Science.gov

Sample records for aging human eye

  1. Training the brain to overcome the effect of aging on the human eye

    PubMed Central

    Polat, Uri; Schor, Clifton; Tong, Jian-Liang; Zomet, Ativ; Lev, Maria; Yehezkel, Oren; Sterkin, Anna; Levi, Dennis M.

    2012-01-01

    Presbyopia, from the Greek for aging eye, is, like death and taxes, inevitable. Presbyopia causes near vision to degrade with age, affecting virtually everyone over the age of 50. Presbyopia has multiple negative effects on the quality of vision and the quality of life, due to limitations on daily activities – in particular, reading. In addition presbyopia results in reduced near visual acuity, reduced contrast sensitivity, and slower processing speed. Currently available solutions, such as optical corrections, are not ideal for all daily activities. Here we show that perceptual learning (repeated practice on a demanding visual task) results in improved visual performance in presbyopes, enabling them to overcome and/or delay some of the disabilities imposed by the aging eye. This improvement was achieved without changing the optical characteristics of the eye. The results suggest that the aging brain retains enough plasticity to overcome the natural biological deterioration with age. PMID:22363834

  2. The 3895-bp mitochondrial DNA deletion in the human eye: a potential involvement in corneal ageing and macular degeneration.

    PubMed

    Gendron, Sébastien P; Bastien, Nathalie; Mallet, Justin D; Rochette, Patrick J

    2013-03-01

    In human skin, the 3895-bp deletion of mitochondrial DNA (mtDNA(3895)) is catalysed by ultraviolet (UV) light through the generation of reactive oxygen species. Given its function in vision, the human eye is exposed to oxidising UV and blue light in its anterior (cornea, iris) and posterior (retina) structures. In this study, we employed a highly sensitive quantitative PCR technique to determine mtDNA(3895) occurrence in human eye. Our analysis shows that the mtDNA(3895) is concentrated in both the cornea and the retina. Within the cornea, the highest mtDNA(3895) level is found in the stroma, the cellular layer conferring transparency and rigidity to the human cornea. Moreover, mtDNA(3895) accumulates with age in the stroma, suggesting a role of this deletion in corneal ageing. Within the retina, mtDNA(3895) is concentrated in the macular region of both the neural retina and the retinal pigment epithelium, supporting the hypothesis that this deletion is implicated in retinal pathologies such as age-related macular degenerescence. Taken together, our results imply that UV and blue light catalyse mtDNA(3895) induction in the human eye.

  3. Aging and dry eye disease.

    PubMed

    Ding, Juan; Sullivan, David A

    2012-07-01

    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.

  4. 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

  5. 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

  6. FDA Approves Eye Implant for Aging Boomers

    MedlinePlus

    ... fullstory_159648.html FDA Approves Eye Implant for Aging Boomers Tiny lens reshapes cornea to improve focus ... 2016 (HealthDay News) -- An implant that helps the aging eye focus on small print and nearby objects ...

  7. 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...

  8. 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. PMID:25620292

  9. 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.

  10. Aging effects upon pursuit eye movements.

    PubMed

    Kato, I; Sakuma, A; Ogino, S; Takahashi, K; Okada, T

    1995-01-01

    Quantitative assessment of aging effects upon pursuit eye movements was done in step-ramp stimulus conditions using 32 normal individuals. Eye movements were recorded with infrared reflection oculography. The target was a spot of 0.5 degree red lazar light. The light spot was blanked for 5 ms while the mirror galvanometer moved to a new position. Eye and target position were sampled at 250 Hz and analysed by a personal computer. In onward stimulation in which 2 degrees, 4 degrees, 6 degrees and 8 degrees position steps were followed by fixed ramp speed (10 degrees/s), and also in backward stimulation in which 2 degrees, 4 degrees, 6 degrees step positions were followed by 9 degrees, 17 degrees and 27 degrees/s, eye acceleration increased depending upon increase of retinal slip velocity in the younger group below 49 years. Among the factors effecting aging effects, the cerebrum might be important because visual recognition and eye acceleration are performed in the parietal lobe. PMID:8749143

  11. 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.

  12. Clinical Applications of Dexamethasone for Aged Eyes.

    PubMed

    Abadia, Beatriz; Calvo, Pilar; Ferreras, Antonio; Bartol, Fran; Verdes, Guayente; Pablo, Luis

    2016-09-01

    The risk of severe eye problems has been found to increase significantly with age, particularly between the fifth and sixth decades of life. Cataracts, dry eye, neovascular age-related macular degeneration, diabetic retinopathy and retinal vein occlusion (RVO) are very common and very different age-related ocular diseases that reduce the patient's quality of life. The rationale for using corticosteroids to treat anterior and posterior ocular segment diseases is driven by inflammation. Dexamethasone, one of the most powerful corticosteroids available, is widely used for topical or intravitreal administration. Topical dexamethasone has proven efficacy for the management of postoperative inflammation in the anterior segment after cataract surgery and symptom relief in dry-eye disease. A new sustained-release 700 µg dexamethasone intravitreal implant (DEX) was recently approved for the treatment of macular edema following RVO, diabetic macular edema, or non-infectious uveitis, and its use is increasing, especially when other therapeutic agents have failed. The most common side effects are increased intraocular pressure and cataract formation. The potency of DEX, alone or in combination with other agents, makes DEX a promising option for treating several retinal diseases. PMID:27566619

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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. PMID:23521031

  18. Optical analysis of human eye using electromagnetic wave theory.

    PubMed

    Can, Melih G; Oner, Bilgehan B; Kurt, Hamza

    2013-10-01

    We present a two-dimensional electromagnetic analysis of light propagation through the human eye to examine the eye's optical properties. The electromagnetic approach has intriguing advantages over the conventional and frequently implemented ray optics analysis. The chromatic, spherical, and coma aberrations and the intensity of the focused light at the retina are computed in this work via full-wave analysis. We also investigate the effects of the cornea's and lens's curved structures on the focusing mechanism. The focal length and chromatic and spherical aberrations are observed to change owing to age-related refractive index variation in the lens. In addition, the effects of the lens and curvatures of the human eye on focusing are analyzed. Consequently, for both young and old human eye lenses, the differences due to the aberration variations, curvature surfaces, and gradient index are explored by the wave approach. The intensity distributions on the retina for both on- and off-axis illumination are calculated. A strong correlation between the locations of the nerve fibers and the intensity distribution is confirmed. On the basis of the findings, we can conclude that visual impairment due to deterioration of the human eye structure is more dramatic than that due to aging.

  19. Adaptive Optics for the Human Eye

    NASA Astrophysics Data System (ADS)

    Williams, D. R.

    2000-05-01

    Adaptive optics can extend not only the resolution of ground-based telescopes, but also the human eye. Both static and dynamic aberrations in the cornea and lens of the normal eye limit its optical quality. Though it is possible to correct defocus and astigmatism with spectacle lenses, higher order aberrations remain. These aberrations blur vision and prevent us from seeing at the fundamental limits set by the retina and brain. They also limit the resolution of cameras to image the living retina, cameras that are a critical for the diagnosis and treatment of retinal disease. I will describe an adaptive optics system that measures the wave aberration of the eye in real time and compensates for it with a deformable mirror, endowing the human eye with unprecedented optical quality. This instrument provides fresh insight into the ultimate limits on human visual acuity, reveals for the first time images of the retinal cone mosaic responsible for color vision, and points the way to contact lenses and laser surgical methods that could enhance vision beyond what is currently possible today. Supported by the NSF Science and Technology Center for Adaptive Optics, the National Eye Institute, and Bausch and Lomb, Inc.

  20. Study of Light Scattering in the Human Eye

    NASA Astrophysics Data System (ADS)

    Perez, I. Kelly; Bruce, N. C.; Valdos, L. R. Berriel

    2008-04-01

    In this paper we present a numerical model of the human eye to be used in studies of the scattering of light in different components of the eye's optical system. Different parts of the eye are susceptible to produce scattering for different reasons; age, illness or injury. For example, cataracts can appear in the human lens or injuries or fungi can appear on the cornea. The aim of the study is to relate the backscattered light, which is what doctors measure or detect, to the forward scattered light, which is what affects the patient's vision. We present the model to be used, the raytrace procedure and some preliminary results for the image on the retina without scattering.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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

  7. 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

  8. Adaptive optics in ophthalmology: human eye wavefront generator

    NASA Astrophysics Data System (ADS)

    Galetskiy, Sergey O.; Cherezova, Tatyana Y.; Kudryashov, Alexis V.

    2008-02-01

    We present human eye wavefront generator (HEWG) introduced inside aberrometer for dynamic reproduction of human eye aberrations. It's main element is bimorph deformable mirror and a telescope. Deformable mirror generates human eye aberrations in real time. We have recorded aberrations time traces for plurality of subjects using aberrometer and reproduced them with the help of the generator at 10Hz frequency, that is inherit to human eye aberrations dynamics. Experimental results indicate that HEWG can reproduce dynamics of human eye aberrations with residual error less than λ/10 microns. Such a model can be useful for testing, for example, customized contact lenses or wavefront guided aberrometers.

  9. Optical clearing of human eye sclera

    NASA Astrophysics Data System (ADS)

    Bashkatov, Alexey N.; Genina, Elina A.; Kochubey, Vyacheslav I.; Kamenskikh, Tatyana G.; Tuchin, Valery V.

    2009-02-01

    We present experimental results of investigation of the optical properties of the human eye sclera controlled by administration of osmotically active chemical, such as 40%-glucose solution. Administration of the chemical agent induces diffusion of matter and as a result equalization of the refractive indices of collagen and ground material. Results of the experimental study of influence of the glucose solution on the absorption and scattering properties of human sclera are presented. In vitro reflectance and transmittance spectra of the human sclera samples were measured by commercially available spectrophotometer CARY-2415 in the spectral range from 400 to 1800 nm. The reduced scattering coefficient of human sclera samples is significantly decreased under action of the osmotical solution were demonstrated.

  10. An attempt to age mallards using eye lens proteins

    USGS Publications Warehouse

    Henny, C.J.; Ludke, J.L.

    1974-01-01

    An analysis of insoluble protein content of eye lenses from 59 known-age mallards (Anas platyrhynchos) indicated a slight increase between 8-9 months and 7 years of age. Nearly a complete overlapping of the insoluble protein content of individuals of different ages was apparent showing that the technique cannot be used to separate adult year classes of mallards. These results are contrary to findings reported for selected mammalian species; a possible explanation for the dissimilarity is discussed.

  11. 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.

  12. 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

  13. Biodemography of human ageing

    PubMed Central

    Vaupel, James W.

    2014-01-01

    Human senescence has been delayed by a decade. This finding, documented in 1994 and bolstered since, is a fundamental discovery about the biology of human ageing, and one with profound implications for individuals, society and the economy. Remarkably, the rate of deterioration with age seems to be constant across individuals and over time: it seems that death is being delayed because people are reaching old age in better health. Research by demographers, epidemiologists and other biomedical researchers suggests that further progress is likely to be made in advancing the frontier of survival — and healthy survival — to even greater ages. PMID:20336136

  14. 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.

  15. 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. PMID:24721554

  16. 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)

  17. 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

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. Longitudinal chromatic aberration of the human infant eye

    PubMed Central

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

    2008-01-01

    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. PMID:18758552

  3. 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.

  4. 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

  5. Molecular Diagnosis of Human Taenia martis Eye Infection.

    PubMed

    Koch, Till; Schoen, Christoph; Muntau, Birgit; Addo, Marylyn; Ostertag, Helmut; Wiechens, Burkhard; Tappe, Dennis

    2016-05-01

    Taenia martis, a tapeworm harbored in the intestine of mustelids, is a rarely encountered zoonotic cysticercosis pathogen. The larval stage closely resembles the Taenia solium cysticercus, but the natural host and thus the epidemiology of the disease is different. We here report a human eye infection diagnosed molecularly in a previously healthy female German patient. The case represents the third human infection described worldwide; the two previous cases were also European, involving eye and brain. PMID:26928837

  6. 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)

  7. Human eye haptics-based multimedia.

    PubMed

    Velandia, David; Uribe-Quevedo, Alvaro; Perez-Gutierrez, Byron

    2014-01-01

    Immersive and interactive multimedia applications offer complementary study tools in anatomy as users can explore 3D models while obtaining information about the organ, tissue or part being explored. Haptics increases the sense of interaction with virtual objects improving user experience in a more realistic manner. Common eye studying tools are books, illustrations, assembly models, and more recently these are being complemented with mobile apps whose 3D capabilities, computing power and customers are increasing. The goal of this project is to develop a complementary eye anatomy and pathology study tool using deformable models within a multimedia application, offering the students the opportunity for exploring the eye from up close and within with relevant information. Validation of the tool provided feedback on the potential of the development, along with suggestions on improving haptic feedback and navigation.

  8. Heat Shock Proteins in the Human Eye

    PubMed Central

    Urbak, Lærke; Vorum, Henrik

    2010-01-01

    Heat shock proteins (Hsps) are believed to primarily protect and maintain cell viability under stressful conditions such as those occurring during thermal and oxidative challenges chiefly by refolding and stabilizing proteins. Hsps are found throughout the various tissues of the eye where they are thought to confer protection from disease states such as cataract, glaucoma, and cancer. This minireview summarizes the placement, properties, and roles of Hsps in the eye and aims to provide a better comprehension of their function and involvement in ocular disease pathogenesis. PMID:22084677

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

    PubMed Central

    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. PMID:25852522

  10. Human frontal eye fields and target switching.

    PubMed

    Muggleton, Neil G; Juan, Chi-Hung; Cowey, Alan; Walsh, Vincent; O'Breathnach, Uinsionn

    2010-02-01

    The frontal eye fields (FEF) have typically been predominantly investigated in terms of their role in the generation of eye movements. Lesions to this area, either accidental or experimental, disrupt saccades and electrical stimulation elicits eye movements. Recently there has been increasing interest in the involvement of this area in visual processes, including in tasks where eye movements were either not required or were precluded. In addition to being involved in a range of visual tasks, evidence from visual search paradigms has suggested that this area might be important when the defining quality of the target is unpredictable or that it may be involved in priming. We investigated the role of FEF in a task requiring localisation of a target defined by colour, in which the target colour was either maintained or switched across trials. Disruption of performance was seen on the task when transcranial magnetic stimulation (TMS) was delivered over the left FEF, specifically elevating response times on trials when the target and distracter colours were switched rather than affecting any benefit of repetition of the target attribute (priming). This result is consistent with altered modulation of extrastriate areas, consequently affecting the speed with which a switch of the target colour could be detected. This both offers an explanation for effects seen in unpredictable feature search and is consistent with other TMS and microstimulation studies showing that FEF modulates responses of extrastriate cortex. PMID:19409541

  11. Aging, Eye Movements, and Object-Location Memory

    PubMed Central

    Shih, Shui-I; Meadmore, Katie L.; Liversedge, Simon P.

    2012-01-01

    This study investigated whether “intentional” instructions could improve older adults' object memory and object-location memory about a scene by promoting object-oriented viewing. Eye movements of younger and older adults were recorded while they viewed a photograph depicting 12 household objects in a cubicle with or without the knowledge that memory about these objects and their locations would be tested (intentional vs. incidental encoding). After viewing, participants completed recognition and relocation tasks. Both instructions and age affected viewing behaviors and memory. Relative to incidental instructions, intentional instructions resulted in more accurate memory about object identity and object-location binding, but did not affect memory accuracy about overall positional configuration. More importantly, older adults exhibited more object-oriented viewing in the intentional than incidental condition, supporting the environmental support hypothesis. PMID:22428060

  12. 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

  13. Wave aberration of human eyes and new descriptors of image optical quality and visual performance.

    PubMed

    Lombardo, Marco; Lombardo, Giuseppe

    2010-02-01

    The expansion of wavefront-sensing techniques redefined the meaning of refractive error in clinical ophthalmology. Clinical aberrometers provide detailed measurements of the eye's wavefront aberration. The distribution and contribution of each higher-order aberration to the overall wavefront aberration in the individual eye can now be accurately determined and predicted. Using corneal or ocular wavefront sensors, studies have measured the interindividual and age-related changes in the wavefront aberration in the normal population with the goal of optimizing refractive surgery outcomes for the individual. New objective optical-quality metrics would lead to better use and interpretation of newly available information on aberrations in the eye. However, the first metrics introduced, based on sets of Zernike polynomials, is not completely suitable to depict visual quality because they do not directly relate to the quality of the retinal image. Thus, several approaches to describe the real, complex optical performance of human eyes have been implemented. These include objective metrics that quantify the quality of the optical wavefront in the plane of the pupil (ie, pupil-plane metrics) and others that quantify the quality of the retinal image (ie, image-plane metrics). These metrics are derived by wavefront aberration information from the individual eye. This paper reviews the more recent knowledge of the wavefront aberration in human eyes and discusses the image-quality and optical-quality metrics and predictors that are now routinely calculated by wavefront-sensor software to describe the optical and image quality in the individual eye.

  14. 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".

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

    PubMed

    Chader, Gerald J; Taylor, Allen

    2013-12-13

    This volume presents articles based on a workshop held June 14 to 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 accelerating translation of research findings to effective clinical care. In this workshop, the subject of the "The Aging Eye" was addressed, including the prevalence of eye diseases in aging and the economic burden imposed by these diseases. New research work was highlighted on the genetics, biology, biochemistry, neurochemistry, and the impact of nutrition and the environment on function in the older eye. By identifying "low-hanging fruit" (i.e., the best opportunities for successful transition of laboratory research for the prevention of and new treatments and cures for ocular diseases), we seek to spur funding at both the basic research and clinical levels, resulting in sight-saving and sight-restoration measures in the near future.

  16. Eye Conditions in Older Adults: Age-Related Macular Degeneration.

    PubMed

    Iroku-Malize, Tochi; Kirsch, Scott

    2016-06-01

    Age-related macular degeneration (AMD) causes a progressive loss of photoreceptors in the macula. It is the most common cause of legal blindness in the United States, and some form of AMD is thought to affect more than 9 million individuals. Risk factors include older age, smoking, dyslipidemia, obesity, white race, female sex, and a family history of AMD. There are two types of advanced AMD: nonexudative (dry or geographic atrophy) and exudative (wet or neovascular). Both cause progressive central vision loss with intact peripheral vision. Nonexudative AMD accounts for 80% to 90% of all advanced cases, and more than 90% of patients with severe vision loss have exudative AMD. On ophthalmoscopic examination, early findings include drusen (ie, yellow deposits in the retina). Prominent choroidal vessels, subretinal edema, and/or hemorrhage are seen in wet AMD. Regular eye examinations, visual field testing, fluorescein angiography, and optical coherence tomography are used for diagnosis and to guide management. There is no specific therapy for dry AMD, but antioxidant supplementation may be helpful. Intravitreal injection of a vascular endothelial growth factor inhibitor is the treatment of choice for wet AMD. Optical aids and devices can help to maximize function for patients with AMD. PMID:27348529

  17. Eye Conditions in Older Adults: Age-Related Macular Degeneration.

    PubMed

    Iroku-Malize, Tochi; Kirsch, Scott

    2016-06-01

    Age-related macular degeneration (AMD) causes a progressive loss of photoreceptors in the macula. It is the most common cause of legal blindness in the United States, and some form of AMD is thought to affect more than 9 million individuals. Risk factors include older age, smoking, dyslipidemia, obesity, white race, female sex, and a family history of AMD. There are two types of advanced AMD: nonexudative (dry or geographic atrophy) and exudative (wet or neovascular). Both cause progressive central vision loss with intact peripheral vision. Nonexudative AMD accounts for 80% to 90% of all advanced cases, and more than 90% of patients with severe vision loss have exudative AMD. On ophthalmoscopic examination, early findings include drusen (ie, yellow deposits in the retina). Prominent choroidal vessels, subretinal edema, and/or hemorrhage are seen in wet AMD. Regular eye examinations, visual field testing, fluorescein angiography, and optical coherence tomography are used for diagnosis and to guide management. There is no specific therapy for dry AMD, but antioxidant supplementation may be helpful. Intravitreal injection of a vascular endothelial growth factor inhibitor is the treatment of choice for wet AMD. Optical aids and devices can help to maximize function for patients with AMD.

  18. HUMAN EYE OPTICS: Determination of positions of optical elements of the human eye

    NASA Astrophysics Data System (ADS)

    Galetskii, S. O.; Cherezova, T. Yu

    2009-02-01

    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.

  19. 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...

  20. 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

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

    PubMed

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

    2015-10-13

    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.

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

    PubMed

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

    2015-10-13

    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

  3. A novel Eyes Absent 2 protein is expressed in the human eye.

    PubMed

    Fee, Brian E; Doyle, Christina A; Cleveland, John L

    2002-02-20

    The Drosophila eyes absent (eya) gene has a role in regulating cell death and/or differentiation and is expressed throughout development. We evaluated the transcripts and proteins encoded by one of the human homologues of Drosophila eya coined Eyes Absent 2 (EYA2). Interestingly, EYA2 was expressed in several neuroblastoma cell lines as four distinct transcripts having alternative 5'-ends, whereas only one EYA2 transcript was expressed in the normal human eye. Due to different translation start sites on the four unique transcripts, two isoforms of EYA2 protein (one previously identified and one novel) could be generated in neuroblastoma cells, but the sole EYA2 transcript expressed in the eye can only encode the novel isoform. Immunoblot analyses suggest that EYA2 may also be post-translationally modified. Finally, the alternative EYA2 transcripts have dissimilar numbers of upstream open reading frames in their 5'-untranslated regions. Therefore, in addition to encoding alternative isoforms of EYA2, regulation of EYA2 expression appears to involve both transcriptional and translational components.

  4. Progress and Standardization in Eye Movement Work with Human Infants

    ERIC Educational Resources Information Center

    Haith, Marshall M.

    2004-01-01

    This article presents the author's comments on a set of articles representing an unusual collation of work by investigators from different parts of the world, using similar high-tech instrumentation and procedures to measure eye movements in infants who lie in a fairly constrained age range. Although the articles in this thematic collection share…

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. Skin mirrors human aging.

    PubMed

    Nikolakis, Georgios; Makrantonaki, Evgenia; Zouboulis, Christos C

    2013-12-01

    Abstract Aged skin exhibits disturbed lipid barrier, angiogenesis, production of sweat, immune functions, and calcitriol synthesis as well as the tendency towards development of certain benign or malignant diseases. These complex biological processes comprise endogenous and exogenous factors. Ethnicity also markedly influences the phenotype of skin aging. The theories of cellular senescence, telomere shortening and decreased proliferative capacity, mitochondrial DNA single mutations, the inflammation theory, and the free radical theory try to explain the biological background of the global aging process, which is mirrored in the skin. The development of advanced glycation end-products and the declining hormonal levels are major factors influencing intrinsic aging. Chronic photodamage of the skin is the prime factor leading to extrinsic skin aging. The deterioration of important skin functions, due to intrinsic and extrinsic aging, leads to clinical manifestations, which mirror several internal age-associated diseases such as diabetes, arterial hypertension and malignancies.

  10. Galaxies, human eyes, and artificial neural networks.

    PubMed

    Lahav, O; Naim, A; Buta, R J; Corwin, H G; de Vaucouleurs, G; Dressler, A; Huchra, J P; van den Bergh, S; Raychaudhury, S; Sodré, L; Storrie-Lombardi, M C

    1995-02-10

    The quantitative morphological classification of galaxies is important for understanding the origin of type frequency and correlations with environment. However, galaxy morphological classification is still mainly done visually by dedicated individuals, in the spirit of Hubble's original scheme and its modifications. The rapid increase in data on galaxy images at low and high redshift calls for a re-examination of the classification schemes and for automatic methods. Here are shown results from a systematic comparison of the dispersion among human experts classifying a uniformly selected sample of more than 800 digitized galaxy images. These galaxy images were then classified by six of the authors independently. The human classifications are compared with each other and with an automatic classification by an artificial neural network, which replicates the classification by a human expert to the same degree of agreement as that between two human experts. PMID:17813914

  11. Age-related effects of bilateral frontal eye fields lesions on rapid eye movements during REM sleep in rhesus monkeys.

    PubMed

    Yu, Shan; Liu, Ning; Zeng, Tao; Tian, Shaohua; Chen, Nanhui; Zhou, Yifeng; Ma, Yuanye

    2004-08-01

    Rapid eye movement (REM) is one of the most characteristic features of REM sleep, but the mechanisms underlying its regulation remain unclear. The present study aims to investigate whether the frontal eye field (FEF) is involved in the regulation of the rapid eye movements during REM sleep. To address this question, we ablated the FEF in four rhesus monkeys and observed the effects of the lesions on sleep architecture. After lesions, two adult monkeys did not show any lesion effect. However, in the other two adolescent monkeys, both the total duration and percentage of the rapid eye movements during REM sleep were decreased moderately. The result suggests that the relation between the FEF and the regulation of the rapid eye movements during REM sleep may be affected by age factor, also indicating that both the functions of the FEF and the mechanisms underlying the control of rapid eye movements during REM sleep might not be the same throughout the whole life span of an animal. PMID:15265590

  12. 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.

  13. Coherent fiber optic sensor for early detection of cataractogenesis in a human eye lens

    NASA Technical Reports Server (NTRS)

    Dhadwal, Harbans S.; Ansari, Rafat R.; Dellavecchia, Michael A.

    1993-01-01

    A lensless backscatter fiber optic probe is used to measure the size distribution of protein molecules inside an excised, but intact, human eye lens. The fiber optic probe, about 5 mm in diameter, can be positioned arbitrarily close to the anterior surface of the eye; it is a trans-receiver, which delivers a Gaussian laser beam into a small region inside the lens and provides a coherent detection of the laser light scattered by the protein molecules in the backward direction. Protein sizes determined from the fast and slow diffusion coefficients show good correlation with the age of the lens and cataractogenesis.

