (ADS)

    Fernández, Enrique J.; Unterhuber, Angelika; Považay, Boris; Hermann, Boris; Artal, Pablo; Drexler, Woflgang

    2006-06-01

    An achromatizing lens has been designed for the human eye in the near infrared range, from 700 to 900 nm, for retinal imaging purposes. Analysis of the performance of the lens, including tolerance to misalignments, has been mathematically accomplished by using an existing eye model. The calculations have shown a virtually perfect correction of the ocular longitudinal chromatic aberration, while still keeping a high optical quality. Ocular aberrations in five subjects have been measured with and without the achromatizing lens by using a Hartmann-Shack wavefront sensor and a broad bandwidth femtosecond Ti:sapphire laser in the spectral range of interest with a set of interference filters, studying the benefits and limits in the use of the achromatizing lens. Ocular longitudinal chromatic aberration has been experimentally demonstrated to be fully corrected by the proposed lens, with no induction of any other parasitic aberration. The practical implementation of the achromatizing lens for Ophthalmoscopy, specifically for optical coherence tomography where the use of polychromatic light sources in the near infrared portion of the spectrum is mandatory, has been considered. The potential benefits of using this lens in combination with adaptive optics to achieve a full aberration correction of the human eye for retinal imaging have also been discussed.

  8. Three-dimensional ray tracing for refractive correction of human eye ametropies

    NASA Astrophysics Data System (ADS)

    Jimenez-Hernandez, J. A.; Diaz-Gonzalez, G.; Trujillo-Romero, F.; Iturbe-Castillo, M. D.; Juarez-Salazar, R.; Santiago-Alvarado, A.

    2016-09-01

    Ametropies of the human eye, are refractive defects hampering the correct imaging on the retina. The most common ways to correct them is by means of spectacles, contact lenses, and modern methods as laser surgery. However, in any case it is very important to identify the ametropia grade for designing the optimum correction action. In the case of laser surgery, it is necessary to define a new shape of the cornea in order to obtain the wanted refractive correction. Therefore, a computational tool to calculate the focal length of the optical system of the eye versus variations on its geometrical parameters is required. Additionally, a clear and understandable visualization of the evaluation process is desirable. In this work, a model of the human eye based on geometrical optics principles is presented. Simulations of light rays coming from a punctual source at six meter from the cornea are shown. We perform a ray-tracing in three dimensions in order to visualize the focusing regions and estimate the power of the optical system. The common parameters of ametropies can be easily modified and analyzed in the simulation by an intuitive graphic user interface.

  9. Learning robotic eye-arm-hand coordination from human demonstration: a coupled dynamical systems approach.

    PubMed

    Lukic, Luka; Santos-Victor, José; Billard, Aude

    2014-04-01

    We investigate the role of obstacle avoidance in visually guided reaching and grasping movements. We report on a human study in which subjects performed prehensile motion with obstacle avoidance where the position of the obstacle was systematically varied across trials. These experiments suggest that reaching with obstacle avoidance is organized in a sequential manner, where the obstacle acts as an intermediary target. Furthermore, we demonstrate that the notion of workspace travelled by the hand is embedded explicitly in a forward planning scheme, which is actively involved in detecting obstacles on the way when performing reaching. We find that the gaze proactively coordinates the pattern of eye-arm motion during obstacle avoidance. This study provides also a quantitative assessment of the coupling between the eye-arm-hand motion. We show that the coupling follows regular phase dependencies and is unaltered during obstacle avoidance. These observations provide a basis for the design of a computational model. Our controller extends the coupled dynamical systems framework and provides fast and synchronous control of the eyes, the arm and the hand within a single and compact framework, mimicking similar control system found in humans. We validate our model for visuomotor control of a humanoid robot.

  10. Chromatic aberration correction of the human eye for retinal imaging in the near infrared.

    PubMed

    Fernández, Enrique J; Unterhuber, Angelika; Povazay, Boris; Hermann, Boris; Artal, Pablo; Drexler, Woflgang

    2006-06-26

    An achromatizing lens has been designed for the human eye in the near infrared range, from 700 to 900 nm, for retinal imaging purposes. Analysis of the performance of the lens, including tolerance to misalignments, has been mathematically accomplished by using an existing eye model. The calculations have shown a virtually perfect correction of the ocular longitudinal chromatic aberration, while still keeping a high optical quality. Ocular aberrations in five subjects have been measured with and without the achromatizing lens by using a Hartmann-Shack wavefront sensor and a broad bandwidth femtosecond Ti:sapphire laser in the spectral range of interest with a set of interference filters, studying the benefits and limits in the use of the achromatizing lens. Ocular longitudinal chromatic aberration has been experimentally demonstrated to be fully corrected by the proposed lens, with no induction of any other parasitic aberration. The practical implementation of the achromatizing lens for Ophthalmoscopy, specifically for optical coherence tomography where the use of polychromatic light sources in the near infrared portion of the spectrum is mandatory, has been considered. The potential benefits of using this lens in combination with adaptive optics to achieve a full aberration correction of the human eye for retinal imaging have also been discussed.

  11. Automated measurement of choroidal thickness in the human eye by polarization sensitive optical coherence tomography

    PubMed Central

    Torzicky, Teresa; Pircher, Michael; Zotter, Stefan; Bonesi, Marco; Götzinger, Erich; Hitzenberger, Christoph K.

    2015-01-01

    We present a new method to automatically segment the thickness of the choroid in the human eye by polarization sensitive optical coherence tomography (PS-OCT). A swept source PS-OCT instrument operating at a center wavelength of 1040 nm is used. The segmentation method is based entirely on intrinsic, tissue specific polarization contrast mechanisms. In a first step, the anterior boundary of the choroid, the retinal pigment epithelium, is segmented based on depolarization. In a second step, the choroid-sclera interface is found by using the birefringence of the sclera. The method is demonstrated in five healthy eyes. The mean repeatability (standard deviation) of thickness measurement was found to be 18.3 μm. PMID:22453435

  12. Will vaccination against human papillomavirus prevent eye disease? A review of the evidence.

    PubMed

    Hughes, D S; Powell, N; Fiander, A N

    2008-04-01

    The role of human papillomavirus (HPV) infection in eye disease is controversial. However, a recent case illustrates the possible role of HPV in conjunctival squamous carcinoma and the potentially devastating effects of this disease. The development of two vaccines to prevent infection with HPV types most commonly associated with anogenital cancers has led to debate about the pros and cons of a national immunisation programme to prevent cervical cancer. The introduction of such a vaccination programme may have an additional beneficial effect on the occurrence of some head and neck, including ocular, cancers. This review discusses the nature of papillomaviruses, mechanisms of infection and carcinogenesis, the possible role of HPV in eye disease, and finally the likely impact of the new prophylactic vaccines.

  13. Influence of age on the temperature of the anterior segment of the eye. Measurements by infrared thermometry.

    PubMed

    Aliò, J; Padron, M

    1982-01-01

    The absolute temperatures of five characteristic points of the orbito-ocular thermogram were studied by means of infrared thermometry in a group of 96 normal subjects, randomly selected between ages from 15 days to 80 years. Significant differences were found between older and younger age groups concerning absolute temperatures of the centre of the cornea, limbus, sclera and outer canthus. Inner canthus temperature showed very little variation with age, being the most constant thermometric point of the five selected for study. Mean absolute temperatures of the anterior segment of the eye and outer canthus measured by infrared thermometry significantly decreased with age. To the best of our knowledge this finding has not been previously reported.

  14. [Carotenoids of the human eye in prenatal and early postnatal development].

    PubMed

    Panova, I G; Stroeva, O G; Ostrovskiĭ, M A

    2013-09-01

    The review deals with the role of carotenoids in the formation of the structural and functional differentiation of the macula--the area of the highest visual acuity of the human retina. The review also presents the data on detection of carotenoids (lutein) in the vitreous body of the human eye during its prenatal development and discusses their possible role in the development of the retina, particularly in relation to differentiation of the macular area. Macular dystrophy has been considered till recently as senile pathology. According to modern ophthalmologic observations, the number of cases of appearance of this pathology increases in young humans. Such a shift can be prevented by addition of carotenoids to the diet. This permits a conclusion that the permanent presence of carotenoids in the course of the whole human life is necessary for the formation and retention of structural and functional integrity of the macula.

  15. Aging attenuates the vestibulosympathetic reflex in humans

    NASA Technical Reports Server (NTRS)

    Ray, Chester A.; Monahan, Kevin D.

    2002-01-01

    BACKGROUND: The vestibular system contributes to sympathetic activation by engagement of the otolith organs. However, there is a significant loss of vestibular function with aging. Therefore, the purpose of the present study was to determine if young and older individuals differ in their cardiovascular and sympathetic responses to otolithic stimulation (ie, head-down rotation, HDR). We hypothesized that responses to otolithic stimulation would be attenuated in older adults because of morphological and physiological alterations that occur in the vestibular system with aging. METHODS AND RESULTS: Arterial blood pressure, heart rate, muscle sympathetic nerve activity (MSNA), and head rotation were measured during HDR in 11 young (26 +/- 1 years) and 11 older (64 +/- 1 years) subjects in the prone posture. Five older subjects performed head rotation (chin to chest) in the lateral decubitus position, which simulates HDR but does not alter afferent inputs from the vestibular system. MSNA responses to HDR were significantly attenuated in older as compared with young subjects (P<0.01). MSNA increased in the older subjects by only 12 +/- 5% as compared with 85 +/- 16% in the young. Furthermore, HDR elicited significant reductions in mean arterial blood pressure in older (Delta-6 +/- 1 mm Hg; P<0.01) but not young subjects (Delta1 +/- 1 mm Hg). In contrast to HDR, head rotation performed in the lateral decubitus position did not elicit hypotension. MSNA responses to baroreceptor unloading and the cold pressor test were not different between the age groups. CONCLUSIONS: These data indicate that aging attenuates the vestibulosympathetic reflex in humans and may contribute to the increased prevalence of orthostatic hypotension with age.

  16. Age Differences in Online Processing of Video: An Eye Movement Study

    ERIC Educational Resources Information Center

    Kirkorian, Heather L.; Anderson, Daniel R.; Keen, Rachel

    2012-01-01

    Eye movements were recorded while sixty-two 1-year-olds, 4-year-olds, and adults watched television. Of interest was the extent to which viewers looked at the same place at the same time as their peers because high similarity across viewers suggests systematic viewing driven by comprehension processes. Similarity of gaze location increased with…

  17. The Age-Related Eye Disease Study (AREDS) System for Classifying Cataracts From Photographs: AREDS Report No. 4

    PubMed Central

    2006-01-01

    • PURPOSE: To describe the system for grading cataracts from photographs in the Age-Related Eye Disease Study (AREDS). • METHODS: The system for grading cataracts in AREDS uses photographs taken in a standardized fashion with specially modified cameras at 11 clinical centers. The photographs are evaluated by graders for quality and cataract severity at a central reading center. The area of lens involvement is used to assess the severity of cortical and posterior subcapsular opacities. Optical density of nuclear opacity is graded against a series of seven standard photographs. Contemporaneous variability in grading is evaluated periodically by having a second examiner regrade a subset of the photographs. Temporal variability is assessed by annually regrading a subset of photographs. • RESULTS: Photographs of 925 eyes, most with no or early lens opacities, were regraded to assess intergrader reliability. For cortical opacities, there was an absolute difference of 10% or greater of area involved in 1.9% of the replicate gradings. For posterior subcapsular opacities an absolute difference of 5% of area involved was noted in 2.8% of the regraded photographs. For nuclear opacities, absolute differences of 1.5 or more steps were observed in 0.6% of eyes. There was little evidence of temporal drift in grading any of the three types of opacity during four annual regrades. • CONCLUSIONS: We have demonstrated a high degree of reliability in grading the severity of lens opacities in a large study cohort with mostly early lens changes, the type of cohort most likely to be entered in clinical trials involving cataract prevention. The Age-Related Eye Disease Study System for Classifying Cataracts From Photographs could be useful in studies where there is a need to standardize data collection over time and across different data collection sites. Limitations of the system include the cost of implementation and, currently, the limited amount of data on grading

  18. Effects of intravitreal ranibizumab on the untreated eye and systemic gene expression profile in age-related macular degeneration.

    PubMed

    Michalska-Małecka, Katarzyna; Kabiesz, Adam; Kimsa, Malgorzata W; Strzałka-Mrozik, Barbara; Formińska-Kapuścik, Maria; Nita, Malgorzata; Mazurek, Urszula

    2016-01-01

    The purpose of this study was to evaluate the systemic effects of intravitreal ranibizumab (Lucentis) treatment in patients with neovascular age-related macular degeneration (AMD). The impact of intravitreal ranibizumab injections on central retinal thickness (CRT) of treated and contralateral untreated eyes, and differences in gene expression patterns in the peripheral blood mononuclear cells were analyzed. The study included 29 patients aged 50 years old and over with diagnosed neovascular AMD. The treatment was defined as 0.5 mg of ranibizumab injected intravitreally in the form of one injection every month during the period of 3 months. CRT was measured by optical coherence tomography. The gene expression profile was assigned using oligonucleotide microarrays of Affymetrix HG-U133A. Studies have shown that there was a change of CRT between treated and untreated eyes, and there were differences in CRT at baseline and after 1, 2, and 3 months of ranibizumab treatment. Three months after intravitreal injection, mean CRT was reduced in the treated eyes from 331.97±123.62 to 254.31±58.75 μm, while mean CRT in the untreated fellow eyes reduced from 251.07±40.29 to 235.45±36.21 μm at the same time. Furthermore, the research has shown that among all transcripts, 3,097 expresses change after the ranibizumab treatment in relation to controls. Among these transcripts, 1,339 were up-regulated, whereas 1,758 were down-regulated. Our results show the potential systemic effects of anti-VEGF therapy for AMD. Moreover, our study indicated different gene expression in peripheral blood mononuclear cells before and after intravitreal ranibizumab treatment.

  19. Effects of intravitreal ranibizumab on the untreated eye and systemic gene expression profile in age-related macular degeneration

    PubMed Central

    Michalska-Małecka, Katarzyna; Kabiesz, Adam; Kimsa, Malgorzata W; Strzałka-Mrozik, Barbara; Formińska-Kapuścik, Maria; Nita, Malgorzata; Mazurek, Urszula

    2016-01-01

    The purpose of this study was to evaluate the systemic effects of intravitreal ranibizumab (Lucentis) treatment in patients with neovascular age-related macular degeneration (AMD). The impact of intravitreal ranibizumab injections on central retinal thickness (CRT) of treated and contralateral untreated eyes, and differences in gene expression patterns in the peripheral blood mononuclear cells were analyzed. The study included 29 patients aged 50 years old and over with diagnosed neovascular AMD. The treatment was defined as 0.5 mg of ranibizumab injected intravitreally in the form of one injection every month during the period of 3 months. CRT was measured by optical coherence tomography. The gene expression profile was assigned using oligonucleotide microarrays of Affymetrix HG-U133A. Studies have shown that there was a change of CRT between treated and untreated eyes, and there were differences in CRT at baseline and after 1, 2, and 3 months of ranibizumab treatment. Three months after intravitreal injection, mean CRT was reduced in the treated eyes from 331.97±123.62 to 254.31±58.75 μm, while mean CRT in the untreated fellow eyes reduced from 251.07±40.29 to 235.45±36.21 μm at the same time. Furthermore, the research has shown that among all transcripts, 3,097 expresses change after the ranibizumab treatment in relation to controls. Among these transcripts, 1,339 were up-regulated, whereas 1,758 were down-regulated. Our results show the potential systemic effects of anti-VEGF therapy for AMD. Moreover, our study indicated different gene expression in peripheral blood mononuclear cells before and after intravitreal ranibizumab treatment. PMID:27069359

  20. Neovascular age-related macular degeneration without drusen in the fellow eye: clinical spectrum and therapeutic outcome

    PubMed Central

    Chung, Wing H; van Dijk, Elon H C; Mohabati, Danial; Dijkman, Greet; Yzer, Suzanne; de Jong, Eiko K; Fauser, Sascha; Schlingemann, Reinier O; Hoyng, Carel B; Boon, Camiel J F

    2017-01-01

    Purpose To investigate the clinical characteristics and therapeutic outcome of patients with neovascular age-related macular degeneration (nAMD) in 1 eye, without drusen in the fellow eye. Patients and methods Medical records of 381 patients were analyzed to identify the cases. The main outcomes included Early Treatment Diabetic Retinopathy Study (ETDRS) best-corrected visual acuity (BCVA) and change in central retinal thickness (CRT). These parameters were reviewed at baseline, first follow-up visit, and after 6, 12, and 24 months. Results Out of 381 patients, 29 cases (8%) were included (of whom 3 had polypoidal choroidal vasculopathy [PCV]) who were treated with anti-vascular endothelial growth factor (anti-VEGF) therapy which was supplemented by photodynamic therapy (PDT) in the PCV patients. Overall, no statistically significant change in mean BCVA was observed during follow-up. BCVA improved or remained stable (defined as a gain in BCVA, a stable BCVA, or a loss of <5 ETDRS letters) in 22 patients (76%), and 7 patients (23%) had lost ≥5 ETDRS letters at final follow-up. A gain of ≥15 ETDRS letters at final follow-up was seen in 5 patients (17%). Mean CRT had decreased significantly with 99 µm (P<0.001) at 24 months after the initial visit. Conclusion There is a clinical spectrum of nAMD that is not associated with drusen in the fellow eye. Patients with nAMD without drusen in the fellow eye respond to anti-VEGF treatment and, in cases of PCV, to supplemental PDT. The pathophysiology of this spectrum of nAMD may be different from drusen-associated age-related macular degeneration. PMID:28053502

  1. Aging of oocyte, ovary, and human reproduction.

    PubMed

    Ottolenghi, Chris; Uda, Manuela; Hamatani, Toshio; Crisponi, Laura; Garcia, Jose-Elias; Ko, Minoru; Pilia, Giuseppe; Sforza, Chiarella; Schlessinger, David; Forabosco, Antonino

    2004-12-01

    We review age-related changes in the ovary and their effect on female fertility, with particular emphasis on follicle formation, follicle dynamics, and oocyte quality. The evidence indicates that the developmental processes leading to follicle formation set the rules determining follicle quiescence and growth. This regulatory system is maintained until menopause and is directly affected in at least some models of premature ovarian failure (POF), most strikingly in the Foxl2 mouse knockout, a model of human POF with monogenic etiology (blepharophimosis/ptosis/epicanthus inversus syndrome). Several lines of evidence indicate that if the ovarian germ cell lineage maintains regenerative potential, as recently suggested in the mouse, a role in follicle dynamics for germ stem cells, if any, is likely indirect or secondary. In addition, age-related variations in oocyte quality in animal models suggest that reproductive competence is acquired progressively and might depend on parallel growth and differentiation of follicle cells and stroma. Genomewide analyses of the mouse oocyte transcriptome have begun to be used to systematically investigate the mechanisms of reproductive competence that are altered with aging. Investigative and therapeutic strategies can benefit from considering the role of continuous interactions between follicle cells and oocytes from the beginning of histogenesis to full maturation.

  2. Melatonin and aging: prospects for human treatment.

    PubMed

    Bubenik, G A; Konturek, S J

    2011-02-01

    Human life span, with or without modern medicine is around 85-95 years. All living creatures have their inner clock that measures their daily (circadian) and their seasonal (circannual) time. These time changes are mediated by the alteration of levels of melatonin, an evolutionary ancient hormone, which is produced in many body tissues, including the pineal gland, retina and the gastrointestinal tract (GIT). Light is blocking the production of melatonin in the pineal gland, darkness is stimulating it. So, the diurnal changes of light intensity of melatonin, provide a "daily clock" and the seasonal changes provide a "seasonal clock". Finally, the reduction of melatonin observed with aging, may indicate the presence of an "age clock". Melatonin is a strong antioxidant (often it is called scavenger of free radicals), which protects the body from the effects of noxious compounds. Therefore it was hypothesized that the reduction of melatonin levels with age contributes to the aging process. So far, the only remedy to extend the life span was a 40% reduction in caloric intake, which prolonged the life in mice, rats, dogs and monkeys by 30-50%. A large group of people imitate these experiments performed on animals, but the results of these experiments will not be known for several decades. How is being hungry prolonging the life span? There is a connection between caloric reduction and melatonin levels in GIT. Several experiments indicate that fasting in animals substantially increased their production of GIT melatonin. Therefore, instead of being permanently hungry, a prolongation of human life could be achieved by a replacement melatonin therapy. A daily intake of melatonin before bed time might achieve the same effect as fasting e.g. an increase of body melatonin levels, which will protect the individual from the ravages of old age. That includes Parkinson's disease and Alzheimer's disease. There is a large group of people taking melatonin daily who believe that

  3. Expression of Human β-Defensins in Conjunctival Epithelium: Relevance to Dry Eye Disease

    PubMed Central

    Narayanan, Srihari; Miller, William L.; McDermott, Alison M.

    2006-01-01

    Purpose. The goals of this study were to investigate whether β-defensins are differentially expressed in the conjunctival epithelium of patients with moderate dry eye when compared with normal subjects and whether proinflammatory cytokines or bacteria can modulate the expression of human β-defensins (hBDs)-1, -2, and -3 by conjunctival epithelial cells. Methods. RNA extracted from conjunctival impression cytology specimens of eight normal subjects and nine patients with moderate dry eye was used in RT-PCR to detect mRNA for hBDs-1, -2, and -3. Two conjunctival epithelial cell lines and primary cultured conjunctival epithelial cells were treated with proinflammatory cytokines or heat-killed Pseudomonas aeruginosa. RT-PCR and immunoblot analysis were used to detect mRNA for hBD-1, -2, and -3 and protein secretion of hBD-2, respectively. Results. hBD-2 message was detected in RNA samples of eight of nine patients with dry eye, but not in any of the normal subjects’ samples, whereas hBD-1 and -3 were detected in all subjects tested. RT-PCR revealed an upregulation of hBD-2 but no difference in expression of hBD-1 and -3 in cultured conjunctival cells after a 24-hour treatment with 10 ng/mL interleukin (IL)-1β, IL-1β and tumor necrosis factor-α (10 ng/mL) or heat-killed Pseudomonas aeruginosa (1 million colony-forming units; n = 3). hBD-2 expression was upregulated from 4 hours of treatment with IL-1β (at 10 ng/mL; (n = 2–3) and at a concentration of 0.1 ng/mL IL-1β (24-hour treatment; n = 2–3). Immunoblots demonstrated protein secretion results corresponding to the RT-PCR data. Conclusions. hBD-2 was expressed only in the conjunctival epithelium of patients with moderate dry eye. Because cytokines such as IL-1β and TNF-α induced the expression of hBD-2 by conjunctival epithelial cells and because increased proinflammatory cytokine activity is a feature of dry eye disease, it can be speculated that the hBD-2 upregulation observed in subjects with moderate

  4. Optics of the human cornea influence the accuracy of stereo eye-tracking methods: a simulation study.

    PubMed

    Barsingerhorn, A D; Boonstra, F N; Goossens, H H L M

    2017-02-01

    Current stereo eye-tracking methods model the cornea as a sphere with one refractive surface. However, the human cornea is slightly aspheric and has two refractive surfaces. Here we used ray-tracing and the Navarro eye-model to study how these optical properties affect the accuracy of different stereo eye-tracking methods. We found that pupil size, gaze direction and head position all influence the reconstruction of gaze. Resulting errors range between ± 1.0 degrees at best. This shows that stereo eye-tracking may be an option if reliable calibration is not possible, but the applied eye-model should account for the actual optics of the cornea.

  5. Homology of the eyeless gene of Drosophila to the Small eye gene in mice and Aniridia in humans.

    PubMed

    Quiring, R; Walldorf, U; Kloter, U; Gehring, W J

    1994-08-05

    A Drosophila gene that contains both a paired box and a homeobox and has extensive sequence homology to the mouse Pax-6 (Small eye) gene was isolated and mapped to chromosome IV in a region close to the eyeless locus. Two spontaneous mutations, ey2 and eyR, contain transposable element insertions into the cloned gene and affect gene expression, particularly in the eye primordia. This indicates that the cloned gene encodes ey. The finding that ey of Drosophila, Small eye of the mouse, and human Aniridia are encoded by homologous genes suggests that eye morphogenesis is under similar genetic control in both vertebrates and insects, in spite of the large differences in eye morphology and mode of development.

  6. Optics of the human cornea influence the accuracy of stereo eye-tracking methods: a simulation study

    PubMed Central

    Barsingerhorn, A. D.; Boonstra, F. N.; Goossens, H. H. L. M.

    2017-01-01

    Current stereo eye-tracking methods model the cornea as a sphere with one refractive surface. However, the human cornea is slightly aspheric and has two refractive surfaces. Here we used ray-tracing and the Navarro eye-model to study how these optical properties affect the accuracy of different stereo eye-tracking methods. We found that pupil size, gaze direction and head position all influence the reconstruction of gaze. Resulting errors range between ± 1.0 degrees at best. This shows that stereo eye-tracking may be an option if reliable calibration is not possible, but the applied eye-model should account for the actual optics of the cornea. PMID:28270978

  7. FDTD computation of human eye exposure to ultra-wideband electromagnetic pulses.

    PubMed

    Simicevic, Neven

    2008-03-21

    With an increase in the application of ultra-wideband (UWB) electromagnetic pulses in the communications industry, radar, biotechnology and medicine, comes an interest in UWB exposure safety standards. Despite an increase of the scientific research on bioeffects of exposure to non-ionizing UWB pulses, characterization of those effects is far from complete. A numerical computational approach, such as a finite-difference time domain (FDTD) method, is required to visualize and understand the complexity of broadband electromagnetic interactions. The FDTD method has almost no limits in the description of the geometrical and dispersive properties of the simulated material, it is numerically robust and appropriate for current computer technology. In this paper, a complete calculation of exposure of the human eye to UWB electromagnetic pulses in the frequency range of 3.1-10.6, 22-29 and 57-64 GHz is performed. Computation in this frequency range required a geometrical resolution of the eye of 0.1 mm and an arbitrary precision in the description of its dielectric properties in terms of the Debye model. New results show that the interaction of UWB pulses with the eye tissues exhibits the same properties as the interaction of the continuous electromagnetic waves (CWs) with the frequencies from the pulse's frequency spectrum. It is also shown that under the same exposure conditions the exposure to UWB pulses is from one to many orders of magnitude safer than the exposure to CW.

  8. Model propagation of a femtosecond laser radiation in the vitreous of the human eye

    NASA Astrophysics Data System (ADS)

    Rogov, P. Y.; Bespalov, V. G.

    2016-04-01

    The paper presents a mathematical model of linear and nonlinear processes occurring due to propagation of femtosecond laser pulses in vitreous of the human eye. By methods of numerical simulation, we have solved a nonlinear spectral equation describing dynamics of two-dimensional TE-polarized radiation. The solution was performed in a homogeneous isotropic medium with instantaneous cubic nonlinearity without using slowly varying envelope approximation. For simulation we used medium with parameters close to the optical media of the eye. The model of femtosecond radiation takes into account the dynamics of the process of dispersion pulse broadening in time and occurrence of self-focusing of the retina when passing through vitreous body of the eye. The dependence between pulse duration on the retina and duration of the input pulse was found, as well as the values of power density at which self-focusing occurs. It was shown that the main mechanism of radiation damage caused while using Ti-sapphire laser is photoionization. The results coincide with the results obtained by other scientists. They can be used to create Russian laser safety standards for femtosecond laser systems.

  9. Learning from biotechnology: milestones in the prenatal engineering of an intelligent optical sensor--the human eye

    NASA Astrophysics Data System (ADS)

    Lauinger, Norbert

    2001-10-01

    The analysis of the prenatal engineering of the human brain and more specifically that of the human eye may encourage new interpretations and better understanding of cortical processors and lead to better ideas about how to build optical sensors. What human vision at its first processing stages realizes is an adaptive transformation of physical parameters from an outer 4D-spatiotemporal into an inner psychological world or its reciprocal projection and construction of an illusionary (inner or outer) world. The description of some of the most remarkable steps in the development of the human eye before birth, very critical for the optical functionalities in vision, will illustrate the new interpretations.

  10. Quick-Eye: Examination of Human Performance Characteristics Using Eye Tracking and Manual-Based Control Systems for Monitoring Multiple Displays

    DTIC Science & Technology

    2013-03-01

    locating the pupil by detecting light reflected off the retina . Four pan-tilt-zoom Vivotek Inc. networked cameras were integrated with the system...interaction interface design human performance 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UL 18. NUMBER OF PAGES 64 19a...tracker plus four pan-tilt-zoom networked cameras into a simulated surveillance system, called Quick-Eye. However, the results of the study were

  11. A practical efficient human computer interface based on saccadic eye movements for people with disabilities.

    PubMed

    Soltani, Sima; Mahnam, Amin

    2016-03-01

    Human computer interfaces (HCI) provide new channels of communication for people with severe motor disabilities to state their needs, and control their environment. Some HCI systems are based on eye movements detected from the electrooculogram. In this study, a wearable HCI, which implements a novel adaptive algorithm for detection of saccadic eye movements in eight directions, was developed, considering the limitations that people with disabilities have. The adaptive algorithm eliminated the need for calibration of the system for different users and in different environments. A two-stage typing environment and a simple game for training people with disabilities to work with the system were also developed. Performance of the system was evaluated in experiments with the typing environment performed by six participants without disabilities. The average accuracy of the system in detecting eye movements and blinking was 82.9% at first tries with an average typing rate of 4.5cpm. However an experienced user could achieve 96% accuracy and 7.2cpm typing rate. Moreover, the functionality of the system for people with movement disabilities was evaluated by performing experiments with the game environment. Six people with tetraplegia and significant levels of speech impairment played with the computer game several times. The average success rate in performing the necessary eye movements was 61.5%, which increased significantly with practice up to 83% for one participant. The developed system is 2.6×4.5cm in size and weighs only 15g, assuring high level of comfort for the users.

  12. Towards Quantum Experiments with Human Eyes as Detectors Based on Cloning via Stimulated Emission

    NASA Astrophysics Data System (ADS)

    Sekatski, Pavel; Brunner, Nicolas; Branciard, Cyril; Gisin, Nicolas; Simon, Christoph

    2009-09-01

    We show theoretically that a large Bell inequality violation can be obtained with human eyes as detectors, in a “micro-macro” experiment where one photon from an entangled pair is greatly amplified via stimulated emission. The violation is robust under photon loss. This leads to an apparent paradox, which we resolve by noting that the violation proves the existence of entanglement before the amplification. The same is true for the micro-macro experiments performed so far with conventional detectors. However, we also prove that there is genuine micro-macro entanglement even for high loss.

  13. iPSC technology to study human aging and aging-related disorders.

    PubMed

    Liu, Guang-Hui; Ding, Zhichao; Izpisua Belmonte, Juan Carlos

    2012-12-01

    A global aging population, normally accompanied by a high incidence of aging-associated diseases, has prompted a renewed interest in basic research on human aging. Although encouraging progress has been achieved using animal models, the underlying fundamental mechanisms of aging remain largely unknown. Here, we review the human induced pluripotent stem cell (hiPSC)-based models of aging and aging-related diseases. These models seek to advance our knowledge of aging molecular mechanisms and help to develop strategies for treating aging-associated human diseases.