  14. Double-pass imaging polarimetry in the human eye.

    PubMed

    Bueno, J M; Artal, P

    1999-01-01

    A Mueller-matrix imaging polarimeter was developed to measure spatially resolved polarization properties in the living human eye. The apparatus is a double-pass setup that incorporates two liquid-crystal variable retarders and a slow-scan CCD camera in the recording stage. Series of 16 images for the combinations of independent polarization states in the first and second passages were recorded for two experimental conditions: with the camera conjugated either with the retina or with the eye's pupil plane. Spatially resolved collections of Mueller matrices and the degree of polarization were calculated from those images for both retinal and pupil planes. PMID:18071409

  15. 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

  16. 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.

  17. Detecting Blood Flow Response to Stimulation of the Human Eye.

    PubMed

    Pechauer, Alex D; Huang, David; Jia, Yali

    2015-01-01

    Retinal blood supply is tightly regulated under a variety of hemodynamic considerations in order to satisfy a high metabolic need and maintain both vessel structure and function. Simulation of the human eye can induce hemodynamics alterations, and attempt to assess the vascular reactivity response has been well documented in the scientific literature. Advancements in noninvasive imaging technologies have led to the characterization of magnitude and time course in retinal blood flow response to stimuli. This allowed for a better understanding of the mechanism in which blood flow is regulated, as well as identifying functional impairments in the diseased eye. Clinically, the ability to detect retinal blood flow reactivity during stimulation of the eye offers potential for the detection, differentiation, and diagnosis of diseases.

  18. 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.

  19. Molecular restrictions for human eye irritation by chemical vapors

    SciTech Connect

    Cometto-Muniz, J. Enrique . E-mail: ecometto@ucsd.edu; Cain, William S.; Abraham, Michael H.

    2005-09-15

    Previous research showed a cut-off along homologous volatile organic compounds (VOCs) in their ability to produce acute human mucosal irritation. The present study sought to specify the particular cut-off homolog for sensory eye irritation in an acetate and n-alcohol series. A 1900-ml glass vessel system and a three-alternative forced-choice procedure served to test nonyl, decyl, and dodecyl acetate, and 1-nonanol, 1-decanol, and 1-undecanol. Flowrate to the eye ranged from 2 to 8 L/min and time of exposure from 3 to 24 s. Decyl acetate and 1-undecanol were the shortest homologs that failed to produce eye irritation under all conditions, producing a cut-off effect. Increasing the vapor concentration of decyl acetate and 1-undecanol by 3 and 8 times, respectively, via heating them to 37 deg C made either or both VOCs detectable to only half of the 12 subjects tested, even though the higher vapor concentration was well above a predicted eye irritation threshold. When eye irritation thresholds for homologous acetates and n-alcohols were plotted as a function of the longest unfolded length of the molecule, the values for decyl acetate and 1-undecanol fell within a restricted range of 18 to 19 A. The outcome suggests that the basis for the cut-off is biological, that is, the molecule lacks a key size or structure to trigger transduction, rather than physical, that is, the vapor concentration is too low to precipitate detection.

  20. 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…

  1. Image-based modeling of the human eye.

    PubMed

    François, Guillaume; Gautron, Pascal; Breton, Gaspard; Bouatouch, Kadi

    2009-01-01

    Rendering realistic organic materials is a challenging issue. The human eye is an important part of nonverbal communication which, consequently, requires specific modeling and rendering techniques to enhance the realism of virtual characters. We propose an image-based method for estimating both iris morphology and scattering features in order to generate convincing images of virtual eyes. In this regard, we develop a technique to unrefract iris photographs. We model the morphology of the human iris as an irregular multilayered tissue. We then approximate the scattering features of the captured iris. Finally, we propose a real-time rendering technique based on the subsurface texture mapping representation and introduce a precomputed refraction function as well as a caustic function, which accounts for the light interactions at the corneal interface. PMID:19590107

  2. Wavefront sensorless adaptive optics ophthalmoscopy in the human eye.

    PubMed

    Hofer, Heidi; Sredar, Nripun; Queener, Hope; Li, Chaohong; Porter, Jason

    2011-07-18

    Wavefront sensor noise and fidelity place a fundamental limit on achievable image quality in current adaptive optics ophthalmoscopes. Additionally, the wavefront sensor 'beacon' can interfere with visual experiments. We demonstrate real-time (25 Hz), wavefront sensorless adaptive optics imaging in the living human eye with image quality rivaling that of wavefront sensor based control in the same system. A stochastic parallel gradient descent algorithm directly optimized the mean intensity in retinal image frames acquired with a confocal adaptive optics scanning laser ophthalmoscope (AOSLO). When imaging through natural, undilated pupils, both control methods resulted in comparable mean image intensities. However, when imaging through dilated pupils, image intensity was generally higher following wavefront sensor-based control. Despite the typically reduced intensity, image contrast was higher, on average, with sensorless control. Wavefront sensorless control is a viable option for imaging the living human eye and future refinements of this technique may result in even greater optical gains.

  3. Non-invasive glucose determination in the human eye

    NASA Astrophysics Data System (ADS)

    Schrader, Wolfgang; Meuer, Petra; Popp, Jürgen; Kiefer, Wolfgang; Menzebach, Johannes-Ulrich; Schrader, Bernhard

    2005-02-01

    For non-invasive in vivo glucose determinations by means of near-infrared spectroscopy, the anterior chamber of the human eye is a promising site. An optical set-up for the non-invasive glucose determination in the human eye precisely in the anterior chamber with a beam reflected from the surface of the eye lens is presented here. As the anterior chamber has a depth of 3.13±0.50 mm, the beam follows an optical path of 5.3-7.3 mm depending on the angle of incidence, which is individually constant. We will show that it is possible to acquire good concentration predictions for physiological glucose concentrations with such a long optical path. A chemometric study of NIR glucose spectra with concentrations of glucose in water of 10-350 mg/dL (0.56-1.94 mmol/L) resulted in a calibration model which was able to predict physiological glucose concentrations with a root mean square error of prediction RMSEPTest=15.41 mg/dL. The Clarke error grid diagram shows that the model performs well according to medical impact. Using a first in vivo set-up, the precision is not sufficient for a reliable prediction of glucose concentration, especially due to the flickering of the patient's eye and the low reflectivity of the eye lens. Therefore, we have designed a new in vivo set-up: a prototype for a self-monitoring device with controlled geometry and laser radiation at several distinct wavelengths instead of the halogen lamp as light source. This allows a far higher signal/noise ratio under much better reproducible geometrical conditions and at the same time a much smaller necessary light flux.

  4. 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.

  5. Head-Eye Coordination Increases with Age and Varies across Countries

    PubMed Central

    Poirier, Frédéric J.A.M.; Giraudet, Guillaume; Faubert, Jocelyn

    2015-01-01

    ABSTRACT Purpose Head movements in older people may contribute to their dizziness and equilibrium problems. Head gain is the ratio of head movement to total movement (head + eye) when executing a saccade to an eccentric target. Two studies have investigated the relationship between head gain and age but have provided conflicting results. Methods We report head gain data collected from research laboratories and optician stores. Our sample sizes are much larger (n = 657 for laboratory, n = 64,458 for optician stores), permitting more detailed analyses. Results The head-eye coefficient, expressed as 100 times the square root of head gain, was bimodal with one mode of primarily eye movers and one mode of eye-and-head movers. Head-eye coefficient increased with age and was invariant with eye correction and gender. We also found an effect of nation that seemed associated with gross domestic product or by latitude (in the northern hemisphere) and log population density. Discussion Assuming that head movements and visual distortions contribute to dizziness and equilibrium problems, our study suggests that customizing eyewear based on age and country may help in reducing the prevalence of problems associated with head and/or eye movements. PMID:26421683

  6. Extralenticular and Lenticular Aspects of Accommodation and Presbyopia in Human Versus Monkey Eyes

    PubMed Central

    Croft, Mary Ann; McDonald, Jared P.; Katz, Alexander; Lin, Ting-Li; Lütjen-Drecoll, Elke; Kaufman, Paul L.

    2013-01-01

    Purpose. To determine if the accommodative forward movements of the vitreous zonule and lens equator occur in the human eye, as they do in the rhesus monkey eye; to investigate the connection between the vitreous zonule posterior insertion zone and the posterior lens equator; and to determine which components—muscle apex width, lens thickness, lens equator position, vitreous zonule, circumlental space, and/or other intraocular dimensions, including those stated in the objectives above—are most important in predicting accommodative amplitude and presbyopia. Methods. Accommodation was induced pharmacologically in 12 visually normal human subjects (ages 19–65 years) and by midbrain electrical stimulation in 11 rhesus monkeys (ages 6–27 years). Ultrasound biomicroscopy imaged the entire ciliary body, anterior and posterior lens surfaces, and the zonule. Relevant distances were measured in the resting and accommodated eyes. Stepwise regression analysis determined which variables were the most important predictors. Results. The human vitreous zonule and lens equator move forward (anteriorly) during accommodation, and their movements decline with age, as in the monkey. Over all ages studied, age could explain accommodative amplitude, but not as well as accommodative lens thickening and resting muscle apex thickness did together. Accommodative change in distances between the vitreous zonule insertion zone and the posterior lens equator or muscle apex were important for predicting accommodative lens thickening. Conclusions. Our findings quantify the movements of the zonule and ciliary muscle during accommodation, and identify their age-related changes that could impact the optical change that occurs during accommodation and IOL function. PMID:23745002

  7. 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

  8. The origins of human ageing.

    PubMed Central

    Kirkwood, T B

    1997-01-01

    The origins of human ageing are to be found in the origins and evolution of senescence as a general feature in the life histories of higher animals. Ageing is an intriguing problem in evolutionary biology because a trait that limits the duration of life, including the fertile period, has a negative impact on Darwinian fitness. Current theory suggests that senescence occurs because the force of natural selection declines with age and because longevity is only acquired at some metabolic cost. In effect, organisms may trade late survival for enhanced reproductive investments in earlier life. The comparative study of ageing supports the general evolutionary theory and reveals that human senescence, while broadly similar to senescence in other mammalian species, has distinct features, such as menopause, that may derive from the interplay of biological and social evolution. PMID:9460059

  9. Routine Eye Examinations for Persons 20-64 Years of Age

    PubMed Central

    2006-01-01

    - stage (early ARM) and a late-stage (AMD). AMD is the leading cause of blindness in developed countries. The prevalence of AMD increases with increasing age. It is estimated that 1% of people 55 years of age, 5% aged 75 to 84 years and 15% 80 years of age and older have AMD. ARM can be diagnosed during fundoscopy (ophthalmoscopy) which is a visual inspection of the retina by a physician or optometrist, or from a photograph of the retina. There is no cure or prevention for ARM. Likewise, there is currently no treatment to restore vision lost due to AMD. However, there are treatments to delay the progression of the disease and further loss of vision. The Technology A periodic oculo-visual assessment is defined “as an examination of the eye and vision system rendered primarily to determine if a patient has a simple refractive error (visual acuity assessment) including myopia, hypermetropia, presbyopia, anisometropia or astigmatism.” This service includes a history of the presenting complaint, past medical history, visual acuity examination, ocular mobility examination, slit lamp examination of the anterior segment, ophthalmoscopy, and tonometry (measurement of IOP) and is completed by either a physician or an optometrist. Review Strategy The Medical Advisory Secretariat conducted a computerized search of the literature in the following databases: OVID MEDLINE, MEDLINE, In-Process & Other Non-Indexed Citations, EMBASE, INAHTA and the Cochrane Library. The search was limited to English-language articles with human subjects, published from January 2000 to March 2006. In addition, a search was conducted for published guidelines, health technology assessments, and policy decisions. Bibliographies of references of relevant papers were searched for additional references that may have been missed in the computerized database search. Studies including participants 20 years and older, population-based prospective cohort studies, population-based cross-sectional studies when

  10. 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. PMID:26518743

  11. 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.

  12. A superfusion apparatus for ex vivo human eye irritation investigations.

    PubMed

    Elbadawy, Hossein Mostafa; Salvalaio, Gianni; Parekh, Mohit; Ruzza, Alessandro; Baruzzo, Mattia; Cagini, Carlo; Ponzin, Diego; Ferrari, Stefano

    2015-10-01

    A superfusion apparatus (SA) was developed to maintain isolated human corneas ex vivo under conditions which mimic the natural eye environment in vivo, including controlled temperature, tear flow and intraocular pressure. The SA was designed, developed and tested for use in ophthalmic pre-clinical research and to test new pharmaceutical formulations. Corneas undergo an equilibration process in the new physiological environment for one day. The test was then initiated by the application of the test substance, incubation, and temporal assessment of corneal damage using various parameters. The effects of mild and severe irritant concentrations of NaOH (2% and 8%, respectively) on corneal opacity, swelling and epithelial integrity were studied, and the inflammatory status assessed using F4/80 and MPO as macrophages and neutrophils markers, respectively. The SA was then used to test new artificial tear formulations supplemented with silver ions as an active constituent, showing different degrees of inflammatory responses as indicated by the migration of MPO and F4/80 positive cells towards the epithelium. The human cornea superfusion apparatus was proposed as a model for acute eye irritation research.

  13. 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.

  14. Image analysis and statistical evaluation of two-dimensional human eye retina images of healthy and glaucomatous eyes

    NASA Astrophysics Data System (ADS)

    Pluhacek, Frantisek; Pospisil, Jaroslav

    2003-11-01

    In this paper, a new automatic glaucoma diagnostics method which enables to determine the probability of glaucoma occurrence in a studied eye is described. This method is based on the computer image analysis of two-dimensional images of the blind spot of the human eye retina and on the successive statistical evaluation of the obtained data. First, the characteristic symptoms of glaucoma are shortly described. Next, a suitable numerical parameter of the retina blind spot is defined. The computer image analysis method of the automatic determination of the mentioned parameter is described and it is applied to a set of normal healthy eye images and to a set of glaucomatous eye images. The probability of glaucoma occurrence for each value of the introduced parameter is suitably defined and computed by virtue of the statistical evaluation of the obtained results.

  15. 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

  16. The Stability of Human Eye Orientation During Visual Fixation

    NASA Technical Reports Server (NTRS)

    Ott, Dietmar; Seidman, Scott H.; Leigh, R. John

    1992-01-01

    Using the magnetic search coil technique, gaze stability in the horizontal, vertical and torsional planes was measured binocularly in human subjects during visual fixation. Horizontal and vertical eye rotations exhibited a mixture of slow drifts and resetting microsaccades yielding an average standard deviation of 0.11 and 0.10 deg. respectively. In contrast, torsional rotations showed unsystematic smooth drifts with fewer saccades yielding an average standard deviation of 0.18 deg. The lower precision of gaze control in the torsional plane may reflect (1) a discrepancy between the encoding of retinal images in two dimensions but of ocular motor control signals in three dimensions, and (2) the visual consequences of ocular drifts in the torsional plane, which differ from those in the horizontal and vertical planes.

  17. 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.

  18. Mobile Eye Tracking Reveals Little Evidence for Age Differences in Attentional Selection for Mood Regulation

    PubMed Central

    Isaacowitz, Derek M.; Livingstone, Kimberly M.; Harris, Julia A.; Marcotte, Stacy L.

    2014-01-01

    We report two studies representing the first use of mobile eye tracking to study emotion regulation across adulthood. Past research on age differences in attentional deployment using stationary eye tracking has found older adults show relatively more positive looking, and seem to benefit more mood-wise from this looking pattern, compared to younger adults. However, these past studies have greatly constrained the stimuli participants can look at, despite real-world settings providing numerous possibilities for what to choose to look at. We therefore used mobile eye tracking to study age differences in attentional selection, as indicated by fixation patterns to stimuli of different valence freely chosen by the participant. In contrast to stationary eye tracking studies of attentional deployment, Study 1 showed that younger and older individuals generally selected similar proportions of valenced stimuli, and attentional selection had similar effects on mood across age groups. Study 2 replicated this pattern with an adult lifespan sample including middle-aged individuals. Emotion regulation-relevant attention may thus differ depending on whether stimuli are freely chosen or not. PMID:25527965

  19. 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

  20. 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…

  1. Collagens in the aged human macula.

    PubMed

    Marshall, G E; Konstas, A G; Reid, G G; Edwards, J G; Lee, W R

    1994-03-01

    Immunogold cytochemistry was used to investigate the fine structural distribution of collagen types I-VI in Bruch's membrane and choroid of the aged human macula. Macular tissue was obtained from ten eyes, and processed for cryoultramicrotomy and London Resin white embedding. Striated collagen fibrils within the inner and outer collagenous layers were found to contain collagen types I, III and V. In addition, type V collagen was also present in the basement membrane of the choriocapillaris. Gross thickening of the choriocapillaris basement membrane was attributed to the deposition of type IV collagen. However, type IV collagen appeared to be absent from the basement membrane of the retinal pigment epithelium. The interesting location of type VI collagen on the choroidal side of the choriocapillaris suggested that its function is to anchor the choriocapillaris onto the choroid. The collagens studied were absent from fibrous banded material, long-spacing collagen, the elastic layer and amorphous granular material. It was concluded that, of the collagen types studied, only the deposition of type IV collagen contributes to the age-related thickening of Bruch's membrane.

  2. 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.

  3. 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...

  4. Towards a better understanding of human eye disease: insights from the zebrafish, Danio rerio

    PubMed Central

    Bibliowicz, Jonathan; Tittle, Rachel K.; Gross, Jeffrey M.

    2011-01-01

    Visual impairment and blindness is widespread across the human population, and the development of therapies for ocular pathologies is of high priority. The zebrafish represents a valuable model organism for studying human ocular disease; it is utilized in eye research to understand underlying developmental processes, to identify potential causative genes for human disorders, and to develop therapies. Zebrafish eyes are similar in morphology, physiology, gene expression and function to human eyes. Furthermore, zebrafish are highly amenable to laboratory research. This review outlines the use of zebrafish as a model for human ocular diseases such as colobomas, glaucoma, cataracts, photoreceptor degeneration, as well as dystrophies of the cornea and retinal pigmented epithelium. PMID:21377629

  5. Genotype-phenotype associations and human eye color.

    PubMed

    White, Désirée; Rabago-Smith, Montserrat

    2011-01-01

    Although eye color is usually modeled as a simple, Mendelian trait, further research and observation has indicated that eye color does not follow the classical paths of inheritance. Eye color phenotypes demonstrate both epistasis and incomplete dominance. Although there are about 16 different genes responsible for eye color, it is mostly attributed to two adjacent genes on chromosome 15, hect domain and RCC1-like domain-containing protein 2 (HERC2) and ocular albinism (that is, oculocutaneous albinism II (OCA2)). An intron in HERC2 contains the promoter region for OCA2, affecting its expression. Therefore, single-nucleotide polymorphisms in either of these two genes have a large role in the eye color of an individual. Furthermore, with all genetic expression, aberration also occurs. Some individuals may express two phenotypes--one in each eye--or a complete lack of pigmentation, ocular albinism. In addition, the evolutionary and population roles of the different expressions are significant.

  6. Genotype-phenotype associations and human eye color.

    PubMed

    White, Désirée; Rabago-Smith, Montserrat

    2011-01-01

    Although eye color is usually modeled as a simple, Mendelian trait, further research and observation has indicated that eye color does not follow the classical paths of inheritance. Eye color phenotypes demonstrate both epistasis and incomplete dominance. Although there are about 16 different genes responsible for eye color, it is mostly attributed to two adjacent genes on chromosome 15, hect domain and RCC1-like domain-containing protein 2 (HERC2) and ocular albinism (that is, oculocutaneous albinism II (OCA2)). An intron in HERC2 contains the promoter region for OCA2, affecting its expression. Therefore, single-nucleotide polymorphisms in either of these two genes have a large role in the eye color of an individual. Furthermore, with all genetic expression, aberration also occurs. Some individuals may express two phenotypes--one in each eye--or a complete lack of pigmentation, ocular albinism. In addition, the evolutionary and population roles of the different expressions are significant. PMID:20944644

  7. Healthy Eyes

    MedlinePlus

    ... please turn Javascript on. Healthy Eyes Maintaining Your Vision Click for more information Taking good care of ... are qualified to perform eye exams. Aging and Vision Changes As you age, it is normal to ...

  8. 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.

  9. Chinese Eye Exercises and Myopia Development in School Age Children: A Nested Case-control Study

    PubMed Central

    Kang, Meng-Tian; Li, Shi-Ming; Peng, Xiaoxia; Li, Lei; Ran, Anran; Meng, Bo; Sun, Yunyun; Liu, Luo-Ru; Li, He; Millodot, Michel; Wang, Ningli

    2016-01-01

    Chinese eye exercises have been implemented in China as an intervention for controlling children’s myopia for over 50 years. This nested case-control study investigated Chinese eye exercises and their association with myopia development in junior middle school children. Outcome measures were the onset and progression of myopia over a two-year period. Cases were defined as 1. Myopia onset (cycloplegic spherical equivalent ≤ −0.5 diopter in non-myopic children). 2. Myopia progression (myopia shift of ≥1.0 diopter in those who were myopic at baseline). Two independent investigators assessed the quality of Chinese eye exercises performance at the end of the follow-up period. Of 260 children at baseline (mean age was 12.7 ± 0.5 years), 201 were eligible for this study. There was no association between eye exercises and the risk of myopia-onset (OR = 0.73, 95%CI: 0.24–2.21), nor myopia progression (OR = 0.79, 95%CI: 0.41–1.53). The group who performed high quality exercises had a slightly lower myopia progression of 0.15 D than the children who did not perform the exercise over a period of 2 years. However, the limited sample size, low dosage and performance quality of Chinese eye exercises in children did not result in statistical significance and require further studies. PMID:27329615

  10. 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...

  11. 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. PMID:19278018

  12. 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.

  13. 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

  14. 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

  15. VEGF mRNA and Protein Concentrations in the Developing Human Eye

    PubMed Central

    Ma, Irene T.; McConaghy, Suzanne; Namachivayam, Kopperuncholan; Halloran, Brian A.; Kurundkar, Ashish R.; MohanKumar, Krishnan; Maheshwari, Akhil; Ohls, Robin K.

    2014-01-01

    Background Vascular endothelial growth factor (VEGF), a well-characterized regulator of angiogenesis, has been mechanistically implicated in retinal neovascularization and in the pathogenesis of ROP. However, the ontogeny of VEGF expression in the human fetal retina is not well known. Because retinal vasculature grows with gestational maturation, we hypothesized that VEGF expression also increases in the midgestation human fetal eye as a function of gestational age. Methods To identify changes in VEGF gene expression during normal human development, we measured VEGF mRNA by quantitative PCR and measured VEGF protein by ELISA and western blots in 10-24 week gestation fetal vitreous, retina, and serum. Results VEGF mRNA expression in the retina increased with gestational age. VEGF isoform A, particularly its VEGF121 splice variant, contributed to this positive correlation. Consistent with these findings, we detected increasing VEGF121 protein concentrations in vitreous humor from fetuses of 10-24 weeks gestation, while VEGF concentrations decreased in fetal serum. Conclusions VEGF121 mRNA and protein concentrations increase with increasing gestational age in the developing human retina. We speculate that VEGF plays an important role in normal retinal vascular development, and that preterm delivery affects production of this vascular growth factor. PMID:25588190

  16. Genetics of rapid eye movement sleep in humans

    PubMed Central

    Adamczyk, M; Ambrosius, U; Lietzenmaier, S; Wichniak, A; Holsboer, F; Friess, E

    2015-01-01

    The trait-like nature of electroencephalogram (EEG) is well established. Furthermore, EEG of wake and non-rapid eye movement (non-REM) sleep has been shown to be highly heritable. However, the genetic effects on REM sleep EEG microstructure are as yet unknown. REM sleep is of special interest since animal and human data suggest a connection between REM sleep abnormalities and the pathophysiology of psychiatric and neurological diseases. Here we report the results of a study in monozygotic (MZ) and dizygotic (DZ) twins examining the heritability of REM sleep EEG. We studied the architecture, spectral composition and phasic parameters of REM sleep and identified genetic effects on whole investigated EEG frequency spectrum as well as phasic REM parameters (REM density, REM activity and organization of REMs in bursts). In addition, cluster analysis based on the morphology of the EEG frequency spectrum revealed that the similarity among MZ twins is close to intra-individual stability. The observed strong genetic effects on REM sleep characteristics establish REM sleep as an important source of endophenotypes for psychiatric and neurological diseases. PMID:26151926

  17. Efficacy of Chinese Eye Exercises on Reducing Accommodative Lag in School-Aged Children: A Randomized Controlled Trial

    PubMed Central

    Li, Shi-Ming; Kang, Meng-Tian; Peng, Xiao-xia; Li, Si-Yuan; Wang, Yang; Li, Lei; Yu, Jing; Qiu, Li-Xin; Sun, Yun-Yun; Liu, Luo-Ru; Li, He; Sun, Xin; Millodot, Michel; Wang, Ningli

    2015-01-01

    Purpose To evaluate the efficacy of Chinese eye exercises on reducing accommodative lag in children by a randomized, double-blinded controlled trial. Methods A total of 190 children aged 10 to 14 years with emmetropia to moderate myopia were included. They were randomly allocated to three groups: standard Chinese eye exercises group (trained for eye exercises by doctors of traditional Chinese medicine); sham point eye exercises group (instructed to massage on non-acupoints); and eyes closed group (asked to close their eyes without massage). Primary outcome was change in accommodative lag immediately after intervention. Secondary outcomes included changes in corrected near and distant visual acuity, and visual discomfort score. Results Children in the standard Chinese eye exercises group had significantly greater alleviation of accommodative lag (-0.10D) than those in sham point eye exercises group (-0.03D) and eyes closed group (0.07D) (P = 0.04). The proportion of children with alleviation of accommodative lag was significantly higher in the standard Chinese eye exercises group (54.0%) than in the sham point eye exercises group (32.8%) and the eyes closed group (34.9%) (P = 0.03). No significant differences were found in secondary outcomes. Conclusion Chinese eye exercises as performed daily in primary and middle schools in China have statistically but probably clinically insignificant effect in reducing accommodative lag of school-aged children in the short-term. Considering the higher amounts of near work load of Chinese children, the efficacy of eye exercises may be insufficient in preventing myopia progression in the long-term. Trial Registration ClinicalTrials.gov NCT01756287 PMID:25742161

  18. Snow blindness and other eye problems during the heroic age of Antarctic exploration.

    PubMed

    Guly, Henry R

    2012-03-01

    During the heroic age of Antarctic exploration, snow blindness was a common problem, but not all the descriptions of it fit the modern view of the disease, and some of the explorers complained of long-term problems. This article describes the snow blindness and other eye problems that occurred during this era. It also describes how snow blindness was prevented and treated. PMID:22441095

  19. Measurement of intraocular distances in human eyes by using Fourier domain low-coherence interferometry

    NASA Astrophysics Data System (ADS)

    Feng, Liang; Zhu, Lida; Li, Qinghua; Ma, Zhenhe; Wang, Bo; Wang, Yi

    2016-03-01

    We introduce a system for rapidly measuring the intraocular distances of human eyes in vivo with high sensitivity by using Fourier domain low-coherence interferometry. The system mainly consisting of a rapid focus displacement unit and a reference arm which has a variable optical path length. This system is capable of providing a complete biometrical assessment of a human eye in a single measurement procedure, including cornea thickness, anterior chamber depth, lens thickness, and axial length. The system is experimentally verified by measuring the four parameters of a human eye in vivo.

  20. 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.

  1. 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.

  2. Imaging shear stress distribution and evaluating the stress concentration factor of the human eye

    NASA Astrophysics Data System (ADS)

    Joseph Antony, S.

    2015-03-01

    Healthy eyes are vital for a better quality of human life. Historically, for man-made materials, scientists and engineers use stress concentration factors to characterise the effects of structural non-homogeneities on their mechanical strength. However, such information is scarce for the human eye. Here we present the shear stress distribution profiles of a healthy human cornea surface in vivo using photo-stress analysis tomography, which is a non-intrusive and non-X-ray based method. The corneal birefringent retardation measured here is comparable to that of previous studies. Using this, we derive eye stress concentration factors and the directional alignment of major principal stress on the surface of the cornea. Similar to thermometers being used for monitoring the general health in humans, this report provides a foundation to characterise the shear stress carrying capacity of the cornea, and a potential bench mark for validating theoretical modelling of stresses in the human eye in future.

  3. 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

  4. The Minnesota Grading System Using Fundus Autofluorescence of Eye Bank Eyes: A Correlation To Age-Related Macular Degeneration (An AOS Thesis)

    PubMed Central

    Olsen, Timothy W.

    2008-01-01

    Purpose To establish a grading system of eye bank eyes using fundus autofluorescence (FAF) and identify a methodology that correlates FAF to age-related macular degeneration (AMD) with clinical correlation to the Age-Related Eye Disease Study (AREDS). Methods Two hundred sixty-two eye bank eyes were evaluated using a standardized analysis of FAF. Measurements were taken with the confocal scanning laser ophthalmoscope (cSLO). First, high-resolution, digital, stereoscopic, color images were obtained and graded according to AREDS criteria. With the neurosensory retina removed, mean FAF values were obtained from cSLO images using software analysis that excludes areas of atrophy and other artifact, generating an FAF value from a grading template. Age and AMD grade were compared to FAF values. An internal fluorescence reference standard was tested. Results Standardization of the cSLO machine demonstrated that reliable data could be acquired after a 1-hour warm-up. Images obtained prior to 1 hour had falsely elevated levels of FAF. In this initial analysis, there was no statistical correlation of age to mean FAF. There was a statistically significant decrease in FAF from AREDS grade 1, 2 to 3, 4 (P < .0001). An internal fluorescent standard may serve as a quantitative reference. Conclusions The Minnesota Grading System (MGS) of FAF (MGS-FAF) establishes a standardized methodology for grading eye bank tissue to quantify FAF compounds in the retinal pigment epithelium and correlate these findings to the AREDS. Future studies could then correlate specific FAF to the aging process, histopathology AMD phenotypes, and other maculopathies, as well as to analyze the biochemistry of autofluorescent fluorophores. PMID:19277247

  5. Neighborhood Deprivation and Risk of Age-Related Eye Diseases: A Follow-up Study in Sweden

    PubMed Central

    Hamano, Tsuyoshi; Li, Xinjun; Tanito, Masaki; Nabika, Toru; Shiwaku, Kuninori; Sundquist, Jan; Sundquist, Kristina

    2016-01-01

    Purpose To examine whether there is an association between neighborhood deprivation and age-related eye diseases, particularly macular degeneration, cataract, diabetes-related eye complications, and glaucoma. Methods The study population comprised a nationwide sample of 2,060,887 men and 2,250,851 women aged 40 years or older living in Sweden who were followed from 1 January 2000 until the first hospitalization/outpatient registration for age-related eye disease during the study period, death, emigration, or the end of the study period on 31 December 2010. Multilevel logistic regression was used to estimate the association between neighborhood deprivation and age-related eye diseases. Results In men, the odds ratio (OR) for age-related eye diseases for those living in high-deprivation neighborhoods compared to those living in low-deprivation neighborhoods remained significant after adjustment for potential confounding factors (macular degeneration, OR 1.08, 95% confidence interval, CI, 1.03–1.12; cataract, OR 1.31, 95% CI 1.26–1.35; diabetes-related eye complications, OR 1.36, 95% CI 1.30–1.43; glaucoma, OR 1.11, 95% CI 1.06–1.15). In women, similar patterns were observed (macular degeneration, OR 1.11, 95% CI 1.07–1.15; cataract, OR 1.36, 95% CI 1.31–1.40; diabetes-related eye complications, OR 1.50, 95% CI 1.42–1.59; glaucoma, OR 1.12, 95% CI 1.08–1.17). Conclusion Our results suggest that neighborhood deprivation is associated with age-related eye diseases in both men and women. These results implicate that individual- as well as neighborhood-level factors are important for preventing age-related eye diseases. PMID:26395658

  6. 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.

  7. 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.

  8. [Aging of the human testis].

    PubMed

    Sibert, Louis; Lacarrière, Emeric; Safsaf, Athmane; Rives, Nathalie

    2014-02-01

    The morphological and histological changes related to testicular aging are: volume decrease, arteriolar sclerosis, degeneration of Leydig cells and Sertoli, depletion of germ cells and thickening of the tunica albuginea testis. The participation in testicular androgen decline in aging is related to the decrease in the number of Leydig cells associated with alterations in the functioning of the hypothalamic-pituitary axis Sperm volume, concentration and total number, motility and morphology of sperm decrease with aging male. The interindividual variability of sperm parameters, the variability of methodologies for data collection and selection of patients must be careful in interpreting the published results. Overall, the quality of sperm decreases progressively with age, without any age limit that can be individualized. Alterations of spermatogenesis do not seem significantly compromising fertility in the elderly. The clinical impact of testicular aging implies androgen production decrease and diseases associated with aging.

  9. 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.

  10. 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.

  11. [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.

  12. [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. PMID:26743051

  13. 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…

  14. Human breathing and eye blink rate responses to airborne chemicals.

    PubMed Central

    Walker, J C; Kendal-Reed, M; Utell, M J; Cain, W S

    2001-01-01

    Increased levels of air pollution have been linked with morbidity and mortality, but mechanisms linking physiologic responses to quality of life and productivity issues remain largely unknown. Individuals often report irritation of the nose and/or eyes upon exposures to environmental contaminants. Evaluation of these self-reports would be greatly aided by the development of valid physiological markers. Chamber studies (unencumbered exposures) of nonsmoker responses to environmental tobacco smoke offer two candidate end points: (a) Tidal volume increases and breathing frequency declines with stimuli that elicit only moderate irritation. (b) Eye blink rate increases only with a concentration sufficiently high to cause progressive worsening of eye irritation with prolonged exposure. Experiments with very brief nasal-only presentations also suggest the value of breathing changes as sensitive markers of irritation: (a) Tidal volume is inversely related to perceived nasal irritation (NI) intensity in both normal and anosmic (lacking olfactory input) individuals, although normals exhibit greater NI sensitivity. (b) Inhalation duration, in both groups, declines only with trigeminal activation sufficient to cause readily perceptible NI in anosmics. Changes in eye blink rate and breathing may be useful in the investigation of irritation and other effects of air pollution, and could be quite useful in investigations of mixtures of volatile organic compounds. PMID:11544155

  15. The Age-Related Eye Disease Study (AREDS): Design Implications AREDS Report No. 1

    PubMed Central

    2006-01-01

    The Age-Related Eye Disease Study (AREDS) was initially conceived as a long-term multicenter, prospective study of the clinical course of age-related macular degeneration (AMD) and age-related cataract. Data on progression rates and risk factors from the study will increase understanding of the clinical course of both conditions, generate hypotheses about etiology, and aid in the design of clinical trials of potential interventions. In addition to collecting natural history data, AREDS includes a clinical trial of high-dose vitamin and mineral supplements for AMD and a clinical trial of high-dose vitamin supplements for cataract. The clinical trials were initiated largely because of the widespread public use in the United States of commercially available pharmacologic doses of vitamins and minerals to treat these two eye conditions and the absence of definitive studies on the safety and efficacy of their use. Important design issues for the clinical trials include: defining cataract and AMD, estimating event rates, determining the type and dosage of vitamins and minerals to be tested for each condition, and identifying the parameters necessary for monitoring safety and efficacy. This paper describes the AREDS design, including the study rationale and operational structure, and the approach adopted to combine, for two diseases, clinical trials with a natural history study. PMID:10588299

  16. Age-related changes in human vitreous structure.

    PubMed

    Sebag, J

    1987-01-01

    Changes in vitreous structure that occur with aging are important in the pathogenesis of vitreous liquefaction (synchisis senilis), vitreous detachment, and retinal disease. Vitreous morphology was studied in 59 human eyes post-mortem using dark-field horizontal slit illumination of the entire dissected vitreous. In many individuals younger than 30 years, the vitreous was homogeneous in structure. Middle-aged individuals had macroscopic fibers in the central vitreous, which coursed anteroposteriorly and inserted into the vitreous base and the vitreous cortex, posteriorly. During senescence, the vitreous volume was reduced, the vitreous body was collapsed (syneresis), and the fibers were thickened, tortuous, and surrounded by liquid vitreous. This sequence of age-related changes probably results from a progressive reorganization of the hyaluronic acid and collagen molecular networks. Characterization of the molecular events underlying these changes will elucidate the mechanisms of the phenomena of synchisis, syneresis, and detachment, and may provide methods with which to prevent or induce vitreous detachment prophylactically.

  17. Multimodal instrument for high-sensitivity autofluorescence and spectral optical coherence tomography of the human eye fundus

    PubMed Central

    Komar, Katarzyna; Stremplewski, Patrycjusz; Motoczyńska, Marta; Szkulmowski, Maciej; Wojtkowski, Maciej

    2013-01-01

    In this paper we present a multimodal device for imaging fundus of human eye in vivo which combines functionality of autofluorescence by confocal SLO with Fourier domain OCT. Native fluorescence of human fundus was excited by modulated laser beam (λ = 473 nm, 20 MHz) and lock-in detection was applied resulting in improving sensitivity. The setup allows for acquisition of high resolution OCT and high contrast AF images using fluorescence excitation power of 50-65 μW without averaging consecutive images. Successful functioning of constructed device have been demonstrated for 8 healthy volunteers of different age ranging from 24 to 83 years old. PMID:24298426

  18. Effects of Aging and Anatomic Location on Gene Expression in Human Retina

    PubMed Central

    Cai, Hui; Fields, Mark A.; Hoshino, Risa; Priore, Lucian V. Del

    2012-01-01

    Objective: To determine the effects of age and topographic location on gene expression in human neural retina. Methods: Macular and peripheral neural retina RNA was isolated from human donor eyes for DNA microarray and quantitative RT-PCR analyses. Results: Total RNA integrity from human donors was preserved. Hierarchical clustering analysis demonstrates that the gene expression profiles of young, old, macula, and peripheral retina cluster into four distinct groups. Genes which are highly expressed in macular, peripheral, young, or old retina were identified, including inhibitors of Wnt Signaling Pathway (DKK1, FZD10, and SFRP2) which are preferably expressed in the periphery. Conclusion: The transcriptome of the human retina is affected by age and topographic location. Wnt pathway inhibitors in the periphery may maintain peripheral retinal cells in an undifferentiated state. Understanding the effects of age and topographic location on gene expression may lead to the development of new therapeutic interventions for age-related eye diseases. PMID:22666212

  19. 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

  20. 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.

  1. Eye tracking and its application in human computer interfaces

    NASA Astrophysics Data System (ADS)

    Carroll, Thomas; Rogers, Aaron; Charalampidis, Dimitrios; Chen, Huimin

    2011-06-01

    Current research on gaze tracking, specifically relating to mouse control, is often limited to infrared cameras. Since these can be costly and unsafe to operate, inexpensive optical cameras are a viable alternative. This paper presents image processing techniques and algorithms to control a computer mouse using an optical camera. Usually, eye tracking techniques utilize cameras mounted on devices located relatively far away from the user, such as a computer monitor. However, in such cases, the techniques used to determine the direction of gaze are inaccurate due to the constraints imposed by the camera resolution in conjunction to limited size of the pupil. In order to achieve higher accuracy in pupil detection, and therefore mouse control, the camera used is head-mounted and placed near one of the user's eyes.

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

    PubMed

    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

    2015-02-01

    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.

  3. Genotype × age interaction in human transcriptional ageing

    PubMed Central

    Kent, Jack W.; Göring, Harald H. H.; Charlesworth, Jac C.; Drigalenko, Eugene; Diego, Vincent P.; Curran, Joanne E.; Johnson, Matthew P.; Dyer, Thomas D.; Cole, Shelley A.; Jowett, Jeremy B. M.; Mahaney, Michael C.; Comuzzie, Anthony G.; Almasy, Laura; Moses, Eric K.; Blangero, John; Williams-Blangero, Sarah

    2012-01-01

    Individual differences in biological ageing (i.e., the rate of physiological response to the passage of time) may be due in part to genotype-specific variation in gene action. However, the sources of heritable variation in human age-related gene expression profiles are largely unknown. We have profiled genome-wide expression in peripheral blood mononuclear cells from 1,240 individuals in large families and found 4,472 human autosomal transcripts, representing ~4,349 genes, significantly correlated with age. We identified 623 transcripts that show genotype by age interaction in addition to a main effect of age, defining a large set of novel candidates for characterization of the mechanisms of differential biological ageing. We applied a novel SNP genotype×age interaction test to one of these candidates, the ubiquilin-like gene UBQLNL, and found evidence of joint cis-association and genotype by age interaction as well as trans-genotype by age interaction for UBQLNL expression. Both UBQLNL expression levels at recruitment and cis genotype are associated with longitudinal cancer risk in our study cohort. PMID:22871458

  4. Crowding is proportional to visual acuity in young and aging eyes.

    PubMed

    Yehezkel, Oren; Sterkin, Anna; Lev, Maria; Polat, Uri

    2015-01-01

    Spatial crowding decreases object recognition and conscious visual perception in clutter. In a previous study we used brief presentation times to reveal the effects of a crowded presentation in the fovea. Here we aimed to test the relationships between varying visual acuity (VA) and crowding in the fovea, under the assumption that in uncorrected presbyopia, the processing is relatively normal, whereas the retinal input is blurred. We tested whether normal participants whose near VA is gradually reduced due to age-related deterioration (presbyopia, or "aging eye") will show an acuity-dependent increase in foveal crowding. We used brief presentations and acuity-threshold letter targets in order to magnify the crowding-effect amplitude in the fovea. A total of 195 participants with an age range of 20-68 years and an average of 44.3 ± 11.7 years (M ± SD) were divided into four age groups, all without any optical correction for the near distance. Our findings show that crowding is proportional to VA. This proportionality is affected by VA-age dependency, with a nonlinear S-shaped pattern: A steep VA reduction begins to develop, which is compatible with the normal onset age of presbyopia symptoms and a saturation in the VA-age dependency in the oldest age group, for which we propose a VA-eccentricity account. Finally, there is a high variance in the crowding amplitude in the young, even before the onset age of presbyopia symptoms, suggesting crowding conditions with limited presentation times as a highly sensitive measure of VA, which predicts visual performance in complex tasks, such as reading.

  5. 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.

  6. Melatonin and human skin aging

    PubMed Central

    Kleszczynski, Konrad; Fischer, Tobias W.

    2012-01-01

    Like the whole organism, skin follows the process of aging during life-time. Additional to internal factors, several environmental factors, such as solar radiation, considerably contribute to this process. While fundamental mechanisms regarding skin aging are known, new aspects of anti-aging agents such as melatonin are introduced. Melatonin is a hormone produced in the glandula pinealis that follows a circadian light-dependent rhythm of secretion. It has been experimentally implicated in skin functions such as hair cycling and fur pigmentation, and melatonin receptors are expressed in many skin cell types including normal and malignant keratinocytes, melanocytes and fibroblasts. It possesses a wide range of endocrine properties as well as strong antioxidative activity. Regarding UV-induced solar damage, melatonin distinctly counteracts massive generation of reactive oxygen species, mitochondrial and DNA damage. Thus, there is considerable evidence for melatonin to be an effective anti-skin aging compound, and its various properties in this context are described in this review. PMID:23467217

  7. 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)

  8. [Techniques for preparing postmortem human eyes to perform anterior segment intraocular surgery].

    PubMed

    Vargas, L G; Werner, L; Pandey, S K; Werner, L P; Schmidbauer, J M; Zuleta, V; Escobar-Gómez, M; Apple, D J

    2003-02-01

    We describe different methods to prepare postmortem human or animal eyes used at the Center for Research in Ocular Therapeutics and Biodevices at the Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA. These techniques have been utilized for performing different surgical procedures (phacoemulsification, extracapsular cataract extraction, etc.), and for training of surgeons in-transition. Performing these techniques in the wet-laboratory contributed to improve surgical skills to perform the critical steps of the phacoemulsification surgery. Pathological evaluation of pseudophakic postmortem human eyes using the Miyake-Apple posterior view and histology was helpful to analyze postoperative complications of cataract surgery (anterior capsule opacification and posterior capsule opacification) secondary to postoperative proliferation of lens epithelial cells into the capsular bag. Modifications in the surgical techniques and/or lens design may be helpful to reduce these postoperative complications. Implantation of various aphakic and phakic intraocular lenses in postmortem human eyes as well as animal eyes was helpful to analyze the sizing and fitting of new lens designs within the eye.

  9. 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.

  10. 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.

  11. Human neurologic function and the aging process.

    PubMed

    Potvin, A R; Syndulko, K; Tourtellotte, W W; Lemmon, J A; Potvin, J H

    1980-01-01

    Sixty-one normal men whose ages ranged from 20 to 80 years were evaluated on two occasions by means of a comprehensive series of 128 instrumented tests of neurologic function. The tests measured cognition, vision, strength, steadiness, reactions, speed, coordination, fatigue, gait, station, sensations, and tasks of daily living. The reliability of each test measured was determined, and any measure found unreliable (r less than or equal to 0.41) was not further analyzed. Significant age-related linear decreases were found for almost all neurologic functions. The declines over the age span varied from less than 10 percent to more than 90 percent for different functions. For the upper extremities, the largest declines (greater than 50 percent) were in hand-force steadiness, speed of hand-arm movements, and vibration sense; for the lower extremities, the largest declines were in one-legged balance with eyes closed and in vibration sense. For 13 of 14 tests in which significant dominant body-side effects were found, larger re-testing 7-10 days later, the subjects improved their scores by more than 5 percent on only 17 tests, 9 of which concerned the activities of daily living. No significant differential learning effects were found across age groups. The results point to the importance of developing a data bank on age-based neurologic function so that therapeutic effects can be evaluated in terms of age- and sex-matched normal functioning.

  12. 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.

  13. 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. PMID:25739360

  14. 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.

  15. 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).

  16. 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. PMID:23847729

  17. Integral modeling of human eyes: from anatomy to visual response

    NASA Astrophysics Data System (ADS)

    Navarro, Rafael

    2006-02-01

    Three basic stages towards the global modeling of the eye are presented. In the first stage, an adequate choice of the basis geometrical model, general ellipsoid in this case, permits, to fit in a natural way the typical "melon" shape of the cornea with minimum complexity. In addition it facilitates to extract most of its optically relevant parameters, such as the position and orientation of it optical axis in the 3D space, the paraxial and overall refractive power, the amount and axis of astigmatism, etc. In the second level, this geometrical model, along with optical design and optimization tools, is applied to build customized optical models of individual eyes, able to reproduce the measured wave aberration with high fidelity. Finally, we put together a sequence of schematic, but functionally realistic models of the different stages of image acquisition, coding and analysis in the visual system, along with a probabilistic Bayesian maximum a posteriori identification approach. This permitted us to build a realistic simulation of the all the essential processes involved in a visual acuity clinical exam. It is remarkable that at all three levels, it has been possible for the models to predict the experimental data with high accuracy.

  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. PMID:24009300

  19. 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

  20. 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.

  1. A noninvasive video-based method for measuring lens transmission properties of the human eye.

    PubMed

    Johnson, C A; Howard, D L; Marshall, D; Shu, H

    1993-11-01

    The Lens Absorption Monitor (LAM) is an automated video-based system for obtaining rapid objective noninvasive measurements of the spectral transmission properties of the human lens. The technique is based on intensity measurements of the 4th Purkinje image for different wavelengths, and incorporates several features that overcome some of the difficulties associated with previous studies using this approach. LAM transmission measures for the visible spectrum can be obtained in approximately 2 s, and in most instances can be obtained without having to dilate the subject's eye. This paper describes the technique and presents our initial findings for 40 normal observers between the ages of 24 and 77 years. Results of the LAM technique show that it is able to measure the wavelength-dependent properties of the lens accurately and to identify age-related changes in "yellowing" of the lens. Test-retest reliability of the LAM is better than for psychophysical estimates of ocular media transmission. LAM and psychophysical measures in the same subjects were found to be correlated, although LAM measures produced consistently lower values of lens density than the psychophysical determinations. There was only moderate agreement between LAM and psychophysical measures of lens density. Possible explanations for these differences are discussed. Future research will determine whether this technique is able to detect and quantify early cataract development.

  2. Geometrical theory to predict eccentric photorefraction intensity profiles in the human eye

    NASA Astrophysics Data System (ADS)

    Roorda, Austin; Campbell, Melanie C. W.; Bobier, W. R.

    1995-08-01

    In eccentric photorefraction, light returning from the retina of the eye is photographed by a camera focused on the eye's pupil. We use a geometrical model of eccentric photorefraction to generate intensity profiles across the pupil image. The intensity profiles for three different monochromatic aberration functions induced in a single eye are predicted and show good agreement with the measured eccentric photorefraction intensity profiles. A directional reflection from the retina is incorporated into the calculation. Intensity profiles for symmetric and asymmetric aberrations are generated and measured. The latter profile shows a dependency on the source position and the meridian. The magnitude of the effect of thresholding on measured pattern extents is predicted. Monochromatic aberrations in human eyes will cause deviations in the eccentric photorefraction measurements from traditional crescents caused by defocus and may cause misdiagnoses of ametropia or anisometropia. Our results suggest that measuring refraction along the vertical meridian is preferred for screening studies with the eccentric photorefractor.

  3. Robot Arm Control and Having Meal Aid System with Eye Based Human-Computer Interaction (HCI)

    NASA Astrophysics Data System (ADS)

    Arai, Kohei; Mardiyanto, Ronny

    Robot arm control and having meal aid system with eye based HCI is proposed. The proposed system allows disabled person to select desirable food from the meal tray by their eyes only. Robot arm which is used for retrieving the desirable food is controlled by human eye. At the tip of the robot arm, tiny camera is equipped. Disabled person wear a glass of which a single Head Mount Display: HMD and tiny camera is mounted so that disabled person can take a look at the desired food and retrieve it by looking at the food displayed onto HMD. Experimental results show that disabled person can retrieve the desired food successfully. It also is confirmed that robot arm control by eye based HCI is much faster than that by hands.

  4. 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.

  5. 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

  6. Invited review: aging and human temperature regulation.

    PubMed

    Kenney, W Larry; Munce, Thayne A

    2003-12-01

    This mini-review focuses on the effects of aging on human temperature regulation. Although comprehensive reviews have been published on this topic (Kenney WL. Exercise and Sport Sciences Reviews, Baltimore: Williams & Wilkins, 1997, p. 41-76; Pandolf KB. Exp Aging Res 17: 189-204, 1991; Van Someren EJ, Raymann RJ, Scherder EJ, Daanen HA, and Swaab DF. Ageing Res Rev 1: 721-778, 2002; and Young AJ. Exp Aging Res 17: 205-213, 1991), this mini-review concisely summarizes the present state of knowledge about human temperature regulation and aging in thermoneutral conditions, as well as during hypo- and hyperthermic challenges. First, we discuss age-related effects on baseline body core temperature and phasing rhythms of the circadian temperature cycle. We then examine the altered physiological responses to cold stress that result from aging, including attenuated peripheral vasoconstriction and reduced cold-induced metabolic heat production. Finally, we present the age-related changes in sweating and cardiovascular function associated with heat stress. Although epidemiological evidence of increased mortality among older adults from hypo- and hyperthermia exists, this outcome does not reflect an inability to thermoregulate with advanced age. In fact, studies that have attempted to separate the effects of chronological age from concurrent factors, such as fitness level, body composition, and the effects of chronic disease, have shown that thermal tolerance appears to be minimally compromised by age.