  14. Human head orientation and eye visibility as indicators of attention for goats (Capra hircus)

    PubMed Central

    2017-01-01

    Animals domesticated for working closely with humans (e.g. dogs) have been shown to be remarkable in adjusting their behaviour to human attentional stance. However, there is little evidence for this form of information perception in species domesticated for production rather than companionship. We tested domestic ungulates (goats) for their ability to differentiate attentional states of humans. In the first experiment, we investigated the effect of body and head orientation of one human experimenter on approach behaviour by goats. Test subjects (N = 24) significantly changed their behaviour when the experimenter turned its back to the subjects, but did not take into account head orientation alone. In the second experiment, goats (N = 24) could choose to approach one of two experimenters, while only one was paying attention to them. Goats preferred to approach humans that oriented their body and head towards the subject, whereas head orientation alone had no effect on choice behaviour. In the third experiment, goats (N = 32) were transferred to a separate test arena and were rewarded for approaching two experimenters providing a food reward during training trials. In subsequent probe test trials, goats had to choose between the two experimenters differing in their attentional states. Like in Experiments 1 and 2, goats did not show a preference for the attentive person when the inattentive person turned her head away from the subject. In this last experiment, goats preferred to approach the attentive person compared to a person who closed their eyes or covered the whole face with a blind. However, goats showed no preference when one person covered only the eyes. Our results show that animals bred for production rather than companionship show differences in their approach and choice behaviour depending on human attentive state. However, our results contrast with previous findings regarding the use of the head orientation to attribute attention and show the importance

  15. Human head orientation and eye visibility as indicators of attention for goats (Capra hircus).

    PubMed

    Nawroth, Christian; McElligott, Alan G

    2017-01-01

    Animals domesticated for working closely with humans (e.g. dogs) have been shown to be remarkable in adjusting their behaviour to human attentional stance. However, there is little evidence for this form of information perception in species domesticated for production rather than companionship. We tested domestic ungulates (goats) for their ability to differentiate attentional states of humans. In the first experiment, we investigated the effect of body and head orientation of one human experimenter on approach behaviour by goats. Test subjects (N = 24) significantly changed their behaviour when the experimenter turned its back to the subjects, but did not take into account head orientation alone. In the second experiment, goats (N = 24) could choose to approach one of two experimenters, while only one was paying attention to them. Goats preferred to approach humans that oriented their body and head towards the subject, whereas head orientation alone had no effect on choice behaviour. In the third experiment, goats (N = 32) were transferred to a separate test arena and were rewarded for approaching two experimenters providing a food reward during training trials. In subsequent probe test trials, goats had to choose between the two experimenters differing in their attentional states. Like in Experiments 1 and 2, goats did not show a preference for the attentive person when the inattentive person turned her head away from the subject. In this last experiment, goats preferred to approach the attentive person compared to a person who closed their eyes or covered the whole face with a blind. However, goats showed no preference when one person covered only the eyes. Our results show that animals bred for production rather than companionship show differences in their approach and choice behaviour depending on human attentive state. However, our results contrast with previous findings regarding the use of the head orientation to attribute attention and show the importance

  16. Eating for Your Eyes

    ERIC Educational Resources Information Center

    Stastny, Sherri Nordstrom; Garden-Robinson, Julie

    2011-01-01

    An educational program targeting older adults was developed to increase knowledge regarding nutrition and eye health. With age, the chance for eye disease increases, so prevention is critical. The Eating for Your Eyes program has promoted behavior changes regarding eye health among the participants. This program is easily replicated and use is…

  17. The golden age of rapid eye movement sleep discoveries. 1. Lucretius--1964.

    PubMed

    Gottesmann, C

    2001-10-01

    Although there were several premonitory signs of a sleep stage with dreaming, it was only in 1953 that such a stage was identified with certainty. This paper analyses the observations and research related to this dreaming stage (rapid eye movement sleep) until 1964. During these 11 years of research, the main psychological and physiological characteristics of this sleep stage were first described. Where the few results or discussions were later questioned, today's current state of knowledge is briefly outlined.

  18. The Prevalence of Age-Related Eye Diseases and Cataract Surgery among Older Adults in the City of Lodz, Poland.

    PubMed

    Nowak, Michal Szymon; Smigielski, Janusz

    2015-01-01

    Purpose. To determine the prevalence of age-related eye diseases and cataract surgery among older adults in the city of Lodz, in central Poland. Material and Methods. The study design was cross-sectional and observational study. A total of 1107 women and men of predominantly Caucasian origin were successfully enumerated and recruited for the study. All selected subjects were interviewed and underwent detailed ophthalmic examinations. Results. Overall 8.04% (95% CI 6.44-9.64) subjects had cataract surgery in either eye. After excluding subjects with bilateral cataract surgery, the prevalence of cataract was 12.10% (95% CI 10.18-14.03). AMD was found in 4.33% (95% CI 3.14-5.54 ) of all subjects. Of them 3.25% (95% CI 2.21-4.30 ) had early AMD and 1.08% (95% CI 0.47-1.69) had late AMD. Various types of glaucoma were diagnosed in 5.51% (95% CI 4.17-6.85) of subjects and 2.62% (95% CI 1.68-3.56) had OHT. The prevalence rates of DR and myopic macular degeneration were 1.72% (95% CI 0.95-2.48) and 0.45% (95% CI 0.06-0.85), respectively. All multiple logistic regression models were only significantly associated with older age. The highest rate of visual impairment was observed among subjects with retinal diseases. Conclusions. The study revealed high prevalence of age-related eye diseases in this older population.

  19. Human-Computer Interface Controlled by Horizontal Directional Eye Movements and Voluntary Blinks Using AC EOG Signals

    NASA Astrophysics Data System (ADS)

    Kajiwara, Yusuke; Murata, Hiroaki; Kimura, Haruhiko; Abe, Koji

    As a communication support tool for cases of amyotrophic lateral sclerosis (ALS), researches on eye gaze human-computer interfaces have been active. However, since voluntary and involuntary eye movements cannot be distinguished in the interfaces, their performance is still not sufficient for practical use. This paper presents a high performance human-computer interface system which unites high quality recognitions of horizontal directional eye movements and voluntary blinks. The experimental results have shown that the number of incorrect inputs is decreased by 35.1% in an existing system which equips recognitions of horizontal and vertical directional eye movements in addition to voluntary blinks and character inputs are speeded up by 17.4% from the existing system.

  20. The Membrane Attack Complex in Aging Human Choriocapillaris

    PubMed Central

    Mullins, Robert F.; Schoo, Desi P.; Sohn, Elliott H.; Flamme-Wiese, Miles J.; Workamelahu, Grefachew; Johnston, Rebecca M.; Wang, Kai; Tucker, Budd A.; Stone, Edwin M.

    2015-01-01

    Age-related macular degeneration (AMD) is a common disease that can result in severe visual impairment. Abnormal regulation of the complement system has been implicated in its pathogenesis, and CFH polymorphisms contribute substantially to risk. How these polymorphisms exert their effects is poorly understood. We performed enzyme-linked immunosorbent assay (ELISA) analysis on young, aged, and AMD choroids to determine the abundance of the membrane attack complex (MAC) and performed immunofluorescence studies on eyes from 117 donors to evaluate the MAC in aging, early AMD, and advanced AMD. Morphometric studies were performed on eyes with high- or low-risk CFH genotypes. ELISA confirmed that MAC increases significantly with aging and with AMD. MAC was localized to Bruch’s membrane and the choriocapillaris and was detectable at low levels as early as 5 years of age. Hard drusen were labeled with anti-MAC antibody, but large or confluent drusen and basal deposits were generally unlabeled. Labeling of retinal pigment epithelium was observed in some cases of advanced AMD, but not in early disease. Eyes homozygous for the high-risk CFH genotype had thinner choroids than low-risk homozygotes (P < 0.05). These findings suggest that increased complement activation in AMD and in high-risk genotypes can lead to loss of endothelial cells in early AMD. Treatments to protect the choriocapillaris in early AMD are needed. PMID:25204844

  1. The aging human recipient of transfusion products.

    PubMed

    Nydegger, Urs E; Luginbühl, Martin; Risch, Martin

    2015-06-01

    In this review the different mechanisms of aging and frailty such as DNA defects due to impaired DNA repair, inflammatory processes, disturbances of oxidative phosphorylation are discussed together with mechanisms of cell repair. Components of blood plasma, such as the growth-differentiation protein GDF11, were shown to enhance neurogenesis and to improve the vasculature in the animal cortex and to rejuvenate muscle tissue. Advances in laboratory assays allow to identify plasma proteins that may affect tissue regeneration. This new knowledge from animal research might affect transfusion practice in geriatric patients in the future. Provided it can be translated and confirmed in human research, blood products might no longer be considered only as oxygen carriers or drugs to improve hemostasis. In the present time blood transfusion (RBCs, plasma or platelets) should be directed by differentiated guidelines considering not only cut-off values of hemoglobin, platelet count or coagulation but also old age-specific biologic variation, comorbidities and the clinical context e.g. of bleeding.

  2. Visual orienting in children with autism: Hyper‐responsiveness to human eyes presented after a brief alerting audio‐signal, but hyporesponsiveness to eyes presented without sound

    PubMed Central

    Thorup, Emilia; Falck‐Ytter, Terje

    2016-01-01

    Autism Spectrum Disorder (ASD) has been associated with reduced orienting to social stimuli such as eyes, but the results are inconsistent. It is not known whether atypicalities in phasic alerting could play a role in putative altered social orienting in ASD. Here, we show that in unisensory (visual) trials, children with ASD are slower to orient to eyes (among distractors) than controls matched for age, sex, and nonverbal IQ. However, in another condition where a brief spatially nonpredictive sound was presented just before the visual targets, this group effect was reversed. Our results indicate that orienting to social versus nonsocial stimuli is differently modulated by phasic alerting mechanisms in young children with ASD. Autism Res 2017, 10: 246–250. © 2016 The Authors Autism Research published by Wiley Periodicals, Inc. on behalf of International Society for Autism Research. PMID:27454075

  3. Visual orienting in children with autism: Hyper-responsiveness to human eyes presented after a brief alerting audio-signal, but hyporesponsiveness to eyes presented without sound.

    PubMed

    Kleberg, Johan Lundin; Thorup, Emilia; Falck-Ytter, Terje

    2017-02-01

    Autism Spectrum Disorder (ASD) has been associated with reduced orienting to social stimuli such as eyes, but the results are inconsistent. It is not known whether atypicalities in phasic alerting could play a role in putative altered social orienting in ASD. Here, we show that in unisensory (visual) trials, children with ASD are slower to orient to eyes (among distractors) than controls matched for age, sex, and nonverbal IQ. However, in another condition where a brief spatially nonpredictive sound was presented just before the visual targets, this group effect was reversed. Our results indicate that orienting to social versus nonsocial stimuli is differently modulated by phasic alerting mechanisms in young children with ASD. Autism Res 2017, 10: 246-250. © 2016 The Authors Autism Research published by Wiley Periodicals, Inc. on behalf of International Society for Autism Research.

  4. Age- and Race-Related Differences in Human Scleral Material Properties

    PubMed Central

    Grytz, Rafael; Fazio, Massimo A.; Libertiaux, Vincent; Bruno, Luigi; Gardiner, Stuart; Girkin, Christopher A.; Downs, J. Crawford

    2014-01-01

    Purpose. We tested the hypothesis that there are age- and race-related differences in posterior scleral material properties, using eyes from human donors of European (20–90 years old, n = 40 eyes) and African (23–74 years old, n = 22 eyes) descent. Methods. Inflation tests on posterior scleral shells were performed while full-field, three-dimensional displacements were recorded using laser speckle interferometry. Scleral material properties were fit to each eye using a microstructure-based constitutive formulation that incorporates the collagen fibril crimp and the local anisotropic collagen architecture. The effects of age and race were estimated using Generalized Estimating Equations, while accounting for intradonor correlations. Results. The shear modulus significantly increased (P = 0.038) and collagen fibril crimp angle significantly decreased with age (P = 0.002). Donors of African descent exhibited a significantly higher shear modulus (P = 0.019) and showed evidence of a smaller collagen fibril crimp angle (P = 0.057) compared to donors of European descent. The in-plane strains in the peripapillary sclera were significantly lower with age (P < 0.015) and African ancestry (P < 0.015). Conclusions. The age- and race-related differences in scleral material properties result in a loss of scleral compliance due to a higher shear stiffness and a lower level of stretch at which the collagen fibrils uncrimp. The loss of compliance should lead to larger high frequency IOP fluctuations and changes in the optic nerve head (ONH) biomechanical response in the elderly and in persons of African ancestry, and may contribute to the higher susceptibility to glaucoma in these at-risk populations. PMID:25389203

  5. Expression of transforming growth factor-β2in vitreous body and adjacent tissues during prenatal development of human eye.

    PubMed

    Sukhikh, G T; Panova, I G; Smirnova, Yu A; Milyushina, L A; Firsova, N V; Markitantova, Yu V; Poltavtseva, R A; Zinov'eva, R D

    2010-12-01

    Expression of transforming growth factor-β2 was detected by PCR in the vitreous body, lens, retina, and ciliary-iris complex of human eye at early stages of fetal development. Immunochemical assay of the corresponding protein in eye tissues revealed a correlation between the localization of transforming growth factor-β2 and the development of intraocular hyaloid vascular network, its regression, formation of the vitreous body, and development of definite retinal vessels.

  6. The role of calcium in human aging.

    PubMed

    Beto, Judith A

    2015-01-01

    Calcium is an essential nutrient that is necessary for many functions in human health. Calcium is the most abundant mineral in the body with 99% found in teeth and bone. Only 1% is found in serum. The serum calcium level is tightly monitored to remain within normal range by a complex metabolic process. Calcium metabolism involves other nutrients including protein, vitamin D, and phosphorus. Bone formation and maintenance is a lifelong process. Early attention to strong bones in childhood and adulthood will provide more stable bone mass during the aging years. Research has shown that adequate calcium intake can reduce the risk of fractures, osteoporosis, and diabetes in some populations. The dietary requirements of calcium and other collaborative nutrients vary slightly around the world. Lactose intolerance due to lactase deficiency is a common cause of low calcium intake. Strategies will be discussed for addressing this potential barrier to adequate intake. The purpose of this narrative review is a) to examine the role of calcium in human health, b) to compare nutrient requirements for calcium across lifecycle groups and global populations, c) to review relationships between calcium intake, chronic disease risk, and fractures, and d) to discuss strategies to address diet deficiencies and lactose intolerance.

  7. The Role of Calcium in Human Aging

    PubMed Central

    2015-01-01

    Calcium is an essential nutrient that is necessary for many functions in human health. Calcium is the most abundant mineral in the body with 99% found in teeth and bone. Only 1% is found in serum. The serum calcium level is tightly monitored to remain within normal range by a complex metabolic process. Calcium metabolism involves other nutrients including protein, vitamin D, and phosphorus. Bone formation and maintenance is a lifelong process. Early attention to strong bones in childhood and adulthood will provide more stable bone mass during the aging years. Research has shown that adequate calcium intake can reduce the risk of fractures, osteoporosis, and diabetes in some populations. The dietary requirements of calcium and other collaborative nutrients vary slightly around the world. Lactose intolerance due to lactase deficiency is a common cause of low calcium intake. Strategies will be discussed for addressing this potential barrier to adequate intake. The purpose of this narrative review is a) to examine the role of calcium in human health, b) to compare nutrient requirements for calcium across lifecycle groups and global populations, c) to review relationships between calcium intake, chronic disease risk, and fractures, and d) to discuss strategies to address diet deficiencies and lactose intolerance. PMID:25713787

  8. Spatiotemporal Filter for Visual Motion Integration from Pursuit Eye Movements in Humans and Monkeys.

    PubMed

    Mukherjee, Trishna; Liu, Bing; Simoncini, Claudio; Osborne, Leslie C

    2017-02-08

    Despite the enduring interest in motion integration, a direct measure of the space-time filter that the brain imposes on a visual scene has been elusive. This is perhaps because of the challenge of estimating a 3D function from perceptual reports in psychophysical tasks. We take a different approach. We exploit the close connection between visual motion estimates and smooth pursuit eye movements to measure stimulus-response correlations across space and time, computing the linear space-time filter for global motion direction in humans and monkeys. Although derived from eye movements, we find that the filter predicts perceptual motion estimates quite well. To distinguish visual from motor contributions to the temporal duration of the pursuit motion filter, we recorded single-unit responses in the monkey middle temporal cortical area (MT). We find that pursuit response delays are consistent with the distribution of cortical neuron latencies and that temporal motion integration for pursuit is consistent with a short integration MT subpopulation. Remarkably, the visual system appears to preferentially weight motion signals across a narrow range of foveal eccentricities rather than uniformly over the whole visual field, with a transiently enhanced contribution from locations along the direction of motion. We find that the visual system is most sensitive to motion falling at approximately one-third the radius of the stimulus aperture. Hypothesizing that the visual drive for pursuit is related to the filtered motion energy in a motion stimulus, we compare measured and predicted eye acceleration across several other target forms.SIGNIFICANCE STATEMENT A compact model of the spatial and temporal processing underlying global motion perception has been elusive. We used visually driven smooth eye movements to find the 3D space-time function that best predicts both eye movements and perception of translating dot patterns. We found that the visual system does not appear to use

  9. Collaborative EDNAP exercise on the IrisPlex system for DNA-based prediction of human eye colour.

    PubMed

    Chaitanya, Lakshmi; Walsh, Susan; Andersen, Jeppe Dyrberg; Ansell, Ricky; Ballantyne, Kaye; Ballard, David; Banemann, Regine; Bauer, Christiane Maria; Bento, Ana Margarida; Brisighelli, Francesca; Capal, Tomas; Clarisse, Lindy; Gross, Theresa E; Haas, Cordula; Hoff-Olsen, Per; Hollard, Clémence; Keyser, Christine; Kiesler, Kevin M; Kohler, Priscila; Kupiec, Tomasz; Linacre, Adrian; Minawi, Anglika; Morling, Niels; Nilsson, Helena; Norén, Lina; Ottens, Renée; Palo, Jukka U; Parson, Walther; Pascali, Vincenzo L; Phillips, Chris; Porto, Maria João; Sajantila, Antti; Schneider, Peter M; Sijen, Titia; Söchtig, Jens; Syndercombe-Court, Denise; Tillmar, Andreas; Turanska, Martina; Vallone, Peter M; Zatkalíková, Lívia; Zidkova, Anastassiya; Branicki, Wojciech; Kayser, Manfred

    2014-07-01

    The IrisPlex system is a DNA-based test system for the prediction of human eye colour from biological samples and consists of a single forensically validated multiplex genotyping assay together with a statistical prediction model that is based on genotypes and phenotypes from thousands of individuals. IrisPlex predicts blue and brown human eye colour with, on average, >94% precision accuracy using six of the currently most eye colour informative single nucleotide polymorphisms (HERC2 rs12913832, OCA2 rs1800407, SLC24A4 rs12896399, SLC45A2 (MATP) rs16891982, TYR rs1393350, and IRF4 rs12203592) according to a previous study, while the accuracy in predicting non-blue and non-brown eye colours is considerably lower. In an effort to vigorously assess the IrisPlex system at the international level, testing was performed by 21 laboratories in the context of a collaborative exercise divided into three tasks and organised by the European DNA Profiling (EDNAP) Group of the International Society of Forensic Genetics (ISFG). Task 1 involved the assessment of 10 blood and saliva samples provided on FTA cards by the organising laboratory together with eye colour phenotypes; 99.4% of the genotypes were correctly reported and 99% of the eye colour phenotypes were correctly predicted. Task 2 involved the assessment of 5 DNA samples extracted by the host laboratory from simulated casework samples, artificially degraded, and provided to the participants in varying DNA concentrations. For this task, 98.7% of the genotypes were correctly determined and 96.2% of eye colour phenotypes were correctly inferred. For Tasks 1 and 2 together, 99.2% (1875) of the 1890 genotypes were correctly generated and of the 15 (0.8%) incorrect genotype calls, only 2 (0.1%) resulted in incorrect eye colour phenotypes. The voluntary Task 3 involved participants choosing their own test subjects for IrisPlex genotyping and eye colour phenotype inference, while eye photographs were provided to the organising

  10. Application of Fourier Domain OCT Imaging Technology to the Anterior Segment of the Human Eye

    NASA Astrophysics Data System (ADS)

    Wojtkowski, Maciej; Marcos, Susana; Ortiz, Sergio; Grulkowski, Ireneusz

    The anterior segment is the front part of the human eye, which forms the optical system and hence directly impacts vision. Traumatic or pathological changes in the anterior segment may lead to vision loss and, in some cases, even blindness. Since the eighteenth century, optical instrumentation for measuring and imaging the anterior segment of the human eye has been developing along with modern ophthalmology. The application of OCT to the anterior segment imaging is particularly of interest, since this could potentially provide substantial complementary information regarding the large-scale architecture of the cornea and the crystalline lens, or on small portions of tissue imaged with high spatial resolutions comparable to regular microscopy. Especially an introduction of Fourier domain detection in OCT has opened new frontiers in OCT ophthalmic applications. The resultant substantial speed improvement enables rapid image acquisition, helping to reduce artifacts due to patient motion. Thus, it is currently possible to perform high-speed, in vivo, three-dimensional volumetric imaging over large scales within a reasonable time limit and without reducing system sensitivity. This chapter describes the state-of the art OCT technology dedicated to anterior segment imaging and indicates all important parameters which are required for optimization of the performance of OCT instrument.

  11. An interactive method for teaching anatomy of the human eye for medical students in ophthalmology clinical rotations.

    PubMed

    Kivell, Tracy L; Doyle, Sara K; Madden, Richard H; Mitchell, Terry L; Sims, Ershela L

    2009-01-01

    Much research has shown the benefits of additional anatomical learning and dissection beyond the first year of medical school human gross anatomy, all the way through postgraduate medical training. We have developed an interactive method for teaching eye and orbit anatomy to medical students in their ophthalmology rotation at Duke University School of Medicine. We provide review lectures on the detailed anatomy of the adult human eye and orbit as well as the developmental anatomy of the eye. These lectures are followed by a demonstration of the anatomy of the orbit using conventional frontal and superior exposures on a prosected human cadaver. The anatomy is projected onto a large LCD screen using a mounted overhead camera. Following a brief lecture on clinically relevant anatomy, each student then dissects a fresh porcine (pig) eye under low magnification using a dissecting microscope. These dissections serve to identify structures extrinsic to the eyeball, including extraocular muscle attachments, small vessels, optic nerve stalk, and fascial sheath of the eyeball (Tenon's fascia). Dissection then shifts to the internal anatomy of the eyeball. The size and anatomy of the porcine eye is comparable with that of the human and the dissection provides students with a valuable hands-on learning opportunity that is otherwise not available in embalmed human cadavers. Students and clinical faculty feedback reveal high levels of satisfaction with the presentation of anatomy and its scheduling early during the ophthalmology clerkship.

  12. High-speed adaptive optics for imaging of the living human eye

    PubMed Central

    Yu, Yongxin; Zhang, Tianjiao; Meadway, Alexander; Wang, Xiaolin; Zhang, Yuhua

    2015-01-01

    The discovery of high frequency temporal fluctuation of human ocular wave aberration dictates the necessity of high speed adaptive optics (AO) correction for high resolution retinal imaging. We present a high speed AO system for an experimental adaptive optics scanning laser ophthalmoscope (AOSLO). We developed a custom high speed Shack-Hartmann wavefront sensor and maximized the wavefront detection speed based upon a trade-off among the wavefront spatial sampling density, the dynamic range, and the measurement sensitivity. We examined the temporal dynamic property of the ocular wavefront under the AOSLO imaging condition and improved the dual-thread AO control strategy. The high speed AO can be operated with a closed-loop frequency up to 110 Hz. Experiment results demonstrated that the high speed AO system can provide improved compensation for the wave aberration up to 30 Hz in the living human eye. PMID:26368408

  13. Holographic interferometry of intact and radially incised human eye-bank corneas.

    PubMed

    Smolek, M K

    1994-05-01

    Many methods to measure corneal elasticity destroy the tissue and thereby produce erroneous results. Holographic interferometry, a highly precise nondestructive optical comparison technique, was used to evaluate corneal elasticity of intact eye-bank eyes. A double-pulse holographic interferometer operating at 632.8 nm was used to measure corneal deformation in 20 whole-globe eyes from donors 45 to 83 years of age for intraocular pressures from 16 mm Hg to 21 mm Hg. Stress was computed from LaPlace's law, and arc length strain was derived from z-axis distention of the central cornea. The stress-strain relationship in the normal physiological range of intraocular pressure was linear with a Young's elastic modulus of 1.03 gigapascals for the central cornea (r = 0.999). During interferometry of radial keratotomy of the cornea, interference fringe patterns developed in association with each incision as it was made. When four incisions were placed deep along each of the primary semimeridians, the fringe pattern developed as expected, based on current keratotomy models. When incisions were shallow (approximately 50% depth) and placed asymmetrically along the nasal, temporal, and superior semimeridians, the resulting surface strain was symmetrical about the central cornea, forming an annular pattern of interference fringes. These results indicate that when the cornea was stressed at physiological pressures as part of the intact whole globe, it was less elastic than excised corneal tissue tested by strip extensiometry. Radially incised corneas demonstrated strain patterns suggestive of inherent structural anisotropy with a possible inferior quadrant weakness.

  14. Eye Diseases and Impaired Vision as Possible Risk Factors for Recurrent Falls in the Aged: A Systematic Review

    PubMed Central

    Salonen, Liisa; Kivelä, Sirkka-Liisa

    2012-01-01

    Background. Recurrent falls are common among the aged. Vision is needed in maintaining balance, and impaired vision may be an intrinsic risk factor of recurrent falls. The aim was to perform a systematic review about the relationships between eye diseases or impaired vision and the risk of recurrent falls in the aged. Material and Methods. MEDLINE and CINAHL databases were searched in order to find longitudinal epidemiological studies about the associations between eye diseases or impaired vision and the risk of recurrent falls. Altogether 19 studies were found. A qualitative systematic analysis of these studies was performed. Results and Conclusions. The evidence about poor depth perception/stereoacuity and poor low-contrast visual acuity as risk factors of recurrent falls is quite convincing. Discrepant vision, a decrease in visual acuity, and loss of visual field may be risk factors, but more studies are needed. The results concerning the relationships between poor visual acuity and poor contrast sensitivity and the risk of recurrent falls are controversial. More studies about the relationships between different measures of vision and the risk of recurrent falls are needed before final conclusions about poor vision as a risk factor for recurrent falling can be done. PMID:22927843

  15. Immunolocalisation pattern of complex I-V in ageing human retina: Correlation with mitochondrial ultrastructure.

    PubMed

    Nag, Tapas Chandra; Wadhwa, Shashi

    2016-11-01

    Earlier studies reported accumulation of mitochondrial DNA mutations in ageing and age-related macular degeneration. To know about the mitochondrial status with age, we examined immunoreactivity (IR) to markers of mitochondria (anti-mitochondrial antibody and voltage-dependent anion channel-1) and complex I-V (that mediate oxidative phosphorylation, OXPHOS) in donor human retinas (age: 19-94years; N=26; right eyes). In all samples, at all ages, IR to anti-mitochondrial antibody and voltage-dependent anion channel-1 was prominent in photoreceptor cells. Between second and seventh decade of life, strong IR to complex I-V was present in photoreceptors over macular to peripheral retina. With progressive ageing, the photoreceptors showed a decrease in complex I-IR (subunit NDUFB4) at eighth decade, and a weak or absence of IR in 10 retinas between ninth and tenth decade. Patchy IR to complex III and complex IV was detected at different ages. IR to ND1 (complex I) and complex II and V remained unaltered with ageing. Nitrosative stress (evaluated by IR to a nitro-tyrosine antibody) was found in photoreceptors. Superoxide dismutase-2 was found upregulated in photoreceptors with ageing. Mitochondrial ultrastructure was examined in two young retinas with intact complex IR and six aged retinas whose counterparts showed weak to absence of IR. Observations revealed irregular, photoreceptor inner segment mitochondria in aged maculae and mid-peripheral retina between eighth and ninth decade; many cones possessed autophagosomes with damaged mitochondria, indicating age-related alterations. A trend in age-dependent reduction of complex I-IR was evident in aged photoreceptors, whereas patchy complex IV-IR (subunits I and II) was age-independent, suggesting that the former is prone to damage with ageing perhaps due to oxidative stress. These changes in OXPHOS system may influence the energy budget of human photoreceptors, affecting their viability.

  16. Change in choroidal thickness after intravitreal aflibercept in pretreated and treatment-naive eyes for neovascular age-related macular degeneration

    PubMed Central

    Mazaraki, Kyriaki; Fassnacht-Riederle, Heidi; Blum, Robert; Becker, Matthias; Michels, Stephan

    2015-01-01

    Aim Evaluation of effects of intravitreal aflibercept therapy on choroidal thickness (CT) in neovascular age-related macular degeneration. Methods Retrospective cohort study evaluating the change in CT following a loading dose of three intravitreal aflibercept injections at 4 weeks interval. Pretreated and treatment-naive eyes as well as untreated fellow eyes were evaluated at five retinal locations (subfoveal, 300 and 2500 µm nasal and temporal to the fovea) using spectral domain optical coherence tomography prior to and 4 weeks after a loading dose of three intravitreal aflibercept injections. Results A total of 84 treated eyes (61 pretreated, 23 treatment naive) and 48 fellow eyes were enrolled into the study. Treatment-naive and pretreated eyes showed a significant reduction in CT at all retinal locations. The effect was more pronounced in treatment-naive eyes. In the pretreated group, the mean reduction in CT was greatest at 2500 µm temporal to the fovea at 10.7 µm compared with 22.4 at 300 µm nasal to the fovea in the treatment-naive group. Only the fellow eyes in the treatment-naive group showed a significant CT reduction 12 weeks after initiation of therapy to the partner eye. Conclusions Aflibercept induces a reduction in CT in treatment-naive and pretreated eyes with neovascular age-related macular degeneration. There is some evidence of a systemic effect of aflibercept reflected by CT reduction in untreated fellow eyes. PMID:25877895

  17. A longitudinal study assessing lens thickness changes in the eye of the growing beagle using ultrasound scanning: relevance to age of dogs in regulatory toxicology studies.

    PubMed

    Maynard, Juliana; Sykes, Angela; Powell, Helen; Healing, Guy; Scott, Marietta; Holmes, Andrew; Ricketts, Sally-Ann; Stewart, Jane; Davis, Stewart

    2014-12-01

    The lens is formed in utero with new secondary lens fibres added as outer layers throughout life in a growth pattern characteristic of the species. This study examined the time course of beagle lens growth to better understand the optimal starting age of dogs for safety studies to support adult versus paediatric indications, and to assess the feasibility of non-invasively monitoring lens growth with high frequency ultrasound. Ultrasound scanning was performed in six female beagle dogs using the Vevo770. All dogs were imaged in B-mode using local anaesthetic but without sedation. Imaging was carried out every 2 weeks from 8 to 22 weeks of age and then monthly until 62 weeks of age. The dogs tolerated the procedure well. The lens was visible in all dogs and measuring the lens thickness with high frequency ultrasound demonstrated good analytical reproducibility [Root Mean Square (RMS) = 3.13%]. No differences between the left and right eye existed and lens thickness correlated with body weight. The highest weekly growth rate was before 12 weeks of age. A statistically significant difference between monthly thickness was detected until 42 weeks of age at which point growth reached a plateau. During the experiment, lenses grew by 29.7% reaching an average thickness of 6.4 mm ± 0.03. By 10 months of age (the typical age used for routine toxicological evaluation), beagles have reached a plateau in lens growth that is analogous to human adults. Where lens is a target organ of concern it is suggested that beagles under 6 months old may be a better model for determining paediatric safety.

  18. The anorexia of aging in humans.

    PubMed

    Hays, Nicholas P; Roberts, Susan B

    2006-06-30

    Energy intake is reduced in older individuals, with several lines of evidence suggesting that both physiological impairment of food intake regulation and non-physiological mechanisms are important. Non-physiological causes of the anorexia of aging include social (e.g. poverty, isolation), psychological (e.g. depression, dementia), medical (e.g. edentulism, dysphagia), and pharmacological factors. Physiological factors include changes in taste and smell, diminished sensory-specific satiety, delayed gastric emptying, altered digestion-related hormone secretion and hormonal responsiveness, as well as food intake-related regulatory impairments for which specific mechanisms remain largely unknown. Studies in healthy elderly individuals have shown that men who consume diets over several weeks providing either too few or too many calories relative to dietary energy needs subsequently do not compensate for the resulting energy deficit or surplus when provided an ad libitum diet. Healthy elders have also been shown to be less hungry at meal initiation and to become more rapidly satiated during a standard meal compared to younger adults. Studies in animal models are required to investigate potential mechanisms underlying these observations, while human studies should focus on examining the potential consequences of this phenomenon and practical therapeutic strategies for the maintenance of appropriate energy intake with increasing age. In light of this need, we have recently demonstrated that low reported hunger assessed using a simple questionnaire predicts unintentional weight loss in a sample of healthy older women, and thus may provide a clinically useful tool for identifying older individuals at risk for undesirable weight change and therefore at high priority for intervention.

  19. Objective straylight assessment of the human eye with a novel device

    NASA Astrophysics Data System (ADS)

    Schramm, Stefan; Schikowski, Patrick; Lerm, Elena; Kaeding, André; Klemm, Matthias; Haueisen, Jens; Baumgarten, Daniel

    2016-03-01

    Forward scattered light from the anterior segment of the human eye can be measured by Shack-Hartmann (SH) wavefront aberrometers with limited visual angle. We propose a novel Point Spread Function (PSF) reconstruction algorithm based on SH measurements with a novel measurement devise to overcome these limitations. In our optical setup, we use a Digital Mirror Device as variable field stop, which is conventionally a pinhole suppressing scatter and reflections. Images with 21 different stop diameters were captured and from each image the average subaperture image intensity and the average intensity of the pupil were computed. The 21 intensities represent integral values of the PSF which is consequently reconstructed by derivation with respect to the visual angle. A generalized form of the Stiles-Holladay-approximation is fitted to the PSF resulting in a stray light parameter Log(IS). Additionaly the transmission loss of eye is computed. For the proof of principle, a study on 13 healthy young volunteers was carried out. Scatter filters were positioned in front of the volunteer's eye during C-Quant and scatter measurements to generate straylight emulating scatter in the lens. The straylight parameter is compared to the C-Quant measurement parameter Log(ISC) and scatter density of the filters SDF with a partial correlation. Log(IS) shows significant correlation with the SDF and Log(ISC). The correlation is more prominent between Log(IS) combined with the transmission loss and the SDF and Log(ISC). Our novel measurement and reconstruction technique allow for objective stray light analysis of visual angles up to 4 degrees.

  20. Absorption of 308-nm excimer laser radiation by balanced salt solution, sodium hyaluronate, and human cadaver eyes

    SciTech Connect

    Keates, R.H.; Bloom, R.T.; Schneider, R.T.; Ren, Q.; Sohl, J.; Viscardi, J.J. )

    1990-11-01

    Absorption of the excimer laser radiations of 193-nm argon fluorine and 308-nm xenon chloride in balanced salt solution, sodium hyaluronate, and human cadaver eyes was measured. The absorption of these materials as considerably different for the two wavelengths; we found that 308-nm light experienced much less absorption than the 193-nm light. The extinction coefficient (k) for 308 nm was k = 0.19/cm for balanced salt solution and k = 0.22/cm for sodium hyaluronate. In contrast to this, the extinction coefficient for 193 nm was k = 140/cm for balanced salt solution and k = 540/cm for sodium hyaluronate. Two 1-day-old human phakic cadaver eyes showed complete absorption with both wavelengths. Using aphakic eyes, incomplete absorption was noted at the posterior pole with 308 nm and complete absorption was noted with 193 nm. The extinction in the anterior part of aphakic eyes (the first 6 mm) was 4.2/cm for 308 nm, meaning that the intensity of the light is reduced by a factor of 10 after traveling the first 5.5 mm. However, we observed that the material in the eye fluoresces, meaning the 308 nm is transformed into other (longer) wavelengths that travel through the total eye with minimal absorption. Conclusions drawn from this experiment are that the use of the 308-nm wavelength may have undesirable side effects, while the use of the 193-nm wavelength should be consistent with ophthalmic use on both the cornea and the lens.

  1. The influence of human eye aberrations on the resolution and field of view of fundus-cameras

    NASA Astrophysics Data System (ADS)

    Dubinin, Alexander; Cherezova, Tatyana; Belyakov, Alexey; Kudryashov, Alexis

    2007-05-01

    In this paper we estimate isoplanatic patch size of human eye using experimental results of human eye aberrations measurements. For examined subjects it was found to be in the range 1.1° to 2.5°. The size of isoplanatic patch for Gulistrand-Navarro model was calculated, it was found to be close to values obtained experimentally. We also measured contribution of corneal surface and internal optics into total aberrations of the eye. We modified Gullstrand-Navarro eye model to reproduce on-axis and off-axis performance of the eyes of each measured subject. The distribution of aberrations between optical elements of the eye was taken into account when modeling. We also investigated isoplanatic patch size widening methods such as average phase correction using 2 beacons and immersion method based on compensation of external corneal surface refraction with immersion liquid. Immersion method was found to be the most appropriate for isoplanatic patch widening as it allows us to increase isoplanatic patch size almost twice without loss of image quality at the center of the image.

  2. Age-related changes and sex differences in postural control adaptability in children during periodic floor oscillation with eyes closed.

    PubMed

    Fujiwara, Katsuo; Kiyota, Takeo; Mammadova, Aida; Yaguchi, Chie

    2011-01-01

    We investigated age-related changes and sex differences in adaptability of anticipatory postural control in children. Subjects comprised 449 children (4-12 years old) and 109 young adults (18-29 years old). Subjects stood with eyes closed on a force-platform fixed to a floor oscillator. We conducted five trials of 1-minute oscillation (0.5 Hz frequency, 2.5 cm amplitude) in the anteroposterior direction. Postural steadiness was quantified as the mean speed of the center of pressure in the anteroposterior direction (CoPy). In young adults, CoPy speed decreased rapidly until the third trial for both sexes. Adaptability was evaluated by changes in steadiness. The adaptability of children was categorized as "good," "moderate," and "poor," compared with a standard variation of the mean CoPy speed regression line between the first and fifth trials in young adults. Results were as follows: (1) anticipatory postural control adaptability starts to develop from age 6 in boys and 5 in girls, and greatly improves at age 7-8 in boys and 6 in girls; (2) the adaptability of children at age 11-12 (74% of boys and 63% of girls were categorized as "good") has not yet reached the same level as for young adults; (3) the adaptability at age 11-12 for girls is temporarily disturbed due to early puberty.

  3. Strabismus and eye muscle function.

    PubMed

    Lennerstrand, Gunnar

    2007-11-01

    Studies of external eye muscle morphology and physiology are reviewed, with respect to both motor and sensory functions in concomitant strabismus. The eye muscles have a more complex fibre composition than other striated muscle, and they are among the fastest and most fatigue-resistant muscles in the body. However, it is not generally believed that concomitant strabismus is due to a primary abnormality of the eye muscles or the ocular motor system. The gross anatomy of eye muscles, including the shape and position of the eye muscle pulleys, was not changed in strabismus. The histology of the eye muscle fibres was also basically the same, but changes have been observed in the cellular and biochemical machinery of the fibres, most notably in the singly innervated orbital fibres. Functionally, this was seen as slower contractions and reduced fatigue resistance of eye muscles in animals with strabismus and defects of binocular vision. Most likely the changes represented an adaptation to modified visual demands on the ocular motor control, because of the defects of binocular vision in strabismus from an early age. Adaptation of eye muscle function to visual demands could be seen also in the adult human ocular motor system, but here the effects could be reversed with treatment in some conditions. External eye muscles in the human have sensory organs, muscle spindles and tendon organs, responding to changes in muscle force and length. It is not known how these proprioceptors are used more specifically in ocular motor control, and there is no stretch reflex in the external eye muscles. However, a clear influence on space localization and eye position can be demonstrated with vibratory stimulation of the eye muscles, presumably activating muscle spindles. Different effects were observed in normal subjects and in adult patients with strabismus, which would indicate that the proprioceptive input from one eye of strabismic patients could be suppressed by the other eye, similar

  4. On the Visual Input Driving Human Smooth-Pursuit Eye Movements

    NASA Technical Reports Server (NTRS)

    Stone, Leland S.; Beutter, Brent R.; Lorenceau, Jean

    1996-01-01

    Current computational models of smooth-pursuit eye movements assume that the primary visual input is local retinal-image motion (often referred to as retinal slip). However, we show that humans can pursue object motion with considerable accuracy, even in the presence of conflicting local image motion. This finding indicates that the visual cortical area(s) controlling pursuit must be able to perform a spatio-temporal integration of local image motion into a signal related to object motion. We also provide evidence that the object-motion signal that drives pursuit is related to the signal that supports perception. We conclude that current models of pursuit should be modified to include a visual input that encodes perceived object motion and not merely retinal image motion. Finally, our findings suggest that the measurement of eye movements can be used to monitor visual perception, with particular value in applied settings as this non-intrusive approach would not require interrupting ongoing work or training.

  5. Fast ray-tracing of human eye optics on Graphics Processing Units.

    PubMed

    Wei, Qi; Patkar, Saket; Pai, Dinesh K

    2014-05-01

    We present a new technique for simulating retinal image formation by tracing a large number of rays from objects in three dimensions as they pass through the optic apparatus of the eye to objects. Simulating human optics is useful for understanding basic questions of vision science and for studying vision defects and their corrections. Because of the complexity of computing such simulations accurately, most previous efforts used simplified analytical models of the normal eye. This makes them less effective in modeling vision disorders associated with abnormal shapes of the ocular structures which are hard to be precisely represented by analytical surfaces. We have developed a computer simulator that can simulate ocular structures of arbitrary shapes, for instance represented by polygon meshes. Topographic and geometric measurements of the cornea, lens, and retina from keratometer or medical imaging data can be integrated for individualized examination. We utilize parallel processing using modern Graphics Processing Units (GPUs) to efficiently compute retinal images by tracing millions of rays. A stable retinal image can be generated within minutes. We simulated depth-of-field, accommodation, chromatic aberrations, as well as astigmatism and correction. We also show application of the technique in patient specific vision correction by incorporating geometric models of the orbit reconstructed from clinical medical images.

  6. Ion therapy for uveal melanoma in new human eye phantom based on GEANT4 toolkit.

    PubMed

    Mahdipour, Seyed Ali; Mowlavi, Ali Asghar

    2016-01-01

    Radiotherapy with ion beams like proton and carbon has been used for treatment of eye uveal melanoma for many years. In this research, we have developed a new phantom of human eye for Monte Carlo simulation of tumors treatment to use in GEANT4 toolkit. Total depth-dose profiles for the proton, alpha, and carbon incident beams with the same ranges have been calculated in the phantom. Moreover, the deposited energy of the secondary particles for each of the primary beams is calculated. The dose curves are compared for 47.8MeV proton, 190.1MeV alpha, and 1060MeV carbon ions that have the same range in the target region reaching to the center of tumor. The passively scattered spread-out Bragg peak (SOBP) for each incident beam as well as the flux curves of the secondary particles including neutron, gamma, and positron has been calculated and compared for the primary beams. The high sharpness of carbon beam׳s Bragg peak with low lateral broadening is the benefit of this beam in hadrontherapy but it has disadvantages of dose leakage in the tail after its Bragg peak and high intensity of neutron production. However, proton beam, which has a good conformation with tumor shape owing to the beam broadening caused by scattering, can be a good choice for the large-size tumors.

  7. Ion therapy for uveal melanoma in new human eye phantom based on GEANT4 toolkit

    SciTech Connect

    Mahdipour, Seyed Ali; Mowlavi, Ali Asghar

    2016-07-01

    Radiotherapy with ion beams like proton and carbon has been used for treatment of eye uveal melanoma for many years. In this research, we have developed a new phantom of human eye for Monte Carlo simulation of tumors treatment to use in GEANT4 toolkit. Total depth−dose profiles for the proton, alpha, and carbon incident beams with the same ranges have been calculated in the phantom. Moreover, the deposited energy of the secondary particles for each of the primary beams is calculated. The dose curves are compared for 47.8 MeV proton, 190.1 MeV alpha, and 1060 MeV carbon ions that have the same range in the target region reaching to the center of tumor. The passively scattered spread-out Bragg peak (SOBP) for each incident beam as well as the flux curves of the secondary particles including neutron, gamma, and positron has been calculated and compared for the primary beams. The high sharpness of carbon beam's Bragg peak with low lateral broadening is the benefit of this beam in hadrontherapy but it has disadvantages of dose leakage in the tail after its Bragg peak and high intensity of neutron production. However, proton beam, which has a good conformation with tumor shape owing to the beam broadening caused by scattering, can be a good choice for the large-size tumors.

  8. Tissue Distribution of trans-Resveratrol and Its Metabolites after Oral Administration in Human Eyes

    PubMed Central

    Weinreb, Robert N.

    2017-01-01

    Purpose. This study was performed to measure the concentration of trans-resveratrol and its three metabolites in human eyes. Methods. The patients who underwent pars plana vitrectomy for rhegmatogenous retinal detachment were included. The participants were orally given trans-resveratrol-based supplement (Longevinex®). A suitable amount of conjunctiva, aqueous humor, and vitreous humor were obtained during the operation. High-performance liquid chromatography (HPLC) with mass spectrometry (LC/MS/MS) was used to detect the concentration of trans-resveratrol and its three metabolites in the various samples. Results. The average concentration of resveratrol in the conjunctiva was 17.19 ± 15.32 nmol/g (mean ± SD). The concentration of resveratrol in the aqueous humor was close to the limit of detection, but its metabolites could be quantified. The concentrations of resveratrol metabolites in the aqueous humor can be detected. In the vitreous humor, the average concentration of resveratrol-3-O-sulfate was 62.95 ± 41.97 nmol/L. The sulfate conjugations of resveratrol were recovered in the conjunctiva, aqueous humor, and vitreous humor. Conclusions. Resveratrol and its three metabolites can be detected in the ocular tissues after oral administration. Although the concentration of parent resveratrol was low in the eyes, its metabolites could be detected and may have a role in the treatment of ocular diseases.

  9. Frequency-Dependent Modulation of Regional Synchrony in the Human Brain by Eyes Open and Eyes Closed Resting-States

    PubMed Central

    Song, Xiaopeng; Zhou, Shuqin; Zhang, Yi; Liu, Yijun; Zhu, Huaiqiu; Gao, Jia-Hong

    2015-01-01

    The eyes-open (EO) and eyes-closed (EC) states have differential effects on BOLD-fMRI signal dynamics, affecting both the BOLD oscillation frequency of a single voxel and the regional homogeneity (ReHo) of several neighboring voxels. To explore how the two resting-states modulate the local synchrony through different frequency bands, we decomposed the time series of each voxel into several components that fell into distinct frequency bands. The ReHo in each of the bands was calculated and compared between the EO and EC conditions. The cross-voxel correlations between the mean frequency and the overall ReHo of each voxel’s original BOLD series in different brain areas were also calculated and compared between the two states. Compared with the EC state, ReHo decreased with EO in a wide frequency band of 0.01–0.25 Hz in the bilateral thalamus, sensorimotor network, and superior temporal gyrus, while ReHo increased significantly in the band of 0–0.01 Hz in the primary visual cortex, and in a higher frequency band of 0.02–0.1 Hz in the higher order visual areas. The cross-voxel correlations between the frequency and overall ReHo were negative in all the brain areas but varied from region to region. These correlations were stronger with EO in the visual network and the default mode network. Our results suggested that different frequency bands of ReHo showed different sensitivity to the modulation of EO-EC states. The better spatial consistency between the frequency and overall ReHo maps indicated that the brain might adopt a stricter frequency-dependent configuration with EO than with EC. PMID:26545233

  10. Human Growth Hormone (HGH): Does It Slow Aging?

    MedlinePlus

    Healthy Lifestyle Healthy aging Human growth hormone is described by some as the key to slowing the aging ... about proven ways to improve your health. Remember, healthy lifestyle choices — such as eating a healthy diet and ...

  11. Effects of Vitreomacular Traction on Ranibizumab Treatment Response in Eyes with Neovascular Age-related Macular Degeneration

    PubMed Central

    Lee, Kang Hoon; Chin, Hee Seung; Kim, Na Rae

    2015-01-01

    Purpose To investigate the effects of vitreomacular traction (VMT) on ranibizumab treatment response for neovascular age-related macular degeneration (AMD). Methods A retrospective review of 85 eyes of 85 patients newly diagnosed with neovascular AMD was conducted. Patients were eligible if they had received more than three consecutive monthly ranibizumab (0.50 mg) treatments and ophthalmic evaluations. Patients were classified into a VMT (+) group or VMT (-) group according to optical coherence tomography imaging. Best corrected visual acuity and central retinal thickness (CRT) measurements were obtained at three and six months after initial injection. Results One month after the third injection, mean visual acuity (VA) increases of 6.36 and 9.87 letters were observed in the VMT (+) and VMT (-) groups, respectively. The corresponding mean CRT values decreased by 70.29 µm and 121.68 µm, respectively. A total 41 eyes were identified as eligible for a subsequent fourth injection; 71.1% of patients (27 eyes) in the VMT (+) group but only 29.8% of patients in the VMT (-) group needed a subsequent fourth injection. Follow-up was extended to six months for 42 of the 85 enrolled patients (49.4%). The trends in VA and optical coherence tomography were found to be maintained at six-month follow-up. Conclusions VA and CRT appeared to be more improved after ranibizumab treatment in the VMT (-) group compared to the VMT (+) group. VMT might antagonize the effect of ranibizumab treatment in a subpopulation of AMD patients. PMID:26635456

  12. Reconstituted human corneal epithelium: a new alternative to the Draize eye test for the assessment of the eye irritation potential of chemicals and cosmetic products.

    PubMed

    Doucet, O; Lanvin, M; Thillou, C; Linossier, C; Pupat, C; Merlin, B; Zastrow, L

    2006-06-01

    The aim of this study was to evaluate the interest of a new three-dimensional epithelial model cultivated from human corneal cells to replace animal testing in the assessment of eye tolerance. To this end, 65 formulated cosmetic products and 36 chemicals were tested by means of this in vitro model using a simplified toxicokinetic approach. The chemicals were selected from the ECETOC data bank and the EC/HO International validation study list. Very satisfactory results were obtained in terms of concordance with the Draize test data for the formulated cosmetic products. Moreover, the response of the corneal model appeared predictive of human ocular response clinically observed by ophthalmologists. The in vitro scores for the chemicals tested strongly correlated with their respective scores in vivo. For all the compounds tested, the response of the corneal model to irritants was similar regardless of their chemical structure, suggesting a good robustness of the prediction model proposed. We concluded that this new three-dimensional epithelial model, developed from human corneal cells, could be promising for the prediction of eye irritation induced by chemicals and complex formulated products, and that these two types of materials should be tested using a similar protocol. A simple shortening of the exposure period was required for the chemicals assumed to be more aggressively irritant to the epithelial tissues than the cosmetic formulae.

  13. Dietary compound score and risk of age-related macular degeneration in the Age-Related Eye Disease Study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Purpose: Because foods provide many nutrients, which may interact with each other to modify risk for multifactorial diseases such as age-related macular degeneration (AMD), we sought to develop a composite scoring system to summarize the combined effect of multiple dietary nutrients on AMD risk. Th...

  14. Numerical study on statistical properties of speckle pattern in laser projection display based on human eye model

    NASA Astrophysics Data System (ADS)

    Cui, Zhe; Wang, Anting; Ma, Qianli; Ming, Hai

    2013-12-01

    In this paper, the laser speckle pattern on human retina for a laser projection display is simulated. By introducing a specific eye model `Indiana Eye', the statistical properties of the laser speckle are numerical investigated. The results show that the aberrations of human eye (mostly spherical and chromatic) will decrease the speckle contrast felt by people. When the wavelength of the laser source is 550 nm (green), people will feel the strongest speck pattern and the weakest when the wavelength is 450 nm (blue). Myopia and hyperopia will decrease the speckle contrast by introducing large spherical aberrations. Although aberration is good for speckle reduction, but it will degrade the imaging capability of the eye. The results show that laser source (650 nm) will have the best image quality on the retina. At last, we compare the human eye with an aberration-free imaging system. Both the speckle contrast and the image quality appear different behavior in these two imaging systems. The results are useful when a standardized measurement procedure for speckle contrast needs to be built.

  15. An exploratory study on the driving method of speech synthesis based on the human eye reading imaging data

    NASA Astrophysics Data System (ADS)

    Gao, Pei-pei; Liu, Feng

    2016-10-01

    With the development of information technology and artificial intelligence, speech synthesis plays a significant role in the fields of Human-Computer Interaction Techniques. However, the main problem of current speech synthesis techniques is lacking of naturalness and expressiveness so that it is not yet close to the standard of natural language. Another problem is that the human-computer interaction based on the speech synthesis is too monotonous to realize mechanism of user subjective drive. This thesis introduces the historical development of speech synthesis and summarizes the general process of this technique. It is pointed out that prosody generation module is an important part in the process of speech synthesis. On the basis of further research, using eye activity rules when reading to control and drive prosody generation was introduced as a new human-computer interaction method to enrich the synthetic form. In this article, the present situation of speech synthesis technology is reviewed in detail. Based on the premise of eye gaze data extraction, using eye movement signal in real-time driving, a speech synthesis method which can express the real speech rhythm of the speaker is proposed. That is, when reader is watching corpora with its eyes in silent reading, capture the reading information such as the eye gaze duration per prosodic unit, and establish a hierarchical prosodic pattern of duration model to determine the duration parameters of synthesized speech. At last, after the analysis, the feasibility of the above method is verified.

  16. Computer-aided geometric modeling of the human eye and orbit.

    PubMed

    Parshall, R F

    1991-01-01

    The author advocates, as a long-term development agenda for the profession, a shift in the working methods of medical illustrators from a two-dimensional image processing mode to a computer-aided design and drafting (CADD) mode. Existing CADD technology, which can make short work of the complex graphic construction problems of anatomical visualization, performs virtually all of its manipulations through systematic exercise of graphic geometry which illustrators tend to reduce to an intuitive, almost vestigial supplement to 2D image processing methods. The primary barrier to the immediate use of CADD is a lack of geometric database materials on anatomical component systems of the body. An on-going experimental project in modeling the human eye and orbit, utilizing a Silicon Graphics Iris workstation and Control Data Corporation's Integrated Computerized Engineering and Manufacturing (ICEM) software, exemplifies the preparatory work needed to create such database materials.

  17. Particulate matter contamination in the corneal stroma of severe eye burns in humans.

    PubMed

    Schrage, N F; Reim, M; Burchard, W G

    1990-01-01

    Corneal buttons obtained from keratoplasty were examined by energy dispersive x-ray analysis (EDXA) combined with scanning electron microscopy (SEM). This method enables to assay the mineral composition of minute parts of tissue samples identified in SEM images. Samples were cut from paraffin embedded corneae, deparaffinized in xylol, dried in aceton, critical-point desiccated, covered by evaporating with a thin layer of carbon and examined by SEM. In healthy human donor eyes, only some iron particles had been found. In the 22 patients samples high amounts of different particles were identified, materials from rubber stoppers, chromesteel, titanium pigments, talcum, barium and glass. Furthermore a lot of different metal particles containing varying amounts of Na, Mg, Al, Si, P, S, Cl, K, Ca, Fe, Cu, Cr, Zn, La and Ce were detected. Some particles may be caused by the initial trauma, others by therapy. Such contaminations might have supported leucocyte and fibrocyte invasion increasing the inflammatory reaction in the burnt cornea.

  18. OCT Study of Mechanical Properties Associated with Trabecular Meshwork and Collector Channel Motion in Human Eyes

    PubMed Central

    Xin, Chen; Johnstone, Murray; Wang, Ningli; Wang, Ruikang K.

    2016-01-01

    We report the use of a high-resolution optical coherence tomography (OCT) imaging platform to identify and quantify pressure-dependent aqueous outflow system (AOS) tissue relationships and to infer mechanical stiffness through examination of tissue properties in ex vivo human eyes. Five enucleated human eyes are included in this study, with each eye prepared with four equal-sized quadrants, each encompassing 90 degrees of the limbal circumference. In radial limbal segments perfusion pressure within Schlemm’s canal (SC) is controlled by means of a perfusion cannula inserted into the canal lumen, while the other end of the cannula leads to a reservoir at a height that can control the pressure in the cannula. The OCT system images the sample with a spatial resolution of about 5 μm from the trabecular meshwork (TM) surface. Geometric parameters are quantified from the 2D OCT images acquired from the sample subjected to controlled changes in perfusion pressures; parameters include area and height of the lumen of SC, collector channel entrances (CCE) and intrascleral collector channels (ISCC). We show that 3D OCT imaging permits the identification of 3-D relationships of the SC, CCE and ISCC lumen dimensions. Collagen flaps or leaflets are found at CCE that are attached or hinged at only one end, whilst the flaps are connected to the TM by cylindrical structures spanning SC. Increasing static SC pressures resulted in SC lumen enlargement with corresponding enlargement of the CCE and ISCC lumen. Pressure-dependent SC lumen area and height changes are significant at the 0.01 levels for ANOVA, and at the 0.05 for both polynomial curves and Tukey paired comparisons. Dynamic measurements demonstrate a synchronous increase in SC, CCE and ISCC lumen height in response to pressure changes from 0 to 10, 30 or 50 mm Hg, respectively, and the response time is within the 50-millisecond range. From the measured SC volume and corresponding IOP values, we demonstrate that an

  19. A new measurement method for color discrimination thresholds of human eyes based on PWM light-mixing technology

    NASA Astrophysics Data System (ADS)

    Zhang, Jiyan; Dong, Jinxin

    2016-09-01

    The color discrimination is a powerful tool for detection of eye diseases, and it is is necessary to produce different kinds of color rapidly and precisely for testing color discrimination thresholds of human eyes. Three channels' pulse-width modulation (PWM) and light-mixing technology is a new way to mixing color, and a new measurement method for color discrimination thresholds of human eyes based on PWM light-mix technology can generate kinds of color stimuli. In this study, 5 youth volunteers were measured via this equipment after the test for the stability of the device's illumination and chrominance. Though the theory of Macadam ellipses and the interleaved staircase method, a psychophysical experiment was made to study the color discrimination threshold of the human eyes around a basic color center. By analyzing the data of the chromatic ellipse and the color discrimination threshold, the result shows that each color is not uniform in a single color region and the color difference threshold of normal human is around the third Macadam ellipses. The experimental results show that the repeatability and accuracy of the observer can meet the accuracy requirements of the relevant experiments, and the data is reliable and effective, which means the measurement method is an effective way to measure the color discrimination thresholds of human visual system.

  20. Reactive Oxygen Species and the Aging Eye: Specific Role of Metabolically Active Mitochondria in Maintaining Lens Function and in the Initiation of the Oxidation-Induced Maturity Onset Cataract--A Novel Platform of Mitochondria-Targeted Antioxidants With Broad Therapeutic Potential for Redox Regulation and Detoxification of Oxidants in Eye Diseases.

    PubMed

    Babizhayev, Mark A; Yegorov, Yegor E

    2016-01-01

    The aging eye appears to be at considerable risk from oxidative stress. A great deal of research indicates that dysfunctional mitochondria are the primary site of reactive oxygen species (ROS). More than 95% of O2 produced during normal metabolism is generated by the electron transport chain in the inner mitochondrial membrane. Mitochondria are also the major target of ROS. Cataract formation, the opacification of the eye lens, is one of the leading causes of human blindness worldwide, accounting for 47.8% of all causes of blindness. Cataracts result from the deposition of aggregated proteins in the eye lens and lens fiber cell plasma membrane damage, which causes clouding of the lens, light scattering, and obstruction of vision. ROS-induced damage in the lens cell may consist of oxidation of proteins, DNA damage, and/or lipid peroxidation, all of which have been implicated in cataractogenesis. This article is an attempt to integrate how mitochondrial ROS are altered in the aging eye along with those protective and repair therapeutic systems believed to regulate ROS levels in ocular tissues and how damage to these systems contributes to age-onset eye disease and cataract formation. Mitochondria-targeted antioxidants might be used to effectively prevent ROS-induced oxidation of lipids and proteins in the inner mitochondrial membrane in vivo. As a result of the combination of weak metal chelating, OH and lipid peroxyl radicals scavenging, reducing activities to liberated fatty acid, and phospholipid hydroperoxides, carnosine and carcinine appear to be physiological antioxidants able to efficiently protect the lipid phase of biologic membranes and aqueous environments and act as the antiapoptotic natural drug compounds The authors developed and patented the new ophthalmic compositions, including N-acetylcarnosine, acting as a prodrug of naturally targeted to mitochondria L-carnosine endowed with pluripotent antioxidant activities combined with mitochondria

  1. Tissue resident memory T cells in the human conjunctiva and immune signatures in human dry eye disease

    PubMed Central

    Bose, Tanima; Lee, Ryan; Hou, Aihua; Tong, Louis; Chandy, K. George

    2017-01-01

    Non-recirculating resident memory (TRM) and recirculating T cells mount vigorous immune responses to both self and foreign antigens in barrier tissues like the skin, lung and gastrointestinal tract. Using impression cytology followed by flow cytometry we identified two TRM subsets and four recirculating T-subsets in the healthy human ocular surface. In dry eye disease, principal component analysis (PCA) revealed two clusters of patients with distinct T-cell signatures. Increased conjunctival central memory and naïve T cells characterized Cluster-1 patients, and increased CD8+ TRMs and CD4+ recirculating memory T cells characterized Cluster-2 patients. Interestingly these T-cell signatures are associated with different clinical features: the first signature correlated with increased ocular redness, and the second with reduced tear break up times. These findings open the door to immune-based characterization of dry eye disease and T-subset specific immunotherapies to suppress T-subsets involved in disease. They may also help with patient stratification during clinical trials of immunomodulators. PMID:28345628

  2. Tissue resident memory T cells in the human conjunctiva and immune signatures in human dry eye disease.

    PubMed

    Bose, Tanima; Lee, Ryan; Hou, Aihua; Tong, Louis; Chandy, K George

    2017-03-27

    Non-recirculating resident memory (TRM) and recirculating T cells mount vigorous immune responses to both self and foreign antigens in barrier tissues like the skin, lung and gastrointestinal tract. Using impression cytology followed by flow cytometry we identified two TRM subsets and four recirculating T-subsets in the healthy human ocular surface. In dry eye disease, principal component analysis (PCA) revealed two clusters of patients with distinct T-cell signatures. Increased conjunctival central memory and naïve T cells characterized Cluster-1 patients, and increased CD8(+) TRMs and CD4(+) recirculating memory T cells characterized Cluster-2 patients. Interestingly these T-cell signatures are associated with different clinical features: the first signature correlated with increased ocular redness, and the second with reduced tear break up times. These findings open the door to immune-based characterization of dry eye disease and T-subset specific immunotherapies to suppress T-subsets involved in disease. They may also help with patient stratification during clinical trials of immunomodulators.