  7. 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

  8. The effects of eye movements, age, and expertise on inattentional blindness.

    PubMed

    Memmert, Daniel

    2006-09-01

    Based on various stimuli, the findings for the inattentional blindness paradigm suggest that many observers do not perceive an unexpected object in a dynamic setting. In a first experiment, inattentional blindness was combined with eye tracking data from children. Observers who did not notice the unexpected object in the basketball game test by spent on average as much time (about one second) looking at the unexpected object as those subjects who did perceive it. As such, individual differences that are responsible for the recognition of unexpected objects have to be found as further indicators. In a second experiment, the expert-novice paradigm was used to show that the probability of seeing an unexpected object can be increased with specific previous experience. The results in the same task indicate significant differences between basketball experts and basketball novices. The ages of the subjects in both experiments are discussed in connection with the inattentional blindness paradigm.

  9. Worsening anatomic outcomes following aflibercept for neovascular age-related macular degeneration in eyes previously well controlled with ranibizumab

    PubMed Central

    Nudleman, Eric; Wolfe, Jeremy D; Woodward, Maria A; Yonekawa, Yoshihiro; Williams, George A; Hassan, Tarek S

    2016-01-01

    Purpose Antivascular endothelial growth factor injection is the mainstay of treating neovascular age-related macular degeneration (AMD). Previous studies have shown that switching treatment from ranibizumab to aflibercept led to an improvement in eyes with recalcitrant activity. Herein, we identify a unique subset of patients whose eyes with neovascular AMD were previously well controlled with ranibizumab injections were then worsened after being switched to aflibercept. Methods This is a retrospective interventional case series. Eyes with neovascular AMD, previously well controlled with monthly injections of ranibizumab, which then developed worsening of subretinal fluid after being switched to aflibercept were included. Results A total of 17 eyes were included. All eyes developed increased subretinal fluid when switched from ranibizumab to aflibercept. Fourteen patients were switched back to ranibizumab after a single injection of aflibercept and had subsequent rapid resolution of subretinal fluid. Three patients continued with monthly aflibercept injections for two subsequent months and demonstrated the persistence of the increased subretinal fluid until they were switched back to treatment with ranibizumab at which time the fluid resolved. No eye had persistent decline in visual acuity. Conclusion Switching from intravitreal ranibizumab to aflibercept in eyes with well-controlled neovascular AMD may result in worsening in a subset of patients and resolves when therapy is switched back to ranibizumab. PMID:27354759

  10. 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.

  11. 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.

  12. Leading Cause of Eye Injuries in School-Aged Children are Sports-Related

    MedlinePlus

    ... permanent vision loss. The NEI also states that baseball is the sport responsible for the greatest number ... eye injuries cost $175-200 million every year. · Baseball is a leading cause of eye injuries in ...

  13. 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

  14. Age peculiarities of human motor control in aging.

    PubMed

    Mankovsky, N B; Mints, A Y; Lisenyuk, V P

    1982-01-01

    A clinicophysiological investigation of motor control was carried out in 199 apparently healthy, socially active elderly (aged 60-69 years) and long-living (90 years and over) subjects in order to establish the peculiarities of the motor sphere specific to age-related changes of the nervous system. Analyzing the experimentally induced state of readiness (intention) before a spontaneous movement, we found an increase with age in the latent period of the muscle intentional activity (IA) parallel to an increase in the latent period of the spontaneous movement, a decrease in IA amplitude with more frequent structural deviations of the EMG in the prestarting period and a reduction of the required IA selectiveness. The described changes in the organization of readiness for a spontaneous movement seemed to be related with age impairment of supraspinal (mainly corticospinal) influences and may be used for an explanation of a number of clinical peculiarities of human motor control in late ontogenesis.

  15. 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. PMID:19831305

  16. 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.

  17. 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.

  18. Expression of human Gaucher disease gene GBA generates neurodevelopmental defects and ER stress in Drosophila eye.

    PubMed

    Suzuki, Takahiro; Shimoda, Masami; Ito, Kumpei; Hanai, Shuji; Aizawa, Hidenobu; Kato, Tomoki; Kawasaki, Kazunori; Yamaguchi, Terumi; Ryoo, Hyung Don; Goto-Inoue, Naoko; Setou, Mitsutoshi; Tsuji, Shoji; Ishida, Norio

    2013-01-01

    Gaucher disease (GD) is the most common of the lysosomal storage disorders and is caused by defects in the GBA gene encoding glucocerebrosidase (GlcCerase). The accumulation of its substrate, glucocylceramide (GlcCer) is considered the main cause of GD. We found here that the expression of human mutated GlcCerase gene (hGBA) that is associated with neuronopathy in GD patients causes neurodevelopmental defects in Drosophila eyes. The data indicate that endoplasmic reticulum (ER) stress was elevated in Drosophila eye carrying mutated hGBAs by using of the ER stress markers dXBP1 and dBiP. We also found that Ambroxol, a potential pharmacological chaperone for mutated hGBAs, can alleviate the neuronopathic phenotype through reducing ER stress. We demonstrate a novel mechanism of neurodevelopmental defects mediated by ER stress through expression of mutants of human GBA gene in the eye of Drosophila.

  19. 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. PMID:26974900

  20. Reconstruction of the optical system of the human eye with reverse ray-tracing.

    PubMed

    Goncharov, Alexander V; Nowakowski, Maciej; Sheehan, Matthew T; Dainty, Christopher

    2008-02-01

    We present a practical method for reconstructing the optical system of the human eye from off-axis wavefront measurements. A retinal beacon formed at different locations on the retina allows probing the optical structure of the eye by the outgoing beams that exit the eye through the dilated pupil. A Shack-Hartmann aberrometer measures the amount of wave aberrations in each beam at the exit pupil plane. Wavefront data obtained at different oblique directions is used for tomographic reconstruction by optimizing a generic eye model with reverse ray-tracing. The multi-configuration system is constructed by tracing pre-aberrated beams backwards from each direction through the exit pupil into the optical system of the aberrometer followed by the generic eye model. Matching all wave aberrations measured at each field point is equivalent to minimizing the size of the beacon spots on the retina. The main benefit of having a personalized eye model is the ability to identify the origin of the ocular aberrations and to find the optimal way for their correction.

  1. 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

  2. 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.

  3. Effects of Age and Dysfunction on Human Meibomian Glands

    PubMed Central

    Nien, Chyong Jy; Massei, Salina; Lin, Gloria; Nabavi, Cameron; Tao, Jeremiah; Brown, Donald J.; Paugh, Jerry R.; Jester, James V.

    2015-01-01

    Objective To identify age-related changes in human meibomian glands that may be associated with meibomian gland dysfunction (MGD). Methods Excess eyelid tissue from 36 patients (age range, 18–95 years, 19 female, 17 male) who underwent canthoplasty procedures were used. Dermatologic history, age, and presence of MGD were recorded. Samples were frozen, sectioned, and stained with specific antibodies against peroxisome proliferator–activated receptor γ(PPARγ) to identify meibocyte differentiation, Ki67 nuclear antigen to identify cycling cells, and CD45 to identify inflammatory cell infiltration. Results Staining for PPARγ showed cytoplasmic and nuclear localization in the 2 youngest subjects (ages, 18 and 44 years). Older individuals (>60 years) showed predominantly nuclear staining, with cytoplasmic staining limited to the basal acinar cells in 17 of 31 subjects. The number of Ki67 positively stained basal cells were significantly elevated in the younger compared with older subjects based on linear regression analysis (r2= 0.35; P <.001). There was also a significant correlation between MG expression grade and CD45 cell infiltration (r =0.414; P =.05). Conclusions These results indicate that aging human meibomian glands show decreased meibocyte differentiation and cell cycling that is associated with the development of MGD. Findings also suggest that altered PPARγ signaling may lead to acinar atrophy and development of an age-related hyposecretory MGD. Clinical Relevance Meibomian gland dysfunction and evaporative dry eye are common age-related eyelid disorders. Understanding the underlying mechanism of MGD may lead to the development of novel therapeutic strategies to treat this disease. PMID:21482872

  4. 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.

  5. A role of the human thalamus in predicting the perceptual consequences of eye movements

    PubMed Central

    Ostendorf, Florian; Liebermann, Daniela; Ploner, Christoph J.

    2013-01-01

    Internal monitoring of oculomotor commands may help to anticipate and keep track of changes in perceptual input imposed by our eye movements. Neurophysiological studies in non-human primates identified corollary discharge (CD) signals of oculomotor commands that are conveyed via thalamus to frontal cortices. We tested whether disruption of these monitoring pathways on the thalamic level impairs the perceptual matching of visual input before and after an eye movement in human subjects. Fourteen patients with focal thalamic stroke and 20 healthy control subjects performed a task requiring a perceptual judgment across eye movements. Subjects reported the apparent displacement of a target cue that jumped unpredictably in sync with a saccadic eye movement. In a critical condition of this task, six patients exhibited clearly asymmetric perceptual performance for rightward vs. leftward saccade direction. Furthermore, perceptual judgments in seven patients systematically depended on oculomotor targeting errors, with self-generated targeting errors erroneously attributed to external stimulus jumps. Voxel-based lesion-symptom mapping identified an area in right central thalamus as critical for the perceptual matching of visual space across eye movements. Our findings suggest that trans-thalamic CD transmission decisively contributes to a correct prediction of the perceptual consequences of oculomotor actions. PMID:23630474

  6. [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

  7. 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…

  8. 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…

  9. Social Interactions through the Eyes of Macaques and Humans

    PubMed Central

    McFarland, Richard; Roebuck, Hettie; Yan, Yin; Majolo, Bonaventura; Li, Wu; Guo, Kun

    2013-01-01

    Group-living primates frequently interact with each other to maintain social bonds as well as to compete for valuable resources. Observing such social interactions between group members provides individuals with essential information (e.g. on the fighting ability or altruistic attitude of group companions) to guide their social tactics and choice of social partners. This process requires individuals to selectively attend to the most informative content within a social scene. It is unclear how non-human primates allocate attention to social interactions in different contexts, and whether they share similar patterns of social attention to humans. Here we compared the gaze behaviour of rhesus macaques and humans when free-viewing the same set of naturalistic images. The images contained positive or negative social interactions between two conspecifics of different phylogenetic distance from the observer; i.e. affiliation or aggression exchanged by two humans, rhesus macaques, Barbary macaques, baboons or lions. Monkeys directed a variable amount of gaze at the two conspecific individuals in the images according to their roles in the interaction (i.e. giver or receiver of affiliation/aggression). Their gaze distribution to non-conspecific individuals was systematically varied according to the viewed species and the nature of interactions, suggesting a contribution of both prior experience and innate bias in guiding social attention. Furthermore, the monkeys’ gaze behavior was qualitatively similar to that of humans, especially when viewing negative interactions. Detailed analysis revealed that both species directed more gaze at the face than the body region when inspecting individuals, and attended more to the body region in negative than in positive social interactions. Our study suggests that monkeys and humans share a similar pattern of role-sensitive, species- and context-dependent social attention, implying a homologous cognitive mechanism of social attention

  10. The Human Face: A View From the Infant's Eye.

    ERIC Educational Resources Information Center

    Souther, Arthur F.; Banks, Martin S.

    This study explores the reason why very young infants are unable to respond differentially to faces and the cause for developmental changes in infant face perception by age 3 months. Linear systems analysis (LSA) and the contrast sensitivity function (CSF) were used to estimate the facial pattern information available to 1- and 3-month-old…

  11. 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

  12. 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

  13. Filtered text reveals adult age differences in reading: evidence from eye movements.

    PubMed

    Paterson, Kevin B; McGowan, Victoria A; Jordan, Timothy R

    2013-06-01

    Sensitivity to certain spatial frequencies declines with age and this may have profound effects on reading performance. However, the spatial frequency content of text actually used by older adults (aged 65+), and how this differs from that used by young adults (aged 18-30), remains to be determined. To investigate this issue, the eye movement behavior of young and older adult readers was assessed using a gaze-contingent moving-window paradigm in which text was shown normally within a region centered at the point of gaze, whereas text outside this region was filtered to contain only low, medium, or high spatial frequencies. For young adults, reading times were affected by spatial frequency content when windows of normal text extended up to nine characters wide. Within this processing region, the reading performance of young adults was affected little when text outside the window contained either only high or medium spatial frequencies, but was disrupted substantially when text contained only low spatial frequencies. By contrast, the reading performance of older adults was affected by spatial frequency content when windows extended up to 18 characters wide. Moreover, within this extended processing region, reading performance was disrupted when text contained any one band of spatial frequencies, but was disrupted most of all when text contained only high spatial frequencies. These findings indicate that older adults are sensitive to the spatial frequency content of text from a much wider region than young adults, and rely much more than young adults on coarse-scale components of text when reading.

  14. 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.

  15. Approach to HIR (human-oriented information restructuring) using bird's-eye views

    NASA Astrophysics Data System (ADS)

    Toyota, Koichi; Sekitoh, Makoto; Fujii, Toshiaki; Kimoto, Tadahiko; Tanimoto, Masayuki

    2001-06-01

    In this paper, we describe a system that creates a virtual bird's-eye view from multi-camera images in real-time and its application to 'HIR (Human-Oriented Information Restructuring) system for ITS' we have proposed. In recent years, studies on AHS (Advanced Highway Systems) are seen in many fields. However, there still remains many problems when we try to realize the automated driving, the goal of AHS. To overcome these problems of AHS, we have proposed HIR system, which assists drivers by providing them with integrated and restructured images. The striking point of the proposed system compared with the conventional one is that it is human, not the mechanical cars, that recognizes the situation and controls the car, and for that purpose, we just generate and show easy-to-understand images for human. The step is, integrate and restructure numerous camera images from all driving environment, such as cars and roads, and non-image information like VICS (Vehicle Information and Communication Systems) information. Then pick out the most important information according to the situation and show it in the form of 'image.' This paper proposes a bird's-eye view system as an example of HIR. We describe the algorithm and hardware to create a bird's-eye view in real-time. In the experiment, we show that the bird's-eye view is useful as a driver-assisting image under the situation of right turn at the intersection.

  16. Prevalence of Eye Diseases and Causes of Visual Impairment in School-Aged Children in Western China

    PubMed Central

    Pi, Lian-Hong; Chen, Lin; Liu, Qin; Ke, Ning; Fang, Jing; Zhang, Shu; Xiao, Jun; Ye, Wei-Jiang; Xiong, Yan; Shi, Hui; Zhou, Xi-Yuan; Yin, Zheng-Qin

    2012-01-01

    Background The present study investigated the prevalence of refractive error, visual impairment, and eye diseases in school-aged children in western China. Methods The survey was done in a representative county (Yongchuan District, Chongqing Municipality) of western China. Cluster random sampling was used to select children aged 6 to 15 years. We conducted door-to-door surveys and eye examinations including optometry, stereoscopic vision test, eye position and eye movement, slit lamp examination of the anterior segment, retinoscopy, and fundus examination after cycloplegia with 1% cyclopentolate. Results Among 3469 children, data were available for 3079 (88.76%). The prevalences of eye diseases were, in descending order, refractive error (20.69%; 637/3079), conjunctivitis (11.76%; 362/3079), amblyopia (1.88%; 58/3079), color vision defect (0.52%; 16/3079), keratitis (0.36%; 11/3079), strabismus (0.29%; 9/3079), cataract (0.23%; 7/3079), pathologic myopia (0.19%; 6/3079), and ocular trauma (0.13%; 4/3079). The prevalence of corneal leucoma, corneal staphyloma, optic neuropathy, macular degeneration, and myelinated nerve fibers was 0.03% (1/3079) for each. The prevalence of visual impairment was 7.70% (237/3079), and the major causes of visual impairment were uncorrected refractive error (86.08%; 204/237), amblyopia (9.70%; 23/237), pathologic myopia (1.27%; 3/237), congenital cataract (0.42%; 1/237), and others (2.11%; 5/237). Conclusions Among school-aged children in a less developed area of western China, refractive error was the most prevalent eye disorder, and uncorrected refractive error was the main cause of visual impairment. PMID:22123227

  17. LENS* 4: a program for calculation of geometric optics of the human eye

    SciTech Connect

    Doss, J.D.

    1982-10-01

    A computer program (LENS* 4) has been written that may be used for ray-trace calculations of human or animal eyes. The user enters all relevant eye specifications, and the program calculates ray segments from a (specified) external object. From the ray calculations, the program yields data on image location, image distance from the retina, retinal spot size, and effective pupil diameter. The program also allows entry of simple corrective lens systems that simulate a contact lens or ordinary spectacles. Graphics output illustrating the eye cross section, corrective lens, and rays is provided either on the CRT, thermal printer, or graphics plotter. Although the program is written in BASIC, many of the statements (particularly in the graphics section) are peculiar to the Hewlett-Packard 9845B desktop computer.

  18. 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

  19. Adaptive optics with a magnetic deformable mirror: applications in the human eye

    NASA Astrophysics Data System (ADS)

    Fernandez, Enrique J.; Vabre, Laurent; Hermann, Boris; Unterhuber, Angelika; Povazay, Boris; Drexler, Wolfgang

    2006-10-01

    A novel deformable mirror using 52 independent magnetic actuators (MIRAO 52, Imagine Eyes) is presented and characterized for ophthalmic applications. The capabilities of the device to reproduce different surfaces, in particular Zernike polynomials up to the fifth order, are investigated in detail. The study of the influence functions of the deformable mirror reveals a significant linear response with the applied voltage. The correcting device also presents a high fidelity in the generation of surfaces. The ranges of production of Zernike polynomials fully cover those typically found in the human eye, even for the cases of highly aberrated eyes. Data from keratoconic eyes are confronted with the obtained ranges, showing that the deformable mirror is able to compensate for these strong aberrations. Ocular aberration correction with polychromatic light, using a near Gaussian spectrum of 130 nm full width at half maximum centered at 800 nm, in five subjects is accomplished by simultaneously using the deformable mirror and an achromatizing lens, in order to compensate for the monochromatic and chromatic aberrations, respectively. Results from living eyes, including one exhibiting 4.66 D of myopia and a near pathologic cornea with notable high order aberrations, show a practically perfect aberration correction. Benefits and applications of simultaneous monochromatic and chromatic aberration correction are finally discussed in the context of retinal imaging and vision.

  20. Modeling the influence of LASIK surgery on optical properties of the human eye

    NASA Astrophysics Data System (ADS)

    Szul-Pietrzak, Elżbieta; Hachoł, Andrzej; Cieślak, Krzysztof; Drożdż, Ryszard; Podbielska, Halina

    2011-11-01

    The aim was to model the influence of LASIK surgery on the optical parameters of the human eye and to ascertain which factors besides the central corneal radius of curvature and central thickness play the major role in postsurgical refractive change. Ten patients were included in the study. Pre- and postsurgical measurements included standard refraction, anterior corneal curvature and pachymetry. The optical model used in the analysis was based on the Le Grand and El Hage schematic eye, modified by the measured individual parameters of corneal geometry. A substantial difference between eye refractive error measured after LASIK and estimated from the eye model was observed. In three patients, full correction of the refractive error was achieved. However, analysis of the visual quality in terms of spot diagrams and optical transfer functions of the eye optical system revealed some differences in these measurements. This suggests that other factors besides corneal geometry may play a major role in postsurgical refraction. In this paper we investigated whether the biomechanical properties of the eyeball and changes in intraocular pressure could account for the observed discrepancies.

  1. 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.

  2. Human cortical areas involved in sustaining perceptual stability during smooth pursuit eye movements.

    PubMed

    Trenner, Maja U; Fahle, Manfred; Fasold, Oliver; Heekeren, Hauke R; Villringer, Arno; Wenzel, Rüdiger

    2008-03-01

    Because both, eye movements and object movements induce an image motion on the retina, eye movements must be compensated to allow a coherent and stable perception of our surroundings. The inferential theory of perception postulates that retinal image motion is compared with an internal reference signal related to eye movements. This mechanism allows to distinguish between the potential sources producing retinal image motion. Referring to this theory, we investigated referential calculation during smooth pursuit eye movements (SPEM) in humans using event-related functional magnetic resonance imaging (fMRI). The blood oxygenation level dependent (BOLD) response related to SPEM in front of a stable background was measured for different parametric steps of preceding motion stimuli and therefore assumed for different states of the referential system. To achieve optimally accurate anatomy and more detectable fMRI signal changes in group analysis, we applied cortex-based statistics both to all brain volumes and to defined regions of interest. Our analysis revealed that the activity in a temporal region as well as the posterior parietal cortex (PPC) depended on the velocity of the preceding stimuli. Previous single-cell recordings in monkeys demonstrated that the visual posterior sylvian area (VPS) is relevant for perceptual stability. The activation apparent in our study thus may represent a human analogue of this area. The PPC is known as being strongly related to goal-directed eye movements. In conclusion, temporal and parietal cortical areas may be involved in referential calculation and thereby in sustaining visual perceptual stability during eye movements. PMID:17415782

  3. Gonioscopic differences between eyes with primary open-angle glaucoma and normal eyes in subjects over the age of forty.

    PubMed Central

    Kimura, R; Levene, R Z

    1975-01-01

    Gonioscopy was performed on 110 patients with primary open-angle glaucoma over the age of 40 and an equal number of normal subjects matched by race and age. The frequency distribution of various angle features differed in two groups. In the glaucoma group there were more iris processes at all levels of insertion, a higher insertion of the iris root, and more trabecular pigmentation. We believe that a congenital angle anomaly is an important factor in the pathogenesis of the elevated intraocular pressure. PMID:1246817

  4. Stiffening of Human Skin Fibroblasts with Age

    PubMed Central

    Schulze, Christian; Wetzel, Franziska; Kueper, Thomas; Malsen, Anke; Muhr, Gesa; Jaspers, Soeren; Blatt, Thomas; Wittern, Klaus-Peter; Wenck, Horst; Käs, Josef A.

    2010-01-01

    Changes in mechanical properties are an essential characteristic of the aging process of human skin. Previous studies attribute these changes predominantly to the altered collagen and elastin organization and density of the extracellular matrix. Here, we show that individual dermal fibroblasts also exhibit a significant increase in stiffness during aging in vivo. With the laser-based optical cell stretcher we examined the viscoelastic biomechanics of dermal fibroblasts isolated from 14 human donors aged 27 to 80. Increasing age was clearly accompanied by a stiffening of the investigated cells. We found that fibroblasts from old donors exhibited an increase in rigidity of ∼60% with respect to cells of the youngest donors. A FACS analysis of the content of the cytoskeletal polymers shows a shift from monomeric G-actin to polymerized, filamentous F-actin, but no significant changes in the vimentin and microtubule content. The rheological analysis of fibroblast-populated collagen gels demonstrates that cell stiffening directly results in altered viscoelastic properties of the collagen matrix. These results identify a new mechanism that may contribute to the age-related impairment of elastic properties in human skin. The altered mechanical behavior might influence cell functions involving the cytoskeleton, such as contractility, motility, and proliferation, which are essential for reorganization of the extracellular matrix. PMID:20959083

  5. 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.

  6. 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. PMID:25913071

  7. 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. PMID:25313081

  8. 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.

  9. Human ageing and the sympathoadrenal system.

    PubMed

    Seals, D R; Esler, M D

    2000-11-01

    Over the past three decades the changes in sympathoadrenal function that occur with age in healthy adult humans have been systematically studied using a combination of neurochemical, neurophysiological and haemodynamic experimental approaches. The available experimental evidence indicates that tonic whole-body sympathetic nervous system (SNS) activity increases with age. The elevations in SNS activity appear to be region specific, targeting skeletal muscle and the gut, but not obviously the kidney. The SNS tone of the heart is increased, although this appears to be due in part to reduced neuronal reuptake of noradrenaline (norepinephrine). In contrast to SNS activity, tonic adrenaline (epinephrine) secretion from the adrenal medulla is markedly reduced with age. This is not reflected in plasma adrenaline concentrations because of reduced plasma clearance. Despite widely held beliefs to the contrary, sympathoadrenal responsiveness to acute stress is not exaggerated with age in healthy adults. Indeed, adrenaline release in response to acute stress is substantially attenuated in older men. The mechanisms underlying the age-associated increases in SNS activity have not been established, but our preliminary data are consistent with increased subcortical central nervous system (CNS) sympathetic drive. These changes in sympathoadrenal function with advancing age may have a number of important physiological and pathophysiological consequences for human health and disease. PMID:11060120

  10. Cardiovascular Aging: Perspectives From Humans to Rodents.

    PubMed

    Lakatta, Edward G.

    1998-11-01

    In order to define and target the specific characteristics of cardiovascular aging that render aging as a risk factor for diseases (such as atherosclerosis, hypertension, stroke, and heart failure) that reach epidemic proportions among older individuals, it is essential to develop quantitative information on age-associated alterations in cardiovascular structure and function in health. A sustained effort, over the past two decades, has been applied to characterize the multiple effects of aging on health in cardiovascular structure and function in a single study population (BLSA). In these studies, community-dwelling, volunteer participants are rigorously screened to detect both clinical and occult cardiovascular disease and characterized with respect to lifestyle (e.g., exercise habits), in an attempt to deconvolute interactions among lifestyle, cardiovascular disease, and the aging process in health. Some specific changes in resting cardiovascular structure and function and cardiovascular reserve capacity that occur with advancing age in these healthy humans have been identified and are presented here. These observations in humans are extended by relevant experiments from animal models to provide possible mechanistic insight.