  3. The Association of Statin Use with Age-Related Macular Degeneration Progression The Age-Related Eye Disease Study 2 Report Number 9

    PubMed Central

    Al-Holou, Shaza N.; Tucker, William R.; Agrón, Elvira; Clemons, Traci E.; Cukras, Catherine; Ferris, Frederick L.; Chew, Emily Y.

    2015-01-01

    Objective/purpose To evaluate the association of statin use with progression of age-related macular degeneration (AMD). Design Preplanned, prospective cohort study within a controlled clinical trial of oral supplementation for age-related eye diseases. Subjects Age-Related Eye Disease Study 2 participants, aged 50 to 85 years. Methods Factors, including age, gender, smoking status, aspirin use, and history of diabetes, hypertension, heart disease, angina, and stroke, all known to be associated with statin use, were included in a logistic regression model to estimate propensity scores for each participant. Age-adjusted proportional hazards regression models, with and without propensity score matching, were performed to evaluate the association of statin use with progression to late AMD. Analyses were also performed adjusting for the competing risk of death. Main Outcome Measures Baseline and annual stereoscopic fundus photographs were assessed centrally by masked graders for the development of late AMD, either neovascular AMD or geographic atrophy (GA). Results Of the 3791 participants (2462 with bilateral large drusen and 1329 with unilateral late AMD at baseline), 1659 (43.8%) were statin users. The overall analysis, with no matching of propensity scores and no adjustment for death as a competing risk, showed that statin use was not associated with progression to late AMD (hazard ratios [HR] of 1.08, 95% confidence intervals [CI] of 0.83–1.41, P=0.56). When matched for propensity scores and adjusted for death as a competing risk, the result was not statistically significant with HR: 0.81, 95% CI: 0.55–1.20, P=0.29. Further subgroup analyses of persons with or without late AMD at baseline to the various components of late AMD (neovascular, central geographic atrophy, or any geographic atrophy) also showed no statistically significant association of statin use with progression to AMD. Conclusions Statin use was not statistically significantly associated with the

  4. Numerical abilities of school-age children with Developmental Coordination Disorder (DCD): A behavioral and eye-tracking study.

    PubMed

    Gomez, Alice; Piazza, Manuela; Jobert, Antoinette; Dehaene-Lambertz, Ghislaine; Huron, Caroline

    2016-08-31

    Developmental Coordination Disorder (DCD) is a disorder of motor coordination which interferes with academic achievement. Difficulties in mathematics have been reported. Performance in the number line task is very sensitive to atypical development of numerical cognition. We used a position-to-number task in which twenty 7-to-10years old children with DCD and 20 age-matched typically developing (TD) children had to estimate the number that corresponded to a hatch mark placed on a 0-100 number line. Eye movements were recorded. Children with DCD were less accurate and slower to respond than their peers. However, they were able to map numbers onto space linearly and used anchoring strategies as control. We suggest that the shift to a linear trend reflects the ability of DCD children to use efficient strategies to solve the task despite a possibly more imprecise underlying numerical acuity.

  5. Cell-Deposited Matrix Improves Retinal Pigment Epithelium Survival on Aged Submacular Human Bruch's Membrane

    PubMed Central

    Sugino, Ilene K.; Gullapalli, Vamsi K.; Sun, Qian; Wang, Jianqiu; Nunes, Celia F.; Cheewatrakoolpong, Noounanong; Johnson, Adam C.; Degner, Benjamin C.; Hua, Jianyuan; Liu, Tong; Chen, Wei; Li, Hong

    2011-01-01

    Purpose. To determine whether resurfacing submacular human Bruch's membrane with a cell-deposited extracellular matrix (ECM) improves retinal pigment epithelial (RPE) survival. Methods. Bovine corneal endothelial (BCE) cells were seeded onto the inner collagenous layer of submacular Bruch's membrane explants of human donor eyes to allow ECM deposition. Control explants from fellow eyes were cultured in medium only. The deposited ECM was exposed by removing BCE. Fetal RPE cells were then cultured on these explants for 1, 14, or 21 days. The explants were analyzed quantitatively by light microscopy and scanning electron microscopy. Surviving RPE cells from explants cultured for 21 days were harvested to compare bestrophin and RPE65 mRNA expression. Mass spectroscopy was performed on BCE-ECM to examine the protein composition. Results. The BCE-treated explants showed significantly higher RPE nuclear density than did the control explants at all time points. RPE expressed more differentiated features on BCE-treated explants than on untreated explants, but expressed very little mRNA for bestrophin or RPE65. The untreated young (<50 years) and African American submacular Bruch's membrane explants supported significantly higher RPE nuclear densities (NDs) than did the Caucasian explants. These differences were reduced or nonexistent in the BCE-ECM-treated explants. Proteins identified in the BCE-ECM included ECM proteins, ECM-associated proteins, cell membrane proteins, and intracellular proteins. Conclusions. Increased RPE survival can be achieved on aged submacular human Bruch's membrane by resurfacing the latter with a cell-deposited ECM. Caucasian eyes seem to benefit the most, as cell survival is the worst on submacular Bruch's membrane in these eyes. PMID:21398292

  6. Joint attention without gaze following: human infants and their parents coordinate visual attention to objects through eye-hand coordination.

    PubMed

    Yu, Chen; Smith, Linda B

    2013-01-01

    The coordination of visual attention among social partners is central to many components of human behavior and human development. Previous research has focused on one pathway to the coordination of looking behavior by social partners, gaze following. The extant evidence shows that even very young infants follow the direction of another's gaze but they do so only in highly constrained spatial contexts because gaze direction is not a spatially precise cue as to the visual target and not easily used in spatially complex social interactions. Our findings, derived from the moment-to-moment tracking of eye gaze of one-year-olds and their parents as they actively played with toys, provide evidence for an alternative pathway, through the coordination of hands and eyes in goal-directed action. In goal-directed actions, the hands and eyes of the actor are tightly coordinated both temporally and spatially, and thus, in contexts including manual engagement with objects, hand movements and eye movements provide redundant information about where the eyes are looking. Our findings show that one-year-olds rarely look to the parent's face and eyes in these contexts but rather infants and parents coordinate looking behavior without gaze following by attending to objects held by the self or the social partner. This pathway, through eye-hand coupling, leads to coordinated joint switches in visual attention and to an overall high rate of looking at the same object at the same time, and may be the dominant pathway through which physically active toddlers align their looking behavior with a social partner.

  7. Olfactory phenotypic expression unveils human aging

    PubMed Central

    Mazzatenta, Andrea; Cellerino, Alessandro; Origlia, Nicola; Barloscio, Davide; Sartucci, Ferdinando; Giulio, Camillo Di; Domenici, Luciano

    2016-01-01

    The mechanism of the natural aging of olfaction and its declinein the absence of any overt disease conditions remains unclear. Here, we investigated this mechanism through measurement of one of the parameters of olfactory function, the absolute threshold, in a healthy population from childhood to old age. The absolute olfactory threshold data were collected from an Italian observational study with 622 participants aged 5-105 years. A subjective testing procedure of constant stimuli was used, which was also compared to the ‘staircase’ method, with the calculation of the reliability. The n-butanol stimulus was used as an ascending series of nine molar concentrations that were monitored using an electronic nose. The data were analyzed using nonparametric statistics because of the multimodal distribution. We show that the age-related variations in the absolute olfactory threshold are not continuous; instead, there are multiple olfactory phenotypes. Three distinct age-related phenotypes were defined, termed as ‘juvenile’, ‘mature’ and ‘elder’. The frequency of these three phenotypes depends on age. Our data suggest that the sense of smell does not decrease linearly with aging. Our findings provide the basis for further understanding of olfactory loss as an anticipatory sign of aging and neurodegenerative processes. PMID:27027240

  8. Using Object Boxes to Teach the Form, Function, and Vocabulary of the Parts of the Human Eye

    ERIC Educational Resources Information Center

    Rule, Audrey C.; Welch, Genne

    2008-01-01

    These science activities for elementary students focus on the external structures and functions of the human eye with hands-on object box activities based on the Montessori theory (1966) of concrete learning through manipulation of objects and focus of attention through touch. Object boxes are sets of items and corresponding cards housed in a box.…

  9. An Interactive Method for Teaching Anatomy of the Human Eye for Medical Students in Ophthalmology Clinical Rotations

    ERIC Educational Resources Information Center

    Kivell, Tracy L.; Doyle, Sara K.; Madden, Richard H.; Mitchell, Terry L.; Sims, Ershela L.

    2009-01-01

    Much research has shown the benefits of additional anatomical learning and dissection beyond the first year of medical school human gross anatomy, all the way through postgraduate medical training. We have developed an interactive method for teaching eye and orbit anatomy to medical students in their ophthalmology rotation at Duke University…

  10. Simultaneous Recordings of Human Microsaccades and Drifts with a Contemporary Video Eye Tracker and the Search Coil Technique

    PubMed Central

    McCamy, Michael B.; Otero-Millan, Jorge; Leigh, R. John; King, Susan A.; Schneider, Rosalyn M.; Macknik, Stephen L.; Martinez-Conde, Susana

    2015-01-01

    Human eyes move continuously, even during visual fixation. These “fixational eye movements” (FEMs) include microsaccades, intersaccadic drift and oculomotor tremor. Research in human FEMs has grown considerably in the last decade, facilitated by the manufacture of noninvasive, high-resolution/speed video-oculography eye trackers. Due to the small magnitude of FEMs, obtaining reliable data can be challenging, however, and depends critically on the sensitivity and precision of the eye tracking system. Yet, no study has conducted an in-depth comparison of human FEM recordings obtained with the search coil (considered the gold standard for measuring microsaccades and drift) and with contemporary, state-of-the art video trackers. Here we measured human microsaccades and drift simultaneously with the search coil and a popular state-of-the-art video tracker. We found that 95% of microsaccades detected with the search coil were also detected with the video tracker, and 95% of microsaccades detected with video tracking were also detected with the search coil, indicating substantial agreement between the two systems. Peak/mean velocities and main sequence slopes of microsaccades detected with video tracking were significantly higher than those of the same microsaccades detected with the search coil, however. Ocular drift was significantly correlated between the two systems, but drift speeds were higher with video tracking than with the search coil. Overall, our combined results suggest that contemporary video tracking now approaches the search coil for measuring FEMs. PMID:26035820

  11. Biological psychological and social determinants of old age: bio-psycho-social aspects of human aging.

    PubMed

    Dziechciaż, Małgorzata; Filip, Rafał

    2014-01-01

    The aging of humans is a physiological and dynamic process ongoing with time. In accordance with most gerontologists' assertions it starts in the fourth decade of life and leads to death. The process of human aging is complex and individualized, occurs in the biological, psychological and social sphere. Biological aging is characterized by progressive age-changes in metabolism and physicochemical properties of cells, leading to impaired self-regulation, regeneration, and to structural changes and functional tissues and organs. It is a natural and irreversible process which can run as successful aging, typical or pathological. Biological changes that occur with age in the human body affect mood, attitude to the environment, physical condition and social activity, and designate the place of seniors in the family and society. Psychical ageing refers to human awareness and his adaptability to the ageing process. Among adaptation attitudes we can differentiate: constructive, dependence, hostile towards others and towards self attitudes. With progressed age, difficulties with adjustment to the new situation are increasing, adverse changes in the cognitive and intellectual sphere take place, perception process involutes, perceived sensations and information received is lowered, and thinking processes change. Social ageing is limited to the role of an old person is culturally conditioned and may change as customs change. Social ageing refers to how a human being perceives the ageing process and how society sees it.

  12. Eye Cancer

    MedlinePlus

    ... Cancer > Eye Cancer > Eye Cancer: Overview Request Permissions Eye Cancer: Overview Approved by the Cancer.Net Editorial ... trained to treat intraocular cancer. Parts of the eye The eye is the organ that collects light ...

  13. Eye redness

    MedlinePlus

    Bloodshot eyes; Red eyes; Scleral injection; Conjunctival injection ... There are many causes of a red eye or eyes. Some are medical emergencies. Others are a cause for concern, but not an emergency. Many are nothing to worry about. Eye ...

  14. Molecular aging and rejuvenation of human muscle stem cells

    PubMed Central

    Carlson, Morgan E; Suetta, Charlotte; Conboy, Michael J; Aagaard, Per; Mackey, Abigail; Kjaer, Michael; Conboy, Irina

    2009-01-01

    Very little remains known about the regulation of human organ stem cells (in general, and during the aging process), and most previous data were collected in short-lived rodents. We examined whether stem cell aging in rodents could be extrapolated to genetically and environmentally variable humans. Our findings establish key evolutionarily conserved mechanisms of human stem cell aging. We find that satellite cells are maintained in aged human skeletal muscle, but fail to activate in response to muscle attrition, due to diminished activation of Notch compounded by elevated transforming growth factor beta (TGF-β)/phospho Smad3 (pSmad3). Furthermore, this work reveals that mitogen-activated protein kinase (MAPK)/phosphate extracellular signal-regulated kinase (pERK) signalling declines in human muscle with age, and is important for activating Notch in human muscle stem cells. This molecular understanding, combined with data that human satellite cells remain intrinsically young, introduced novel therapeutic targets. Indeed, activation of MAPK/Notch restored ‘youthful’ myogenic responses to satellite cells from 70-year-old humans, rendering them similar to cells from 20-year-old humans. These findings strongly suggest that aging of human muscle maintenance and repair can be reversed by ‘youthful’ calibration of specific molecular pathways. PMID:20049743

  15. Computer Simulation of Biological Ageing-A Bird's-Eye View

    NASA Astrophysics Data System (ADS)

    Dasgupta, Subinay

    For living organisms, the process of ageing consists of acquiring good and bad genetic mutations, which increase and decrease (respectively) the survival probability. When a child is born, the hereditary mutations of the parents are transmitted to the offspring. Such stochastic processes seem to be amenable to computer simulation. Over the last 10 years, simulation studies of this sort have been done in different parts of the globe to explain ageing. The objective of these studies have been to attempt an explanation of demographic data and of natural phenomena like preference of nature to the process of sexual reproduction (in comparison to the process of asexual reproduction). Here we shall attempt to discuss briefly the principles and the results of these works, with an emphasis on what is called Penna bit-string model.

  16. A thermographic study on eyes affected by Age-related Macular Degeneration: Comparison among various forms of the pathology and analysis of risk factors

    NASA Astrophysics Data System (ADS)

    Matteoli, Sara; Finocchio, Lucia; Biagini, Ilaria; Giacomelli, Giovanni; Sodi, Andrea; Corvi, Andrea; Virgili, Gianni; Rizzo, Stanislao

    2016-05-01

    The aims of this study are to investigate (1) the ocular thermographic profiles in eyes affected by Age related Macular Degeneration (AMD) and age-matched controls to detect possible hemodynamic abnormalities that could be involved in the pathogenesis of the disease, (2) whether any risk factors associated with the disease could affect the development of a form of AMD rather than another. Thirty-four eyes with Age-Related Maculopathy (ARM), 41 eyes with dry AMD, 60 eyes affected by wet AMD, and 74 eyes with fibrotic AMD were included in the study. The control group consisted of 48 healthy eyes. Exclusion criteria were represented by any other ocular diseases other than AMD, tear film abnormalities, systemic cardiovascular abnormalities, systemic diseases and a body temperature higher than 37.5 °C. A total of 210 eyes without pupil dilation were investigated by infrared thermography (FLIR A320). The Ocular Surface Temperature (OST) of five ocular areas was calculated by means of an image processing technique from the infrared images. Two-sample t-test, one-way ANOVA test and multivariate analysis were used for statistical analyses. ANOVA analyses showed no significant differences among AMD groups (P-value > 0.05), however, OST in AMD patients was significantly lower than in controls (P-value < 0.0001). Smokers showed higher possibility (P-value = 0.012) of developing wet AMD instead of dry AMD. Infrared thermography may be a helpful, non-invasive and not time-consuming method to be used in the management of patients with this common degenerative maculopathy.

  17. Myths of Human Sexuality in the Aging.

    ERIC Educational Resources Information Center

    Andrus, Charles E.

    Human sexuality is discussed in terms of misconceptions about its function and the changing sexual needs of older adults. A review of history indicates that human sexuality has traditionally been connected with ideas of purity and strict importance of procreation. Judaeo-Christian ethics and the doctrine of Saint Augustine illustrate these…

  18. Investigation of high power, pulsed, neodymium-YAG lasers for correcting opacities of the human eye. Master's thesis

    SciTech Connect

    Riggins, J.

    1982-06-01

    This paper will investigate the use of high peak power, nanosecond laser pulses focused in the posterior chamber of the eye to rupture opacified posterior lens capsule tissue or vitreous strands through the creation of a spark plasma and associated shock wave. The author discusses current theories on the formation of the shock wave and its relation to laser beam parameters along with laboratory experiments designed to create and study shock waves and their effects in pig and human eyes. The experimental procedure will utilize a Q-switched Nd-YAG laser interfaced with an ophthalmic slitlamp to simulate the actual conditions under which the physician would perform the operation.

  19. Localization of vascular adhesion protein-1 (VAP-1) in the human eye.

    PubMed

    Almulki, Lama; Noda, Kousuke; Nakao, Shintaro; Hisatomi, Toshio; Thomas, Kennard L; Hafezi-Moghadam, Ali

    2010-01-01

    Recently we showed a critical role for Vascular Adhesion Protein-1 (VAP-1) in rodents during acute ocular inflammation, angiogenesis, and diabetic retinal leukostasis. However, the expression of VAP-1 in the human eye is unknown. VAP-1 localization was therefore investigated by immunohistochemistry. Five micrometer thick sections were generated from human ocular tissues embedded in paraffin. Sections were incubated overnight with primary mAbs against VAP-1 (5 microg/ml), smooth muscle actin (1 microg/ml), CD31 or isotype-matched IgG at 4 degrees C. Subsequently, a secondary mAb was used for 30 min at room temperature, followed by Dako Envision + HRP (AEC) System for signal detection. The stained sections were examined using light microscopy and the signal intensity was quantified by two evaluators and graded into 4 discrete categories. In all examined ocular tissues, VAP-1 staining was confined to the vasculature. VAP-1 labeling showed the highest intensity in both arteries and veins of neuronal tissues: retina and optic nerve, and the lowest intensity in the iris vasculature (p < 0.05). Scleral and choroidal vessels showed moderate staining for VAP-1. VAP-1 intensity was significantly higher in the arteries compared to veins (p < 0.05). Furthermore, VAP-1 staining in arteries colocalized with both CD31 and smooth muscle actin (sm-actin) staining, suggesting expression of VAP-1 in endothelial cells, smooth muscle cells or potentially pericytes. In conclusion, immunohistochemistry reveals constitutive expression of VAP-1 in human ocular tissues. VAP-1 expression is nearly exclusive to the vasculature with arteries showing significantly higher expression than veins. Furthermore, VAP-1 expression in the ocular vasculature is heterogeneous, with the vessels of the optic nerve and the retina showing highest expressions. These results characterize VAP-1 expression in human ocular tissues.

  20. Localization of Vascular Adhesion Protein-1 (VAP-1) in the Human Eye

    PubMed Central

    Almulki, Lama; Noda, Kousuke; Nakao, Shintaro; Hisatomi, Toshio; Thomas, Kennard L.; Hafezi-Moghadam, Ali

    2009-01-01

    Recently we showed a critical role for Vascular Adhesion Protein-1 (VAP-1) in rodents during acute ocular inflammation, angiogenesis, and diabetic retinal leukostasis. However, the expression of VAP-1 in the human eye is unknown. VAP-1 localization was investigated by immunohistochemistry. Five μm thick sections were generated from human ocular tissues embedded in paraffin. Sections were incubated overnight with primary mAbs against VAP-1 (5μg/ml), smooth muscle actin (1μg/ml), CD31 or isotype-matched IgG at 4°C. Subsequently, a secondary mAb was used for 30min at room temperature, followed by Dako Envision + HRP (AEC) System for signal detection. The stained sections were examined using light microscopy and the signal intensity was quantified by two masked evaluators and graded into 4 discrete categories. In all examined ocular tissues, VAP-1 staining was confined to the vasculature. VAP-1 labeling showed the highest intensity in both arteries and veins of neuronal tissues; retina, and optic nerve, and the lowest intensity in the iris vasculature (p<0.05). Scleral and choroidal vessels showed moderate staining for VAP-1. VAP-1 intensity was significantly higher in the arteries compared to veins (p<0.05). Furthermore, VAP-1 staining in arteries co-localized with both CD31 and smooth muscle actin (sm-actin) staining, suggesting expression of VAP-1 in endothelial cells, smooth muscle cells or potentially pericytes. In conclusion, Immunohistochemistry reveals constitutive expression of VAP-1 in human ocular tissues. VAP-1 expression is exclusive to the vasculature with arteries showing significantly higher expression than veins. Furthermore, VAP-1 expression in the ocular vasculature is heterogeneous, with the vessels of the optic nerve and the retina showing highest expressions. These results characterize VAP-1 expression in human ocular tissues. PMID:19761765

  1. Visual and auditory cue integration for the generation of saccadic eye movements in monkeys and lever pressing in humans.

    PubMed

    Schiller, Peter H; Kwak, Michelle C; Slocum, Warren M

    2012-08-01

    This study examined how effectively visual and auditory cues can be integrated in the brain for the generation of motor responses. The latencies with which saccadic eye movements are produced in humans and monkeys form, under certain conditions, a bimodal distribution, the first mode of which has been termed express saccades. In humans, a much higher percentage of express saccades is generated when both visual and auditory cues are provided compared with the single presentation of these cues [H. C. Hughes et al. (1994) J. Exp. Psychol. Hum. Percept. Perform., 20, 131-153]. In this study, we addressed two questions: first, do monkeys also integrate visual and auditory cues for express saccade generation as do humans and second, does such integration take place in humans when, instead of eye movements, the task is to press levers with fingers? Our results show that (i) in monkeys, as in humans, the combined visual and auditory cues generate a much higher percentage of express saccades than do singly presented cues and (ii) the latencies with which levers are pressed by humans are shorter when both visual and auditory cues are provided compared with the presentation of single cues, but the distribution in all cases is unimodal; response latencies in the express range seen in the execution of saccadic eye movements are not obtained with lever pressing.

  2. Oxidative Stress in Aging Human Skin

    PubMed Central

    Rinnerthaler, Mark; Bischof, Johannes; Streubel, Maria Karolin; Trost, Andrea; Richter, Klaus

    2015-01-01

    Oxidative stress in skin plays a major role in the aging process. This is true for intrinsic aging and even more for extrinsic aging. Although the results are quite different in dermis and epidermis, extrinsic aging is driven to a large extent by oxidative stress caused by UV irradiation. In this review the overall effects of oxidative stress are discussed as well as the sources of ROS including the mitochondrial ETC, peroxisomal and ER localized proteins, the Fenton reaction, and such enzymes as cyclooxygenases, lipoxygenases, xanthine oxidases, and NADPH oxidases. Furthermore, the defense mechanisms against oxidative stress ranging from enzymes like superoxide dismutases, catalases, peroxiredoxins, and GSH peroxidases to organic compounds such as L-ascorbate, α-tocopherol, beta-carotene, uric acid, CoQ10, and glutathione are described in more detail. In addition the oxidative stress induced modifications caused to proteins, lipids and DNA are discussed. Finally age-related changes of the skin are also a topic of this review. They include a disruption of the epidermal calcium gradient in old skin with an accompanying change in the composition of the cornified envelope. This modified cornified envelope also leads to an altered anti-oxidative capacity and a reduced barrier function of the epidermis. PMID:25906193

  3. Genetic Evidence for Role of Carotenoids in Age-Related Macular Degeneration in the Carotenoids in Age-Related Eye Disease Study (CAREDS)

    PubMed Central

    Meyers, Kristin J.; Mares, Julie A.; Igo, Robert P.; Truitt, Barbara; Liu, Zhe; Millen, Amy E.; Klein, Michael; Johnson, Elizabeth J.; Engelman, Corinne D.; Karki, Chitra K.; Blodi, Barbara; Gehrs, Karen; Tinker, Lesley; Wallace, Robert; Robinson, Jennifer; LeBlanc, Erin S.; Sarto, Gloria; Bernstein, Paul S.; SanGiovanni, John Paul; Iyengar, Sudha K.

    2014-01-01

    Purpose. We tested variants in genes related to lutein and zeaxanthin status for association with age-related macular degeneration (AMD) in the Carotenoids in Age-Related Eye Disease Study (CAREDS). Methods. Of 2005 CAREDS participants, 1663 were graded for AMD from fundus photography and genotyped for 424 single nucleotide polymorphisms (SNPs) from 24 candidate genes for carotenoid status. Of 337 AMD cases 91% had early or intermediate AMD. The SNPs were tested individually for association with AMD using logistic regression. A carotenoid-related genetic risk model was built using backward selection and compared to existing AMD risk factors using the area under the receiver operating characteristic curve (AUC). Results. A total of 24 variants from five genes (BCMO1, BCO2, NPCL1L1, ABCG8, and FADS2) not previously related to AMD and four genes related to AMD in previous studies (SCARB1, ABCA1, APOE, and ALDH3A2) were associated independently with AMD, after adjusting for age and ancestry. Variants in all genes (not always the identical SNPs) were associated with lutein and zeaxanthin in serum and/or macula, in this or other samples, except for BCO2 and FADS2. A genetic risk score including nine variants significantly (P = 0.002) discriminated between AMD cases and controls beyond age, smoking, CFH Y402H, and ARMS2 A69S. The odds ratio (95% confidence interval) for AMD among women in the highest versus lowest quintile for the risk score was 3.1 (2.0–4.9). Conclusions. Variants in genes related to lutein and zeaxanthin status were associated with AMD in CAREDS, adding to the body of evidence supporting a protective role of lutein and zeaxanthin in risk of AMD. PMID:24346170

  4. Aging of the Human Vestibular System

    PubMed Central

    Zalewski, Christopher K.

    2015-01-01

    Aging affects every sensory system in the body, including the vestibular system. Although its impact is often difficult to quantify, the deleterious impact of aging on the vestibular system is serious both medically and economically. The deterioration of the vestibular sensory end organs has been known since the 1970s; however, the measurable impact from these anatomical changes remains elusive. Tests of vestibular function either fall short in their ability to quantify such anatomical deterioration, or they are insensitive to the associated physiologic decline and/or central compensatory mechanisms that accompany the vestibular aging process. When compared with healthy younger individuals, a paucity of subtle differences in test results has been reported in the healthy older population, and those differences are often observed only in response to nontraditional and/or more robust stimuli. In addition, the reported differences are often clinically insignificant insomuch that the recorded physiologic responses from the elderly often fall within the wide normative response ranges identified for normal healthy adults. The damaging economic impact of such vestibular sensory decline manifests itself in an exponential increase in geriatric dizziness and a subsequent higher prevalence of injurious falls. An estimated $10 to $20 billion dollar annual cost has been reported to be associated with falls-related injuries and is the sixth leading cause of death in the elderly population, with a 20% mortality rate. With an estimated 115% increase in the geriatric population over 65 years of age by the year 2050, the number of balanced-disordered patients with a declining vestibular system is certain to reach near epidemic proportions. An understanding of the effects of age on the vestibular system is imperative if clinicians are to better manage elderly patients with balance disorders, dizziness, and vestibular disease. PMID:27516717

  5. Cardiovascular Risk Factors and Age-related Macular Degeneration: The Los Angeles Latino Eye Study

    PubMed Central

    Fraser-Bell, Samantha; Wu, Joanne; Klein, Ronald; Azen, Stanley P.; Hooper, Claire; Foong, Athena W. P.; Varma, Rohit

    2008-01-01

    Purpose To assess the association of cardiovascular risk factors, ocular perfusion pressure with early and advanced age-related macular degeneration (AMD) in Latinos. Design Population-based, cross-sectional study. Methods Data were collected from a population-based sample of self-identified adult Latinos using standardized protocols for assessing blood pressure and intraocular pressure (IOP) measurement and stereoscopic macular photography. Hypertension was defined as either a history of hypertension or systolic blood pressure (SBP) >140mmHg +/− diastolic blood pressure (DBP) ≥85mmHg. Ocular perfusion pressure (OPP) was defined as the difference between mean arterial blood pressure and IOP. AMD was diagnosed from photographic grading by masked trained graders. Logistic regression was used to assess associations. Results Gradable retinal photographs were available in 5875 participants. After adjusting for age, sex, and cigarette smoking, higher DBP and uncontrolled diastolic hypertension were associated with exudative AMD (Odds ratio [OR], 1.8; 95% confidence interval [CI], 1.1−2.8; and OR, 3.3; CI, 1.2−9.3, respectively). Higher OPP was associated with a decreased risk of GA (OR, 0.4 per 10mmHg; CI, 0.3−0.5). Low pulse pressure was associated with a lower risk of exudative AMD (OR, 0.2; CI, 0.1−0.6). Obesity was associated with increased retinal pigment (OR, 1.6; CI, 1.0−2.3). Conclusion These data suggest that in Latinos cardiovascular risk factors may play a role in advanced AMD. Given that Latinos have a high prevalence of cardiovascular risk factors, an intervention aimed at reducing these risk factors may also have a beneficial impact on the risk of having early and advanced AMD. PMID:18222193

  6. Xenopus pax6 mutants affect eye development and other organ systems, and have phenotypic similarities to human aniridia patients.

    PubMed

    Nakayama, Takuya; Fisher, Marilyn; Nakajima, Keisuke; Odeleye, Akinleye O; Zimmerman, Keith B; Fish, Margaret B; Yaoita, Yoshio; Chojnowski, Jena L; Lauderdale, James D; Netland, Peter A; Grainger, Robert M

    2015-12-15

    Mutations in the Pax6 gene cause ocular defects in both vertebrate and invertebrate animal species, and the disease aniridia in humans. Despite extensive experimentation on this gene in multiple species, including humans, we still do not understand the earliest effects on development mediated by this gene. This prompted us to develop pax6 mutant lines in Xenopus tropicalis taking advantage of the utility of the Xenopus system for examining early development and in addition to establish a model for studying the human disease aniridia in an accessible lower vertebrate. We have generated mutants in pax6 by using Transcription Activator-Like Effector Nuclease (TALEN) constructs for gene editing in X. tropicalis. Embryos with putative null mutations show severe eye abnormalities and changes in brain development, as assessed by changes in morphology and gene expression. One gene that we found is downregulated very early in development in these pax6 mutants is myc, a gene involved in pluripotency and progenitor cell maintenance and likely a mediator of some key pax6 functions in the embryo. Changes in gene expression in the developing brain and pancreas reflect other important functions of pax6 during development. In mutations with partial loss of pax6 function eye development is initially relatively normal but froglets show an underdeveloped iris, similar to the classic phenotype (aniridia) seen in human patients with PAX6 mutations. Other eye abnormalities observed in these froglets, including cataracts and corneal defects, are also common in human aniridia. The frog model thus allows us to examine the earliest deficits in eye formation as a result of pax6 lesions, and provides a useful model for understanding the developmental basis for the aniridia phenotype seen in humans.

  7. Dwarf Eye Disorder

    ERIC Educational Resources Information Center

    Science Teacher, 2005

    2005-01-01

    Johns Hopkins researchers at the Wilmer Eye Institute have discovered what appears to be the first human gene mutation that causes extreme farsightedness. The researchers report that nanophthalmos, Greek for "dwarf eye," is a rare, potentially blinding disorder caused by an alteration in a gene called MFRP that helps control eye growth and…

  8. Implicit Processing of the Eyes and Mouth: Evidence from Human Electrophysiology.

    PubMed

    Pesciarelli, Francesca; Leo, Irene; Sarlo, Michela

    2016-01-01

    The current study examined the time course of implicit processing of distinct facial features and the associate event-related potential (ERP) components. To this end, we used a masked priming paradigm to investigate implicit processing of the eyes and mouth in upright and inverted faces, using a prime duration of 33 ms. Two types of prime-target pairs were used: 1. congruent (e.g., open eyes only in both prime and target or open mouth only in both prime and target); 2. incongruent (e.g., open mouth only in prime and open eyes only in target or open eyes only in prime and open mouth only in target). The identity of the faces changed between prime and target. Participants pressed a button when the target face had the eyes open and another button when the target face had the mouth open. The behavioral results showed faster RTs for the eyes in upright faces than the eyes in inverted faces, the mouth in upright and inverted faces. Moreover they also revealed a congruent priming effect for the mouth in upright faces. The ERP findings showed a face orientation effect across all ERP components studied (P1, N1, N170, P2, N2, P3) starting at about 80 ms, and a congruency/priming effect on late components (P2, N2, P3), starting at about 150 ms. Crucially, the results showed that the orientation effect was driven by the eye region (N170, P2) and that the congruency effect started earlier (P2) for the eyes than for the mouth (N2). These findings mark the time course of the processing of internal facial features and provide further evidence that the eyes are automatically processed and that they are very salient facial features that strongly affect the amplitude, latency, and distribution of neural responses to faces.

  9. Human Values in a Technological Age.

    ERIC Educational Resources Information Center

    Gorman, Michael

    2001-01-01

    Discusses technology and its effects on society and humans, particularly library and information technology. Highlights include the evolving history of technology; and values related to technology in libraries, including democracy, stewardship, service, intellectual freedom, privacy, literacy and learning, rationalism, and equity of access. (LRW)

  10. T CELL REPLICATIVE SENESCENCE IN HUMAN AGING

    PubMed Central

    Chou, Jennifer P.; Effros, Rita B.

    2013-01-01

    The decline of the immune system appears to be an intractable consequence of aging, leading to increased susceptibility to infections, reduced effectiveness of vaccination and higher incidences of many diseases including osteoporosis and cancer in the elderly. These outcomes can be attributed, at least in part, to a phenomenon known as T cell replicative senescence, a terminal state characterized by dysregulated immune function, loss of the CD28 costimulatory molecule, shortened telomeres and elevated production of pro-inflammatory cytokines. Senescent CD8 T cells, which accumulate in the elderly, have been shown to frequently bear antigen specificity against cytomegalovirus (CMV), suggesting that this common and persistent infection may drive immune senescence and result in functional and phenotypic changes to the T cell repertoire. Senescent T cells have also been identified in patients with certain cancers, autoimmune diseases and chronic infections, such as HIV. This review discusses the in vivo and in vitro evidence for the contribution of CD8 T cell replicative senescence to a plethora of age-related pathologies and a few possible therapeutic avenues to delay or prevent this differentiative end-state in T cells. The age-associated remodeling of the immune system, through accumulation of senescent T cells has far-reaching consequences on the individual and society alike, for the current healthcare system needs to meet the urgent demands of the increasing proportions of the elderly in the US and abroad. PMID:23061726

  11. On identification of human eye retinas by the covariance analysis of their digital images

    NASA Astrophysics Data System (ADS)

    Skeivalas, Jonas; Parseliunas, Eimuntas

    2013-07-01

    An identification of human eye retinas by applying the covariance function and wavelet theory is presented. The estimations of the autocovariance functions of the two digital images or single image are calculated according to random functions, based on the vectors created from the digital image pixels. The estimations of the pixel's vectors are calculated by spreading the pixel arrays of the digital images into single column. During the changing of the scale of the digital image, the wave frequencies of the colors of the single pixels are prekept, and the influence of the change of a scale in the procedures of the calculations of the covariance functions does not occur. The Red, Green, Blue (RGB) color model of the colors spectrum for the encoding of the digital images was applied. The influence of the RGB spectrum components and the tensor of colors on the estimations of the covariance functions were analyzed. The identity of the digital images is estimated by analysis of the changes of the correlation coefficient values in the corresponding diapason.

  12. Anterior corneal and internal contributions to peripheral aberrations of human eyes

    NASA Astrophysics Data System (ADS)

    Atchison, David A.

    2004-03-01

    Anterior corneal and internal component contributions to overall peripheral aberrations of five human eyes were determined, based on corneal topography and overall aberration measurements. Anterior corneal position and orientation (tilt) were referenced to the line of sight. Ray tracing was performed through the anterior cornea for 6-mm-diameter pupils at angles out to 40° in both the temporal and the nasal visual fields. In general, both component and overall Zernike aberrations were greater for the nasal than for the temporal visual field. In general, the anterior corneal aberration components were considerably higher than the overall aberrations across the visual field and were balanced to a considerable degree by the internal ocular aberration components. The component and overall levels of Zernike third-order aberrations showed linear trends away from the fixation axis, and the component levels of Zernike fourth-order aberrations showed quadratic trends away from the fixation axis. The second-order, but not higher-order, aberration components were susceptible to the choice of image radius of curvature, while disregarding corneal position and orientation affected second- and higher-order aberration components.

  13. Gaze control for an active camera system by modeling human pursuit eye movements

    NASA Astrophysics Data System (ADS)

    Toelg, Sebastian

    1992-11-01

    The ability to stabilize the image of one moving object in the presence of others by active movements of the visual sensor is an essential task for biological systems, as well as for autonomous mobile robots. An algorithm is presented that evaluates the necessary movements from acquired visual data and controls an active camera system (ACS) in a feedback loop. No a priori assumptions about the visual scene and objects are needed. The algorithm is based on functional models of human pursuit eye movements and is to a large extent influenced by structural principles of neural information processing. An intrinsic object definition based on the homogeneity of the optical flow field of relevant objects, i.e., moving mainly fronto- parallel, is used. Velocity and spatial information are processed in separate pathways, resulting in either smooth or saccadic sensor movements. The program generates a dynamic shape model of the moving object and focuses its attention to regions where the object is expected. The system proved to behave in a stable manner under real-time conditions in complex natural environments and manages general object motion. In addition it exhibits several interesting abilities well-known from psychophysics like: catch-up saccades, grouping due to coherent motion, and optokinetic nystagmus.

  14. Human discrimination of visual direction of motion with and without smooth pursuit eye movements

    NASA Technical Reports Server (NTRS)

    Krukowski, Anton E.; Pirog, Kathleen A.; Beutter, Brent R.; Brooks, Kevin R.; Stone, Leland S.

    2003-01-01

    It has long been known that ocular pursuit of a moving target has a major influence on its perceived speed (Aubert, 1886; Fleischl, 1882). However, little is known about the effect of smooth pursuit on the perception of target direction. Here we compare the precision of human visual-direction judgments under two oculomotor conditions (pursuit vs. fixation). We also examine the impact of stimulus duration (200 ms vs. 800 ms) and absolute direction (cardinal vs. oblique). Our main finding is that direction discrimination thresholds in the fixation and pursuit conditions are indistinguishable. Furthermore, the two oculomotor conditions showed oblique effects of similar magnitudes. These data suggest that the neural direction signals supporting perception are the same with or without pursuit, despite remarkably different retinal stimulation. During fixation, the stimulus information is restricted to large, purely peripheral retinal motion, while during steady-state pursuit, the stimulus information consists of small, unreliable foveal retinal motion and a large efference-copy signal. A parsimonious explanation of our findings is that the signal limiting the precision of direction judgments is a neural estimate of target motion in head-centered (or world-centered) coordinates (i.e., a combined retinal and eye motion signal) as found in the medial superior temporal area (MST), and not simply an estimate of retinal motion as found in the middle temporal area (MT).

  15. At what distance can the human eye detect a candle flame?

    NASA Astrophysics Data System (ADS)

    Krisciunas, Kevin; Carona, Don W.

    2015-01-01

    Various claims in television commercials and on the web suggest that the human eye can detect a candle flame 3.5 to 30 miles away. These claims are wrong, in large part because the background light of the sky is not taken into account. Even at a dark sky site, the V-band sky brightness on a moonless night varies from 21.0 to 22.0 mag/sec2 (136 to 54 nL) over the course of the 11 year solar cycle. One calculation on the web sets the background to 0.1 nL, as if one had a photographic dark room miles in extent. The most direct way to estimate the maximum distance at which a candle can be seen is to first determine how far one has to be situated from a candle such that it is comparable in brightness to a star of magnitude V = 0, such as Vega or Rigel. We find that this distance is 160 to 200 m. This can be double checked with a CCD imager. A candle flame equivalent to a star of magnitude V = 6 would be 15.85 times more distant, or roughly 2.85 km. We present the results of our own experiments and discuss formulations that take into account the background light.

  16. Wide field OCT based microangiography in living human eye (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Zhang, Qinqin; Chen, Chieh-Li; Chu, Zhongdi; Zhang, Anqi; An, Lin; Durbin, Mary; Sharma, Utkarsh; Rosenfeld, Philip J.; Wang, Ruikang K.

    2016-03-01

    To investigate the application of optical microangiography (OMAG) in living human eye. Patients with different macular diseases were recruited, including diabetic retinopathy (DR), geographic atrophy (GA), retinitis pigmentosa (RP), and venous occlusion, et al. Wide field OCT angiography images can be generated by montage scanning protocol based on the tracking system. OMAG algorithm based on complex differentiation was used to extract the blood flow and removed the bulk motion by 2D cross-correlation method. The 3D angiography was segmented into 3 layers in the retina and 2 layers in the choroid. The en-face maximum projection was used to obtain 2-dimensional angiograms of different layers coded with different colors. Flow and structure images were combined for cross-sectional view. En face OMAG images of different macular diseases showed a great agreement with FA. Meanwhile, OMAG gave more distinct vascular network visions that were less affected by hemorrhage and leakage. The MAs were observed in both superficial and middle retinal layers based on OMAG angiograms in different layers of DR patients. The contour line of FAZ was extracted as well, which can be quantitative the retinal diseases. For GA patient, the damage of RPE layer enhanced the penetration of light and enabled the acquisition of choriocapillaries and choroidal vessels. The wide field OMAG angiogram enabled the capability of capturing the entire geographic atrophy. OMAG provides depth-resolved information and detailed vascular images of DR and GA patients, providing a better visualization of vascular network compared to FA.

  17. Co-morbidity of depression and anxiety in common age-related eye diseases: a population-based study of 662 adults.

    PubMed

    Eramudugolla, Ranmalee; Wood, Joanne; Anstey, Kaarin J

    2013-01-01

    This study examined the prevalence of co-morbid age-related eye disease and symptoms of depression and anxiety in late life, and the relative roles of visual function and disease in explaining symptoms of depression and anxiety. A community-based sample of 662 individuals aged over 70 years was recruited through the electoral roll. Vision was measured using a battery of tests including high and low contrast visual acuity, contrast sensitivity, motion sensitivity, stereoacuity, Useful Field of View, and visual fields. Depression and anxiety symptoms were measured using the Goldberg scales. The prevalence of self-reported eye disease [cataract, glaucoma, or age-related macular degeneration (AMD)] in the sample was 43.4%, with 7.7% reporting more than one form of ocular pathology. Of those with no eye disease, 3.7% had clinically significant depressive symptoms. This rate was 6.7% among cataract patients, 4.3% among those with glaucoma, and 10.5% for AMD. Generalized linear models adjusting for demographics, general health, treatment, and disability examined self-reported eye disease and visual function as correlates of depression and anxiety. Depressive symptoms were associated with cataract only, AMD, comorbid eye diseases and reduced low contrast visual acuity. Anxiety was significantly associated with self-reported cataract, and reduced low contrast visual acuity, motion sensitivity and contrast sensitivity. We found no evidence for elevated rates of depressive or anxiety symptoms associated with self-reported glaucoma. The results support previous findings of high rates of depression and anxiety in cataract and AMD, and in addition show that mood and anxiety are associated with objective measures of visual function independently of self-reported eye disease. The findings have implications for the assessment and treatment of mental health in the context of late-life visual impairment.

  18. Co-morbidity of depression and anxiety in common age-related eye diseases: a population-based study of 662 adults

    PubMed Central

    Eramudugolla, Ranmalee; Wood, Joanne; Anstey, Kaarin J.

    2013-01-01

    This study examined the prevalence of co-morbid age-related eye disease and symptoms of depression and anxiety in late life, and the relative roles of visual function and disease in explaining symptoms of depression and anxiety. A community-based sample of 662 individuals aged over 70 years was recruited through the electoral roll. Vision was measured using a battery of tests including high and low contrast visual acuity, contrast sensitivity, motion sensitivity, stereoacuity, Useful Field of View, and visual fields. Depression and anxiety symptoms were measured using the Goldberg scales. The prevalence of self-reported eye disease [cataract, glaucoma, or age-related macular degeneration (AMD)] in the sample was 43.4%, with 7.7% reporting more than one form of ocular pathology. Of those with no eye disease, 3.7% had clinically significant depressive symptoms. This rate was 6.7% among cataract patients, 4.3% among those with glaucoma, and 10.5% for AMD. Generalized linear models adjusting for demographics, general health, treatment, and disability examined self-reported eye disease and visual function as correlates of depression and anxiety. Depressive symptoms were associated with cataract only, AMD, comorbid eye diseases and reduced low contrast visual acuity. Anxiety was significantly associated with self-reported cataract, and reduced low contrast visual acuity, motion sensitivity and contrast sensitivity. We found no evidence for elevated rates of depressive or anxiety symptoms associated with self-reported glaucoma. The results support previous findings of high rates of depression and anxiety in cataract and AMD, and in addition show that mood and anxiety are associated with objective measures of visual function independently of self-reported eye disease. The findings have implications for the assessment and treatment of mental health in the context of late-life visual impairment. PMID:24106477

  19. Apnea-induced rapid eye movement sleep disruption impairs human spatial navigational memory.

    PubMed

    Varga, Andrew W; Kishi, Akifumi; Mantua, Janna; Lim, Jason; Koushyk, Viachaslau; Leibert, David P; Osorio, Ricardo S; Rapoport, David M; Ayappa, Indu

    2014-10-29

    Hippocampal electrophysiology and behavioral evidence support a role for sleep in spatial navigational memory, but the role of particular sleep stages is less clear. Although rodent models suggest the importance of rapid eye movement (REM) sleep in spatial navigational memory, a similar role for REM sleep has never been examined in humans. We recruited subjects with severe obstructive sleep apnea (OSA) who were well treated and adherent with continuous positive airway pressure (CPAP). Restricting CPAP withdrawal to REM through real-time monitoring of the polysomnogram provides a novel way of addressing the role of REM sleep in spatial navigational memory with a physiologically relevant stimulus. Individuals spent two different nights in the laboratory, during which subjects performed timed trials before and after sleep on one of two unique 3D spatial mazes. One night of sleep was normally consolidated with use of therapeutic CPAP throughout, whereas on the other night, CPAP was reduced only in REM sleep, allowing REM OSA to recur. REM disruption via this method caused REM sleep reduction and significantly fragmented any remaining REM sleep without affecting total sleep time, sleep efficiency, or slow-wave sleep. We observed improvements in maze performance after a night of normal sleep that were significantly attenuated after a night of REM disruption without changes in psychomotor vigilance. Furthermore, the improvement in maze completion time significantly positively correlated with the mean REM run duration across both sleep conditions. In conclusion, we demonstrate a novel role for REM sleep in human memory formation and highlight a significant cognitive consequence of OSA.

  20. Infrared Eye: Prototype 2

    DTIC Science & Technology

    2016-06-07

    The Infrared (IR) Eye was developed with support from the National Search and Rescue Secretariat (NSS), in view of improving the efficiency of...airborne search-and rescue operations. The IR Eye concept is based on the human eye and uses simultaneously two fields of view to optimize area coverage and...within the wide field and slaved to the operator’s line of sight by means of an eye -tracking system. The images from both cameras are fused and shown

  1. A gene for the mouse pink-eyed dilution locus and for human type II oculocutaneous albinism.

    PubMed

    Rinchik, E M; Bultman, S J; Horsthemke, B; Lee, S T; Strunk, K M; Spritz, R A; Avidano, K M; Jong, M T; Nicholls, R D

    1993-01-07

    The mouse pink-eyed dilution (p) locus on chromosome 7 is associated with defects of skin, eye and coat pigmentation. Mutations at p cause a reduction of eumelanin (black-brown) pigment and altered morphology of black pigment granules (eumelanosomes), but have little effect on pheomelanin (yellow-red) pigment. We show here that the human complementary DNA DN10, linked to the p locus in mice, identifies the human homologue (P) of the mouse p gene, and appears to encode an integral membrane transporter protein. The expression pattern of this gene in various p mutant mice correlates with the pigmentation phenotype; moreover, an abnormally sized messenger RNA is detected in one mutant, p(un), which reverts to the normal size in p(un) revertants. The human P gene corresponds to the D15S12 locus within the chromosome segment 15q11-q13, which is typically deleted in patients with Prader-Willi and Angelman syndrome (see ref. 5 for review). These disorders are phenotypically distinct, depending on the parent of origin of the deleted chromosome, but both syndromes are often associated with hypopigmentation of the skin, hair and eyes (see ref. 8 for review), and deletion of the P gene may be responsible for this hypopigmentation. In addition, we report a mutation in both copies of the human P gene in one case of tyrosinase-positive (type II) oculocutaneous albinism, recently linked to 15q11-q13 (ref. 9).

  2. Characterization of the vitreous body of the human eye using a cyanine dye as a spectral and fluorescent probe

    NASA Astrophysics Data System (ADS)

    Panova, Ina G.; Tatikolov, Alexander S.

    2009-02-01

    We used one of cyanine dyes as a spectral and fluorescent probe in the study of the composition of the extracellular matrix of the human eye (its vitreous body). Owing to the unique ability of the dye to bind to collagens and human serum albumin, we revealed the simultaneous presence of both types of biomacromolecules in the vitreous body. The formation of the dye complex with human serum albumin leads to appearance of a long-wavelength absorption band (~612 nm) and a steep rise of fluorescence, whereas in the presence of collagens the dye forms J-aggregates with a longer-wavelength absorption band (640-660 nm) and moderate fluorescence. In this work we studied the composition of the human fetus vitreous body and its dynamics from 9 to 31 gestation weeks. On the basis of the data obtained by this method, we may assume that albumin, being a carrier protein, probably provides the vitreous body and surrounding tissues with necessary growth factors, hormones, lipids, vitamins, and some other biomolecules. The data show that the dye is promising not only for study of albumin functions in eye development, but also for characterization of some eye diseases and for analysis of other extracellular media.

  3. Ray tracing in the human eye: measurement and modeling of optical aberrations

    NASA Astrophysics Data System (ADS)

    Navarro, Rafael M.; Rodriguez, P.; Gonzalez, L.; Aporta, J.; Hdez-Matamoros, J. L.

    2004-10-01

    The rapid development of cataract and refractive surgery requires new methods to assess the optical quality of the eye. The optimized optical design of custom treatments to improve the optical performance of individual eyes requires, at least, to have the technology to (1) measure the geometry (anatomy) of the optics of the eye; (2) measure the optical performance (refractive state, aberrations, etc); (3) Build a custom optical and anatomical model of the individual eye to treat; (4) Optimal design of custom treatments. In this communication we will present the work carried out by our group to develop methods for measuring and modeling the optical performance of the eye. In particular, we will focus, first, on the Laser Ray Tracing method that we have developed to measure the optical aberrations of the eye, as a physical in vivo implementation of the classical numerical ray tracing used by optical designers; and second, on the development of custom optical models of the eye to perform that numerical ray tracing which predicts with a high fidelity experimental measurements. The methods developed have been applied to design both custom surgery and optical aids to improve optical performance.

  4. Heat waves, aging, and human cardiovascular health.

    PubMed

    Kenney, W Larry; Craighead, Daniel H; Alexander, Lacy M

    2014-10-01

    This brief review is based on a President's Lecture presented at the Annual Meeting of the American College of Sports Medicine in 2013. The purpose of this review was to assess the effects of climate change and consequent increases in environmental heat stress on the aging cardiovascular system. The earth's average global temperature is slowly but consistently increasing, and along with mean temperature changes come increases in heat wave frequency and severity. Extreme passive thermal stress resulting from prolonged elevations in ambient temperature and prolonged physical activity in hot environments creates a high demand on the left ventricle to pump blood to the skin to dissipate heat. Even healthy aging is accompanied by altered cardiovascular function, which limits the extent to which older individuals can maintain stroke volume, increase cardiac output, and increase skin blood flow when exposed to environmental extremes. In the elderly, the increased cardiovascular demand during heat waves is often fatal because of increased strain on an already compromised left ventricle. Not surprisingly, excess deaths during heat waves 1) occur predominantly in older individuals and 2) are overwhelmingly cardiovascular in origin. Increasing frequency and severity of heat waves coupled with a rapidly growing at-risk population dramatically increase the extent of future untoward health outcomes.

  5. Age effects on B cells and humoral immunity in humans

    PubMed Central

    Frasca, Daniela; Diaz, Alain; Romero, Maria; Landin, Ana Marie; Blomberg, Bonnie B

    2010-01-01

    Both humoral and cellular immune responses are impaired in aged individuals, leading to decreased vaccine responses. Although T cell defects occur, defects in B cells play a significant role in age-related humoral immune changes. The ability to undergo class switch recombination (CSR), the enzyme for CSR, AID (activation-induced cytidine deaminase) and the transcription factor E47 are all decreased in aged stimulated B cells. We here present an overview of age-related changes in human B cell markers and functions, and also discuss some controversies in the field of B cell aging. PMID:20728581

  6. Dependences between kinetics of the human eye pupil and blood pulsation

    NASA Astrophysics Data System (ADS)

    Szmigiel, Marta A.; Kasprzak, Henryk; Klysik, Anna

    2016-09-01

    The study presents measurement and numerical analysis of time variability of the eye pupil geometry and its position, as well as their correlations with blood pulsation. The image of the eye pupil was recorded by use of the fast CCD camera with 200 fps rates. Blood pulsation was synchronously recorded by use of pulse transducer with the sampling frequency of 200 Hz. Each single image from a sequence was numerically processed. Contour of the eye pupil was approximated, and its selected geometrical parameters as well as center positions were calculated. Spectral and coherence analysis of time variability of calculated pupil parameters and blood pulsation were determined.

  7. Effect of topical isopropyl unoprostone on macular atrophy progression in eyes with exudative age-related macular degeneration

    PubMed Central

    Shiragami, Chieko; Miyake, Masahiro; Fujiwara, Atsushi; Morizane, Yuki; Tsujikawa, Akitaka; Yamashita, Ayana; Shiraga, Fumio

    2017-01-01

    Abstract Background: To evaluate the efficacy and safety of topical isopropyl unoprostone (IU) in treating macular atrophy in age-related macular degeneration (AMD) patients. Methods: Fifty-two AMD patients with macular atrophy were included and randomly assigned (1:1) to the treatment (topical 0.15% IU) or placebo group. Subjects used study eye drops 3 times a day for 54 weeks. The macular atrophy was documented on fundus autofluorescence photographs and measured using RegionFinder. The enlargement rate of macular atrophy and the changes in visual acuity were examined statistically between baseline and 54 weeks. Results: Forty-eight subjects were included in the analyses because 4 subjects withdrew from the study. The differences between the IU and placebo groups in mean and median area of macular atrophy were not statistically significant at baseline. The baseline median lesion size of macular atrophy was 2.33 mm2 in the IU group and 1.63 mm2 in the placebo group (P = 0.51). The intergroup difference in the enlargement ratio of macular atrophy (21 ± 15% in the IU group and 111 ± 96% in the placebo group) was statistically significant (P < 0.001). Additionally, visual acuity tended to improve over baseline in the IU group. No serious adverse events were observed. Conclusions: Topical IU therapy is safe and effective for treating macular atrophy in AMD patients. PMID:28328847

  8. Sleep spindles and rapid eye movement sleep as predictors of next morning cognitive performance in healthy middle-aged and older participants.

    PubMed

    Lafortune, Marjolaine; Gagnon, Jean-François; Martin, Nicolas; Latreille, Véronique; Dubé, Jonathan; Bouchard, Maude; Bastien, Célyne; Carrier, Julie

    2014-04-01

    Spindles and slow waves are hallmarks of non-rapid eye movement sleep. Both these oscillations are markers of neuronal plasticity, and play a role in memory and cognition. Normal ageing is associated with spindle and slow wave decline and cognitive changes. The present study aimed to assess whether spindle and slow wave characteristics during a baseline night predict cognitive performance in healthy older adults the next morning. Specifically, we examined performance on tasks measuring selective and sustained visual attention, declarative verbal memory, working memory and verbal fluency. Fifty-eight healthy middle-aged and older adults (aged 50-91 years) without sleep disorders underwent baseline polysomnographic sleep recording followed by neuropsychological assessment the next morning. Spindles and slow waves were detected automatically on artefact-free non-rapid eye movement sleep electroencephalogram. All-night stage N2 spindle density (no./min) and mean frequency (Hz) and all-night non-rapid eye movement sleep slow wave density (no./min) and mean slope (μV/s) were analysed. Pearson's correlations were performed between spindles, slow waves, polysomnography and cognitive performance. Higher spindle density predicted better performance on verbal learning, visual attention and verbal fluency, whereas spindle frequency and slow wave density or slope predicted fewer cognitive performance variables. In addition, rapid eye movement sleep duration was associated with better verbal learning potential. These results suggest that spindle density is a marker of cognitive functioning in older adults and may reflect neuroanatomic integrity. Rapid eye movement sleep may be a marker of age-related changes in acetylcholine transmission, which plays a role in new information encoding.

  9. Eye pain

    MedlinePlus

    Ophthalmalgia; Pain - eye ... Pain in the eye can be an important symptom of a health problem. Make sure you tell your health care provider if you have eye pain that does not go away. Tired eyes or ...

  10. Healthy Eyes

    MedlinePlus

    ... of this page please turn Javascript on. Healthy Eyes Maintaining Your Vision Click for more information Taking ... have a comprehensive dilated eye exam. Who Performs Eye Exams? An eye care professional is either an ...

  11. Functional visual improvement after cataract surgery in eyes with age-related macular degeneration; Results of the Ophthalmic Surgical Outcomes Data (OSOD) Project.

    PubMed

    Stock, Michael V; Vollman, David E; Baze, Elizabeth F; Chomsky, Amy S; Daly, Mary K; Lawrence, Mary

    2015-03-03

    Purpose: To determine if cataract surgery on eyes with age-related macular degeneration (AMD) confers as much functional visual improvement as on eyes without retinal pathology. Methods: This is a retrospective analysis of 4,924 cataract surgeries from the VA Ophthalmic Surgical Outcomes Data Project. We included cases of eyes with AMD which had both preoperative and postoperative NEI-VFQ-25 questionnaires submitted and compared their outcomes to controls without retinal pathology. We excluded patients with other retinal pathologies. The analyses compared changes in visual acuity and overall functional visual improvement and its subscales. Results: Preoperative and postoperative questionnaires were submitted by 58.3% of AMD and 63.8% of controls. Analysis of overall score showed that cataract surgery on eyes with AMD led to increased visual function (13.8± 2.4 NEI-VFQ units, P<0.0001); however, increases were significantly less when compared to controls (-6.4± 2.9 NEI-VFQ units, P<0.0001). Preoperative best corrected visual acuity (preBCVA) in AMD was predictive of postoperative visual function (r=-0.38, P<0.0001). In controls, postoperative visual function was only weakly associated with preBCVA (r=-0.075, P=0.0002). AMD patients with vision of 20/40 or better had overall outcomes similar to controls (-2.2± 4.7 NEI-VFQ units, P=0.37). Conclusions: Cataract surgery on eyes with AMD offers an increase in functional visual improvement; however, the amount of benefit is associated with the eye's preBCVA. For eyes with preBCVA ≥20/40, the improvement is similar to that of patients without retinal pathology. However, if preBCVA is <20/40, the amount of improvement was shown to be significantly less and decreased with decreasing preBCVA.

  12. Optical Coherence Tomography Based Observation of Natural History of Drusenoid Lesion in Eyes with Dry Age-Related Macular Degeneration

    PubMed Central

    Ouyang, Yanling; Heussen, Florian M.; Hariri, Amirhossein; Keane, Pearse A.; Sadda, Srinivas R.

    2013-01-01

    Purpose To use spectral domain optical coherence tomography (SD-OCT) to investigate risk factors predictive for development of atrophy of drusenoid lesions (drusen and drusenoid pigment epithelium detachment) in eyes with non-neovascular age-related macular degeneration (NNVAMD). Design Cohort study. Participants Forty-one eyes from 29 patients with NNVAMD. Methods Patients with NNVAMD who underwent registered SD-OCT imaging over a minimum period of six months, were reviewed. Drusenoid lesions that accompanied by new atrophy onset at 6 month or last follow up were further analyzed. Detailed lesion change was described throughout the study period. Odds ratios (OR) and risk for new local atrophy onset were calculated. Main Outcomes Measures Drusenoid lesion features and longitudinal changes in features including maximum lesion height, lesion diameter, lesion internal reflectivity, presence and extent of overlying intraretinal hyperreflective features (HRF). Subfoveal choroidal thickness and choroidal thickness measured below each lesion. Results 543 individual drusenoid lesions were identified at baseline, while 28 lesions developed during follow-up. The mean follow-up time was 21.3 ± 8.6 (range, 6-44) months. 3.2% (18/571) of drusenoid lesions progressed to atrophy within 18.3±9.5 (range: 5-28) months of initial visit. Drusenoid lesions with heterogenous internal reflectivity were significantly associated with new atrophy onset at 6 month (OR=5.614, 95% confidence interval (CI) =1.277-24.673) and new atrophy onset at last follow up (OR=7.005, CI=2.300-21.337). Lesions with presence of HRF also were significant predictors for new atrophy onset at 6 month (OR=30.161, CI=4.766-190.860) and at last follow up (OR=11.211, CI=2.513-50.019). Lesions with a baseline maximum height over 80 microns or choroidal thickness less than 135 microns showed positive association with the new atrophy onset at last follow up (OR=7.886, CI=2.105-29.538 and OR=3.796, CI=1

  13. Will the Affordable Care Act (ACA) Improve Racial/Ethnic Disparity of Eye Examination Among US Working-Age Population with Diabetes?

    PubMed

    Shi, Qian; Fonseca, Vivian; Krousel-Wood, Marie; Zhao, Yingnan; Nellans, Frank P; Luo, Qingyang; Shi, Lizheng

    2016-07-01

    This study aimed to examine the racial/ethnic disparity of eye examination rates among US adults with diabetes before and after the ACA. Working-age adults (18-64 years) with diabetes for years 2014-2017 were simulated by bootstrapping from the working-age diabetes patient sample of Medical Expenditure Panel Survey (MEPS) Household Component 2011. Insurance coverage rates were separately predicted for each racial/ethnic group based on the Congressional Budgeting Office (CBO) report in 2014 and the proportions of Medicaid eligibility. Eye examination rates were weighted to national estimates and compared between racial/ethnic groups. Confidence intervals were estimated using the bootstrap percentile method. Health insurance coverage after the ACA is projected to increase from 90.23 % in 2011 to 98.33 % in 2014 among non-Hispanic Whites (NHW), reaching 98.96 % in 2017. Minorities are forecasted to have about 15 % expansion of insurance coverage from 2011 (80.65 %) to 2014 (96.00 %), reaching 97.25 % in 2017. In 2011, 63.01 % of NHW had eye examinations with forecasted increase to 65.83 % in 2014 and 66.05 % in 2017, while the eye examination rate in the minorities will increase from 55.75 % in 2011 to 59.23 % in 2014 and remain at 59.48 % in 2017. Therefore, racial disparity in eye examination rates is forecasted to persist (ranging from 6.57 % in 2017 to 6.69 % in 2016). The ACA is projected to improve the eye examination rate along with the expansion in insurance coverage. Although predicted racial/ethnic disparities will improve, some differences will persist. Comprehensive strategies need to be developed to eliminate the disparity.