  11. 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

  12. 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

  13. Digital quantification of human eye color highlights genetic association of three new loci.

    PubMed

    Liu, Fan; Wollstein, Andreas; Hysi, Pirro G; Ankra-Badu, Georgina A; Spector, Timothy D; Park, Daniel; Zhu, Gu; Larsson, Mats; Duffy, David L; Montgomery, Grant W; Mackey, David A; Walsh, Susan; Lao, Oscar; Hofman, Albert; Rivadeneira, Fernando; Vingerling, Johannes R; Uitterlinden, André G; Martin, Nicholas G; Hammond, Christopher J; Kayser, Manfred

    2010-05-06

    Previous studies have successfully identified genetic variants in several genes associated with human iris (eye) color; however, they all used simplified categorical trait information. Here, we quantified continuous eye color variation into hue and saturation values using high-resolution digital full-eye photographs and conducted a genome-wide association study on 5,951 Dutch Europeans from the Rotterdam Study. Three new regions, 1q42.3, 17q25.3, and 21q22.13, were highlighted meeting the criterion for genome-wide statistically significant association. The latter two loci were replicated in 2,261 individuals from the UK and in 1,282 from Australia. The LYST gene at 1q42.3 and the DSCR9 gene at 21q22.13 serve as promising functional candidates. A model for predicting quantitative eye colors explained over 50% of trait variance in the Rotterdam Study. Over all our data exemplify that fine phenotyping is a useful strategy for finding genes involved in human complex traits.

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

    PubMed

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

    2011-07-01

    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.

  15. Effects of aqueous humor hydrodynamics on human eye heat transfer under external heat sources.

    PubMed

    Tiang, Kor L; Ooi, Ean H

    2016-08-01

    The majority of the eye models developed in the late 90s and early 00s considers only heat conduction inside the eye. This assumption is not entirely correct, since the anterior and posterior chambers are filled aqueous humor (AH) that is constantly in motion due to thermally-induced buoyancy. In this paper, a three-dimensional model of the human eye is developed to investigate the effects AH hydrodynamics have on the human eye temperature under exposure to external heat sources. If the effects of AH flow are negligible, then future models can be developed without taking them into account, thus simplifying the modeling process. Two types of external thermal loads are considered; volumetric and surface irradiation. Results showed that heat convection due to AH flow contributes to nearly 95% of the total heat flow inside the anterior chamber. Moreover, the circulation inside the anterior chamber can cause an upward shift of the location of hotspot. This can have significant consequences to our understanding of heat-induced cataractogenesis.

  16. Effects of aqueous humor hydrodynamics on human eye heat transfer under external heat sources.

    PubMed

    Tiang, Kor L; Ooi, Ean H

    2016-08-01

    The majority of the eye models developed in the late 90s and early 00s considers only heat conduction inside the eye. This assumption is not entirely correct, since the anterior and posterior chambers are filled aqueous humor (AH) that is constantly in motion due to thermally-induced buoyancy. In this paper, a three-dimensional model of the human eye is developed to investigate the effects AH hydrodynamics have on the human eye temperature under exposure to external heat sources. If the effects of AH flow are negligible, then future models can be developed without taking them into account, thus simplifying the modeling process. Two types of external thermal loads are considered; volumetric and surface irradiation. Results showed that heat convection due to AH flow contributes to nearly 95% of the total heat flow inside the anterior chamber. Moreover, the circulation inside the anterior chamber can cause an upward shift of the location of hotspot. This can have significant consequences to our understanding of heat-induced cataractogenesis. PMID:27340100

  17. 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.

  18. 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. PMID:26764332

  19. Noncoding Transcriptional Landscape in Human Aging.

    PubMed

    Costa, Marina C; Leitão, Ana Lúcia; Enguita, Francisco J

    2016-01-01

    Aging is a universal phenomenon in metazoans, characterized by a general decline of the organism physiology associated with an increased risk of mortality and morbidity. Aging of an organism correlates with a decline in function of its cells, as shown for muscle, immune, and neuronal cells. As the DNA content of most cells within an organism remains largely identical throughout the life span, age-associated transcriptional changes must be achieved by epigenetic mechanisms. However, how aging may impact on the epigenetic state of cells is only beginning to be understood. In light of a growing number of studies demonstrating that noncoding RNAs can provide molecular signals that regulate expression of protein-coding genes and define epigenetic states of cells, we hypothesize that noncoding RNAs could play a direct role in inducing age-associated profiles of gene expression. In this context, the role of long noncoding RNAs (lncRNAs) as regulators of gene expression might be important for the overall transcriptional landscape observed in aged human cells. The possible functions of lncRNAs and other noncoding RNAs, and their roles in the regulation of aging-related cellular pathways will be analyzed.

  20. 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

  1. 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

  2. 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

  3. Inverse U-shaped curve for age dependency of torsional eye movement responses to galvanic vestibular stimulation.

    PubMed

    Jahn, Klaus; Naessl, Andrea; Schneider, Erich; Strupp, Michael; Brandt, Thomas; Dieterich, Marianne

    2003-07-01

    To investigate age dependent changes we analysed torsional eye movement responses to binaural and monaural galvanic vestibular stimulation (GVS) in 57 healthy subjects (20-69 years old). GVS (1-3 mA) induced torsional eye movements consisting of static torsion toward the anode (amplitude 1-6 degrees ) and superimposed torsional nystagmus (slow phase velocity 0.5-3 degrees /s, quick phase amplitude 0.5-2 degrees, nystagmus frequency 0.75-1.5 s-1). Static ocular torsion and torsional nystagmus increased from the third to the sixth decade and decreased in older subjects, e.g. slow phase velocity increased from 1.5 degrees /s (20-29 years) to 2.9 degrees /s (50-59 years) and decreased to 2.5 degrees /s for the seventh decade (60-69 years). Thus, an inverse U-shaped curve was found for the dependence of torsional eye movement responses on age. All structures relevant for vestibular function degenerate with age, but at varying times. Since hair cell loss precedes those seen in the vestibular nerve and Scarpa's ganglion, the decrease in hair cell counts could be compensated for by increased sensitivity of afferent nerve fibres or central mechanisms. Increased sensitivity could thus maintain normal function despite reduced peripheral input. As GVS acts at the vestibular nerve (thereby bypassing the hair cells), electrical stimulation should be more efficient in subjects with the beginning of hair cell degeneration, as seen in our data up to the sixth decade. The degeneration of nerve fibres, ganglion cells and central neurons becomes evident at older ages. Thus, the compensatory increase in sensitivity breaks down and GVS-induced eye movements decline-a finding that is reflected by the inverse U-shaped curve for age dependency presented in this study.

  4. 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.

  5. Ultra-long scan depth optical coherence tomography for imaging the anterior segment of human eye

    NASA Astrophysics Data System (ADS)

    Zhu, Dexi; Shen, Meixiao; Leng, Lin

    2012-12-01

    Spectral domain optical coherence tomography (SD-OCT) was developed in order to image the anterior segment of human eye. The optical path at reference arm was switched to compensate the sensitivity drop in OCT images. An scan depth of 12.28 mm and an axial resolution of 12.8 μm in air were achieved. The anterior segment from cornea to posterior surface of crystalline lens was clearly imaged and measured using this system. A custom designed Badal optometer was coupled into the sample arm to induce the accommodation, and the movement of crystalline lens was traced after the image registration. Our research demonstrates that SD-OCT with ultra-long scan depth can be used to image the human eye for accommodation research.

  6. Phacoemulsification surgery in eyes with neovascular age-related macular degeneration.

    PubMed

    Grixti, Andre; Papavasileiou, Evangelia; Cortis, Dominic; Kumar, Balakrishna Vineeth; Prasad, Som

    2014-01-01

    Purpose. To evaluate the visual outcomes and effect of phacoemulsification surgery on the progression of neovascular age-related macular degeneration (AMD). Methods. Retrospective, noncomparative, and interventional case series. Thirty eyes from 29 subjects with neovascular AMD treated with intravitreal antivascular endothelial growth factor (VEGF) injections who underwent phacoemulsification and had a postsurgery follow-up of 6 months were included. LogMAR best corrected visual acuity (BCVA) was assessed preoperatively; 1 month, 3 months, and 6 months postoperatively; and finally at the last visit. The frequency of anti-VEGF therapy, calculated as the number of intravitreal injections per month, and central macular thickness (CMT) before and after cataract surgery were determined. Results. Median (range) logMAR BCVA was 0.69 (0.16 to 1.32) preoperatively; 0.55 (-0.04 to 1.32) at 1 month, 0.52 (-0.1 to 1.32) at 3 months, and 0.50 (0.0 to 1.32) at 6 months postoperatively; and 0.6 (0.0 to 1.4) at final visit (P = 0.0011). There was no difference in the frequency of anti-VEGF injections between the immediate 6 months before and after phacoemulsification, which was equal to 0.1667 injections per month (P = 0.6377). Median CMT measured 203  μ m preoperatively, which temporarily increased to 238  μ m at 1 month after surgery (P = 0.0093) and then spontaneously returned to baseline, measuring 212.5  μ m at 3 months postoperatively (P = 0.3811). Conclusion. Phacoemulsification surgery significantly improved vision in patients with neovascular AMD, with no increased need for anti-VEGF injections to keep the macula dry postoperatively.

  7. Phacoemulsification Surgery in Eyes with Neovascular Age-Related Macular Degeneration

    PubMed Central

    Papavasileiou, Evangelia; Kumar, Balakrishna Vineeth; Prasad, Som

    2014-01-01

    Purpose. To evaluate the visual outcomes and effect of phacoemulsification surgery on the progression of neovascular age-related macular degeneration (AMD). Methods. Retrospective, noncomparative, and interventional case series. Thirty eyes from 29 subjects with neovascular AMD treated with intravitreal antivascular endothelial growth factor (VEGF) injections who underwent phacoemulsification and had a postsurgery follow-up of 6 months were included. LogMAR best corrected visual acuity (BCVA) was assessed preoperatively; 1 month, 3 months, and 6 months postoperatively; and finally at the last visit. The frequency of anti-VEGF therapy, calculated as the number of intravitreal injections per month, and central macular thickness (CMT) before and after cataract surgery were determined. Results. Median (range) logMAR BCVA was 0.69 (0.16 to 1.32) preoperatively; 0.55 (−0.04 to 1.32) at 1 month, 0.52 (−0.1 to 1.32) at 3 months, and 0.50 (0.0 to 1.32) at 6 months postoperatively; and 0.6 (0.0 to 1.4) at final visit (P = 0.0011). There was no difference in the frequency of anti-VEGF injections between the immediate 6 months before and after phacoemulsification, which was equal to 0.1667 injections per month (P = 0.6377). Median CMT measured 203 μm preoperatively, which temporarily increased to 238 μm at 1 month after surgery (P = 0.0093) and then spontaneously returned to baseline, measuring 212.5 μm at 3 months postoperatively (P = 0.3811). Conclusion. Phacoemulsification surgery significantly improved vision in patients with neovascular AMD, with no increased need for anti-VEGF injections to keep the macula dry postoperatively. PMID:24719771

  8. 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

  9. 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.

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

    PubMed

    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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. An eye on nutrition: The role of vitamins, essential fatty acids, and antioxidants in age-related macular degeneration, dry eye syndrome, and cataract.

    PubMed

    McCusker, Meagen M; Durrani, Khayyam; Payette, Michael J; Suchecki, Jeanine

    2016-01-01

    Visual impairment is a global epidemic. In developing countries, nutritional deficiency and cataracts continue to be the leading cause of blindness, whereas age-related macular degeneration (AMD) and cataracts are the leading causes in developed nations. The World Health Organization has instituted VISION 2020: "The Right to Sight" as a global mission to put an end to worldwide blindness. In industrialized societies, patients, physicians, researchers, nutritionists, and biochemists have been looking toward vitamins and nutrients to prevent AMD, cataracts, and dry eye syndrome (DES). Nutrients from the AREDS2 study (lutein, zeaxanthin, vitamin C, vitamin E, zinc, copper, eicosapentanoic acid [EPA], and docosahexanoic acid [DHA]) set forth by the National Institutes of Health remain the most proven nutritional therapy for reducing the rate of advanced AMD. Omega-3 fatty acids, especially DHA, have been found to improve DES in randomized clinical trials. Conflicting results have been seen with regard to multivitamin supplementation on the prevention of cataract. PMID:26903189

  17. Human eye movements during various forms of linear acceleration and weightlessness. [electronystagmographic recordings of human and fish responses to gravitoinertial conditions

    NASA Technical Reports Server (NTRS)

    Vonbaumgarten, R. J.; Thumler, R.; Shillinger, G. L., Jr.; Baldrighi, G.

    1973-01-01

    Eye movements of human subjects were recorded electronystagmographically in complete darkness during rectilinear horizontal accelerations as achieved in cars on the ground and also during aircraft parabolic flight. The results were compared to the movements of blinded goldfish subjected to similar changes of gravitoinertial forces. The results indicate that there is a human correlation with the gravity reference response of fish. During horizontal forward accelerations on the ground the human eyes turn downward and during horizontal backward acceleration the eyes turn upward. The human eye response to g-loads below 1 g and to weightlessness is the reverse of the tilt of the fish. While fish dive down during low g, or loop forward during weightlessness, the eyes of subjects sitting upright in an aircraft which flies at 0 g move upward.

  18. Defensive eye-blink startle responses in a human experimental model of anxiety.

    PubMed

    Pinkney, Verity; Wickens, Robin; Bamford, Susan; Baldwin, David S; Garner, Matthew

    2014-09-01

    Inhalation of low concentrations of carbon dioxide (CO2) triggers anxious behaviours in rodents via chemosensors in the amygdala, and increases anxiety, autonomic arousal and hypervigilance in healthy humans. However, it is not known whether CO2 inhalation modulates defensive behaviours coordinated by this network in humans. We examined the effect of 7.5% CO2 challenge on the defensive eye-blink startle response. A total of 27 healthy volunteers completed an affective startle task during inhalation of 7.5% CO2 and air. The magnitude and latency of startle eye-blinks were recorded whilst participants viewed aversive and neutral pictures. We found that 7.5% CO2 increased state anxiety and raised concurrent measures of skin conductance and heart rate (HR). CO2 challenge did not increase startle magnitude, but slowed the onset of startle eye-blinks. The effect of CO2 challenge on HR covaried with its effects on both subjective anxiety and startle latency. Our findings are discussed with reference to startle profiles during conditions of interoceptive threat, increased cognitive load and in populations characterised by anxiety, compared with acute fear and panic. PMID:24899597

  19. 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

  20. The Age-Related Eye Disease Study 2 (AREDS2): Study Design and Baseline Characteristics (AREDS2 Report Number 1)

    PubMed Central

    Chew, Emily Y.; Clemons, Traci; SanGiovanni, John Paul; Danis, Ronald; Domalpally, Amitha; McBee, Wendy; Sperduto, Robert; Ferris, Frederick L.

    2012-01-01

    Purpose The Age-Related Eye Disease Study (AREDS) demonstrated beneficial effects of oral supplementation with antioxidant vitamins and minerals on the development of advanced age-related macular degeneration (AMD) in persons with at least intermediate AMD (bilateral large drusen with or without pigment changes). Observational data suggest that other oral nutrient supplements might further reduce the risk of progression to advanced AMD. The primary purpose of Age-Related Eye Disease Study 2 (AREDS2) is to evaluate the efficacy and safety of lutein+zeaxanthin (L+Z) and/or omega-3 long-chain polyunsaturated fatty acid (LCPUFA) supplementation in reducing the risk of developing advanced AMD. The study will also assess the reduction in zinc and the omission of beta-carotene from original AREDS formulation. Design Multicenter phase 3 randomized controlled clinical trial Participants Persons age 50 to 85 with bilateral intermediate AMD or advanced AMD in one eye Methods All participants were randomly assigned to: 1) placebo (n=1012); 2) L+Z (10 mg/2 mg, n=1044); 3) ω-3 LCPUFAs (eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) [650gmg/350 mg] n=1069); or 4) the combination of L+Z and ω -3 LCPUFAs (n=1078). All participants were offered a secondary randomization to 1 of 4 variations of the original AREDS formulation keeping vitamins C (500 mg), E (400 IU), and copper (2 mg) unchanged while varying zinc and beta-carotene as follows: zinc remains at the original level (80mg), lower only zinc to 25mg, omit beta-carotene only, or lower zinc to 25 mg and omit beta-carotene. Main Outcome Measures Progression to advanced AMD determined by centralized grading of annual fundus photographs. Results 4,203 participants were enrolled at 82 clinical centers located in the U.S. Population characteristics at baseline were as follows: mean age 74 years, 57% female, 97% white, 7% current smokers, 19% with prior cardiovascular disease and 44% and 50% taking statin-class cholesterol

  1. Identification of Active Retinaldehyde Dehydrogenase Isoforms in the Postnatal Human Eye

    PubMed Central

    Harper, Angelica R.; Wiechmann, Allan F.; Moiseyev, Gennadiy; Ma, Jian-Xing; Summers, Jody A.

    2015-01-01

    Background/Objectives Retinaldehyde dehydrogenase 2 (RALDH2) has been implicated in regulating all-trans-retinoic acid (atRA) synthesis in response to visual signals in animal models of myopia. To explore the potential role of retinaldehyde dehydrogenase (RALDH) enzymes and atRA in human postnatal ocular growth, RALDH activity, along with the distribution of RALDH1, RALDH2, and RALDH3 in the postnatal eye was determined. Methodology Retina, retinal pigment epithelium (RPE), choroid, and sclera were isolated from donor human eyes. RALDH catalytic activity was measured in tissue homogenates using an in vitro atRA synthesis assay together with HPLC quantification of synthesized atRA. Homogenates were compared by western blotting for RALDH1, RALDH2, and RALDH3 protein. Immunohistochemistry was used to determine RALDH1 and RALDH2 localization in posterior fundal layers of the human eye. Principal Findings In the postnatal human eye, RALDH catalytic activity was detected in the choroid (6.84 ± 1.20 pmol/hr/ug), RPE (5.46 ± 1.18 pmol/hr/ug), and retina (4.21 ± 1.55 pmol/hr/ug), indicating the presence of active RALDH enzymes in these tissues. RALDH2 was most abundant in the choroid and RPE, in moderate abundance in the retina, and in relatively low abundance in sclera. RALDH1 was most abundant in the choroid, in moderate abundance in the sclera, and substantially reduced in the retina and RPE. RALDH3 was undetectable in human ocular fundal tissues. In the choroid, RALDH1 and RALDH2 localized to slender cells in the stroma, some of which were closely associated with blood vessels. Conclusions/Significance Results of this study demonstrated that: 1) Catalytically active RALDH is present in postnatal human retina, RPE, and choroid, 2) RALDH1 and RALDH2 isoforms are present in these ocular tissues, and 3) RALDH1 and RALDH2 are relatively abundant in the choroid and/or RPE. Taken together, these results suggest that RALDH1 and 2 may play a role in the regulation of

  2. Chronological ageing of human hair keratin fibres.

    PubMed

    Thibaut, S; de Becker, E; Bernard, B A; Huart, M; Fiat, F; Baghdadli, N; Luengo, G S; Leroy, F; Angevin, P; Kermoal, A M; Muller, S; Peron, M; Provot, G; Kravtchenko, S; Saint-Léger, D; Desbois, G; Gauchet, L; Nowbuth, K; Galliano, A; Kempf, J Y; Silberzan, I

    2010-12-01

    Examination of very long hair (length > 2.4 m) using a large range of evaluation methods including physical, chemical, biochemical and microscopic techniques has enabled to attain a detailed understanding of natural ageing of human hair keratin fibres. Scrutinizing hair that has undergone little or no oxidative aggression--because of the absence of action of chemical agents such as bleaching or dyeing--from the root to the tip shows the deterioration process, which gradually takes place from the outside to the inside of the hair shaft: first, a progressive abrasion of the cuticle, whilst the cortex structure remains unaltered, is evidenced along a length of roughly 1 m onwards together with constant shine, hydrophobicity and friction characteristics. Further along the fibre, a significant damage to cuticle scales occurs, which correlates well with ceramides and 18-Methyl Eicosanoic Acid (18-MEA) decline, and progressive decrease in keratin-associated protein content. Most physical descriptors of mechanical and optical properties decay significantly. This detailed description of natural ageing of human hair fibres by a fine analysis of hair components and physical parameters in relationship with cosmetic characteristics provides a time-dependent 'damage scale' of human hair, which may help in designing new targeted hair care formulations.

  3. Nonpenetrating glaucoma surgery using the CO2 laser: experimental studies in human cadaver eyes

    NASA Astrophysics Data System (ADS)

    Assia, Ehud I.; Barequet, Irina S.; Rosner, Mordechai; Belkin, Michael

    2001-06-01

    Non-penetrating trabeculectomy (NPT) is a potential replacement to conventional trabeculectomy, as it eliminates the necessity of penetrating the eye which is the cause of most of the complications entailed by the latter operation. NPT however, requires considerable surgical skill, is time consuming and entails complications of its own. We have shown that it can be easily performed by using the CO2 laser to ablate the sclera and corneoscleral tissues to the required depth. The use of the CO2 laser eliminates the danger of inadvertent perforation, a common complication of NPT as the tissue ablation ceases when the end-point of the operation, the aqueous humor percolation, is reached. Our experiments, performed on animal and human cadaver eyes showed that CO2 laser NPT rapid is easily mastered and performed rapid and eliminates almost completely the risk of complications.

  4. Diabetes-Associated Dry Eye Syndrome in a New Humanized Transgenic Model of Type 1 Diabetes

    PubMed Central

    Imam, Shahnawaz; Elagin, Raya B.

    2013-01-01

    Purpose Patients with Type 1 Diabetes (T1D) are at high risk of developing lacrimal gland dysfunction. We have developed a new model of human T1D using double-transgenic mice carrying HLA-DQ8 diabetes-susceptibility haplotype instead of mouse MHC-class II and expressing the human beta cell autoantigen Glutamic Acid Decarboxylase in pancreatic beta cells. We report here the development of dry eye syndrome (DES) after diabetes induction in our humanized transgenic model. Methods Double-transgenic mice were immunized with DNA encoding human GAD65, either naked or in adenoviral vectors, to induce T1D. Mice monitored for development of diabetes developed lacrimal gland dysfunction. Results Animals developed lacrimal gland disease (classically associated with diabetes in Non Obese Diabetic [NOD] mice and with T1D in humans) as they developed glucose intolerance and diabetes. Animals manifested obvious clinical signs of dry eye syndrome (DES), from corneal erosions to severe keratitis. Histological studies of peri-bulbar areas revealed lymphocytic infiltration of glandular structures. Indeed, infiltrative lesions were observed in lacrimal/Harderian glands within weeks following development of glucose intolerance. Lesions ranged from focal lymphocytic infiltration to complete acinar destruction. We observed a correlation between the severity of the pancreatic infiltration and the severity of the ocular disease. Conclusions Our results demonstrate development of DES in association with antigen-specific insulitis and diabetes following immunization with clinically relevant human autoantigen concomitantly expressed in pancreatic beta cells of diabetes-susceptible mice. As in the NOD mouse model and as in human T1D, our animals developed diabetes-associated DES. This specific finding stresses the relevance of our model for studying these human diseases. We believe our model will facilitate studies to prevent/treat diabetes-associated DES as well as human diabetes. PMID

  5. [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.

  6. Optical clearing of human eye sclera under the action of glucose solution

    NASA Astrophysics Data System (ADS)

    Bashkatov, Alexey N.; Genina, Elina A.; Kochubey, Vyacheslav I.; Gavrilova, Anna A.; Kamenskikh, Tatyana G.; Galanzha, Vladimir A.; Tuchin, Valery V.

    2007-05-01

    We present experimental results of investigation of the optical properties of the human eye sclera controlled by administration of osmotically active chemical, such as 40%-glucose solution. Administration of the chemical agent induces diffusion of matter and as a result equalization of the refractive indices of collagen and ground material. Results of the experimental study of influence of the glucose solution on the absorption and scattering properties of human sclera are presented. In vitro reflectance and transmittance spectra of the human sclera samples were measured by commercially available spectrophotometer CARY-2415 in the spectral range from 400 to 1800 nm. The reduced scattering coefficient of human sclera samples is significantly decreased under action of the osmotical solution were demonstrated.

  7. Preserving humanity in an age of technology.

    PubMed

    Mann, R E

    1992-03-01

    Preserving humanity in the present technological age can be a challenge for all health care workers, but perhaps particularly for staff working within an intensive care environment. This article highlights some of the potential effects of such technology on staff, patients and relatives, particularly bringing to light some of the disadvantages brought about by the use of such technology. Areas considered include the role of nurses within a technological environment, patients' and relatives' reactions to technology, the potential effect on autonomy and responsibility for both patients and nurses, economic issues, and finally ethical and moral issues raised by the advent of further technology. Despite many positive contributions to nursing care which arise from the use of technology, there are disadvantages attributed to technology which have only been mentioned superficially in previous literature on this subject. The question arises as to whether nurses are able to balance preserving the humanity of patients with the extensive use of technology in an intensive care environment today.