  14. Spectrum of congenital defects of the eye and its adnexia in the pediatric age group; experience at a tertiary facility in Nigeria.

    PubMed

    Adekoya, Bola J; Balogun, Modupe M; Balogun, Bola G; Ngwu, Rosemary A

    2015-06-01

    The aim of this study was to investigate the types and presentation pattern of congenital defects of the eye and adnexia in our center. This is a retrospective review of congenital defects of the eye and adnexia over a 20-month period at a tertiary referral center in Lagos, Nigeria. Records were analyzed for age at presentation, laterality, gender, vision assessment, and type(s) of abnormality. Out of 412 pediatric patients, 40 (9.7 %) were seen to have congenital abnormality of the eye and/or its adnexia during the study period. There were 17 (42.5 %) males. Twelve patients (30.0 %) presented with involvement of the right eyes, nine (22.5 %) with left eyes, while 19 (47.5 %) had bilateral involvement. Twenty-eight patients (70.0 %) were aged 1 year or less at the time of presentation. A total of 69 entities were recognized as some children had two or more malformations. The common congenital defects identified were cataract (39.1 %), ptosis (17.4 %), glaucoma (8.7 %), and cornea opacity (7.2 %). Other less common congenital defects include: microphthalmos, anophthalmos, coloboma (lid and iris), dermoid cyst, and aniridia. All of the patients with available visual acuity documentation had visual impairment. A high proportion of the patients were lost to follow-up. Cataract, ptosis, and glaucoma were the commonest congenital defects of the eye and adnexia in our center and were associated with visual impairments. The significant loss of the patients during follow-up needs urgent investigation and attention to forestall this trend.

  15. Real Time Eye Tracking and Hand Tracking Using Regular Video Cameras for Human Computer Interaction

    DTIC Science & Technology

    2011-01-01

    19 3.4 Result of Software Usage The system is set up with a display screen or projector , and two cameras installed in...structure and 3D file/ scene visualization tool) by utilizing multi-modal modalities, including head, pose, eye, expressions, hand gesture, body gesture...Dera, T., Bardins, S., Schneider, E., and Brandt, T., “ Mobile Eye Tracking as a Basis for Real-Time Control of a Gaze Driven Head-Mounted Video Camera

  16. Uniquely Human Self-Control Begins at School Age

    ERIC Educational Resources Information Center

    Herrmann, Esther; Misch, Antonia; Hernandez-Lloreda, Victoria; Tomasello, Michael

    2015-01-01

    Human beings have remarkable skills of self-control, but the evolutionary origins of these skills are unknown. Here we compare children at 3 and 6 years of age with one of humans' two nearest relatives, chimpanzees, on a battery of reactivity and self-control tasks. Three-year-old children and chimpanzees were very similar in their abilities to…

  17. A novel EOG/EEG hybrid human-machine interface adopting eye movements and ERPs: application to robot control.

    PubMed

    Ma, Jiaxin; Zhang, Yu; Cichocki, Andrzej; Matsuno, Fumitoshi

    2015-03-01

    This study presents a novel human-machine interface (HMI) based on both electrooculography (EOG) and electroencephalography (EEG). This hybrid interface works in two modes: an EOG mode recognizes eye movements such as blinks, and an EEG mode detects event related potentials (ERPs) like P300. While both eye movements and ERPs have been separately used for implementing assistive interfaces, which help patients with motor disabilities in performing daily tasks, the proposed hybrid interface integrates them together. In this way, both the eye movements and ERPs complement each other. Therefore, it can provide a better efficiency and a wider scope of application. In this study, we design a threshold algorithm that can recognize four kinds of eye movements including blink, wink, gaze, and frown. In addition, an oddball paradigm with stimuli of inverted faces is used to evoke multiple ERP components including P300, N170, and VPP. To verify the effectiveness of the proposed system, two different online experiments are carried out. One is to control a multifunctional humanoid robot, and the other is to control four mobile robots. In both experiments, the subjects can complete tasks effectively by using the proposed interface, whereas the best completion time is relatively short and very close to the one operated by hand.

  18. Epigenetic Mechanisms of the Aging Human Retina.

    PubMed

    Pennington, Katie L; DeAngelis, Margaret M

    2015-01-01

    Degenerative retinal diseases, such as glaucoma, age-related macular degeneration, and diabetic retinopathy, have complex etiologies with environmental, genetic, and epigenetic contributions to disease pathology. Much effort has gone into elucidating both the genetic and the environmental risk factors for these retinal diseases. However, little is known about how these genetic and environmental risk factors bring about molecular changes that lead to pathology. Epigenetic mechanisms have received extensive attention of late for their promise of bridging the gap between environmental exposures and disease development via their influence on gene expression. Recent studies have identified epigenetic changes that associate with the incidence and/or progression of each of these retinal diseases. Therefore, these epigenetic modifications may be involved in the underlying pathological mechanisms leading to blindness. Further genome-wide epigenetic studies that incorporate well-characterized tissue samples, consider challenges similar to those relevant to gene expression studies, and combine the genome-wide epigenetic data with genome-wide genetic and expression data to identify additional potentially causative agents of disease are needed. Such studies will allow researchers to create much-needed therapeutics to prevent and/or intervene in disease progression. Improved therapeutics will greatly enhance the quality of life and reduce the burden of disease management for millions of patients living with these potentially blinding conditions.

  19. Epigenetic Mechanisms of the Aging Human Retina

    PubMed Central

    Pennington, Katie L.; DeAngelis, Margaret M.

    2015-01-01

    Degenerative retinal diseases, such as glaucoma, age-related macular degeneration, and diabetic retinopathy, have complex etiologies with environmental, genetic, and epigenetic contributions to disease pathology. Much effort has gone into elucidating both the genetic and the environmental risk factors for these retinal diseases. However, little is known about how these genetic and environmental risk factors bring about molecular changes that lead to pathology. Epigenetic mechanisms have received extensive attention of late for their promise of bridging the gap between environmental exposures and disease development via their influence on gene expression. Recent studies have identified epigenetic changes that associate with the incidence and/or progression of each of these retinal diseases. Therefore, these epigenetic modifications may be involved in the underlying pathological mechanisms leading to blindness. Further genome-wide epigenetic studies that incorporate well-characterized tissue samples, consider challenges similar to those relevant to gene expression studies, and combine the genome-wide epigenetic data with genome-wide genetic and expression data to identify additional potentially causative agents of disease are needed. Such studies will allow researchers to create much-needed therapeutics to prevent and/or intervene in disease progression. Improved therapeutics will greatly enhance the quality of life and reduce the burden of disease management for millions of patients living with these potentially blinding conditions. PMID:26966390

  20. Epigenetic Age Acceleration Assessed With Human White-Matter Images.

    PubMed

    Hodgson, Karen; Carless, Melanie A; Kulkarni, Hemant; Curran, Joanne E; Sprooten, Emma; Knowles, Emma E; Mathias, Samuel; Göring, Harald Hh; Yao, Nailin; Olvera, Rene L; Fox, Peter T; Almasy, Laura; Duggirala, Ravi; Blangero, John; Glahn, David C

    2017-04-06

    The accurate estimation of age using methylation data has proved a useful and heritable biomarker, with acceleration in epigenetic age predicting a number of age-related phenotypes. Measures of white matter integrity in the brain are also heritable and highly sensitive to both normal and pathological aging processes across adulthood. We consider the phenotypic and genetic interrelationships between epigenetic age acceleration and white matter integrity in humans. Our goal was to investigate processes that underlie inter-individual variability in age-related changes in the brain. Using blood taken from a Mexican-American extended pedigree sample (n=628; age=23.28-93.11 years), epigenetic age was estimated using the method developed by S. Horvath (2013). For n=376 individuals, DTI scans were also available. The interrelationship between epigenetic age acceleration and global white matter integrity were investigated with variance decomposition methods. To test for neuroanatomical specificity, 16 specific tracts were additionally considered. We observed negative phenotypic correlations between epigenetic age acceleration and global white matter tract integrity (ρpheno=-0.119, p=0.028), with evidence of shared genetic (ρgene=-0.463, p=0.013) but not environmental influences. Negative phenotypic and genetic correlations with age acceleration were also seen for a number of specific white matter tracts, along with additional negative phenotypic correlations between granulocyte abundance and white matter integrity. These findings that increased acceleration in epigenetic age in peripheral blood correlates with reduced white matter integrity in the brain, and shares common genetic influences. provide a window into the neurobiology of aging processes within the brain and a potential biomarker of normal and pathological brain aging.SIGNIFICANCE STATEMENTEpigenetic measures can be used to predict age with a high degree of accuracy and so capture acceleration in biological age

  1. The many faces of human ageing: toward a psychological culture of old age.

    PubMed

    Baltes, P B

    1991-11-01

    In an effort to distil major findings about the nature of human ageing, seven propositions are presented as a guiding frame of reference. This propositional framework is then used to specify some conditions for a positive culture of old age and to advance one possible model of good psychological ageing. This model focuses on the dynamic interplay between three processes: selection, optimization, and compensation. The model is universal in its basic features, but at the same time emphasizes individual variations in phenotypic manifestation.

  2. Physiology and pathology of eye-head coordination.

    PubMed

    Proudlock, Frank Antony; Gottlob, Irene

    2007-09-01

    Human head movement control can be considered as part of the oculomotor system since the control of gaze involves coordination of the eyes and head. Humans show a remarkable degree of flexibility in eye-head coordination strategies, nonetheless an individual will often demonstrate stereotypical patterns of eye-head behaviour for a given visual task. This review examines eye-head coordination in laboratory-based visual tasks, such as saccadic gaze shifts and combined eye-head pursuit, and in common tasks in daily life, such as reading. The effect of the aging process on eye-head coordination is then reviewed from infancy through to senescence. Consideration is also given to how pathology can affect eye-head coordination from the lowest through to the highest levels of oculomotor control, comparing conditions as diverse as eye movement restrictions and schizophrenia. Given the adaptability of the eye-head system we postulate that this flexible system is under the control of the frontal cortical regions, which assist in planning, coordinating and executing behaviour. We provide evidence for this based on changes in eye-head coordination dependant on the context and expectation of presented visual stimuli, as well as from changes in eye-head coordination caused by frontal lobe dysfunction.

  3. Surface Wave Elastometry of the Cornea in Porcine and Human Donor Eyes

    PubMed Central

    Dupps, William J.; Netto, Marcelo V.; Herekar, Satish; Krueger, Ronald R.

    2007-01-01

    PURPOSE To introduce a nondestructive technique for characterization of corneal stiffness, determine measurement precision, and investigate comparative stiffness values along central, radial, and circumferential vectors in porcine corneas. The effects of epithelial debridement, relaxing incisions, and crosslink-mediated stiffening on surface wave velocity are also studied. METHODS A handheld prototype system was used to measure ultrasound surface wave propagation time between two fixed-distance transducers along a ten-position map. Repeatability was assessed with replicate measurements in 6 porcine corneas. In 12 porcine globes with controlled intraocular pressure (IOP), serial measurements were performed before and after epithelial removal, then after 250- and 750-μm-deep relaxing incisions. In human globes with constant intravitreal pressure, central wave velocity and transcorneal IOP measurements were compared before and after collagen cross-linking. RESULTS Measurement repeatability across all regions was between 2.2% and 8.1%. Epithelial removal resulted in increases in measured stiffness in 67% of eyes, but statistical power was insufficient to detect a systematic change. Wave velocity across a central incision decreased significantly after 250-μm keratotomy (P<.001), but did not undergo a significant further decrease with deeper keratotomy. Meridional stiffness changes consistent with coupling effects were detected after keratotomy. Surface wave velocity and transcorneal IOP measurements increased markedly after collagen cross-linking despite maintenance of a constant IOP. CONCLUSIONS Handheld corneal elastometry provides a repeatable measure of regional stiffness changes after relaxing incisions and collagen cross-linking in in vitro experiments. Surface wave elastometry allows focal assessment of corneal biomechanical properties that are relevant in refractive surgery, ectatic disease, and glaucoma. PMID:17269246

  4. Shared Sensory Estimates for Human Motion Perception and Pursuit Eye Movements

    PubMed Central

    Mukherjee, Trishna; Battifarano, Matthew; Simoncini, Claudio

    2015-01-01

    Are sensory estimates formed centrally in the brain and then shared between perceptual and motor pathways or is centrally represented sensory activity decoded independently to drive awareness and action? Questions about the brain's information flow pose a challenge because systems-level estimates of environmental signals are only accessible indirectly as behavior. Assessing whether sensory estimates are shared between perceptual and motor circuits requires comparing perceptual reports with motor behavior arising from the same sensory activity. Extrastriate visual cortex both mediates the perception of visual motion and provides the visual inputs for behaviors such as smooth pursuit eye movements. Pursuit has been a valuable testing ground for theories of sensory information processing because the neural circuits and physiological response properties of motion-responsive cortical areas are well studied, sensory estimates of visual motion signals are formed quickly, and the initiation of pursuit is closely coupled to sensory estimates of target motion. Here, we analyzed variability in visually driven smooth pursuit and perceptual reports of target direction and speed in human subjects while we manipulated the signal-to-noise level of motion estimates. Comparable levels of variability throughout viewing time and across conditions provide evidence for shared noise sources in the perception and action pathways arising from a common sensory estimate. We found that conditions that create poor, low-gain pursuit create a discrepancy between the precision of perception and that of pursuit. Differences in pursuit gain arising from differences in optic flow strength in the stimulus reconcile much of the controversy on this topic. PMID:26041919

  5. Glycosaminoglycans in the Human Cornea: Age-Related Changes

    PubMed Central

    Pacella, Elena; Pacella, Fernanda; De Paolis, Giulio; Parisella, Francesca Romana; Turchetti, Paolo; Anello, Giulia; Cavallotti, Carlo

    2015-01-01

    AIM To investigate possible age-related changes in glycosaminoglycans (GAGs) in the human cornea. The substances today called GAGs were previously referred to as mucopolysaccharides. METHODS Samples of human cornea were taken from 12 younger (age 21 ± 1.2) and 12 older (age 72 ± 1.6) male subjects. Samples were weighed, homogenized, and used for biochemical and molecular analyses. All the quantitative results were statistically analyzed. RESULTS The human cornea appears to undergo age-related changes, as evidenced by our biochemical and molecular results. The total GAG and hyaluronic acid counts were significantly higher in the younger subjects than in the older subjects. The sulfated heavy GAGs, such as chondroitin, dermatan, keratan, and heparan sulfate, were lower in the younger subjects than in the older subjects. DISCUSSION GAGs of the human cornea undergo numerous age-related changes. Their quantity is significantly altered in the elderly in comparison with younger subjects. GAGs play an important role in age-related diseases of the human cornea. PMID:25674020

  6. Age estimation based on aspartic acid racemization in human sclera.

    PubMed

    Klumb, Karolin; Matzenauer, Christian; Reckert, Alexandra; Lehmann, Klaus; Ritz-Timme, Stefanie

    2016-01-01

    Age estimation based on racemization of aspartic acid residues (AAR) in permanent proteins has been established in forensic medicine for years. While dentine is the tissue of choice for this molecular method of age estimation, teeth are not always available which leads to the need to identify other suitable tissues. We examined the suitability of total tissue samples of human sclera for the estimation of age at death. Sixty-five samples of scleral tissue were analyzed. The samples were hydrolyzed and after derivatization, the extent of aspartic acid racemization was determined by gas chromatography. The degree of AAR increased with age. In samples from younger individuals, the correlation of age and D-aspartic acid content was closer than in samples from older individuals. The age-dependent racemization in total tissue samples proves that permanent or at least long-living proteins are present in scleral tissue. The correlation of AAR in human sclera and age at death is close enough to serve as basis for age estimation. However, the precision of age estimation by this method is lower than that of age estimation based on the analysis of dentine which is due to molecular inhomogeneities of total tissue samples of sclera. Nevertheless, the approach may serve as a valuable alternative or addition in exceptional cases.

  7. Instrumental evaluation of anti-aging effects of cosmetic formulations containing palmitoyl peptides, Silybum marianum seed oil, vitamin E and other functional ingredients on aged human skin

    PubMed Central

    Hahn, Hyung Jin; Jung, Ho Jung; Schrammek-Drusios, Med Christine; Lee, Sung Nae; Kim, Ji-Hyun; Kwon, Seung Bin; An, In-Sook; An, Sungkwan; Ahn, Kyu Joong

    2016-01-01

    Anti-aging cosmetics are widely used for improving signs of aged skin such as skin wrinkles, decreased elasticity, low dermal density and yellow skin tone. The present study evaluated the effects of cosmetic formulations, eye cream and facial cream, containing palmitoyl peptides, Silybum marianum (S. marianum) seed oil, vitamin E and other functional ingredients on the improvement of facial wrinkles, elasticity, dermal density and skin tone after 4 weeks period of application on aged human skin. Healthy volunteers (n=20) with aged skin were recruited to apply the test materials facially twice per day for 4 weeks. Skin wrinkles, elasticity, dermal density and skin tone were measured instrumentally for assessing the improvement of skin aging. All the measurements were conducted prior to the application of test materials and at 2 and 4 weeks of treatment. Crow's feet wrinkles were decreased 5.97% after 2 weeks of test material application and 14.07% after 4 weeks of application in comparison of pre-application. Skin elasticity was increased 6.81% after 2 weeks and 8.79% after 4 weeks. Dermal density was increased 16.74% after 2 weeks and 27.63% after 4 weeks. With the L* value indicating skin brightness and the a* value indicating erythema (redness), the results showed that brightness was increased 1.70% after 2 weeks and 2.14% after 4 weeks, and erythema was decreased 10.45% after 2 weeks and 22.39% after 4 weeks. Hence, the test materials appear to exert some degree of anti-aging effects on aged human skin. There were no abnormal skin responses from the participants during the trial period. We conclude that the facial and eye cream containing palmitoyl peptides and S. marianum seed oil, vitamin E and other ingredients have effects on the improvement of facial wrinkles, elasticity, dermal density and skin tone. PMID:27446338

  8. Instrumental evaluation of anti-aging effects of cosmetic formulations containing palmitoyl peptides, Silybum marianum seed oil, vitamin E and other functional ingredients on aged human skin.

    PubMed

    Hahn, Hyung Jin; Jung, Ho Jung; Schrammek-Drusios, Med Christine; Lee, Sung Nae; Kim, Ji-Hyun; Kwon, Seung Bin; An, In-Sook; An, Sungkwan; Ahn, Kyu Joong

    2016-08-01

    Anti-aging cosmetics are widely used for improving signs of aged skin such as skin wrinkles, decreased elasticity, low dermal density and yellow skin tone. The present study evaluated the effects of cosmetic formulations, eye cream and facial cream, containing palmitoyl peptides, Silybum marianum (S. marianum) seed oil, vitamin E and other functional ingredients on the improvement of facial wrinkles, elasticity, dermal density and skin tone after 4 weeks period of application on aged human skin. Healthy volunteers (n=20) with aged skin were recruited to apply the test materials facially twice per day for 4 weeks. Skin wrinkles, elasticity, dermal density and skin tone were measured instrumentally for assessing the improvement of skin aging. All the measurements were conducted prior to the application of test materials and at 2 and 4 weeks of treatment. Crow's feet wrinkles were decreased 5.97% after 2 weeks of test material application and 14.07% after 4 weeks of application in comparison of pre-application. Skin elasticity was increased 6.81% after 2 weeks and 8.79% after 4 weeks. Dermal density was increased 16.74% after 2 weeks and 27.63% after 4 weeks. With the L* value indicating skin brightness and the a* value indicating erythema (redness), the results showed that brightness was increased 1.70% after 2 weeks and 2.14% after 4 weeks, and erythema was decreased 10.45% after 2 weeks and 22.39% after 4 weeks. Hence, the test materials appear to exert some degree of anti-aging effects on aged human skin. There were no abnormal skin responses from the participants during the trial period. We conclude that the facial and eye cream containing palmitoyl peptides and S. marianum seed oil, vitamin E and other ingredients have effects on the improvement of facial wrinkles, elasticity, dermal density and skin tone.

  9. Expression profile of the matricellular protein osteopontin in primary open-angle glaucoma and the normal human eye.

    PubMed

    Chowdhury, Uttio Roy; Jea, Seung-Youn; Oh, Dong-Jin; Rhee, Douglas J; Fautsch, Michael P

    2011-08-16

    PURPOSE. To characterize the role of osteopontin (OPN) in primary open-angle glaucoma (POAG) and normal eyes. METHODS. OPN quantification was performed by enzyme-linked immunosorbent assay in aqueous humor (AH) obtained from human donor eyes (POAG and normal) and surgical samples (POAG and elective cataract removal). OPN expression and localization in whole eye tissue sections and primary normal human trabecular meshwork (NTM) cells were studied by Western blot and immunohistochemistry. Latanoprost-free acid (LFA)-treated NTM cells were analyzed for OPN gene and protein expression. Intraocular pressure was measured by tonometry, and central corneal thickness was measured by optical coherence tomography in young OPN(-/-) and wild-type mice. RESULTS. OPN levels were significantly reduced in donor POAG AH compared with normal AH (0.54 ± 0.18 ng/μg [n = 8] vs. 0.77 ± 0.23 ng/μg [n = 9]; P = 0.039). A similar trend was observed in surgical AH (1.05 ± 0.31 ng/μg [n = 20] vs. 1.43 ± 0.88 ng/μg [n = 20]; P = 0.083). OPN was present in the trabecular meshwork, corneal epithelium and endothelium, iris, ciliary body, retina, vitreous humor, and optic nerve. LFA increased OPN gene expression, but minimal change in OPN protein expression was observed. No difference in intraocular pressure (17.5 ± 2.0 mm Hg [n = 56] vs. 17.3 ± 1.9 mm Hg [n = 68]) but thinner central corneal thickness (91.7 ± 3.6 μm [n = 50] vs. 99.2 ± 5.5 μm [n = 70]) was noted between OPN(-/-) and wild-type mice. CONCLUSIONS. OPN is widely distributed in the human eye and was found in lower concentrations in POAG AH. Reduction of OPN in young mice does not affect IOP.

  10. A renal-like organic anion transport system in the ciliary epithelium of the bovine and human eye.

    PubMed

    Lee, Jonghwa; Shahidullah, Mohammad; Hotchkiss, Adam; Coca-Prados, Miguel; Delamere, Nicholas A; Pelis, Ryan M

    2015-04-01

    The purpose of this study was to determine the direction of organic anion (OA) transport across the ciliary body and the transport proteins that may contribute. Transport of several OAs across the bovine ciliary body was examined using ciliary body sections mounted in Ussing chambers and a perfused eye preparation. Microarray, reverse-transcription polymerase chain reaction (RT-PCR), immunoblotting, and immunohistochemistry were used to examine OA transporter expression in human ocular tissues. Microarray analysis showed that many OA transporters common to other barrier epithelia are expressed in ocular tissues. mRNA (RT-PCR) and protein (immunoblotting) for OAT1, OAT3, NaDC3, and MRP4 were detected in extracts of the human ciliary body from several donors. OAT1 and OAT3 localized to basolateral membranes of nonpigmented epithelial cells and MRP4 to basolateral membranes of pigmented cells in the human eye. Para-aminohippurate (PAH) and estrone-3-sulfate transport across the bovine ciliary body in the Ussing chambers was greater in the aqueous humor-to-blood direction than in the blood-to-aqueous humor direction, and active. There was little net directional movement of cidofovir. Probenecid (0.1 mM) or novobiocin (0.1 mM) added to the aqueous humor side of the tissue, or MK571 (5-(3-(2-(7-chloroquinolin-2-yl)ethenyl)phenyl)-8-dimethylcarbamyl-4,6-dithiaoctanoic acid; 0.1 mM) added to the blood side significantly reduced net active PAH transport. The rate of 6-carboxyfluorescein elimination from the aqueous humor of the perfused eye was reduced 80% when novobiocin (0.1 mM) was present in the aqueous humor. These data indicate that the ciliary body expresses a variety of OA transporters, including those common to the kidney. They are likely involved in clearing potentially harmful endobiotic and xenobiotic OAs from the eye.

  11. Human 14-3-3 gamma protein results in abnormal cell proliferation in the developing eye of Drosophila melanogaster

    PubMed Central

    Hong, Sophia W; Qi, Wenqing; Brabant, Marc; Bosco, Giovanni; Martinez, Jesse D

    2008-01-01

    Background 14-3-3 proteins are a family of adaptor proteins that participate in a wide variety of cellular processes. Recent evidence indicates that the expression levels of these proteins are elevated in some human tumors providing circumstantial evidence for their involvement in human cancers. However, the mechanism through which these proteins act in tumorigenesis is uncertain. Results To determine whether elevated levels of 14-3-3 proteins may perturb cell growth we overexpressed human 14-3-3 gamma (h14-3-3 gamma) in Drosophila larvae using the heat shock promoter or the GMR-Gal4 driver and then examined the effect that this had on cell proliferation in the eye imaginal discs of third instar larvae. We found that induction of h14-3-3 gamma resulted in the abnormal appearance of replicating cells in the differentiating proneural photoreceptor cells of eye imaginal discs where h14-3-3 gamma was driven by the heat shock promoter. Similarly, we found that driving h14-3-3 gamma expression specifically in developing eye discs with the GMR-Gal4 driver resulted in increased numbers of replicative cells following the morphogenetic furrow. Interestingly, we found that the effects of overexpressing h1433 gamma on eye development were increased in a genetic background where String (cdc25) function was compromised. Conclusion Taken together our results indicate that h14-3-3 gamma can promote abnormal cell proliferation and may act through Cdc25. This has important implications for 14-3-3 gamma as an oncogene as it suggests that elevated levels of 14-3-3 may confer a growth advantage to cells that overexpress it. PMID:18194556

  12. The Aging Eye

    MedlinePlus

    ... Search Search Search the NEI Website NEI on Social Media | Search A-Z | en español | Text size S M ... Outreach Tools and Tips Watch, Listen, and Learn Social Media Glaucoma Glaucoma Learn About Glaucoma Keep Vision in ...

  13. The Toxicity of Nonsteroidal Anti-inflammatory Eye Drops against Human Corneal Epithelial Cells in Vitro.

    PubMed

    Lee, Jong Soo; Kim, Young Hi; Park, Young Min

    2015-12-01

    This study investigated the toxicity of commercial non-steroid anti-inflammatory drug (NSAID) eye solutions against corneal epithelial cells in vitro. The biologic effects of 1/100-, 1/50-, and 1/10-diluted bromfenac sodium, pranoprofen, diclofenac sodium, and the fluorometholone on corneal epithelial cells were evaluated after 1-, 4-, 12-, and 24-hr of exposure compared to corneal epithelial cell treated with balanced salt solution as control. Cellular metabolic activity, cellular damage, and morphology were assessed. Corneal epithelial cell migration was quantified by the scratch-wound assay. Compared to bromfenac and pranoprofen, the cellular metabolic activity of diclofenac and fluorometholone significantly decreased after 12-hr exposure, which was maintained for 24-hr compared to control. Especially, at 1/10-diluted eye solution for 24-hr exposure, the LDH titers of fluorometholone and diclofenac sodium markedly increased more than those of bromfenac and pranoprofen. In diclofenac sodium, the Na(+) concentration was lower and amount of preservatives was higher than other NSAIDs eye solutions tested. However, the K(+) and Cl(-) concentration, pH, and osmolarity were similar for all NSAIDs eye solutions. Bromfenac and pranoprofen significantly promoted cell migration, and restored wound gap after 48-hr exposure, compared with that of diclofenac or fluorometholone. At 1/50-diluted eye solution for 48-hr exposure, the corneal epithelial cellular morphology of diclofenac and fluorometholone induced more damage than that of bromfenac or pranoprofen. Overall, the corneal epithelial cells in bromfenac and pranoprofen NSAID eye solutions are less damaged compared to those in diclofenac, included fluorometholone as steroid eye solution.

  14. TECHNICAL BRIEF: Isolation of total DNA from postmortem human eye tissues and quality comparison between iris and retina

    PubMed Central

    Wang, Jay Ching Chieh; Wang, Aikun; Gao, Jiangyuan; Cao, Sijia; Samad, Idris; Zhang, Dean; Ritland, Carol; Cui, Jing Z.

    2012-01-01

    Background Recent genomic technologies have propelled our understanding of the mechanisms underlying complex eye diseases such as age-related macular degeneration (AMD). Genotyping postmortem eye tissues for known single nucleotide polymorphisms (SNPs) associated with AMD may prove valuable, especially when combined with information obtained through other methods such as immunohistochemistry, western blot, enzyme-linked immunosorbent assay (ELISA), and proteomics. Initially intending to genotype postmortem eye tissues for AMD-related SNPs, our group became interested in isolating and comparing the quality of DNA from the iris and retina of postmortem donor eyes. Since there is no previously published protocol in the literature on this topic, we present a protocol suitable for isolating high-quality DNA from postmortem eye tissues for genomic studies. Methods DNA from 33 retinal samples and 35 iris samples was extracted using the phenol-chloroform-isoamyl method from postmortem donor eye tissues. The quantity of DNA was measured with a spectrophotometer while the quality was checked using gel electrophoresis. The DNA samples were then amplified with PCR for the complement factor H (CFH) gene. The purified amplified products were then genotyped for the SNPs in the CFH gene. Results Regarding concentration, the retina yielded 936 ng/μl of DNA, while the iris yielded 78 ng/μl of DNA. Retinal DNA was also purer than iris DNA (260/280=1.78 vs. 1.46, respectively), and produced superior PCR results. Retinal tissue yielded significantly more DNA than the iris tissue per mg of sample (21.7 ng/μl/mg vs. 7.42 ng/μl/mg). Retinal DNA can be readily amplified with PCR, while iris DNA can also be amplified by adding bovine serum albumin. Overall, retinal tissues yielded DNA of superior quality, quantity, and suitability for genotyping and genomic studies. Conclusions The protocol presented here provides a clear and reliable method for isolating total DNA from postmortem eye

  15. Nanodissection of human chromosomes and ultraprecise eye surgery with nanojoule near-infrared femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Koenig, Karsten; Riemann, Iris; Krauss, Oliver; Fritzsche, Wolfgang

    2002-04-01

    Nanojoule and sub-nanojoule 80 MHz femtosecond laser pulses at 750-850 nm of a compact titanium:sapphire laser have been used for highly precise nanoprocessing of DNA as well as of intracellular and intratissue compartments. In particular, a mean power between 15 mW and 100 mW, 170 fs pulse width, submicron distance of illumination spots and microsecond beam dwell times on spots have been used for multiphoton- mediated nanoprocessing of human chromosomes, brain and ocular intrastromal tissue. By focusing the laser beam with high numerical aperture focusing optics of the laser scan system femt-O-cut and of modified multiphoton scanning microscopes to diffraction-limited spots and TW/cm2 light intensities, precise submicron holes and cuts have been processed by single spot exposure and line scans. A minimum FWHM cut size below 70 nm during the partial dissection of the human chromosome 3 was achieved. Complete chromosome dissection could be performed with FWHM cut sizes below 200 nm. Intracellular chromosome dissection was possible. Intratissue processing in depths of 50 - 100micrometers and deeper with a precision of about 1micrometers including cuts through a nuclei of a single intratissue cell without destructive photo-disruption effects to surrounding tissue layers have been demonstrated in brain and eye tissues. The femt-O-cut system includes a diagnostic system for optical tomography with submicron resolution based on multiphoton- excited autofluorescence imaging (MAI) and second harmonic generation. This system was used to localize the intracellular and intratissue targets and to control the effects of nanoprocessing. These studies show, that in contrast to conventional approaches of material processing with amplified femtosecond laser systems and (mu) J pulse energies, nanoprocessing of materials including biotissues can be performed with nJ and sub-nJ high repetition femtosecond laser pulses of turn-key compact lasers without collateral damage. Potential

  16. Evaluation of potential organ culture media for eye banking using human donor corneas

    PubMed Central

    Moller-Pedersen, T; Hartmann, U; Moller, H; Ehlers, N; Engelmann, K

    2001-01-01

    AIM—To evaluate the ability of different commercially available cell culture solutions to preserve human donor corneas during 3 weeks of "closed system" organ culture at physiological temperature. This screening was performed in an attempt to establish a rational basis for the development of a serum-free organ culture medium for eye banking.
METHODS—72 normal human donor corneas were organ cultured for 21 days at 31°C in eight different test media (nine corneas in each group). The basic culture solutions included: minimal essential medium (MEM), MEM with stabilised L-glutamine, M199, DIF-1000, SFM, F99, and F99 with ascorbic acid, insulin, bFGF, transferrin, selenium, and lipids (termed F99-Sr). All media were supplemented with 2% fetal calf serum (FCS), except for MEM, which was also studied at 8% FCS. The evaluation parameters included: (1) the endothelial cell loss as evaluated using trypan blue staining; (2) the ability of keratocytes and endothelial cells to incorporate tritiated uridine into RNA as evaluated using autoradiography and digital image analysis; (3) the leakage of immunogenic keratan sulphate as assessed using ELISA; and (4) changes in storage medium pH, glucose, and lactate content.
RESULTS—SFM induced the lowest endothelial cell loss of 14% (SD 2%) and the highest RNA synthesis rates of all test solutions supplemented with 2% FCS. Corneas stored in SFM also showed the least leakage of keratan sulphate and the highest glucose consumption and lactate production. In five media (MEM with 2% FCS, MEM with stabilised L-glutamine, M199, F99, and F99-Sr), comparable and intermediate potentials for organ culture were observed with endothelial cell loss of 16-19%. By contrast, 29% (4%) of the endothelium was lost after storage in DIF-1000. Interestingly, the use of 8% FCS (in MEM) had a marked protective effect on the endothelium, which showed the highest RNA synthetic activity combined with a cell loss of only 11% (4%), compared with 19% (6

  17. Polarization sensitive changes in the human macula associated with normal aging and age-related macular degeneration

    NASA Astrophysics Data System (ADS)

    VanNasdale, Dean Allan, Jr.

    2011-12-01

    The human macula occupies a relatively small, but crucial retinal area, as it is the location responsible for our most acute spatial vision and best color discrimination. Localizing important landmarks in the retina is difficult even in normal eyes where morphological inter-individual variability is high. This becomes even more challenging in the presence of sight-threatening pathology. With respect to the human macula, there remains a significant gap in the understanding of normal structure and function. Even less is known about the pathological mechanisms that occur in sight-threatening diseases including age-related macular degeneration. Because relatively little is known about normal aging changes, it is also difficult to differentiate those changes from changes associated with retinal disease. To better understand normal and pathological changes in the macula, imaging techniques using specific optical signatures are required. Structural features in the macula can be distinguished based on their intrinsic properties using specific light/tissue interactions. Because of the high degree of structural regularity in the macula, polarization sensitive imaging is potentially a useful tool for evaluating the morphology and integrity of the cellular architecture for both normal individuals and those affected by disease. In our investigations, we used polarization sensitive imaging to determining normal landmarks that are important clinically and for research investigations. We found that precision and accuracy in localizing the central macula was greatly improved through the use of polarization sensitive imaging. We also found that specific polarization alterations can be used to demonstrate systematic changes as a function of age, disproportionately affecting the central macular region. When evaluating patients with age-related macular degeneration, we found that precision and accuracy of localizing the central macula was also improved, even when significant pathology

  18. Pharmacokinetics of topically applied recombinant human keratinocyte growth factor-2 in alkali-burned and intact rabbit eye.

    PubMed

    Cai, Jianqiu; Dou, Guifang; Zheng, Long; Yang, Ting; Jia, Xuechao; Tang, Lu; Huang, Yadong; Wu, Wencan; Li, Xiaokun; Wang, Xiaojie

    2015-07-01

    Keratinocyte growth factor-2 (KGF-2), an effective agent in the development of epithelial tissue and regeneration during corneal wound healing, is a potential therapeutic option to treat the corneal diseases with corneal epithelial defects. However the tissue distribution and pharmacokinetics of KGF-2 have not been explored yet in eye upon topical application. Using (125)I-labeled recombinant human KGF-2 ((125)I-rhKGF-2), tissue distribution of rhKGF-2 in alkali-burned and control rabbit eyes was studied. Our results revealed that (125)I-rhKGF-2 was distributed to all eye tissues examined. The highest radioactivity level was found in the cornea, followed by iris, sclera, ciliary body, lens, aqueous humor, vitreous body, and serum in a greatest to least order. The levels of (125)I-rhKGF-2 were higher in corneas of alkali-burned eyes than those in control eyes though without statistical significance. Calculated pharmacokinetic parameters of t1/2, Cmax, and Tmax of rhKGF-2 in the rabbit corneas were 3.4 h, 135.2 ng/ml, and 0.5 h, respectively. In iris, lens, aqueous humor, and tear, t1/2, Cmax, and Tmax values were 6.2, 6.5, 5.2, and 2.5 h; 23.2, 4.5, 24.1, and 29,498.9 ng/ml; and 1.0, 0.5, 0.5, and 1.0 h, respectively. Predominant and rapid accumulation of rhKGF-2 in corneas suggests that therapeutic doses of rhKGF-2 could be delivered by topical application for treatment of corneal diseases.

  19. Stratigraphic placement and age of modern humans from Kibish, Ethiopia.

    PubMed

    McDougall, Ian; Brown, Francis H; Fleagle, John G

    2005-02-17

    In 1967 the Kibish Formation in southern Ethiopia yielded hominid cranial remains identified as early anatomically modern humans, assigned to Homo sapiens. However, the provenance and age of the fossils have been much debated. Here we confirm that the Omo I and Omo II hominid fossils are from similar stratigraphic levels in Member I of the Kibish Formation, despite the view that Omo I is more modern in appearance than Omo II. 40Ar/39Ar ages on feldspar crystals from pumice clasts within a tuff in Member I below the hominid levels place an older limit of 198 +/- 14 kyr (weighted mean age 196 +/- 2 kyr) on the hominids. A younger age limit of 104 +/- 7 kyr is provided by feldspars from pumice clasts in a Member III tuff. Geological evidence indicates rapid deposition of each member of the Kibish Formation. Isotopic ages on the Kibish Formation correspond to ages of Mediterranean sapropels, which reflect increased flow of the Nile River, and necessarily increased flow of the Omo River. Thus the 40Ar/39Ar age measurements, together with the sapropel correlations, indicate that the hominid fossils have an age close to the older limit. Our preferred estimate of the age of the Kibish hominids is 195 +/- 5 kyr, making them the earliest well-dated anatomically modern humans yet described.

  20. Evidence for the hallmarks of human aging in replicatively aging yeast

    PubMed Central

    Janssens, Georges E.; Veenhoff, Liesbeth M.

    2016-01-01

    Recently, efforts have been made to characterize the hallmarks that accompany and contribute to the phenomenon of aging, as most relevant for humans 1. Remarkably, studying the finite lifespan of the single cell eukaryote budding yeast (recently reviewed in 2 and 3) has been paramount for our understanding of aging. Here, we compile observations from literature over the past decades of research on replicatively aging yeast to highlight how the hallmarks of aging in humans are present in yeast. We find strong evidence for the majority of these, and summarize how yeast aging is especially characterized by the hallmarks of genomic instability, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, and mitochondrial dysfunction. PMID:28357364

  1. Thermal elevation in the human eye and head due to the operation of a retinal prosthesis.

    PubMed

    Gosalia, Keyoor; Weiland, James; Humayun, Mark; Lazzi, Gianluca

    2004-08-01

    An explicit finite-difference time-domain formulation of the bio-heat equation is employed with a three-dimensional head eye model to evaluate the temperature increase in the eye and surrounding head tissues due to the operation of the implanted stimulator IC chip of a retinal prosthesis designed to restore partial vision to the blind. As a first step, a validation of the thermal model and method used is carried out by comparison with in vivo measurements of intraocular heating performed in the eyes of dogs. Induced temperature increase in the eye and surrounding tissues is then estimated for several different operational conditions of the implanted chip. In the vitreous cavity, temperature elevation of 0.26 degrees C is observed after 26 min for a chip dissipating 12.4 mW when positioned in the mid-vitreous cavity while it is 0.16 degrees C when the chip is positioned in the anterior portion between the eye's ciliary muscles. Corresponding temperature rises observed on chip are 0.82 degrees C for both the positions of the chip. A comprehensive account of temperature elevations in different tissues under different operational conditions is presented.

  2. Genetic Determinants of Macular Pigments in Women of the Carotenoids in Age-Related Eye Disease Study

    PubMed Central

    Meyers, Kristin J.; Johnson, Elizabeth J.; Bernstein, Paul S.; Iyengar, Sudha K.; Engelman, Corinne D.; Karki, Chitra K.; Liu, Zhe; Igo, Robert P.; Truitt, Barbara; Klein, Michael L.; Snodderly, D. Max; Blodi, Barbara A.; Gehrs, Karen M.; Sarto, Gloria E.; Wallace, Robert B.; Robinson, Jennifer; LeBlanc, Erin S.; Hageman, Gregory; Tinker, Lesley; Mares, Julie A.

    2013-01-01

    Purpose. To investigate genetic determinants of macular pigment optical density in women from the Carotenoids in Age-Related Eye Disease Study (CAREDS), an ancillary study of the Women's Health Initiative Observational Study. Methods. 1585 of 2005 CAREDS participants had macular pigment optical density (MPOD) measured noninvasively using customized heterochromatic flicker photometry and blood samples genotyped for 440 single nucleotide polymorphisms (SNPs) in 26 candidate genes related to absorption, transport, binding, and cleavage of carotenoids directly, or via lipid transport. SNPs were individually tested for associations with MPOD using least-squares linear regression. Results. Twenty-one SNPs from 11 genes were associated with MPOD (P ≤ 0.05) after adjusting for dietary intake of lutein and zeaxanthin. This includes variants in or near genes related to zeaxanthin binding in the macula (GSTP1), carotenoid cleavage (BCMO1), cholesterol transport or uptake (SCARB1, ABCA1, ABCG5, and LIPC), long-chain omega-3 fatty acid status (ELOVL2, FADS1, and FADS2), and various maculopathies (ALDH3A2 and RPE65). The strongest association was for rs11645428 near BCMO1 (βA = 0.029, P = 2.2 × 10−4). Conditional modeling within genes and further adjustment for other predictors of MPOD, including waist circumference, diabetes, and dietary intake of fiber, resulted in 13 SNPs from 10 genes maintaining independent association with MPOD. Variation in these single gene polymorphisms accounted for 5% of the variability in MPOD (P = 3.5 × 10−11). Conclusions. Our results support that MPOD is a multi-factorial phenotype associated with variation in genes related to carotenoid transport, uptake, and metabolism, independent of known dietary and health influences on MPOD. PMID:23404124

  3. Gene expression profiling of transporters in the solute carrier and ATP-binding cassette superfamilies in human eye substructures.

    PubMed

    Dahlin, Amber; Geier, Ethan; Stocker, Sophie L; Cropp, Cheryl D; Grigorenko, Elena; Bloomer, Michele; Siegenthaler, Julie; Xu, Lu; Basile, Anthony S; Tang-Liu, Diane D-S; Giacomini, Kathleen M

    2013-02-04

    The barrier epithelia of the cornea and retina control drug and nutrient access to various compartments of the human eye. While ocular transporters are likely to play a critical role in homeostasis and drug delivery, little is known about their expression, localization and function. In this study, the mRNA expression levels of 445 transporters, metabolic enzymes, transcription factors and nuclear receptors were profiled in five regions of the human eye: cornea, iris, ciliary body, choroid and retina. Through RNA expression profiling and immunohistochemistry, several transporters were identified as putative targets for drug transport in ocular tissues. Our analysis identified SLC22A7 (OAT2), a carrier for the antiviral drug acyclovir, in the corneal epithelium, in addition to ABCG2 (BCRP), an important xenobiotic efflux pump, in retinal nerve fibers and the retinal pigment epithelium. Collectively, our results provide an understanding of the transporters that serve to maintain ocular homeostasis and which may be potential targets for drug delivery to deep compartments of the eye.

  4. Influence of age, irradiation and humanization on NSG mouse phenotypes

    PubMed Central

    Knibbe-Hollinger, Jaclyn S.; Fields, Natasha R.; Chaudoin, Tammy R; Epstein, Adrian A.; Makarov, Edward; Akhter, Sidra P.; Gorantla, Santhi; Bonasera, Stephen J.; Gendelman, Howard E.; Poluektova, Larisa Y.

    2015-01-01

    ABSTRACT Humanized mice are frequently utilized in bench to bedside therapeutic tests to combat human infectious, cancerous and degenerative diseases. For the fields of hematology-oncology, regenerative medicine, and infectious diseases, the immune deficient mice have been used commonly in basic research efforts. Obstacles in true translational efforts abound, as the relationship between mouse and human cells in disease pathogenesis and therapeutic studies requires lengthy investigations. The interplay between human immunity and mouse biology proves ever more complicated when aging, irradiation, and human immune reconstitution are considered. All can affect a range of biochemical and behavioral functions. To such ends, we show age- and irradiation-dependent influences for the development of macrocytic hyper chromic anemia, myelodysplasia, blood protein reductions and body composition changes. Humanization contributes to hematologic abnormalities. Home cage behavior revealed day and dark cycle locomotion also influenced by human cell reconstitutions. Significant age-related day-to-day variability in movement, feeding and drinking behaviors were observed. We posit that this data serves to enable researchers to better design translational studies in this rapidly emerging field of mouse humanization. PMID:26353862

  5. Influence of age, irradiation and humanization on NSG mouse phenotypes.

    PubMed

    Knibbe-Hollinger, Jaclyn S; Fields, Natasha R; Chaudoin, Tammy R; Epstein, Adrian A; Makarov, Edward; Akhter, Sidra P; Gorantla, Santhi; Bonasera, Stephen J; Gendelman, Howard E; Poluektova, Larisa Y

    2015-09-09

    Humanized mice are frequently utilized in bench to bedside therapeutic tests to combat human infectious, cancerous and degenerative diseases. For the fields of hematology-oncology, regenerative medicine, and infectious diseases, the immune deficient mice have been used commonly in basic research efforts. Obstacles in true translational efforts abound, as the relationship between mouse and human cells in disease pathogenesis and therapeutic studies requires lengthy investigations. The interplay between human immunity and mouse biology proves ever more complicated when aging, irradiation, and human immune reconstitution are considered. All can affect a range of biochemical and behavioral functions. To such ends, we show age- and irradiation-dependent influences for the development of macrocytic hyper chromic anemia, myelodysplasia, blood protein reductions and body composition changes. Humanization contributes to hematologic abnormalities. Home cage behavior revealed day and dark cycle locomotion also influenced by human cell reconstitutions. Significant age-related day-to-day variability in movement, feeding and drinking behaviors were observed. We posit that this data serves to enable researchers to better design translational studies in this rapidly emerging field of mouse humanization.

  6. Increased mobilization of aged carbon to rivers by human disturbance

    NASA Astrophysics Data System (ADS)

    Butman, David E.; Wilson, Henry F.; Barnes, Rebecca T.; Xenopoulos, Marguerite A.; Raymond, Peter A.

    2015-02-01

    Approximately 8% of anthropogenic carbon dioxide emissions are estimated to come from land-use change, but this estimate excludes fluxes of terrestrial carbon to aquatic ecosystems from human disturbance. Carbon fluxes from land to rivers have probably increased by 0.1 to 0.2 petagrams of carbon per year as a result of disturbances such as deforestation, agricultural intensification and the injection of human wastewater. Most dissolved organic carbon in rivers originates from young organic carbon from soils and vegetation, but aged carbon removed from the modern carbon cycle is also exported in many systems. Here we analyse a global data set of radiocarbon ages of riverine dissolved organic carbon and spatial data on land cover, population and environmental variables. We find that the age of dissolved organic carbon in rivers increases with population density and the proportion of human-dominated landscapes within a watershed, and decreases with annual precipitation. We reason that disturbance reintroduces aged soil organic matter into the modern carbon cycle, although fossil carbon in fertilizer or petroleum products may also be a source of aged carbon in disturbed watersheds. The total export from the terrestrial environment to freshwater systems remains unknown; nevertheless, our results suggest that 3-9% of dissolved organic carbon in rivers is aged carbon mobilized by human disturbance.

  7. Human rather than ape-like orbital morphology allows much greater lateral visual field expansion with eye abduction

    PubMed Central

    Denion, Eric; Hitier, Martin; Levieil, Eric; Mouriaux, Frédéric

    2015-01-01

    While convergent, the human orbit differs from that of non-human apes in that its lateral orbital margin is significantly more rearward. This rearward position does not obstruct the additional visual field gained through eye motion. This additional visual field is therefore considered to be wider in humans than in non-human apes. A mathematical model was designed to quantify this difference. The mathematical model is based on published computed tomography data in the human neuro-ocular plane (NOP) and on additional anatomical data from 100 human skulls and 120 non-human ape skulls (30 gibbons; 30 chimpanzees / bonobos; 30 orangutans; 30 gorillas). It is used to calculate temporal visual field eccentricity values in the NOP first in the primary position of gaze then for any eyeball rotation value in abduction up to 45° and any lateral orbital margin position between 85° and 115° relative to the sagittal plane. By varying the lateral orbital margin position, the human orbit can be made “non-human ape-like”. In the Pan-like orbit, the orbital margin position (98.7°) was closest to the human orbit (107.1°). This modest 8.4° difference resulted in a large 21.1° difference in maximum lateral visual field eccentricity with eyeball abduction (Pan-like: 115°; human: 136.1°). PMID:26190625

  8. Morphometric measurement of Schlemm's canal in normal human eye using anterior segment swept source optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Shi, Guohua; Wang, Fei; Li, Xiqi; Lu, Jing; Ding, Zhihua; Sun, Xinghuai; Jiang, Chunhui; Zhang, Yudong

    2012-01-01

    We have used anterior segment swept source optical coherence tomography to measure Schlemm's canal (SC) morphometric values in the living human eye. Fifty healthy volunteers with 100 normal eyes were measured in the nasal and temporal side. Comparison with the published SC morphometric values of histologic sections proves the reliability of our results. The statistical results show that there are no significant differences between nasal and temporal SC with respect to their diameter, perimeter, and area in our study (diameter: t=0.122, p=0.903; perimeter: t=-0.003, p=0.998; area: t=-1.169, p=0.244); further, no significant differences in SC morphometric values are found between oculus sinister and oculus dexter (diameter: t=0.943, p=0.35; perimeter: t=1.346, p=0.18; area: t=1.501, p=0.135).

  9. Human motion perception and smooth eye movements show similar directional biases for elongated apertures

    NASA Technical Reports Server (NTRS)

    Beutter, B. R.; Stone, L. S.

    1998-01-01

    Although numerous studies have examined the relationship between smooth-pursuit eye movements and motion perception, it remains unresolved whether a common motion-processing system subserves both perception and pursuit. To address this question, we simultaneously recorded perceptual direction judgments and the concomitant smooth eye-movement response to a plaid stimulus that we have previously shown generates systematic perceptual errors. We measured the perceptual direction biases psychophysically and the smooth eye-movement direction biases using two methods (standard averaging and oculometric analysis). We found that the perceptual and oculomotor biases were nearly identical, suggesting that pursuit and perception share a critical motion processing stage, perhaps in area MT or MST of extrastriate visual cortex.

  10. Human Motion Perception and Smooth Eye Movements Show Similar Directional Biases for Elongated Apertures

    NASA Technical Reports Server (NTRS)

    Beutter, Brent R.; Stone, Leland S.

    1997-01-01

    Although numerous studies have examined the relationship between smooth-pursuit eye movements and motion perception, it remains unresolved whether a common motion-processing system subserves both perception and pursuit. To address this question, we simultaneously recorded perceptual direction judgments and the concomitant smooth eye movement response to a plaid stimulus that we have previously shown generates systematic perceptual errors. We measured the perceptual direction biases psychophysically and the smooth eye-movement direction biases using two methods (standard averaging and oculometric analysis). We found that the perceptual and oculomotor biases were nearly identical suggesting that pursuit and perception share a critical motion processing stage, perhaps in area MT or MST of extrastriate visual cortex.

  11. Perceiving polarization with the naked eye: characterization of human polarization sensitivity

    PubMed Central

    Temple, Shelby E.; McGregor, Juliette E.; Miles, Camilla; Graham, Laura; Miller, Josie; Buck, Jordan; Scott-Samuel, Nicholas E.; Roberts, Nicholas W.

    2015-01-01

    Like many animals, humans are sensitive to the polarization of light. We can detect the angle of polarization using an entoptic phenomenon called Haidinger's brushes, which is mediated by dichroic carotenoids in the macula lutea. While previous studies have characterized the spectral sensitivity of Haidinger's brushes, other aspects remain unexplored. We developed a novel methodology for presenting gratings in polarization-only contrast at varying degrees of polarization in order to measure the lower limits of human polarized light detection. Participants were, on average, able to perform the task down to a threshold of 56%, with some able to go as low as 23%. This makes humans the most sensitive vertebrate tested to date. Additionally, we quantified a nonlinear relationship between presented and perceived polarization angle when an observer is presented with a rotatable polarized light field. This result confirms a previous theoretical prediction of how uniaxial corneal birefringence impacts the perception of Haidinger's brushes. The rotational dynamics of Haidinger's brushes were then used to calculate corneal retardance. We suggest that psychophysical experiments, based upon the perception of polarized light, are amenable to the production of affordable technologies for self-assessment and longitudinal monitoring of visual dysfunctions such as age-related macular degeneration. PMID:26136441

  12. Perceiving polarization with the naked eye: characterization of human polarization sensitivity.

    PubMed

    Temple, Shelby E; McGregor, Juliette E; Miles, Camilla; Graham, Laura; Miller, Josie; Buck, Jordan; Scott-Samuel, Nicholas E; Roberts, Nicholas W

    2015-07-22

    Like many animals, humans are sensitive to the polarization of light. We can detect the angle of polarization using an entoptic phenomenon called Haidinger's brushes, which is mediated by dichroic carotenoids in the macula lutea. While previous studies have characterized the spectral sensitivity of Haidinger's brushes, other aspects remain unexplored. We developed a novel methodology for presenting gratings in polarization-only contrast at varying degrees of polarization in order to measure the lower limits of human polarized light detection. Participants were, on average, able to perform the task down to a threshold of 56%, with some able to go as low as 23%. This makes humans the most sensitive vertebrate tested to date. Additionally, we quantified a nonlinear relationship between presented and perceived polarization angle when an observer is presented with a rotatable polarized light field. This result confirms a previous theoretical prediction of how uniaxial corneal birefringence impacts the perception of Haidinger's brushes. The rotational dynamics of Haidinger's brushes were then used to calculate corneal retardance.We suggest that psychophysical experiments, based upon the perception of polarized light, are amenable to the production of affordable technologies for self-assessment and longitudinal monitoring of visual dysfunctions such as age-related macular degeneration.

  13. Characterizing cognitive aging in humans with links to animal models

    PubMed Central

    Alexander, Gene E.; Ryan, Lee; Bowers, Dawn; Foster, Thomas C.; Bizon, Jennifer L.; Geldmacher, David S.; Glisky, Elizabeth L.

    2012-01-01

    With the population of older adults expected to grow rapidly over the next two decades, it has become increasingly important to advance research efforts to elucidate the mechanisms associated with cognitive aging, with the ultimate goal of developing effective interventions and prevention therapies. Although there has been a vast research literature on the use of cognitive tests to evaluate the effects of aging and age-related neurodegenerative disease, the need for a set of standardized measures to characterize the cognitive profiles specific to healthy aging has been widely recognized. Here we present a review of selected methods and approaches that have been applied in human research studies to evaluate the effects of aging on cognition, including executive function, memory, processing speed, language, and visuospatial function. The effects of healthy aging on each of these cognitive domains are discussed with examples from cognitive/experimental and clinical/neuropsychological approaches. Further, we consider those measures that have clear conceptual and methodological links to tasks currently in use for non-human animal studies of aging, as well as those that have the potential for translation to animal aging research. Having a complementary set of measures to assess the cognitive profiles of healthy aging across species provides a unique opportunity to enhance research efforts for cross-sectional, longitudinal, and intervention studies of cognitive aging. Taking a cross-species, translational approach will help to advance cognitive aging research, leading to a greater understanding of associated neurobiological mechanisms with the potential for developing effective interventions and prevention therapies for age-related cognitive decline. PMID:22988439

  14. Age and gender specific biokinetic model for strontium in humans.

    PubMed

    Shagina, N B; Tolstykh, E I; Degteva, M O; Anspaugh, L R; Napier, B A

    2015-03-01

    A biokinetic model for strontium in humans is necessary for quantification of internal doses due to strontium radioisotopes. The ICRP-recommended biokinetic model for strontium has limitations for use in a population study, because it is not gender specific and does not cover all age ranges. The extensive Techa River data set on (90)Sr in humans (tens of thousands of measurements) is a unique source of data on long-term strontium retention for men and women of all ages at intake. These, as well as published data, were used for evaluation of age- and gender-specific parameters for a new compartment biokinetic model for strontium (Sr-AGe model). The Sr-AGe model has a similar structure to the ICRP model for the alkaline earth elements. The following parameters were mainly re-evaluated: gastrointestinal absorption and parameters related to the processes of bone formation and resorption defining calcium and strontium transfers in skeletal compartments. The Sr-AGe model satisfactorily describes available data sets on strontium retention for different kinds of intake (dietary and intravenous) at different ages (0-80 years old) and demonstrates good agreement with data sets for different ethnic groups. The Sr-AGe model can be used for dose assessment in epidemiological studies of general populations exposed to ingested strontium radioisotopes.

  15. Age and gender specific biokinetic model for strontium in humans

    SciTech Connect

    Shagina, N. B.; Tolstykh, E. I.; Degteva, M. O.; Anspaugh, L. R.; Napier, Bruce A.

    2015-03-01

    A biokinetic model for strontium in humans is necessary for quantification of internal doses due to strontium radioisotopes. The ICRP-recommended biokinetic model for strontium has limitation for use in a population study, because it is not gender specific and does not cover all age ranges. The extensive Techa River data set on 90Sr in humans (tens of thousands of measurements) is a unique source of data on long-term strontium retention for men and women of all ages at intake. These, as well as published data, were used for evaluation of age- and gender-specific parameters for a new compartment biokinetic model for strontium (Sr-AGe model). The Sr-AGe model has similar structure as the ICRP model for the alkaline earth elements. The following parameters were mainly reevaluated: gastro-intestinal absorption and parameters related to the processes of bone formation and resorption defining calcium and strontium transfers in skeletal compartments. The Sr-AGe model satisfactorily describes available data sets on strontium retention for different kinds of intake (dietary and intravenous) at different ages (0–80 years old) and demonstrates good agreement with data sets for different ethnic groups. The Sr-AGe model can be used for dose assessment in epidemiological studies of general population exposed to ingested strontium radioisotopes.

  16. Mitochondrial function and redox control in the aging eye: Role of MsrA and other repair systems in cataract and macular degenerations

    PubMed Central

    Brennan, Lisa A.; Kantorow, Marc

    2009-01-01

    Oxidative stress occurs when the level of prooxidants exceeds the level of antioxidants in cells resulting in oxidation of cellular components and consequent loss of cellular function. Oxidative stress is implicated in wide range of age related disorders including Alzheimer's disease, Parkinson's disease amyotrophic lateral sclerosis (ALS), Huntington's disease and the aging process itself (Lin and Beal, 2006). In the anterior segment of the eye, oxidative stress has been linked to lens cataract (Truscott, 2005) and glaucoma (Tezel, 2006) while in the posterior segment of the eye oxidative stress has been associated with macular degeneration (Hollyfield et al., 2008). Key to many oxidative stress conditions are alterations in the efficiency of mitochondrial respiration resulting in superoxide (O2-) production. Superoxide production precedes subsequent reactions that form potentially more dangerous reactive oxygen species (ROS) species such as the hydroxyl radical (˙OH), hydrogen peroxide (H2O2) and peroxynitrite (OONO-). The major source of ROS in the mitochondria, and in the cell overall, is leakage of electrons from complexes I and III of the electron transport chain. It is estimated that 0.2-2% of oxygen taken up by cells is converted to ROS, through mitochondrial superoxide generation, by the mitochondria (Hansford et al., 1997). Generation of superoxide at complex I and III has been shown to occur at both the matrix side of the inner mitochondrial membrane and the cytosolic side of the membrane (Kakkar and Singh 2007). While exogenous sources of ROS such as UV light, visible light, ionizing radiation, chemotherapeutics, and environmental toxins may contribute to the oxidative milieu, mitochondria are perhaps the most significant contribution to ROS production affecting the aging process. In addition to producing ROS, mitochondria are also a target for ROS which in turn reduces mitochondrial efficiency and leads to the generation of more ROS in a vicious self

  17. Application of SV40 T-transformed human corneal epithelial cells to evaluate potential irritant chemicals for in vitro alternative eye toxicity.

    PubMed

    Kim, Cho-Won; Park, Geon-Tae; Bae, Ok-Nam; Noh, Minsoo; Choi, Kyung-Chul

    2016-01-01

    Assessment of eye irritation potential is important to human safety, and it is necessary for various cosmetics and chemicals that may contact the human eye. Until recently, the Draize test was considered the standard method for estimating eye irritation, despite its disadvantages such as the need to sacrifice many rabbits for subjective scoring. Thus, we investigated the cytotoxicity and inflammatory response to standard eye irritants using SV40 T-transformed human corneal epithelial (SHCE) cells as a step toward development of an animal-free alternative eye irritation test. MTT and NRU assays of cell viability were performed to investigate the optimal experimental conditions for SHCE cell viability when cells were exposed to sodium dodecyl sulfate (SDS) as a standard eye irritant at 6.25×10(-3) to 1×10(-1)%. Additionally, cell viability of SHCE cells was examined in response to six potential eye irritants, benzalkonium chloride, dimethyl sulfoxide, isopropanol, SDS, Triton X-100 and Tween 20 at 5×10(-3) to 1×10(-1)%. Finally, we estimated the secretion level of cytokines in response to stimulation by eye irritants in SHCE cells. SHCE cells showed a good response to potential eye irritants when the cells were exposed to potential irritants for 10min at room temperature (RT), and cytokine production increased in a concentration-dependent manner, indicating that cytotoxicity and cytokine secretion from SHCE cells may be well correlated with the concentrations of irritants. Taken together, these results suggest that SHCE cells could be an excellent alternative in vitro model to replace in vivo animal models for eye irritation tests.