  8. GENETICS OF HUMAN AGE RELATED DISORDERS.

    PubMed

    Srivastava, I; Thukral, N; Hasija, Y

    2015-01-01

    Aging is an inevitable biological phenomenon. The incidence of age related disorders (ARDs) such as cardiovascular diseases, cancer, arthritis, dementia, osteoporosis, diabetes, neurodegenerative diseases increase rapidly with aging. ARDs are becoming a key social and economic trouble for the world's elderly population (above 60 years), which is expected to reach 2 billion by 2050. Advancement in understanding of genetic associations, particularly through genome wide association studies (GWAS), has revealed a substantial contribution of genes to human aging and ARDs. In this review, we have focused on the recent understanding of the extent to which genetic predisposition may influence the aging process. Further analysis of the genetic association studies through pathway analysis several genes associated with multiple ARDs have been highlighted such as apolipoprotein E (APOE), brain-derived neurotrophic factor (BDNF), cadherin 13 (CDH13), CDK5 regulatory subunit associated protein 1 (CDKAL-1), methylenetetrahydrofolate reductase (MTHFR), disrupted in schizophrenia 1 (DISC1), nitric oxide synthase 3 (NOS3), paraoxonase 1 (PON1), indicating that these genes could play a pivotal role in ARD causation. These genes were found to be significantly enriched in Jak-STAT signalling pathway, asthma and allograft rejection. Further, interleukin-6 (IL-6), insulin (INS), vascular endothelial growth factor A (VEGFA), estrogen receptor1 (ESR1), transforming growth factor, beta 1(TGFB1) and calmodulin 1 (CALM1) were found to be highly interconnected in network analysis. We believe that extensive research on the presence of common genetic variants among various ARDs may facilitate scientists to understand the biology behind ARDs causation. PMID:26856084

  9. 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.

  10. Disability Glare in the Aging Eye. Assessment and Impact on Driving☆

    PubMed Central

    van den Berg, Thomas J.T.P.; (René) van Rijn, L.J.; Kaper-Bongers, R.; Vonhoff, D.J.; Völker-Dieben, H.J.; Grabner, G.; Nischler, C.; Emesz, M.; Wilhelm, H.; Gamer, D.; Schuster, A.; Franssen, L.; de Wit, G.C.; Coppens, J.E.

    2010-01-01

    Purpose To compare different methods for the assessment of disability glare sensitivity in the elderly, to arrive at an objective assessment of the condition of the eye. To delineate the importance of straylight values in vision. Methods Three groups of subjects were studied: 1) Young subjects without any eye disease, 2) elderly subjects without any eye disease and 3) elderly subjects with (early) cataract in at least one eye. All subjects underwent 2 glare tests, 2 straylight tests, ETDRS visual acuity test, Pelli Robson contrast sensitivity test, refraction, LOCS III cataract classification. Straylight was quantified by means of the straylight parameter s. Results Repeatability, discriminative ability, and added value as compared to visual acuity were low for the glare tests and good for the straylight measurements. For young normal subjects, with log(s)=0.9, the standard glare situation with low beams gives a contrast reduction of 1.3, whereas for the healthy 77 year olds this increases to 2. With cataract hardly affecting visual acuity, log(s) can be as high as 1.8, resulting in a contrast reduction of 3.4. Conclusion Straylight measurement is of relevance for the assessment of the glare-related hindrance during driving, and can be used to objectify complaints and aid in the decision-making regarding cataract surgery.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  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. 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.

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

    PubMed Central

    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. PMID:25789169

  19. Age-related Defects in Ocular and Nasal Mucosal Immune System and the Immunopathology of Dry Eye Disease

    PubMed Central

    Farid, Marjan; Agrawal, Anshu; Fremgen, Daniel; Tao, Jeremiah; Chuyi, He; Nesburn, Anthony B.; BenMohamed, Lbachir

    2014-01-01

    Dry eye disease (DED) is a prevalent public health concern that affects up to 30% of adults and is particularly chronic and severe in the elderly. Two interconnected mechanisms cause DED: (1) an age-related dysfunction of lacrimal and meibomian glands, which leads to decreased tear production and/or an increase in tear evaporation; and (2) an age-related uncontrolled inflammation of the surface of the eye triggered by yet-to-be-determined internal immunopathological mechanisms, independent of tear deficiency and evaporation. In this review we summarize current knowledge on animal models that mimic both the severity and chronicity of inflammatory DED and that have been reliably used to provide insights into the immunopathological mechanisms of DED, and we provide an overview of the opportunities and limitations of the rabbit model in investigating the role of both ocular and nasal mucosal immune systems in the immunopathology of inflammatory DED and in testing novel immunotherapies aimed at delaying or reversing the uncontrolled age-related inflammatory DED. PMID:25535823

  20. Age-related Defects in Ocular and Nasal Mucosal Immune System and the Immunopathology of Dry Eye Disease.

    PubMed

    Farid, Marjan; Agrawal, Anshu; Fremgen, Daniel; Tao, Jeremiah; Chuyi, He; Nesburn, Anthony B; BenMohamed, Lbachir

    2016-06-01

    Dry eye disease (DED) is a prevalent public health concern that affects up to 30% of adults and is particularly chronic and severe in the elderly. Two interconnected mechanisms cause DED: (1) an age-related dysfunction of lacrimal and meibomian glands, which leads to decreased tear production and/or an increase in tear evaporation; and (2) an age-related uncontrolled inflammation of the surface of the eye triggered by yet-to-be-determined internal immunopathological mechanisms, independent of tear deficiency and evaporation. In this review we summarize current knowledge on animal models that mimic both the severity and chronicity of inflammatory DED and that have been reliably used to provide insights into the immunopathological mechanisms of DED, and we provide an overview of the opportunities and limitations of the rabbit model in investigating the role of both ocular and nasal mucosal immune systems in the immunopathology of inflammatory DED and in testing novel immunotherapies aimed at delaying or reversing the uncontrolled age-related inflammatory DED.

  1. 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

  2. Modulating Human Aging and Age-Associated Diseases

    PubMed Central

    Fontana, Luigi

    2009-01-01

    Population aging is progressing rapidly in many industrialized countries. The United States population aged 65 and over is expected to double in size within the next 25 years. In sedentary people eating Western diets aging is associated with the development of serious chronic diseases, including type 2 diabetes mellitus, cancer and cardiovascular diseases. About 80 percent of adults over 65 years of age have at least one chronic disease, and 50 percent have at least two chronic diseases. These chronic diseases are the most important cause of illness and mortality burden, and they have become the leading driver of healthcare costs, constituting an important burden for our society. Data from epidemiological studies and clinical trials indicate that many age-associated chronic diseases can be prevented, and even reversed, with the implementation of healthy lifestyle interventions. Several recent studies suggest that more drastic interventions (i.e. calorie restriction without malnutrition and moderate protein restriction with adequate nutrition) may have additional beneficial effects on several metabolic and hormonal factors that are implicated in the biology of aging itself. Additional studies are needed to understand the complex interactions of factors that regulate aging and age-associated chronic disease. PMID:19364477

  3. 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. PMID:25713787

  4. 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

  5. Distribution of pseudoexfoliation material on anterior segment structures in human autopsy eyes after cataract surgery with intraocular lens implantation.

    PubMed

    Schmack, Ingo; Auffarth, Gerd Uwe

    2016-06-01

    The purpose of the study was to evaluate the distribution and amount of pseudoexfoliation material (PXM) on anterior segment structures in pseudophakic human autopsy eyes with pseudoexfoliation (PEX) syndrome and to study its impact on fixation and decentration of posterior chamber intraocular lenses (IOLs). Sixteen human autopsy eyes (donor age [mean ± SD] 77.5 ± 8.6 years; range, 70-90 years) with history of cataract surgery and PEX syndrome were analyzed for distribution and accumulation of PXM on structures of the anterior segment by light microscopy. Quantitative IOL decentration measurements were performed using the Miyake-Apple posterior view technique. All 16 eyes displayed IOLs which were either fixed symmetrically in the capsular bag (n = 8) or asymmetrically with one haptic in the sulcus and one in the bag (n = 7) or at the pars plicata of the ciliary body (n = 1). In the majority, PXM was found around the pars plicata (average grade: 1.6 ± 0.53 µm) and the lens capsule (average grade: 1.05 ± 0.46 µm). Minor amounts were detected at the pars plana and the trabecular meshwork. IOL decentration measurements ranged from 0.51 ± 0.35 (symmetrical-fixation) to 0.61 ± 0.43 mm (asymmetrical-fixation). There was only a weak statistically not significant correlation in regard to the amount of PXM and IOL decentration and between PXM distribution and the IOL fixation site. PXM contributes to weakening of the suspensory apparatus of the crystalline lens. Although PXM induced tissue alterations predispose for a broad spectrum of intra- and postoperative complications, the amount and distribution of PXM on different anterior segment structures showed only a weak correlation to IOL decentration or fixation location. PMID:26307751

  6. 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.

  7. Impact of Corneal Endothelial Dysfunctions on Intraocular Oxygen Levels in Human Eyes

    PubMed Central

    Huang, Andrew J. W.; Shui, Ying-Bo; Han, Yu-Ping; Bai, Fang; Siegfried, Carla J.; Beebe, David C.

    2015-01-01

    Purpose We studied the implications of corneal endothelial dysfunctions on oxidative stress in the anterior segment via in vivo measurements of oxygen partial pressure (pO2) in the anterior chamber (AC) of human eyes. Methods We recruited 51 patients undergoing cataract surgery and/or endothelial keratoplasty (EK). Endothelial cell density (ECD; n = 33) and central corneal thickness (CCT; n = 41) were measured on patients with relatively clear corneas. Before surgery, an oxygen sensor was introduced into the AC via a peripheral corneal paracentesis. In all patients, seven measurements of pO2 were obtained by positioning the flexible tip near the endothelium at the central cornea, at four cardinal subendothelial locations near the midperipheral cornea, and in the mid-AC and AC angle. In patients with pseudophakia or eyes undergoing cataract surgery, pO2 also was measured near the lens surface and in the posterior chamber. Results Consistent with our previous reports, a steep oxygen gradient was noted in the anterior segment of normal controls (n = 24). In patients with endothelial dysfunctions (n = 27), there was a significant increase of pO2 at all five subendothelial locations without a significant increase of pO2 in the AC angle. By regression analyses, subendothelial pO2 correlated inversely with ECD and positively with CCT in patients with endothelial dysfunctions. Conclusions This study demonstrates an even steeper intraocular oxygen gradient in eyes with corneal endothelial dysfunctions. It suggests that the reduced oxygen consumption in corneal endothelial cells may increase oxidative stress in the AC and the existence of an alternative aqueous inflow pathway that maintains a relatively low and constant pO2 at the AC angle. PMID:26447982

  8. High Resolution Topography of Age-Related Changes in Non-Rapid Eye Movement Sleep Electroencephalography.

    PubMed

    Sprecher, Kate E; Riedner, Brady A; Smith, Richard F; Tononi, Giulio; Davidson, Richard J; Benca, Ruth M

    2016-01-01

    Sleeping brain activity reflects brain anatomy and physiology. The aim of this study was to use high density (256 channel) electroencephalography (EEG) during sleep to characterize topographic changes in sleep EEG power across normal aging, with high spatial resolution. Sleep was evaluated in 92 healthy adults aged 18-65 years old using full polysomnography and high density EEG. After artifact removal, spectral power density was calculated for standard frequency bands for all channels, averaged across the NREM periods of the first 3 sleep cycles. To quantify topographic changes with age, maps were generated of the Pearson's coefficient of the correlation between power and age at each electrode. Significant correlations were determined by statistical non-parametric mapping. Absolute slow wave power declined significantly with increasing age across the entire scalp, whereas declines in theta and sigma power were significant only in frontal regions. Power in fast spindle frequencies declined significantly with increasing age frontally, whereas absolute power of slow spindle frequencies showed no significant change with age. When EEG power was normalized across the scalp, a left centro-parietal region showed significantly less age-related decline in power than the rest of the scalp. This partial preservation was particularly significant in the slow wave and sigma bands. The effect of age on sleep EEG varies substantially by region and frequency band. This non-uniformity should inform the design of future investigations of aging and sleep. This study provides normative data on the effect of age on sleep EEG topography, and provides a basis from which to explore the mechanisms of normal aging as well as neurodegenerative disorders for which age is a risk factor.

  9. High Resolution Topography of Age-Related Changes in Non-Rapid Eye Movement Sleep Electroencephalography

    PubMed Central

    Sprecher, Kate E.; Riedner, Brady A.; Smith, Richard F.; Tononi, Giulio; Davidson, Richard J.; Benca, Ruth M.

    2016-01-01

    Sleeping brain activity reflects brain anatomy and physiology. The aim of this study was to use high density (256 channel) electroencephalography (EEG) during sleep to characterize topographic changes in sleep EEG power across normal aging, with high spatial resolution. Sleep was evaluated in 92 healthy adults aged 18–65 years old using full polysomnography and high density EEG. After artifact removal, spectral power density was calculated for standard frequency bands for all channels, averaged across the NREM periods of the first 3 sleep cycles. To quantify topographic changes with age, maps were generated of the Pearson’s coefficient of the correlation between power and age at each electrode. Significant correlations were determined by statistical non-parametric mapping. Absolute slow wave power declined significantly with increasing age across the entire scalp, whereas declines in theta and sigma power were significant only in frontal regions. Power in fast spindle frequencies declined significantly with increasing age frontally, whereas absolute power of slow spindle frequencies showed no significant change with age. When EEG power was normalized across the scalp, a left centro-parietal region showed significantly less age-related decline in power than the rest of the scalp. This partial preservation was particularly significant in the slow wave and sigma bands. The effect of age on sleep EEG varies substantially by region and frequency band. This non-uniformity should inform the design of future investigations of aging and sleep. This study provides normative data on the effect of age on sleep EEG topography, and provides a basis from which to explore the mechanisms of normal aging as well as neurodegenerative disorders for which age is a risk factor. PMID:26901503

  10. Simple, Inexpensive Technique for High-Quality Smartphone Fundus Photography in Human and Animal Eyes

    PubMed Central

    Haddock, Luis J.; Kim, David Y.

    2013-01-01

    Purpose. We describe in detail a relatively simple technique of fundus photography in human and rabbit eyes using a smartphone, an inexpensive app for the smartphone, and instruments that are readily available in an ophthalmic practice. Methods. Fundus images were captured with a smartphone and a 20D lens with or without a Koeppe lens. By using the coaxial light source of the phone, this system works as an indirect ophthalmoscope that creates a digital image of the fundus. The application whose software allows for independent control of focus, exposure, and light intensity during video filming was used. With this app, we recorded high-definition videos of the fundus and subsequently extracted high-quality, still images from the video clip. Results. The described technique of smartphone fundus photography was able to capture excellent high-quality fundus images in both children under anesthesia and in awake adults. Excellent images were acquired with the 20D lens alone in the clinic, and the addition of the Koeppe lens in the operating room resulted in the best quality images. Successful photodocumentation of rabbit fundus was achieved in control and experimental eyes. Conclusion. The currently described system was able to take consistently high-quality fundus photographs in patients and in animals using readily available instruments that are portable with simple power sources. It is relatively simple to master, is relatively inexpensive, and can take advantage of the expanding mobile-telephone networks for telemedicine. PMID:24171108

  11. Human saccadic eye movements and tracking by active foveation in log polar space

    NASA Astrophysics Data System (ADS)

    Lim, Fee-Lee; Venkatesh, Svetha; West, Geoffrey A. W.

    1996-04-01

    One of the possible models of the human visual system (HVS) in the computer vision literature has a high resolution fovea and exponentially decreasing resolution periphery. The high resolution fovea is used to extract necessary information in order to solve a vision task and the periphery may be used to detect motion. To obtain the desired information, the fovea is guided by the contents of the scene and other knowledge to position the fovea over areas of interest. These eye movements are called saccades and corrective saccades. A two stage process has been implemented as a mechanism for changing foveation in log polar space. Initially, the open loop stage roughly foveates on the best interest feature and then the closed loop stage is invoked to accurately iteratively converge onto the foveation point. The open loop stage developed for the foveation algorithm is applied to saccadic eye movements and a tracking system. Log polar space is preferred over Cartesian space as: (1) it simultaneously provides high resolution and a wide viewing angle; and (2) feature invariance occurs in the fovea which simplifies the foveation process.

  12. 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.

  13. 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.

  14. Simple, inexpensive technique for high-quality smartphone fundus photography in human and animal eyes.

    PubMed

    Haddock, Luis J; Kim, David Y; Mukai, Shizuo

    2013-01-01

    Purpose. We describe in detail a relatively simple technique of fundus photography in human and rabbit eyes using a smartphone, an inexpensive app for the smartphone, and instruments that are readily available in an ophthalmic practice. Methods. Fundus images were captured with a smartphone and a 20D lens with or without a Koeppe lens. By using the coaxial light source of the phone, this system works as an indirect ophthalmoscope that creates a digital image of the fundus. The application whose software allows for independent control of focus, exposure, and light intensity during video filming was used. With this app, we recorded high-definition videos of the fundus and subsequently extracted high-quality, still images from the video clip. Results. The described technique of smartphone fundus photography was able to capture excellent high-quality fundus images in both children under anesthesia and in awake adults. Excellent images were acquired with the 20D lens alone in the clinic, and the addition of the Koeppe lens in the operating room resulted in the best quality images. Successful photodocumentation of rabbit fundus was achieved in control and experimental eyes. Conclusion. The currently described system was able to take consistently high-quality fundus photographs in patients and in animals using readily available instruments that are portable with simple power sources. It is relatively simple to master, is relatively inexpensive, and can take advantage of the expanding mobile-telephone networks for telemedicine.

  15. 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. PMID:24713524

  16. 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. PMID:26831752

  17. Single-neuron activity and eye movements during human REM sleep and awake vision

    PubMed Central

    Andrillon, Thomas; Nir, Yuval; Cirelli, Chiara; Tononi, Giulio; Fried, Itzhak

    2015-01-01

    Are rapid eye movements (REMs) in sleep associated with visual-like activity, as during wakefulness? Here we examine single-unit activities (n=2,057) and intracranial electroencephalography across the human medial temporal lobe (MTL) and neocortex during sleep and wakefulness, and during visual stimulation with fixation. During sleep and wakefulness, REM onsets are associated with distinct intracranial potentials, reminiscent of ponto-geniculate-occipital waves. Individual neurons, especially in the MTL, exhibit reduced firing rates before REMs as well as transient increases in firing rate immediately after, similar to activity patterns observed upon image presentation during fixation without eye movements. Moreover, the selectivity of individual units is correlated with their response latency, such that units activated after a small number of images or REMs exhibit delayed increases in firing rates. Finally, the phase of theta oscillations is similarly reset following REMs in sleep and wakefulness, and after controlled visual stimulation. Our results suggest that REMs during sleep rearrange discrete epochs of visual-like processing as during wakefulness. PMID:26262924

  18. Eye region-based fusion technique of thermal and dark visual images for human face recognition

    NASA Astrophysics Data System (ADS)

    Bhowmik, Mrinal Kanti; Bhattacharjee, Debotosh; Basu, Dipak Kumar; Nasipuri, Mita

    2012-07-01

    We present an approach for human face recognition using eye region extraction/replacement method under low illumination and varying expression conditions. For conducting experiments, two different sets of face images, namely visual and corresponding thermal, are used from Imaging, Robotics, and Intelligent Systems (IRIS) thermal/visual face data. A decomposition and reconstruction technique of Daubechies wavelet co-efficient (db4) is used to generate the fused image by replacing the eye region in the visual image with the same region from the corresponding thermal image. After that, independent component analysis over the natural logarithm domain (Log-ICA) is used for feature extraction/dimensionality reduction, and finally, a classifier is used to classify the fused face images. Two different image sets, i.e., training and test image sets, are mainly prepared using the IRIS thermal/visual face database for finding the accuracy of the proposed system. Experimental results show the proposed method is more efficient than other image fusion techniques which have used region extraction techniques for dark faces.

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

    PubMed

    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

  20. 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

  1. The digital aqueous humor outflow meter: an alternative tool for screening of the human eye outflow facility

    PubMed Central

    Kozobolis, Vassilios P; Paschalis, Eleftherios I; Foudoulakis, Nikitas C; Koukoula, Stavrenia C; Labiris, Georgios

    2010-01-01

    Purpose: To develop, characterize, and validate a prototype digital aqueous humor outflow tonographer (DAHOM). Material and methods: The DAHOM was developed, characterized, and validated in three phases. Phase 1 involved construction of the sensor. This was broadly based on the fundamental design of a typical Schiotz tonographer with a series of improvements, including corneal indentation, which was converted to an electrical signal via a linear variable differential transducer, an analog signal which was converted to digital via ADC circuitry, and digital data acquisition and processing which was made possible by a serial port interface. Phase 2 comprised development of software for automated assessment of the outflow facility. Automated outflow facility assessment incorporated a series of fundamental improvements in comparison with traditional techniques, including software-based filtering of ripple noise and extreme variations, rigidity impact analysis, and evaluation of the impact of patient age, central corneal thickness, and ocular axial length. Phase 3 comprised characterization and validation of DAHOM, for which we developed an experimental setup using porcine cadaver eyes. DAHOM’s repeatability was evaluated by means of Cronbach’s alpha and intraclass correlation coefficient. The level of agreement with a standard Schiotz tonographer was evaluated by means of paired t-tests and Bland-Altman analysis in human eyes. Results: The experimental setup provided the necessary data for the characterization of DAHOM. A fourth order polynomial equation provided excellent fit (R square >0.999). DAHOM demonstrated high repeatability (Cronbach’s alpha ≥0.997; intraclass correlation coefficient ≥0.987) and an adequate level of agreement with a standard Schiotz tonographer. Conclusions: This study presents the development, characterization, and validation of a prototype digital tonographer. DAHOM demonstrates high repeatability and a sufficient level of

  2. Characterization of human retinal vessel arborisation in normal and amblyopic eyes using multifractal analysis

    PubMed Central

    Tălu, Stefan; Vlăduţiu, Cristina; Lupaşcu, Carmen A.

    2015-01-01

    AIM To characterize the human retinal vessel arborisation in normal and amblyopic eyes using multifractal geometry and lacunarity parameters. METHODS Multifractal analysis using a box counting algorithm was carried out for a set of 12 segmented and skeletonized human retinal images, corresponding to both normal (6 images) and amblyopia states of the retina (6 images). RESULTS It was found that the microvascular geometry of the human retina network represents geometrical multifractals, characterized through subsets of regions having different scaling properties that are not evident in the fractal analysis. Multifractal analysis of the amblyopia images (segmented and skeletonized versions) show a higher average of the generalized dimensions (Dq) for q=0, 1, 2 indicating a higher degree of the tree-dimensional complexity associated with the human retinal microvasculature network whereas images of healthy subjects show a lower value of generalized dimensions indicating normal complexity of biostructure. On the other hand, the lacunarity analysis of the amblyopia images (segmented and skeletonized versions) show a lower average of the lacunarity parameter Λ than the corresponding values for normal images (segmented and skeletonized versions). CONCLUSION The multifractal and lacunarity analysis may be used as a non-invasive predictive complementary tool to distinguish amblyopic subjects from healthy subjects and hence this technique could be used for an early diagnosis of patients with amblyopia. PMID:26558216

  3. 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

  4. 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.

  5. 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. PMID:1874709

  6. Optical quality of intraocular lenses after several years in the human eye

    NASA Astrophysics Data System (ADS)

    Artigas, J. M.; Felipe, A.; Díez-Ajenjo, A.; García-Domene, M. C.; Capilla, P.; Desco, M. C.

    2013-03-01

    The optical quality of explanted intraocular lenses (IOLs) was analysed to verify if their quality is maintained after having been in the human eye for several years. Twenty-five explanted IOLs were studied, 10 because of intraocular luxation and 15 from corneal donors. The dioptric power and modulation transfer function (MTF) were determined to discover the image quality of the IOLs. The spectral transmission was also established to ascertain whether the filter against ultraviolet (UV) radiation was still effective. The results show that the MTF of implanted IOLs is maintained and therefore so is the image quality they provide. Only decay in the MTF of some of the explanted IOLs was observed because of intraocular luxation. The transmission of the UV filters incorporated in the different IOLs hardly varied; thus they maintained their effectiveness.

  7. 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

  8. OCT Study of Mechanical Properties Associated with Trabecular Meshwork and Collector Channel Motion in Human Eyes.

    PubMed

    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 elastance

  9. Molecular mechanism of ocular surface damage: Application to an in vitro dry eye model on human corneal epithelium

    PubMed Central

    De Servi, Barbara; Marasco, Daniela; Del Prete, Salvatore

    2011-01-01

    Purpose The present study was concerned with the development of a new experimental model of dry eye using human reconstructed in vitro corneal epithelium (HCE). The model is based on the use of adapted culture conditions that induce relevant modifications at the cellular and molecular level thus mimicking dry eye. Methods The HCE model was maintained in a controlled environmental setting (relative humidity <40% and 40 °C temperature) for 24 h and up to 72 h to induce dry eye. The evolution of the dry eye condition was assessed by histology, immunohistochemistry staining, scanning electron microscopy, and gene expression by using TaqMan gene assay technology (mucin-4 [MUC4], matrix metallopeptidase-9 [MMP9], tumor necrosis factor-α [TNF-α], and defensin β-2 [DEFB2). The effects of different commercially available tear substitutes on the induced dry eye condition were tested. Results This in vitro dry eye HCE model, that was well established within 24 h, has the characteristic features of a dry eye epithelium and could be satisfactorily used for preliminary assessment of the protective activity of some artificial tears. The transcriptional study of selected biomarkers showed an increase in MUC4, MMP9, TNF-α, and hBD-2 (DEFB2) gene expression. Conclusions By using a dynamic approach, we were able to define a biomarker gene signature of dry eye-induced effects that could be predictive of corneal damage in vivo and to discriminate the efficacy among different commercial artificial tears. PMID:21245952

  10. Physical changes in human meibum with age as measured by infrared spectroscopy.

    PubMed

    Borchman, Douglas; Foulks, Gary N; Yappert, Marta C; Kakar, Shelly; Podoll, Nathan; Rychwalski, Paul; Schwietz, Eric

    2010-01-01

    Both lipids and mucins contribute to the stability of the tear film and lipids may inhibit tears from evaporating. Younger people have lower lipid viscosity, higher lipid volume, and a lower rate of tear evaporation. Since age-related changes in human meibum composition and conformation have never been investigated, as a basis for the study of lipid-associated changes with meibomian gland dysfunction, we used the power of infrared spectroscopy to characterize hydrocarbon chain conformation and packing in meibum from humans without dry eye symptoms in relation to age and sex. Meibum from normal human donors ranging in age from 3 to 88 years was studied. Meibum phase transitions were quantified by fitting them to a 4-parameter 2-state sigmoidal equation. Human meibum order and phase transition temperatures decrease with age and this trend may be attributed to lipid compositional changes. If meibum has the same thermodynamic properties on the surface of the tears as it does on the lid margin, a decrease in lipid-lipid interaction strength with increasing age could decrease the stability of tears since lipid-lipid interactions on the tear surface must be broken for the tear film to break up. This study also serves as a foundation to examine meibum conformational differences in meibum from people with meibomian gland dysfunction.