  18. Do glutathione levels decline in aging human brain?

    PubMed

    Tong, Junchao; Fitzmaurice, Paul S; Moszczynska, Anna; Mattina, Katie; Ang, Lee-Cyn; Boileau, Isabelle; Furukawa, Yoshiaki; Sailasuta, Napapon; Kish, Stephen J

    2016-04-01

    For the past 60 years a major theory of "aging" is that age-related damage is largely caused by excessive uncompensated oxidative stress. The ubiquitous tripeptide glutathione is a major antioxidant defense mechanism against reactive free radicals and has also served as a marker of changes in oxidative stress. Some (albeit conflicting) animal data suggest a loss of glutathione in brain senescence, which might compromise the ability of the aging brain to meet the demands of oxidative stress. Our objective was to establish whether advancing age is associated with glutathione deficiency in human brain. We measured reduced glutathione (GSH) levels in multiple regions of autopsied brain of normal subjects (n=74) aged one day to 99 years. Brain GSH levels during the infancy/teenage years were generally similar to those in the oldest examined adult group (76-99 years). During adulthood (23-99 years) GSH levels remained either stable (occipital cortex) or increased (caudate nucleus, frontal and cerebellar cortices). To the extent that GSH levels represent glutathione antioxidant capacity, our postmortem data suggest that human brain aging is not associated with declining glutathione status. We suggest that aged healthy human brains can maintain antioxidant capacity related to glutathione and that an age-related increase in GSH levels in some brain regions might possibly be a compensatory response to increased oxidative stress. Since our findings, although suggestive, suffer from the generic limitations of all postmortem brain studies, we also suggest the need for "replication" investigations employing the new (1)H MRS imaging procedures in living human brain.

  19. Eye Irritation Test (EIT) for Hazard Identification of Eye Irritating Chemicals using Reconstructed Human Cornea-like Epithelial (RhCE) Tissue Model

    PubMed Central

    Kaluzhny, Yulia; Kandárová, Helena; d’Argembeau-Thornton, Laurence; Kearney, Paul; Klausner, Mitchell

    2015-01-01

    To comply with the Seventh Amendment to the EU Cosmetics Directive and EU REACH legislation, validated non-animal alternative methods for reliable and accurate assessment of ocular toxicity in man are needed. To address this need, we have developed an eye irritation test (EIT) which utilizes a three dimensional reconstructed human cornea-like epithelial (RhCE) tissue model that is based on normal human cells. The EIT is able to separate ocular irritants and corrosives (GHS Categories 1 and 2 combined) and those that do not require labeling (GHS No Category). The test utilizes two separate protocols, one designed for liquid chemicals and a second, similar protocol for solid test articles. The EIT prediction model uses a single exposure period (30 min for liquids, 6 hr for solids) and a single tissue viability cut-off (60.0% as determined by the MTT assay). Based on the results for 83 chemicals (44 liquids and 39 solids) EIT achieved 95.5/68.2/ and 81.8% sensitivity/specificity and accuracy (SS&A) for liquids, 100.0/68.4/ and 84.6% SS&A for solids, and 97.6/68.3/ and 83.1% for overall SS&A. The EIT will contribute significantly to classifying the ocular irritation potential of a wide range of liquid and solid chemicals without the use of animals to meet regulatory testing requirements. The EpiOcular EIT method was implemented in 2015 into the OECD Test Guidelines as TG 492. PMID:26325674

  20. Novel filter providing human eye and optical sensors protection from the visible into the IR

    NASA Astrophysics Data System (ADS)

    Donval, A.; Fisher, T.; Nemet, B.; Oron, R.; Oron, M.; Shvartzer, R.; Eberle, B.; Ritt, G.; Ebert, R.

    2008-04-01

    We introduce into optical systems, susceptible to be interrupted or damaged from laser, novel passive solid-state threshold-triggered Wideband Protection Filter (WPF) that blocks the transmission only if the power exceeds a certain threshold. We present new protection capabilities of our latest filter composed of improved technology. The WPF can be readily used for protection of detectors, cameras, or eye safety.

  1. The Charles F. Prentice Award Lecture 2005: optics of the human eye: progress and problems.

    PubMed

    Charman, W Neil

    2006-06-01

    The history of measurements of ocular aberration is briefly reviewed and recent work using much-improved aberrometers and large samples of eyes is summarized. When on-axis, higher-order, monochromatic aberrations are averaged, undercorrected, positive, fourth-order spherical aberration dominates; other Zernike wavefront aberration coefficients have average values near zero. Individually, however, many eyes show substantial amounts of third-order and other fourth-order aberrations; the value of these varies idiosyncratically about zero. Most normal eyes show only small amounts of axial monochromatic aberration for photopic pupils up to around 3 mm; the limits to retinal image quality are then usually set by diffraction, uncorrected or imperfectly corrected spherocylindrical refractive error, accommodation error, and chromatic aberration. Longitudinal chromatic aberration varies very little across the population. With larger mesopic and scotopic pupils, monochromatic aberration plays a more important optical role, but overall visual performance is increasingly dominated by neural factors. Some remaining problems in measuring and modeling the eye's optical performance are discussed.

  2. Overlapping neural circuits for visual attention and eye movements in the human cerebellum.

    PubMed

    Striemer, Christopher L; Chouinard, Philippe A; Goodale, Melvyn A; de Ribaupierre, Sandrine

    2015-03-01

    Previous research in patients with cerebellar damage suggests that the cerebellum plays a role in covert visual attention. One limitation of some of these studies is that they examined patients with heterogeneous cerebellar damage. As a result, the patterns of reported deficits have been inconsistent. In the current study, we used functional neuroimaging (fMRI) in healthy adults (N=14) to examine whether or not the cerebellum plays a role in covert visual attention. Participants performed two covert attention tasks in which they were cued exogenously (with peripheral flashes) or endogenously (using directional arrows) to attend to marked locations in the visual periphery without moving their eyes. We compared BOLD activation in these covert attention conditions to a number of control conditions including: the same attention tasks with eye movements, a target detection task with no cueing, and a self-paced button-press task. Subtracting these control conditions from the covert attention conditions allowed us to effectively remove the contribution of the cerebellum to motor output. In addition to the usual fronto-parietal networks commonly engaged by these attention tasks, lobule VI of the vermis in the cerebellum was also activated when participants performed the covert attention tasks with or without eye movements. Interestingly, this effect was larger for exogenous compared to endogenous cueing. These results, in concert with recent patient studies, provide independent yet converging evidence that the same cerebellar structures that are involved in eye movements are also involved in visuospatial attention.

  3. Role of Age-Associated Alterations of the Dermal Extracellular Matrix Microenvironment in Human Skin Aging

    PubMed Central

    Quan, Taihao; Fisher, Gary J

    2015-01-01

    Human skin is largely composed of a collagen-rich connective tissue, which provides structural and functional support. The collagen-rich connective tissue is produced, organized, and maintained by dermal fibroblasts. During aging, dermal collagen fibrils undergo progressive loss and fragmentation, leading to thin and structurally weakened skin. Age-related alterations of collagen fibrils impairs skin structure and function and creates a tissue microenvironment that promotes age-related skin diseases, such as delayed wound healing and skin cancer development. This review describes cellular mechanisms that give rise to self-perpetuating, collagen fibril fragmentation that creates an age-associated dermal microenvironment (AADM), which contributes to decline of human skin function. PMID:25660807

  4. Lipofuscin Granules in the Epileptic Human Temporal Neocortex with Age.

    PubMed

    Merlo, Suélen; Nakayama, Ana Beatriz S; Brusco, Janaina; Rossi, Marcos A; Carlotti, Carlos G; Moreira, Jorge E

    2015-01-01

    Lipofuscin granules (LGs), the "age pigments", are autofluorescent cell products from lysosomes that diverge in number and size among brain regions. Human temporal cortex from 20- to 55-year-old epileptic subjects were studied with the fat soluble dye Sudan Black, under confocal and electron microscopy. Ultrastructural analysis showed that with age LGs increase in area, but not in number. Proportionally to the LGs area, the electron lucid portion increases and the electron dense reduces over time. The robust increase in lipid components is possibly due to modifications in the neuronal metabolism with age in physiological and pathological conditions.

  5. CRIM1 haploinsufficiency causes defects in eye development in human and mouse.

    PubMed

    Beleggia, Filippo; Li, Yun; Fan, Jieqing; Elcioğlu, Nursel H; Toker, Ebru; Wieland, Thomas; Maumenee, Irene H; Akarsu, Nurten A; Meitinger, Thomas; Strom, Tim M; Lang, Richard; Wollnik, Bernd

    2015-04-15

    Colobomatous macrophthalmia with microcornea syndrome (MACOM, Online Mendelian Inheritance in Man (OMIM) 602499) is an autosomal dominantly inherited malformation of the eye, which is characterized by microcornea with increased axial length, coloboma of the iris and of the optic disc, and severe myopia. We performed whole-exome sequencing (WES) in two affected individuals from the 2p23-p16-linked MACOM family, which includes 13 affected individuals in 3 generations. As no shared novel variation was found on the linked haplotype, we performed copy number variation (CNV) analysis by comparing the coverage of all exons in the WES data sets of the 2 patients with the coverage of 26 control exomes. We identified a heterozygous deletion predicted to span 22 kb including exons 14-17 of CRIM1 (cysteine-rich transmembrane bone morphogenetic protein (BMP) regulator 1). Quantitative PCR (qPCR) analysis confirmed the deletion, which was present in 11 affected individuals. Split-read analysis of WES data followed by breakpoint PCR and Sanger sequencing determined both breakpoints flanked by a 4-bp microhomology (CTTG). In the mouse, Crim1 is a growth-factor-binding protein with pleiotropic roles in the development of multiple organs, including the eye. To investigate the role of Crim1 during eye development in mice, we crossed a Crim1(flox) mouse line with the Ap2α-cre mouse line, which expresses Cre in the head surface ectoderm. Strikingly, we observed alterations of eye development in homozygous mice leading to severe anatomical and morphological changes overlapping with the anomalies observed in MACOM patients. Taken together, these findings identify CRIM1 as the causative gene for MACOM syndrome and emphasize the importance of CRIM1 in eye development.

  6. Relationship between Human Aging Muscle and Oxidative System Pathway

    PubMed Central

    Doria, Enrico; Buonocore, Daniela; Focarelli, Angela; Marzatico, Fulvio

    2012-01-01

    Ageing is a complex process that in muscle is usually associated with a decrease in mass, strength, and velocity of contraction. One of the most striking effects of ageing on muscle is known as sarcopenia. This inevitable biological process is characterized by a general decline in the physiological and biochemical functions of the major systems. At the cellular level, aging is caused by a progressive decline in mitochondrial function that results in the accumulation of reactive oxygen species (ROS) generated by the addition of a single electron to the oxygen molecule. The aging process is characterized by an imbalance between an increase in the production of reactive oxygen species in the organism and the antioxidant defences as a whole. The goal of this review is to examine the results of existing studies on oxidative stress in aging human skeletal muscles, taking into account different physiological factors (sex, fibre composition, muscle type, and function). PMID:22685621

  7. Responsiveness of the National Eye Institute Visual Function Questionnaire to Progression to Advanced Age-Related Macular Degeneration, Vision Loss, and Lens Opacity

    PubMed Central

    2006-01-01

    Objective To describe the ability of the National Eye Institute Visual Function Questionnaire (NEI-VFQ) to detect meaningful change over time (responsiveness) to the primary Age-Related Eye Disease Study outcomes. Methods The 25-item NEI-VFQ plus appendix was administered at 2 visits at 1- to 4-year intervals to 4119 participants in the Age-Related Eye Disease Study. Events evaluated were progression to advanced age-related macular degeneration (AMD), visual acuity (VA) loss of at least 15 letters, and lens opacity progression. Responsiveness was measured by the t statistic, effect size (ES), responsiveness statistic, and area under the receiver operating characteristic curve. Variance components were used to estimate the contributions of events to variability of the NEI-VFQ score. Results Overall NEI-VFQ score was responsive to AMD progression (t = 14.0; P<.001; ES=0.81) and VA (t = 16.2; P<.001; ES=0.74). Mean changes ranged from 11 to 25 points for the subscales of general vision, near and distance activities, social functioning, mental health, role difficulties, dependency, and driving. The NEI-VFQ was unresponsive to lens opacity progression, although when the event occurred in the eye with the best vision at the first administration, the lens opacity ES was moderate for the color vision (ES = 0.62) and driving subscales (ES=0.66). Progression to advanced AMD and VA loss contributed significantly to the variation in the mean difference in overall VFQ score. Conclusions Changes in the NEI-VFQ overall and subscale scores of 10 points or more are associated with clinically significant changes in vision and AMD. This finding may assist the design of interventional studies of AMD and VA loss that include the NEI-VFQ as an outcome measure. PMID:16157800

  8. Human Aging Is a Metabolome-related Matter of Gender.

    PubMed

    Jové, Mariona; Maté, Ianire; Naudí, Alba; Mota-Martorell, Natalia; Portero-Otín, Manuel; De la Fuente, Mónica; Pamplona, Reinald

    2016-05-01

    A molecular description of the mechanisms by which aging is produced is still very limited. Here, we have determined the plasma metabolite profile by using high-throughput metabolome profiling technologies of 150 healthy humans ranging from 30 to 100 years of age. Using a nontargeted approach, we detected 2,678 metabolite species in plasma, and the multivariate analyses separated perfectly two groups indicating a specific signature for each gender. In addition, there is a set of gender-shared metabolites, which change significantly during aging with a similar tendency. Among the identified molecules, we found vitamin D2-related compound, phosphoserine (40:5), monoacylglyceride (22:1), diacylglyceride (33:2), and resolvin D6, all of them decreasing with the aging process. Finally, we found three molecules that directly correlate with age and seven that inversely correlate with age, independently of gender. Among the identified molecules (6 of 10 according to exact mass and retention time), we found a proteolytic product (l-γ-glutamyl-l-leucine), which increased with age. On the contrary, a hydroxyl fatty acid (25-hydroxy-hexacosanoic), a polyunsaturated fatty acid (eicosapentaenoic acid), two phospholipids (phosphocholine [42:9]and phosphoserine [42:3]) and a prostaglandin (15-keto-prostaglandin F2α) decreased with aging. These results suggest that lipid species and their metabolism are closely linked to the aging process.

  9. Aging in mouse and human systems: a comparative study.

    PubMed

    Demetrius, Lloyd

    2006-05-01

    This article discusses the significance of mouse models as a basis for elucidating the aging process in humans. We identify certain parallels between mouse and human systems and review the theoretical and empirical support for the claim that the large divergence in the rate of aging between the two species resides in differences in the stability of their metabolic networks. We will show that these differences in metabolic stability have their origin in the different ecological constraints the species experience during their evolutionary history. We exploit these ideas to compare the effect of caloric restriction on murine and human systems. The studies predict that the large increases in mean life span and maximum life-span potential observed in laboratory rodents subject to caloric restriction will not obtain in human populations. We predict that, in view of the different metabolic stability of the two systems, caloric restriction will have no effect on the maximum life-span potential of humans, and a relatively minor effect on the mean life span of nonobese populations. This article thus points to certain intrinsic limitations in the use of mouse models in elucidating the aging process in humans. We furthermore contend the view that these limitations can be mitigated by considering the metabolic stability of the two species.

  10. Design and analysis of an adaptive lens that mimics the performance of the crystalline lens in the human eye

    NASA Astrophysics Data System (ADS)

    Santiago-Alvarado, Agustin; Cruz-Félix, Angel S.; Iturbide-Jiménez, F.; Martínez-López, M.; Ramírez-Como, M.; Armengol-Cruz, V.; Vásquez-Báez, I.

    2014-09-01

    Tunable lenses are optical systems that have attracted much attention due to their potential applications in such areas like ophthalmology, machine vision, microscopy and laser processing. In recent years we have been working in the analysis and performance of a liquid-filled variable focal length lens, this is a lens that can modify its focal length by changing the amount of water within it. Nowadays we extend our study to a particular adaptive lens known as solid elastic lens (SEL) that it is formed by an elastic main body made of Polydimethylsiloxane (PDMS Sylgard 184). In this work, we present the design, simulation and analysis of an adaptive solid elastic lens that in principle imitates the accommodation process of the crystalline lens in the human eye. For this work, we have adopted the parameters of the schematic eye model developed in 1985 by Navarro et al.; this model represents the anatomy of the eye as close as possible to reality by predicting an acceptable and accurate quantity of spherical and chromatic aberrations without any shape fitting. An opto-mechanical analysis of the accommodation process of the adaptive lens is presented, by simulating a certain amount of radial force applied onto the SEL using the finite element method with the commercial software SolidWorks®. We also present ray-trace diagrams of the simulated compression process of the adaptive lens using the commercial software OSLO®.

  11. The modelling of the influence of a corneal geometry on the pupil image of the human eye

    NASA Astrophysics Data System (ADS)

    Szczesna, D. H.; Kasprzak, H. T.

    2006-07-01

    In normal conditions, a pupil of the eye is observed through the optical system of the cornea. The cornea is the anterior surface of the eye and is the major refractive element of the human eye. The influence of the corneal shape should not be neglected in measurements of the pupil size. The purpose of this study was to estimate the influence of the corneal geometry, the diameter of the pupil and its position in the anterior chamber on the magnification and position of the image of the pupil. The numerical calculations presented in the paper assume infinitely thin cornea, and the corneal topography was approximated by the elongated ellipsoid. The ray tracing procedure was used in our numerical modelling. The magnification of the pupil image amounted to about 10% and increases with decrease of radius of curvature and eccentricity of the corneal profile and decreases for the largest pupil. The results show also that the pupil image is placed nearer the corneal apex than the real pupil. The image of the pupil is always blurred, which limits the sharp observation of the pupil.

  12. Setting targets for human resources for eye health in sub-Saharan Africa: what evidence should be used?

    PubMed

    Courtright, Paul; Mathenge, Wanjiku; Kello, Amir Bedri; Cook, Colin; Kalua, Khumbo; Lewallen, Susan

    2016-03-16

    With a global target set at reducing vision loss by 25% by the year 2019, sub-Saharan Africa with an estimated 4.8 million blind persons will require human resources for eye health (HReH) that need to be available, appropriately skilled, supported, and productive. Targets for HReH are useful for planning, monitoring, and resource mobilization, but they need to be updated and informed by evidence of effectiveness and efficiency. Supporting evidence should take into consideration (1) ever-changing disease-specific issues including the epidemiology, the complexity of diagnosis and treatment, and the technology needed for diagnosis and treatment of each condition; (2) the changing demands for vision-related services of an increasingly urbanized population; and (3) interconnected health system issues that affect productivity and quality. The existing targets for HReH and some of the existing strategies such as task shifting of cataract surgery and trichiasis surgery, as well as the scope of eye care interventions for primary eye care workers, will need to be re-evaluated and re-defined against such evidence or supported by new evidence.

  13. The Human Right to Leisure in Old Age: Reinforcement of the Rights of an Aging Population.

    PubMed

    Karev, Iris; Doron, Israel Issi

    2016-11-23

    The right to leisure is recognized as a human right under the 1948 United Nations Universal Declaration of Human Rights. The actual meaning and material content of this human right is subject to debate. The aim of this study is to examine the extent and the context to which this human right is specifically recognized with regard to older persons. Methodologically, this study textually analyzed 17 different international older persons' human rights documents. The findings reveal that in the majority of these documents there is no reference to the right to leisure. In the remaining documents, the right to leisure is mostly referred to indirectly or in a narrow legal construction. These findings support the notion that despite the growing body of knowledge regarding the importance of meaningful leisure in old age-and its empowering and anti-ageist nature-this knowledge has not transformed into a legal human rights discourse.

  14. Eye Diseases

    MedlinePlus

    ... the back of the eye Macular degeneration - a disease that destroys sharp, central vision Diabetic eye problems ... defense is to have regular checkups, because eye diseases do not always have symptoms. Early detection and ...

  15. Eye Injuries

    MedlinePlus

    The structure of your face helps protect your eyes from injury. Still, injuries can damage your eye, sometimes severely enough that you could lose your vision. Most eye injuries are preventable. If you play sports or ...

  16. Eye Cancer

    MedlinePlus

    Cancer of the eye is uncommon. It can affect the outer parts of the eye, such as the eyelid, which are made up ... adults are melanoma and lymphoma. The most common eye cancer in children is retinoblastoma, which starts in ...

  17. Watery eyes

    MedlinePlus

    ... the most common causes of excess tearing is dry eyes . Drying causes the eyes to become uncomfortable, which stimulates the body to produce too many tears. One of the main tests for tearing is to check whether the eyes ...

  18. Three-dimensional ray tracing in spherical and elliptical generalized Luneburg lenses for application in the human eye lens.

    PubMed

    Gómez-Correa, J E; Coello, V; Garza-Rivera, A; Puente, N P; Chávez-Cerda, S

    2016-03-10

    Ray tracing in spherical Luneburg lenses has always been represented in 2D. All propagation planes in a 3D spherical Luneburg lens generate the same ray tracing, due to its radial symmetry. A geometry without radial symmetry generates a different ray tracing. For this reason, a new ray tracing method in 3D through spherical and elliptical Luneburg lenses using 2D methods is proposed. The physics of the propagation is shown here, which allows us to make a ray tracing associated with a vortex beam. A 3D ray tracing in a composite modified Luneburg lens that represents the human eye lens is also presented.

  19. ADAPTIVE EYE MODEL - Poster Paper

    NASA Astrophysics Data System (ADS)

    Galetskiy, Sergey O.; Kudryashov, Alexey V.

    2008-01-01

    We propose experimental adaptive eye model based on flexible 18-electrode bimorph mirror reproducing human eye aberrations up to 4th radial order of Zernike polynomials at frequency of 10Hz. The accuracy of aberrations reproduction in most cases is better than λ/10 RMS. The model is introduced to aberrometer for human eye aberrations compensation to improve visual acuity test.

  20. Establishment of a new in vitro test method for evaluation of eye irritancy using a reconstructed human corneal epithelial model, LabCyte CORNEA-MODEL.

    PubMed

    Katoh, Masakazu; Hamajima, Fumiyasu; Ogasawara, Takahiro; Hata, Ken-ichiro

    2013-12-01

    Finding in vitro eye irritation testing alternatives to animal testing such as the Draize eye test, which uses rabbits, is essential from the standpoint of animal welfare. It has been developed a reconstructed human corneal epithelial model, the LabCyte CORNEA-MODEL, which has a representative corneal epithelium-like structure. Protocol optimization (pre-validation study) was examined in order to establish a new alternative method for eye irritancy evaluation with this model. From the results of the optimization experiments, the application periods for chemicals were set at 1min for liquid chemicals or 24h for solid chemicals, and the post-exposure incubation periods were set at 24h for liquids or zero for solids. If the viability was less than 50%, the chemical was judged to be an eye irritant. Sixty-one chemicals were applied in the optimized protocol using the LabCyte CORNEA-MODEL and these results were evaluated in correlation with in vivo results. The predictions of the optimized LabCyte CORNEA-MODEL eye irritation test methods were highly correlated with in vivo eye irritation (sensitivity 100%, specificity 80.0%, and accuracy 91.8%). These results suggest that the LabCyte CORNEA-MODEL eye irritation test could be useful as an alternative method to the Draize eye test.

  1. Magnesium and fluoride distribution in human cementum with age.

    PubMed

    Tsuboi, S; Nakagaki, H; Takami, Y; Eba, H; Kirkham, J; Robinson, C

    2000-12-01

    Sixty-two human teeth, obtained from subjects aged 11 to 80 years, were used to determine the magnesium and fluoride concentration and distribution with age in human cementum. Transverse sections were prepared from the root region of teeth. Samples, each 30 microm thick, were abraded in sequence from the cementum surface and the cemento-dentine junction by an abrasive micro-sampling technique. Magnesium concentrations were lower in the cementum surface, and increased towards the cemento-dentine junction (CDJ), while fluoride concentrations were higher in cementum surfaces and tended to decrease towards CDJ. Fluoride distribution patterns were similar to that reported earlier while average fluoride concentration increased with age, however, either no change or decreasing tendencies were observed with magnesium.

  2. Age effects in the human middle ear: Wideband acoustical measures

    NASA Astrophysics Data System (ADS)

    Feeney, M. Patrick; Sanford, Chris A.

    2004-12-01

    Studies that have examined age effects in the human middle ear using either admittance measures at 220 or 660 Hz or multifrequency tympanometry from 200 to 2000 Hz have had conflicting results. Several studies have suggested an increase in admittance with age, while several others have suggested a decrease in admittance with age. A third group of studies found no significant age effect. This study examined 226 Hz tympanometry and wideband energy reflectance and impedance at ambient pressure in a group of 40 young adults and a group of 30 adults with age >=60 years. The groups did not differ in admittance measures of the middle ear at 226 Hz. However, significant age effects were found in wideband energy reflectance and impedance. In particular, in older adults there was a comparative decrease in reflectance from 800 to 2000 Hz but an increase near 4000 Hz. The results suggest a decrease in middle-ear stiffness with age. The findings of this study hold relevance for understanding the aging process in the auditory system, for the establishment of normative data for wideband energy reflectance, for the possibility of a conductive component to presbycusis, and for the interpretation of otoacoustic emission measurements. .

  3. The Laboratory Rat: Relating Its Age With Human's

    PubMed Central

    Sengupta, Pallav

    2013-01-01

    By late 18th or early 19th century, albino rats became the most commonly used experimental animals in numerous biomedical researches, as they have been recognized as the preeminent model mammalian system. But, the precise correlation between age of laboratory rats and human is still a subject of debate. A number of studies have tried to detect these correlations in various ways, But, have not successfully provided any proper association. Thus, the current review attempts to compare rat and human age at different phases of their life. The overall findings indicate that rats grow rapidly during their childhood and become sexually mature at about the sixth week, but attain social maturity 5-6 months later. In adulthood, every day of the animal is approximately equivalent to 34.8 human days (i.e., one rat month is comparable to three human years). Numerous researchers performed experimental investigations in albino rats and estimated, in general, while considering their entire life span, that a human month resembles every-day life of a laboratory rat. These differences signify the variations in their anatomy, physiology and developmental processes, which must be taken into consideration while analyzing the results or selecting the dose of any research in rats when age is a crucial factor. PMID:23930179

  4. Interventions to Slow Aging in Humans: Are We Ready?

    PubMed Central

    Longo, Valter D; Antebi, Adam; Bartke, Andrzej; Barzilai, Nir; Brown-Borg, Holly M; Caruso, Calogero; Curiel, Tyler J; de Cabo, Rafael; Franceschi, Claudio; Gems, David; Ingram, Donald K; Johnson, Thomas E; Kennedy, Brian K; Kenyon, Cynthia; Klein, Samuel; Kopchick, John J; Lepperdinger, Guenter; Madeo, Frank; Mirisola, Mario G; Mitchell, James R; Passarino, Giuseppe; Rudolph, Karl L; Sedivy, John M; Shadel, Gerald S; Sinclair, David A; Spindler, Stephen R; Suh, Yousin; Vijg, Jan; Vinciguerra, Manlio; Fontana, Luigi

    2015-01-01

    The workshop entitled ‘Interventions to Slow Aging in Humans: Are We Ready?’ was held in Erice, Italy, on October 8–13, 2013, to bring together leading experts in the biology and genetics of aging and obtain a consensus related to the discovery and development of safe interventions to slow aging and increase healthy lifespan in humans. There was consensus that there is sufficient evidence that aging interventions will delay and prevent disease onset for many chronic conditions of adult and old age. Essential pathways have been identified, and behavioral, dietary, and pharmacologic approaches have emerged. Although many gene targets and drugs were discussed and there was not complete consensus about all interventions, the participants selected a subset of the most promising strategies that could be tested in humans for their effects on healthspan. These were: (i) dietary interventions mimicking chronic dietary restriction (periodic fasting mimicking diets, protein restriction, etc.); (ii) drugs that inhibit the growth hormone/IGF-I axis; (iii) drugs that inhibit the mTOR–S6K pathway; or (iv) drugs that activate AMPK or specific sirtuins. These choices were based in part on consistent evidence for the pro-longevity effects and ability of these interventions to prevent or delay multiple age-related diseases and improve healthspan in simple model organisms and rodents and their potential to be safe and effective in extending human healthspan. The authors of this manuscript were speakers and discussants invited to the workshop. The following summary highlights the major points addressed and the conclusions of the meeting. PMID:25902704

  5. Interventions to Slow Aging in Humans: Are We Ready?

    PubMed

    Longo, Valter D; Antebi, Adam; Bartke, Andrzej; Barzilai, Nir; Brown-Borg, Holly M; Caruso, Calogero; Curiel, Tyler J; de Cabo, Rafael; Franceschi, Claudio; Gems, David; Ingram, Donald K; Johnson, Thomas E; Kennedy, Brian K; Kenyon, Cynthia; Klein, Samuel; Kopchick, John J; Lepperdinger, Guenter; Madeo, Frank; Mirisola, Mario G; Mitchell, James R; Passarino, Giuseppe; Rudolph, Karl L; Sedivy, John M; Shadel, Gerald S; Sinclair, David A; Spindler, Stephen R; Suh, Yousin; Vijg, Jan; Vinciguerra, Manlio; Fontana, Luigi

    2015-08-01

    The workshop entitled 'Interventions to Slow Aging in Humans: Are We Ready?' was held in Erice, Italy, on October 8-13, 2013, to bring together leading experts in the biology and genetics of aging and obtain a consensus related to the discovery and development of safe interventions to slow aging and increase healthy lifespan in humans. There was consensus that there is sufficient evidence that aging interventions will delay and prevent disease onset for many chronic conditions of adult and old age. Essential pathways have been identified, and behavioral, dietary, and pharmacologic approaches have emerged. Although many gene targets and drugs were discussed and there was not complete consensus about all interventions, the participants selected a subset of the most promising strategies that could be tested in humans for their effects on healthspan. These were: (i) dietary interventions mimicking chronic dietary restriction (periodic fasting mimicking diets, protein restriction, etc.); (ii) drugs that inhibit the growth hormone/IGF-I axis; (iii) drugs that inhibit the mTOR-S6K pathway; or (iv) drugs that activate AMPK or specific sirtuins. These choices were based in part on consistent evidence for the pro-longevity effects and ability of these interventions to prevent or delay multiple age-related diseases and improve healthspan in simple model organisms and rodents and their potential to be safe and effective in extending human healthspan. The authors of this manuscript were speakers and discussants invited to the workshop. The following summary highlights the major points addressed and the conclusions of the meeting.

  6. Coupling Osmolarity Dynamics within Human Tear Film on an Eye-Shaped Domain

    NASA Astrophysics Data System (ADS)

    Li, Longfei; Braun, R. J.; Driscoll, T. A.; Henshaw, W. D.; Banks, J. W.; King-Smith, P. E.

    2013-11-01

    The concentration of ions in the tear film (osmolarity) is a key variable in understanding dry eye symptoms and disease. We derived a mathematical model that couples osmolarity (treated as a single solute) and fluid dynamics within the tear film on a 2D eye-shaped domain. The model concerns the physical effects of evaporation, surface tension, viscosity, ocular surface wettability, osmolarity, osmosis and tear fluid supply and drainage. We solved the governing system of coupled nonlinear PDEs using the Overture computational framework developed at LLNL, together with a new hybrid time stepping scheme (using variable step BDF and RKC) that was added to the framework. Results of our numerical simulations show good agreement with existing 1D models (for both tear film and osmolarity dynamics) and provide new insight about the osmolarity distribution over the ocular surface during the interblink.

  7. A model for the human tear film with heating from within the eye

    NASA Astrophysics Data System (ADS)

    Li, Longfei; Braun, R. J.

    2012-06-01

    A model for tear film dynamics and cooling during the interblink period is formulated that includes heat transfer from the interior of the eye. Lubrication theory is used to derive an equation for the thickness of the film; the nonlinear partial differential equation for the thickness is solved subject to either a fixed temperature at the substrate or with heat diffusion from within two different model rectangular domains. The model domains are simplified geometries that represent the anterior eye and that may include the cornea and some aqueous humor; one model domain is asymptotically thin