  11. 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

  12. Evaluating the human ongoing visual search performance by eye tracking application and sequencing tests.

    PubMed

    Veneri, Giacomo; Pretegiani, Elena; Rosini, Francesca; Federighi, Pamela; Federico, Antonio; Rufa, Alessandra

    2012-09-01

    Human visual search is an everyday activity that enables humans to explore the real world. Given the visual input, during a visual search, it is necessary to select some aspects of input to shift the gaze to next target. The aim of the study is to develop a mathematical method able to evaluate the visual selection process during the execution of a high cognitively demanding task such as the trial making test part B (TMT). The TMT is a neuro-psychological instrument where numbers and letters should be connected to each other in numeric and alphabetic order. We adapted the TMT to an eye-tracking version, and we used a vector model, the "eight pointed star" (8PS), to discover how selection (fixations) guides next exploration (saccades) and how human top-down factors interact with bottom-up saliency. The results reported a trend to move away from the last fixations correlated to the number of distracters and the execution performance.

  13. 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

  14. 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. PMID:24236151

  15. Assessment of reading behavior with an infrared eye tracker after 360° macular translocation for age-related macular degeneration.

    PubMed

    Uppal, Gurmit; Feely, Mary P; Crossland, Michael D; Membrey, Luke; Lee, John; da Cruz, Lyndon; Rubin, Gary S

    2011-08-01

    PURPOSE. Macular translocation (MT360) is complex surgery used to restore reading in exudative age-related macular degeneration (AMD). MT360 involves retinal rotation and subsequent oculomotor globe counterrotation and is not without significant surgical risk. This study attempts to gauge the optimal potential of MT360 in restoring reading ability and describe the quality and extent of recovery. METHODS. The six best outcomes were examined from a consecutive series of 23 MT360 cases. Reading behavior and fixation characteristics were examined with an infrared eye tracker. Results were compared to age-matched normal subjects and patients with untreated exudative and nonexudative AMD. Retinal sensitivity was examined with microperimetry to establish threshold visual function. RESULTS. MT360 produced significant improvements in visual function over untreated disease and approximated normal function for reading speed and fixation quality. Relative to the comparative groups, eye tracking revealed the MT360 cohort generated a greater number of horizontal and vertical saccades, of longer latency and reduced velocity. In contrast, saccadic behavior when reading (forward and regressive saccades) closely matched normal function. Microperimetry revealed a reduction in the central scotoma with three patients recovering normal foveal sensitivity. CONCLUSIONS. Near normal reading function is recovered despite profound surgical disruption to the anatomy (retinal/oculomotor). MT360 restores foveal function sufficient to produce a single stable locus of fixation, with marked reduction of the central scotoma. Despite the limitations on saccadic function, the quality of reading saccadic behavior is maintained with good reading ability. Oculomotor surgery appears not to limit reading ability, and the results of retinal surgery approximate normal macular function. PMID:21596822

  16. 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

  17. 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…

  18. 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.…

  19. Olfactory phenotypic expression unveils human aging.

    PubMed

    Mazzatenta, Andrea; Cellerino, Alessandro; Origlia, Nicola; Barloscio, Davide; Sartucci, Ferdinando; Di Giulio, Camillo; Domenici, Luciano

    2016-04-12

    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

  20. 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

  1. Minimization of Retinal Slip Cannot Explain Human Smooth-Pursuit Eye Movements

    NASA Technical Reports Server (NTRS)

    Stone, Leland S.; Beutter, Brent R.; Null, Cynthia H. (Technical Monitor)

    1998-01-01

    Existing models assume that pursuit attempts a direct minimization of retinal image motion or "slip" (e.g. Robinson et al., 1986; Krauzlis & Weisberger, 1989). Using occluded line-figure stimuli, we have previously shown that humans can accurately pursue stimuli for which perfect tracking does not zero retinal slip (Neurologic ARCO). These findings are inconsistent with the standard control strategy of matching eye motion to a target-motion signal reconstructed by adding retinal slip and eye motion, but consistent with a visual front-end which estimates target motion via a global spatio-temporal integration for pursuit and perception. Another possible explanation is that pursuit simply attempts to minimize slip perpendicular to the segments (and neglects parallel "sliding" motion). To resolve this, 4 observers (3 naive) were asked to pursue the center of 2 types of stimuli with identical velocity-space descriptions and matched motion energy. The line-figure "diamond" stimulus was viewed through 2 invisible 3 deg-wide vertical apertures (38 cd/m2 equal to background) such that only the sinusoidal motion of 4 oblique line segments (44 cd/m2 was visible. The "cross" was identical except that the segments exchanged positions. Two trajectories (8's and infinity's) with 4 possible initial directions were randomly interleaved (1.25 cycles, 2.5s period, Ax = Ay = 1.4 deg). In 91% of trials, the diamond appeared rigid. Correspondingly, pursuit was vigorous (mean Again: 0.74) with a V/H aspect ratio approx. 1 (mean: 0.9). Despite a valid rigid solution, the cross however appeared rigid in 8% of trials. Correspondingly, pursuit was weaker (mean Hgain: 0.38) with an incorrect aspect ratio (mean: 1.5). If pursuit were just minimizing perpendicular slip, performance would be the same in both conditions.

  2. Eye Infections

    MedlinePlus

    Your eyes can get infections from bacteria, fungi, or viruses. Eye infections can occur in different parts of the eye and can affect just one eye or both. Two common eye infections are Conjunctivitis - also known as pinkeye. Conjunctivitis is ...

  3. GenAge: a genomic and proteomic network map of human ageing.

    PubMed

    de Magalhães, João Pedro; Toussaint, Olivier

    2004-07-30

    The aim of this work was to provide an overview of the genetics of human ageing to gain novel insights about the mechanisms involved. By incorporating findings from model organisms to humans, such as mutations that either delay or accelerate ageing in mice, we constructed the gene networks previously related to ageing: namely, the network related to DNA metabolism and the network involving the GH/IGF-1 axis. Gathering data about the interacting partners of these proteins allowed us to suggest the involvement in ageing of a number of proteins through a "guilt-by-association" methodology. To organize our data, we developed the first curated database of genes related to human ageing: GenAge. With over 200 entries, GenAge may serve as a reference database of genes related to human ageing. Moreover, we rendered the first proteomic network map of human ageing, which suggests a relationship between the genetics of development and the genetics of ageing. Our work serves as a framework upon which a systems-biology understanding of ageing can be developed. GenAge is freely available for academic purposes at: http://genomics.senescence.info/genes/.

  4. 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

  5. Analysis of Schwalbe’s Line (Limbal Smooth Zone) by Scanning Electron Microscopy and Optical Coherence Tomography in Human Eye Bank Eyes

    PubMed Central

    Breazzano, Mark P; Fikhman, Michael; Abraham, Jerrold L; Barker-Griffith, Ann E

    2013-01-01

    Purpose Implantation of intraocular devices may become critical as they decrease in size in the future. Therefore, it is desirable to evaluate the relationship between radial location and Schwalbe’s line (smooth zone) by examining its width with scanning electron microscopy (SEM) and to correlate this with observations by optical coherence tomography (OCT). Methods Full corneoscleral rings were obtained from twenty-six formalin-fixed human phakic donor eyes. SEM of each eye yielded a complete montage of the smooth zone, from which the area was measured, and width was determined in each quadrant. In three different eyes, time domain anterior segment OCT (Visante, Carl Zeiss Meditec Inc., Dublin, CA, USA) and spectral domain OCT (Cirrus 4.0, Carl Zeiss Meditec Inc., Dublin, CA, USA) were used to further characterize Schwalbe’s line. Results The overall smooth zone width was 79±22 µm, (n=15) ranging from 43 to 115 µm. The superior quadrant (103±8 µm, n=19), demonstrated significantly wider smooth zone than both the nasal (71±5 µm, n=19, P<0.001), and inferior (64±5 µm, n=18, P<0.0001) quadrants but not the temporal quadrant (81±7 µm, n=17, P>0.05). SEM findings of the smooth zone were correlated with visualization of Schwalbe’s line by Cirrus and Visante OCT imaging. Conclusion The smooth zone appears widest superiorly and thinnest inferonasally, suggesting that as glaucoma surgical devices become smaller, their placement could be argeted clinically by using OCT with preference to the superior quadrant, to minimize damage to the corneal endothelium. PMID:23825707

  6. 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.

  7. Biological effects of hyaluronan in connective tissues, eye, skin, venous wall. Role in aging.

    PubMed

    Robert, L; Robert, A-M; Renard, G

    2010-06-01

    Hyaluronan, as most macromolecules of the extracellular matrix, are produced by the differentiated mesenchymal cells. These cells produce also enzymes degrading hyaluronan. This results in the presence of several hyaluronan pools of different molecular weights, all capable of interacting with surrounding cells, mediated by hyaluronan binding proteins and receptors. These interactions modulate cell phenotype and produce a variety of effects conditioning the specific functions of tissues. We shall discuss here several examples studied in our laboratory, concerning skin, cornea and the venous wall. Some of these actions might even be harmful, and could play an important role in aging of connective tissues with loss of function. Some of these age-dependent modifications mediated by hyaluronan will be reviewed and commented, especially the upregulation of matrix degrading enzymes as MMP-2 and MMP-9. We shall also mention some of our experiments for finding molecules capable of counteracting the harmful effects mediated by hyaluronan.

  8. 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.

  9. Age, human performance, and physical employment standards.

    PubMed

    Kenny, Glen P; Groeller, Herbert; McGinn, Ryan; Flouris, Andreas D

    2016-06-01

    The proportion of older workers has increased substantially in recent years, with over 25% of the Canadian labour force aged ≥55 years. Along with chronological age comes age-related declines in functional capacity associated with impairments to the cardiorespiratory and muscular systems. As a result, older workers are reported to exhibit reductions in work output and in the ability to perform and/or sustain the required effort when performing work tasks. However, research has presented some conflicting views on the consequences of aging in the workforce, as physically demanding occupations can be associated with improved or maintained physical function. Furthermore, the current methods for evaluating physical function in older workers often lack specificity and relevance to the actual work tasks, leading to an underestimation of physical capacity in the older worker. Nevertheless, industry often lacks the appropriate information and/or tools to accommodate the aging workforce, particularly in the context of physical employment standards. Ultimately, if appropriate workplace strategies and work performance standards are adopted to optimize the strengths and protect against the vulnerability of the aging workers, they can perform as effectively as their younger counterparts. Our aim in this review is to evaluate the impact of different individual (including physiological decline, chronic disease, lifestyle, and physical activity) and occupational (including shift work, sleep deprivation, and cold/heat exposure) factors on the physical decline of older workers, and therefore the risk of work-related injuries or illness. PMID:27277571

  10. 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…

  11. Age-Related Changes of Intraocular Pressure in Elderly People in Southern China: Lingtou Eye Cohort Study

    PubMed Central

    Han, Xiaotong; Niu, Yong; Guo, Xinxing; Hu, Yin; Yan, William; He, Mingguang

    2016-01-01

    Purpose To study age-related changes of intraocular pressure (IOP) and assess the cohort effect in both cross-sectional and longitudinal settings among elderly Chinese adults. Methods Participants were enrolled from the Lingtou Eye Cohort Study with Chinese government officials aged 40 years and older at baseline and received physical check-up and ocular examinations from 2010 to 2012. IOP was measured using a non-contact tonometer according to standardized protocols, as well as systolic blood pressure (SBP), diastolic blood pressure (DBP) and body mass index (BMI). Participants who had attended IOP measurements in both 2010 and 2012 were included in this study. Cross-sectional association of IOP with age was assessed using multivariate liner regression analyses and based on the data of 2010. Longitudinal changes in IOP were assessed by paired t-test. Results A total of 3372 subjects were enrolled in the current analysis (2010 mean [SD] age, 61.9 [7.1] years; 60.2% men). The mean IOP in 2010 was 15.4±2.3 mmHg for women and 15.2±2.3 mmHg for men with an intersex difference (P = 0.029). Cross-sectional analysis showed that IOP was negatively associated with age (P = 0.003, β = -0.033 for women and P<0.001, β = -0.061 for men) adjusted for baseline SBP, DBP and BMI. Paired t-test suggested that IOP was higher in the year 2012 than 2010 in women (P = 0.006) but did not change significantly in men within 2 years (P = 0.345). In addition, the 2-year changes of IOP were not associated with age adjusted for baseline IOP in 2010 (P = 0.249). Conclusion Cross-sectional data suggests that IOP is lower in people with older age. Longitudinal data does not support such findings and thus the identified decreasing pattern with age in cross-sectional analysis is likely caused by cohort effects. PMID:26986222

  12. Oxidative stress in aging human skin.

    PubMed

    Rinnerthaler, Mark; Bischof, Johannes; Streubel, Maria Karolin; Trost, Andrea; Richter, Klaus

    2015-04-21

    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.

  13. 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

  14. What the human eye tells the brain: a new approach toward a hardware-based modeling of mental functions

    NASA Astrophysics Data System (ADS)

    Lauinger, N.

    2007-09-01

    A better understanding of intelligent information processing in human vision can be reached through a closer look at the macro- and micro-hardware available in the hierarchy of cortical processors along the main visual pathway connecting the retina, the CGL (corpus geniculatum laterale) and area V1 (cortical visual area 17). The building of the eye is driven by the brain and the engineering of the main visual pathway back to V1 seems to be driven by the eyes. The human eye offers to the brain much more intelligent information about the outer visible world than a camera producing flat 2D images on a CCD. Intelligent processing of visual information in human vision - a strong cooperation between eyes and brain - relays on axes related symmetry operations relevant for navigation in 4D spectral space-times, on a hierarchy of dynamically balanced equilibrium states, on diffractive-optical transformation of the Visible into RGB space, on range mapping based on RGB data (monocular and binocular 3D vision), on illuminant-adaptive optical correlations of local onto global RGB data (color constancy performances) and on invariant fourier-optical log-polar processing of image data (generic object classification; identification of objects). These performances are more compatible with optical processing of modern diffractive-optical sensors and interference-optical correlators than with cameras. The R+D project NAMIROS (Nano- and Micro-3D gratings for Optical Sensors) [8], coordinated by an interdisciplinary team of specialists at Corrsys 3D Sensors AG, describes the roadmap towards a technical realization of outstanding high-tech performances corresponding to human eye-brain co-processing.

  15. Eye movements of the murine P/Q calcium channel mutant tottering, and the impact of aging.

    PubMed

    Stahl, John S; James, Robert A; Oommen, Brian S; Hoebeek, Freek E; De Zeeuw, Chris I

    2006-03-01

    Mice carrying mutations of the gene encoding the ion pore of the P/Q calcium channel (Cacna1a) are an instance in which cerebellar dysfunction may be attributable to altered electrophysiology and thus provide an opportunity to study how neuronal intrinsic properties dictate signal processing in the ocular motor system. P/Q channel mutations can engender multiple effects at the single neuron, circuit, and behavioral levels; correlating physiological and behavioral abnormalities in multiple allelic strains will ultimately facilitate determining which alterations of physiology are responsible for specific behavioral aberrations. We used videooculography to quantify ocular motor behavior in tottering mutants aged 3 mo to 2 yr and compared their performance to data previously obtained in the allelic mutant rocker and C57BL/6 controls. Tottering mutants shared numerous abnormalities with rocker, including upward deviation of the eyes at rest, increased vestibuloocular reflex (VOR) phase lead at low stimulus frequencies, reduced VOR gain at high stimulus frequencies, reduced gain of the horizontal and vertical optokinetic reflex, reduced time constants of the neural integrator, and reduced plasticity of the VOR as assessed in a cross-axis training paradigm. Unlike rocker, young tottering mutants exhibited normal peak velocities of nystagmus fast phases, arguing against a role for neuromuscular transmission defects in the attenuation of compensatory eye movements. Tottering also differed by exhibiting directional asymmetries of the gains of optokinetic reflexes. The data suggest at least four pathophysiological mechanisms (two congenital and two acquired) are required to explain the ocular motor deficits in the two Cacna1a mutant strains.

  16. [Biofunctional age diagnosis in humans. Potentials and limits].

    PubMed

    Pöthig, D; Gerdes, W; Viol, M; Wagner, P; Simm, A

    2011-06-01

    The demand and requirements for valid, practicable, and reliable procedures for age diagnosis are increasing worldwide. In contrast, few studies and only a small number of procedures exist. The authors review the theoretical and methodological requirements for the development of models for age diagnostics. They describe the fundamentals for further studies, based on an analysis of current gerontological research in this area. A following publication will report the valid systems measuring vitality and biofunctional age(ing) of human beings. PMID:21505938

  17. DNA-related pathways defective in human premature aging.

    PubMed

    Bohr, Vilhelm A

    2002-05-07

    One of the major issues in studies on aging is the choice of biological model system. The human premature aging disorders represent excellent model systems for the study of the normal aging process, which occurs at a much earlier stage in life in these individuals than in normals. The patients with premature aging also get the age associated diseases at an early stage in life, and thus age associated disease can be studied as well. It is thus of great interest to understand the molecular pathology of these disorders.

  18. THE ANOREXIA OF AGING IN HUMANS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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), psycholog...

  19. Differentiating drusen: Drusen and drusen-like appearances associated with ageing, age-related macular degeneration, inherited eye disease and other pathological processes.

    PubMed

    Khan, Kamron N; Mahroo, Omar A; Khan, Rehna S; Mohamed, Moin D; McKibbin, Martin; Bird, Alan; Michaelides, Michel; Tufail, Adnan; Moore, Anthony T

    2016-07-01

    Drusen are discussed frequently in the context of their association with age-related macular degeneration (AMD). Some types may, however, be regarded as a normal consequence of ageing; others may be observed in young age groups. They also occur in a number of inherited disorders and some systemic conditions. Whilst drusen are classically located external (sclerad) to the retinal pigment epithelium, accumulations of material internal (vitread to) this layer can display a drusen-like appearance, having been variously termed pseudodrusen or subretinal drusenoid deposits. This review first briefly presents an overview of drusen biogenesis and subclinical deposit. The (frequently overlapping) subtypes of clinically detectable deposit, seen usually in the context of ageing or AMD, are then described in more detail, together with appearance on imaging modalities: these include hard and soft drusen, cuticular drusen, reticular pseudodrusen and "ghost drusen". Eye disorders other than AMD which may exhibit drusen or drusen-like features are subsequently discussed: these include monogenic conditions as well as conditions with undefined inheritance, the latter including some types of early onset drusen such as large colloid drusen. A number of systemic conditions in which drusen-like deposits may be seen are also considered. Throughout this review, high resolution images are presented for most of the conditions discussed, particularly the rarer ones, providing a useful reference library for images of the range of conditions associated with drusen-like appearances. In the final section, some common themes are highlighted, as well as a brief discussion of some future avenues for research. PMID:27173377

  20. Aging of the Human Vestibular System.

    PubMed

    Zalewski, Christopher K

    2015-08-01

    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

  1. 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

  2. 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.

  3. Prevalence and associated factors of dry eye: Our experience in patients above 40 years of age at a Tertiary Care Center

    PubMed Central

    Shah, Suchi; Jani, Harsha

    2015-01-01

    Context: Dry eye is a very common as well as under-diagnosed ocular disorder. It is not only troublesome in terms of its symptoms but also imposes a great financial burden. Aims: To determine the prevalence of dry eye in ophthalmology out-patients at a Tertiary Care Hospital and its association with various clinico-epidemiological factors. Settings and Design: A hospital-based study at a Tertiary Care Center was conducted including 400 out-patients of age 40 years and above. Materials and Methods: Patients were consecutively selected and underwent a routine ophthalmological examination along with tear film break-up time (TBUT) as a screening tool for detecting the presence of dry eye. Statistical Analysis: We performed a descriptive, univariate and multivariable logistic regression analysis to calculate odds ratios and 95% confidence interval. Results: The mean age of the study population was 58.6 years. The overall prevalence of dry eye was found to be 54.3%. An association was found between dry eye prevalence and outdoor workers, participants working indoor using air conditioners, housewives, diabetics, patients who have undergone previous ocular surgery and those with meibomian gland dysfunction. Conclusions: Dry eye is a very common condition with a high prevalence among the elderly. We recommend the screening of all out-patients by TBUT, which is a simple test to perform and examination of lids for meibomian gland disease, which if present can be treated. Further studies are needed to establish uniform diagnostic criteria for dry eye, which will help to get more concrete prevalence data, as well as its etiological factors. PMID:26903719

  4. 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

  5. Eye cosmetics.

    PubMed

    Draelos, Z K

    1991-01-01

    Eye cosmetics are useful to highlight and emphasize the eyes. Currently available eye cosmetics include eye shadows, eye shadow setting creams, under-eye concealers, eye-liners, mascaras, artificial eyelashes, and eyebrow pencils. Special care must be taken when patients with sensitive skin or contact lens wearers select eye cosmetics. Eye cosmetics may also be the cause of either irritant or allergic contact dermatitis, which are two causes of the upper-eyelid dermatitis syndrome.

  6. Implicit Processing of the Eyes and Mouth: Evidence from Human Electrophysiology

    PubMed Central

    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. PMID:26790153

  7. 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.

  8. 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…

  9. A golden age of human pigmentation genetics.

    PubMed

    Sturm, Richard A

    2006-09-01

    The zebrafish golden mutation is characterized by the production of small and irregular-shaped melanin granules, resulting in a lightening of the pigmented lateral stripes of the animal. The recent positional cloning and localization of the golden gene, combined with genotype-phenotype correlations of alleles of its human orthologue (SLC24A5) in African-American and African-Caribbean populations, provide insights into the genetic and molecular basis of human skin colour. SLC24A5 promotes melanin deposition through maturation of the melanosome, highlighting the importance of ion-exchange in the function of this organelle.

  10. Spatial and temporal factors determine auditory-visual interactions in human saccadic eye movements.

    PubMed

    Frens, M A; Van Opstal, A J; Van der Willigen, R F

    1995-08-01

    In this paper, we show that human saccadic eye movements toward a visual target are generated with a reduced latency when this target is spatially and temporally aligned with an irrelevant auditory nontarget. This effect gradually disappears if the temporal and/or spatial alignment of the visual and auditory stimuli are changed. When subjects are able to accurately localize the auditory stimulus in two dimensions, the spatial dependence of the reduction in latency depends on the actual radial distance between the auditory and the visual stimulus. If, however, only the azimuth of the sound source can be determined by the subjects, the horizontal target separation determines the strength of the interaction. Neither saccade accuracy nor saccade kinematics were affected in these paradigms. We propose that, in addition to an aspecific warning signal, the reduction of saccadic latency is due to interactions that take place at a multimodal stage of saccade programming, where the perceived positions of visual and auditory stimuli are represented in a common frame of reference. This hypothesis is in agreement with our finding that the saccades often are initially directed to the average position of the visual and the auditory target, provided that their spatial separation is not too large. Striking similarities with electrophysiological findings on multisensory interactions in the deep layers of the midbrain superior colliculus are discussed.

  11. 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.

  12. 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).

  13. 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. PMID:2100170

  14. 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.

  15. Biochemical markers of aging for longitudinal studies in humans.

    PubMed

    Engelfriet, Peter M; Jansen, Eugène H J M; Picavet, H Susan J; Dollé, Martijn E T

    2013-01-01

    Much progress has been made in the past decades in unraveling the mechanisms that are responsible for aging. The discovery that particular gene mutations in experimental species such as yeast, flies, and nematodes are associated with longevity has led to many important insights into pathways that regulate aging processes. However, extrapolating laboratory findings in experimental species to knowledge that is valid for the complexity of human physiology remains a major challenge. Apart from the restricted experimental possibilities, studying aging in humans is further complicated by the development of various age-related diseases. The availability of a set of biomarkers that really reflect underlying aging processes would be of much value in disentangling age-associated pathology from specific aging mechanisms. In this review, we survey the literature to identify promising biochemical markers of aging, with a particular focus on using them in longitudinal studies of aging in humans that entail repeated measurements on easily obtainable material, such as blood samples. Our search strategy was a 2-pronged approach, one focused on general mechanisms of aging and one including studies on clinical biomarkers of age-related diseases.

  16. Biochemical Markers of Aging for Longitudinal Studies in Humans

    PubMed Central

    Engelfriet, Peter M.; Jansen, Eugène H. J. M.; Picavet, H. Susan J.; Dollé, Martijn E. T.

    2013-01-01

    Much progress has been made in the past decades in unraveling the mechanisms that are responsible for aging. The discovery that particular gene mutations in experimental species such as yeast, flies, and nematodes are associated with longevity has led to many important insights into pathways that regulate aging processes. However, extrapolating laboratory findings in experimental species to knowledge that is valid for the complexity of human physiology remains a major challenge. Apart from the restricted experimental possibilities, studying aging in humans is further complicated by the development of various age-related diseases. The availability of a set of biomarkers that really reflect underlying aging processes would be of much value in disentangling age-associated pathology from specific aging mechanisms. In this review, we survey the literature to identify promising biochemical markers of aging, with a particular focus on using them in longitudinal studies of aging in humans that entail repeated measurements on easily obtainable material, such as blood samples. Our search strategy was a 2-pronged approach, one focused on general mechanisms of aging and one including studies on clinical biomarkers of age-related diseases. PMID:23382477

  17. 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)

  18. Prevalence of Decreased Visual Acuity among Preschool Aged Children in an American Urban Population: The Baltimore Pediatric Eye Disease Study, Methods and Results

    PubMed Central

    Friedman, David S.; Repka, Michael X.; Katz, Joanne; Giordano, Lydia; Ibironke, Josephine; Hawes, Patricia; Burkom, Diane; Tielsch, James M.

    2008-01-01

    Objective To determine the age- and ethnicity-specific prevalence of decreased visual acuity (VA) in White and African-American preschool aged children. Design Cross-sectional study. Participants The Baltimore Pediatric Eye Disease Study is a population-based evaluation of the prevalence of ocular disorders in children aged 6 through 71 months in Baltimore, Maryland, United States. Among 4,132 children identified, 3,990 eligible children (97%) were enrolled and 2,546 children (62%) were examined. This report focuses on 1,714 of 2,546 examined children (67%) who were aged 30 through 71 months. Methods Field staff identified 63,737 occupied dwelling units in 54 census tracts. Parents or guardians of eligible participants underwent an in-home interview and eligible children underwent a comprehensive eye examination including optotype VA in children aged 30 months and older with protocol-specified retesting of children with VA worse than an age-appropriate standard. Main Outcome Measures The proportion of children aged 30 through 71 months testable for VA and the proportion with decreased VA as defined by preset criteria. Results VA was testable in 1,504 of 1,714 children (87.7%) 30 through 71 months of age. It was decreased at the initial test (wearing glasses if brought to the clinic) in both eyes of 7 of 577 White children (1.21%, 95% Confidence Interval [CI] = 0.49, 2.50) and 13 of 725 African-American children (1.79%, 95% CI = 0.95, 3.08), a difference that is not statistically significant. Decreased VA in both eyes after retesting was found in 3 of 598 White children (0.50%, 95% CI = 0.10, 1.48) and 8 of 757 African-American children (1.06%, 95% CI = 0.45, 2.10), also not statistically significantly different. Uncorrected ametropia explained the decreased VA on initial testing in ten of the twenty children. Conclusions Decreased VA in both eyes of children 30 through 71 months of age at presentation in urban Baltimore was 1.2% among White children and 1.8% among

  19. Apnea-Induced Rapid Eye Movement Sleep Disruption Impairs Human Spatial Navigational Memory

    PubMed Central

    Kishi, Akifumi; Mantua, Janna; Lim, Jason; Koushyk, Viachaslau; Leibert, David P.; Osorio, Ricardo S.; Rapoport, David M.; Ayappa, Indu

    2014-01-01

    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. PMID:25355211

  20. 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.

  1. Eye-movement study and human performance using telepathology virtual slides: implications for medical education and differences with experience.

    PubMed

    Krupinski, Elizabeth A; Tillack, Allison A; Richter, Lynne; Henderson, Jeffrey T; Bhattacharyya, Achyut K; Scott, Katherine M; Graham, Anna R; Descour, Michael R; Davis, John R; Weinstein, Ronald S

    2006-12-01

    A core skill in diagnostic pathology is light microscopy. Remarkably little is known about human factors that affect the proficiency of pathologists as light microscopists. The cognitive skills of pathologists have received relatively little attention in comparison with the large literature on human performance studies in radiology. One reason for this lack of formal visual search studies in pathology has been the physical restrictions imposed by the close positioning of a microscope operator's head to the microscope's eyepieces. This blocks access to the operator's eyes and precludes assessment of the microscopist's eye movements. Virtual slide microscopy now removes this barrier and opens the door for studies on human factors and visual search strategies in light microscopy. The aim of this study was to assess eye movements of medical students, pathology residents, and practicing pathologists examining virtual slides on a digital display monitor. Whole histopathology glass slide digital images, so-called virtual slides, of 20 consecutive breast core biopsy cases were used in a retrospective study. These high-quality virtual slides were produced with an array-microscope equipped DMetrix DX-40 ultrarapid virtual slide processor (DMetrix, Tucson, Ariz). Using an eye-tracking device, we demonstrated for the first time that when a virtual slide reader initially looks at a virtual slide his or her eyes are very quickly attracted to regions of interest (ROIs) within the slide and that these ROIs are likely to contain diagnostic information. In a matter of seconds, critical decisions are made on the selection of ROIs for further examination at higher magnification. We recorded: (1) the time virtual slide readers spent fixating on self-selected locations on the video monitor; (2) the characteristics of the ways the eyes jumped between fixation locations; and (3) x and y coordinates for each virtual slide marking the sites the virtual slide readers manually selected for

  2. 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.

  3. HEAT WAVES, AGING, AND HUMAN CARDIOVASCULAR HEALTH

    PubMed Central

    Kenney, W. Larry; Craighead, Daniel H.; Alexander, Lacy M.

    2014-01-01

    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 is 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, as well as 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 due to 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 increases the extent of future untoward health outcomes. PMID:24598696

  4. Age-related differences in human skin proteoglycans

    PubMed Central

    Carrino, David A; Calabro, Anthony; Darr, Aniq B; Dours-Zimmermann, Maria T; Sandy, John D; Zimmermann, Dieter R; Sorrell, J Michael; Hascall, Vincent C; Caplan, Arnold I

    2011-01-01

    Previous work has shown that versican, decorin and a catabolic fragment of decorin, termed decorunt, are the most abundant proteoglycans in human skin. Further analysis of versican indicates that four major core protein species are present in human skin at all ages examined from fetal to adult. Two of these are identified as the V0 and V1 isoforms, with the latter predominating. The other two species are catabolic fragments of V0 and V1, which have the amino acid sequence DPEAAE as their carboxyl terminus. Although the core proteins of human skin versican show no major age-related differences, the glycosaminoglycans (GAGs) of adult skin versican are smaller in size and show differences in their sulfation pattern relative to those in fetal skin versican. In contrast to human skin versican, human skin decorin shows minimal age-related differences in its sulfation pattern, although, like versican, the GAGs of adult skin decorin are smaller than those of fetal skin decorin. Analysis of the catabolic fragments of decorin from adult skin reveals the presence of other fragments in addition to decorunt, although the core proteins of these additional decorin catabolic fragments have not been identified. Thus, versican and decorin of human skin show age-related differences, versican primarily in the size and the sulfation pattern of its GAGs and decorin in the size of its GAGs. The catabolic fragments of versican are detected at all ages examined, but appear to be in lower abundance in adult skin compared with fetal skin. In contrast, the catabolic fragments of decorin are present in adult skin, but are virtually absent from fetal skin. Taken together, these data suggest that there are age-related differences in the catabolism of proteoglycans in human skin. These age-related differences in proteoglycan patterns and catabolism may play a role in the age-related changes in the physical properties and injury response of human skin. PMID:20947661

  5. 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 ...

  6. Eye Cancer

    MedlinePlus

    ... Eye Cancer - Overview Request Permissions Print to PDF Eye Cancer - Overview Approved by the Cancer.Net Editorial Board , ... Cancer Research and Advocacy Survivorship Blog About Us Eye Cancer Guide Cancer.Net Guide Eye Cancer Overview Statistics ...

  7. Chronologic versus Biologic Aging of the Human Choroid

    PubMed Central

    May, Christian Albrecht

    2013-01-01

    Several aspects of chronologic and biologic aging in the human choroid are reviewed from the literature. They often reveal methodological problems for age-dependent changes of the following parameters: choroidal thickness, choroidal pigmentation, choroidal vasculature and blood flow, and choroidal innervation. On reinterpreting some data of studies concerning Bruch's membrane, changes observed at different age points seem more likely to be nonlinear. Concluding from the data presented so far, chronologic aging should not be used as a factor for physiological changes in the human choroid. Longitudinal study designs are necessary to further establish the impact of age. Meanwhile, a more biologic oriented model of aging processes in the choroid should be established, including specified conditions (e.g., light exposure and refractory state). This would help to define more individual strategies for prevention and early stages of a certain defined disease. PMID:24453840

  8. Contingent negative variation indicates phasic arousal for externally cued unilateral eye blink in human subjects.

    PubMed

    Strenge, H; Kropp, P; Hoffmeister, J; Verri, A; Galli, C; Gerber, W D

    1999-04-30

    The contingent negative variation (CNV) as a slow cortical potential was used to investigate cortical processing of externally cued, voluntary unilateral eye blink. Probands blinked as a response within a modified two-stimulus reaction time paradigm. Reaction time and amplitudes of CNV were determined. The activity of the orbicularis oculi muscles (OO) was registered by surface electromyography (EMG). Probands who performed unilateral eye blinks with accurately inhibiting contralateral OO activity showed a significantly higher negativity of the early CNV component compared with the bilateral eye blink condition. This effect was confined to the beginning of unilateral blinking performance. It is suggested that the unilateral eye blink is a challenging motor task, initially requiring an increased cortically driven arousal and attention as revealed by increased early CNV components. PMID:10336183

  9. Looking for disease being a model of human aging

    PubMed Central

    Hausmanowa-Petrusewicz, I; Madej-Pilarczyk, A

    2007-01-01

    Summary This paper is a part of an introduction to authors’ study on systemic laminopathies and their role in human aging. Of special interest is progeria – a type of systemic laminopathy associated usually with mutation 1824 C > T and presenting phenotype of preliminary aging. The authors analyse the differences between the progeria and other syndrome of preliminary aging – Werner’s syndrome. PMID:18421896

  10. 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.

  11. 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. PMID:25398172

  12. 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.

  13. Effect of Age on Regulation of Human Osteoclast Differentiation

    PubMed Central

    Chung, Ping-Lin; Zhou, Shuanhu; Eslami, Behnam; Shen, Longxiang; LeBoff, Meryl S.; Glowacki, Julie

    2014-01-01

    Human skeletal aging is characterized as a gradual loss of bone mass due to an excess of bone resorption not balanced by new bone formation. Using human marrow cells, we tested the hypothesis that there is an age-dependent increase in osteoclastogenesis due to intrinsic changes in regulatory factors [macrophage-colony stimulating factor (M-CSF), receptor activator of NF-κB ligand (RANKL), and osteoprotegerin (OPG)] and their receptors [c-fms and RANK]. In bone marrow cells (BMCs), c-fms (r=0.61, p=0.006) and RANK expression (r=0.59, p=0.008) were increased with age (27-82 years, n=19). In vitro generation of osteoclasts was increased with age (r=0.89, p=0.007). In enriched marrow stromal cells (MSCs), constitutive expression of RANKL was increased with age (r=0.41, p=0.049) and expression of OPG was inversely correlated with age (r=-0.43, p=0.039). Accordingly, there was an age-related increase in RANKL/OPG (r=0.56, p=0.005). These data indicate an age-related increase in human osteoclastogenesis that is associated with an intrinsic increase in expression of c-fms and RANK in osteoclast progenitors, and, in the supporting MSCs, an increase in pro-osteoclastogenic RANKL expression and a decrease in anti-osteoclastogenic OPG. These findings support the hypothesis that human marrow cells and their products can contribute to skeletal aging by increasing the generation of bone-resorbing osteoclasts. These findings help to explain underlying molecular mechanisms of progressive bone loss with advancing age in humans. PMID:24700654

  14. 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…

  15. 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

  16. Shared sensory estimates for human motion perception and pursuit eye movements.

    PubMed

    Mukherjee, Trishna; Battifarano, Matthew; Simoncini, Claudio; Osborne, Leslie C

    2015-06-01

    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

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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

  2. Morphology and Accommodative Function of the Vitreous Zonule in Human and Monkey Eyes

    PubMed Central

    Lütjen-Drecoll, Elke; Kaufman, Paul L.; Wasielewski, Rainer; Ting-Li, Lin

    2010-01-01

    Purpose. To explore the attachments of the posterior zonule and vitreous in relation to accommodation and presbyopia in monkeys and humans. Methods. Novel scanning electron microscopy (SEM) and ultrasound biomicroscopy (UBM) techniques were used to visualize the anterior, intermediate, and posterior vitreous zonule and their connections to the ciliary body, vitreous membrane, lens capsule, and ora serrata, and to characterize their age-related changes and correlate them with loss of accommodative forward movement of the ciliary body. α-Chymotrypsin was used focally to lyse the vitreous zonule and determine the effect on movement of the accommodative apparatus in monkeys. Results. The vitreous attached to the peripheral lens capsule and the ora serrata directly. The pars plana zonule and the posterior tines of the anterior zonule were separated from the vitreous membrane except for strategically placed attachments, collectively termed the vitreous zonule, that may modulate and smooth the forward and backward movements of the entire system. Age-dependent changes in these relationships correlated significantly with loss of accommodative amplitude. Lysis of the intermediate vitreous zonule partially restored accommodative movement. Conclusions. The vitreous zonule system may help to smoothly translate to the lens the driving forces of accommodation and disaccommodation generated by the ciliary muscle, while maintaining visual focus and protecting the lens capsule and ora serrata from acute tractional forces. Stiffening of the vitreous zonular system may contribute to age-related loss of accommodation and offer a therapeutic target for presbyopia. PMID:19815737

  3. 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

  4. Aqueous humor outflow effects of partial thickness channel created by a femtosecond laser in ex-vivo human eyes

    NASA Astrophysics Data System (ADS)

    Chai, Dongyul; Chaudhary, Gautam; Kurtz, Ron; Juhasz, Tibor

    2007-02-01

    The reduced outflow rate caused by the increased resistance through trabecular meshwork (TM) has been thought to be the main reason for elevated intraocular pressure (IOP). It has been demonstrated that femtosecond laser pulses tuned to 1.7 μm wavelength can create the partial thickness channel in the sclera in ex vivo human eyes [1] and aqueous outflow can be increased by these channels in porcine eyes [2]. It was also shown that the outflow rate is reduced over time in ex vivo human eyes [3]. Therefore, the control experiment without laser treatment at the same condition was conducted and showed that outflow was reduced by 1.5 +/- 0.8 μl/min at 15mmHg and 1.8 +/- 1.0 μl/min at 25mmHg. However, the outflow rate increased by 0.26 μl/min at 15mmHg and 0.15 μl/min at 25mmHg after the partial thickness channel was created, meaning the amount of increased outflow rate might be more than measured considering the outflow reduction in control experiment. We suggest that the femtosecond laser created partial thickness channel can increase the outflow rate and delay the progression of glaucoma.

  5. 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

  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. 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

  8. 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

  9. Attention to irrelevant contexts decreases as training increases: Evidence from eye-fixations in a human predictive learning task.

    PubMed

    Aristizabal, José A; Ramos-Álvarez, Manuel M; Callejas-Aguilera, José E; Rosas, Juan M

    2016-03-01

    Participants were trained in a human predictive learning task in which they had to predict whether the ingestion of a given food (cue) by the imaginary customer of an imaginary restaurant (context) was followed by gastric malaise (outcome). One food was always followed by gastric malaise in one of the contexts, while other foods were not followed by gastric malaise in the same, or in an alternative context. Predictive responses and eye-fixations were recorded throughout the 48 training trials with each cue involved in the task. In agreement with the predictions of the Attentional Theory of Context Processing, attention to the contexts measured through eye-fixations decreased while attention to the cues increased as training progressed. The results of this study give support to the idea that contexts are actively processed at the beginning of acquisition, and that this processing decreases as training increases.

  10. 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).

  11. Comparative spectral analysis between the functionality of the human eye and of the optical part of a digital camera

    NASA Astrophysics Data System (ADS)

    Toadere, Florin

    2015-02-01

    A software that comparatively analysis the spectral functionality of the optical part of the human eye and of the optical image acquisition system of the digital camera, is presented. Comparisons are done using demonstrative images which present the spectral color transformations of an image that is considered the test object. To perform the simulations are presented the spectral models and are computed their effects on the colors of the spectral image, during the propagation of the D48 sun light through the eye and the optics of the digital camera. The simulations are made using a spectral image processing algorithm which converts the spectral image into XYZ color space, CIE CAM02 color appearance model and then into RGB color space.

  12. 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.

  13. 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.

  14. 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.

  15. 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. PMID:26136441

  16. 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

  17. Electrical properties of human skin as aging biomarkers.

    PubMed

    Simić-Krstić, Jovana B; Kalauzi, Aleksandar J; Ribar, Srdjan N; Matija, Lidija R; Misevic, Gradimir N

    2014-09-01

    A non-invasive bioimpedance spectroscopy (BIS) and Cole-Cole impedance model parameters (R0, R∞, τ and α) were used to analyze electrical properties of intact and stripped human skin for both gender subjects divided into younger and older age groups. R0, R∞ and τ significantly increased while α significantly decreased with age in stripped skin for both genders (p<0.031). Using pooled data with respect to age, gender and skin stripping, R0, R∞ and τ values were shown to increase with age (p<0.0034), R0, τ and α were different between genders (p<0.024) and R0, R∞ and τ decreased with skin stripping (p<0.000008). All of four Cole-Cole parameters were age dependent with specific differences observed for genders and intact and stripped skin layers. Therefore, Cole-Cole parameters, obtained by non-invasive BIS measurements, are a new type of age dependent biomarkers.

  18. Human Eye Phantom for Developing Computer and Robot-Assisted Epiretinal Membrane Peeling*

    PubMed Central

    Gupta, Amrita; Gonenc, Berk; Balicki, Marcin; Olds, Kevin; Handa, James; Gehlbach, Peter; Taylor, Russell H.; Iordachita, Iulian

    2014-01-01

    A number of technologies are being developed to facilitate key intraoperative actions in vitreoretinal microsurgery. There is a need for cost-effective, reusable benchtop eye phantoms to enable frequent evaluation of these developments. In this study, we describe an artificial eye phantom for developing intraocular imaging and force-sensing tools. We test four candidate materials for simulating epiretinal membranes using a handheld tremor-canceling micromanipulator with force-sensing micro-forceps tip and demonstrate peeling forces comparable to those encountered in clinical practice. PMID:25571573

  19. [In vitro evaluation for corneal damages by anti-glaucoma combination eye drops using human corneal epithelial cell (HCE-T)].

    PubMed

    Nagai, Noriaki; Murao, Takatoshi; Oe, Kyouhei; Ito, Yoshimasa; Okamoto, Norio; Shimomura, Yoshikazu

    2011-01-01

    The combination of anti-glaucoma eye drops is frequently used in clinical treatment, and it is known that the combination can cause corneal damage. Recently, an anti-glaucoma combination eye drops is developed, and the treatment by the combination eye drops is expected to enhance quality of life. However, effects of the combination eye drops on corneal epithelial cell damage have not been clarified. In this study, we investigated the corneal epithelial cell damage of commercially available anti-glaucoma combination eye drops, such as Xalacom® (latanoprost/timolol maleate combination eye drops), Duotrav® (travoprost/timolol maleate combination eye drops) and Cosopt® (dorzolamide hydrochloride/timolol maleate combination eye drops) using the human corneal epithelial cell (HCE-T). The cytotoxicity in Xalacom® was higher than that in Xalatan® (eye drops containing latanoprost) and Timoptol® (eye drops containing timolol maleate), and the benzalkonium chloride (BAC) and timolol maleate were related to cytotoxicity in Xalacom®. The cytotoxicity in Duotrav® and Cosopt® was lower than that in Timoptol®. The Duotrav® is preserved with a non-BAC system (POLYQUAD, polidronium chloride). Therefore, it was suggested that the POLYQUAD related to the low cytotoxicity in Duotrav®. On the other hand, the D-mannitol reduced the cytotoxicity by BAC in this study. This result suggested that the cytotoxicity in Cosopt® was reduced by D-mannitol. The Duotrav® and Cosopt® may be less damaging to the ocular surface of glaucoma patients receiving long-term eye drop therapy in compared with the combination of anti-glaucoma eye drops.

  20. [In vitro evaluation for corneal damages by anti-glaucoma combination eye drops using human corneal epithelial cell (HCE-T)].

    PubMed

    Nagai, Noriaki; Murao, Takatoshi; Oe, Kyouhei; Ito, Yoshimasa; Okamoto, Norio; Shimomura, Yoshikazu

    2011-01-01

    The combination of anti-glaucoma eye drops is frequently used in clinical treatment, and it is known that the combination can cause corneal damage. Recently, an anti-glaucoma combination eye drops is developed, and the treatment by the combination eye drops is expected to enhance quality of life. However, effects of the combination eye drops on corneal epithelial cell damage have not been clarified. In this study, we investigated the corneal epithelial cell damage of commercially available anti-glaucoma combination eye drops, such as Xalacom® (latanoprost/timolol maleate combination eye drops), Duotrav® (travoprost/timolol maleate combination eye drops) and Cosopt® (dorzolamide hydrochloride/timolol maleate combination eye drops) using the human corneal epithelial cell (HCE-T). The cytotoxicity in Xalacom® was higher than that in Xalatan® (eye drops containing latanoprost) and Timoptol® (eye drops containing timolol maleate), and the benzalkonium chloride (BAC) and timolol maleate were related to cytotoxicity in Xalacom®. The cytotoxicity in Duotrav® and Cosopt® was lower than that in Timoptol®. The Duotrav® is preserved with a non-BAC system (POLYQUAD, polidronium chloride). Therefore, it was suggested that the POLYQUAD related to the low cytotoxicity in Duotrav®. On the other hand, the D-mannitol reduced the cytotoxicity by BAC in this study. This result suggested that the cytotoxicity in Cosopt® was reduced by D-mannitol. The Duotrav® and Cosopt® may be less damaging to the ocular surface of glaucoma patients receiving long-term eye drop therapy in compared with the combination of anti-glaucoma eye drops. PMID:21628988

  1. 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. PMID:27233534

  2. 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.

  3. 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.

  4. 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.

  5. Predictive mechanisms of head-eye coordination and vestibulo-ocular reflex suppression in humans.

    PubMed

    Barnes, G R; Grealy, M A

    1992-01-01

    Head and eye movements of human subjects have been recorded during head-free pursuit in the horizontal plane of a target executing sinusoidal motion at a frequency of 0.26 to 0.78 Hz and a peak velocity of +/- 96 degrees/s. The target was not presented continuously but was exposed for brief durations of 120 to 320 ms as it passed through the centre of the visual field at peak velocity. This technique allowed the timing of each response to be assessed in relation to the onset of target appearance. During the first 3 to 4 target presentations, there was a progressive buildup of both head velocity and the smooth component of gaze velocity, while, simultaneously, the responses became more phase-advanced with respect to target onset. In the steady state, similar temporal response trajectories were observed for head and gaze velocity, which were initiated approximately 500 ms prior to target onset, rose to a peak that increased with the duration of target exposure, and then decayed with a time constant of 0.5 to 1 s. Whenever the target failed to appear as expected, the gaze and head velocity trajectories continued to be made, indicating that predictive suppression of the vestibulo-ocular reflex (VOR) was taking place in darkness. In a further experiment, subjects attempted to suppress the VOR during whole body oscillation at 0.2 or 0.4 Hz on a turntable by fixating a head-fixed target that appeared for 10 to 160 ms at the time of peak head velocity. Again, VOR suppression was initiated prior to target appearance in the same manner as for natural head movements, and when the target suddenly disappeared but rotation continued, predictive VOR suppression was observed in darkness. The similarity of these predictive effects to those obtained previously for head-fixed pursuit provides further support for the hypothesis that both pursuit and visual suppression of the VOR are controlled primarily by identical visual feedback mechanisms. PMID:1342395

  6. 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

  7. Eye Irritation Test (EIT) for Hazard Identification of Eye Irritating Chemicals using Reconstructed Human Cornea-like Epithelial (RhCE) Tissue Model.

    PubMed

    Kaluzhny, Yulia; Kandárová, Helena; d'Argembeau-Thornton, Laurence; Kearney, Paul; Klausner, Mitchell

    2015-08-23

    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.

  8. 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

  9. Eye Irritation Test (EIT) for Hazard Identification of Eye Irritating Chemicals using Reconstructed Human Cornea-like Epithelial (RhCE) Tissue Model.

    PubMed

    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

  10. Optical projectors simulate human eyes to establish operator's field of view

    NASA Technical Reports Server (NTRS)

    Beam, R. A.

    1966-01-01

    Device projects visual pattern limits of the field of view of an operator as his eyes are directed at a given point on a control panel. The device, which consists of two projectors, provides instant evaluation of visual ability at a point on a panel.

  11. Remote control of mobile robots through human eye gaze: the design and evaluation of an interface

    NASA Astrophysics Data System (ADS)

    Latif, Hemin Omer; Sherkat, Nasser; Lotfi, Ahmad

    2008-10-01

    Controlling mobile robots remotely requires the operator to monitor the status of the robot through some sort of feedback. Assuming a vision based feedback system is used the operator is required to closely monitor the images while navigating the robot in real time. This will engage the eyes and the hands of the operator. Since the eyes are engaged in the monitoring task anyway, their gaze can be used to navigate the robot in order to free the hands of the operator. However, the challenge here lies in developing an interaction interface that enables an intuitive distinction to be made between monitoring and commanding. This paper presents a novel means of constructing a user interface to meet this challenge. A range of solutions are constructed by augmenting the visual feedback with command regions to investigate the extent to which a user can intuitively control the robot. An experimental platform comprising a mobile robot together with cameras and eye-gaze system is constructed. The design of the system allows control of the robot, control of onboard cameras and control of the interface through eye-gaze. A number of tasks are designed to evaluate the proposed solutions. This paper presents the design considerations and the results of the evaluation. Overall it is found that the proposed solutions provide effective means of successfully navigating the robot for a range of tasks.

  12. 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.

  13. Dose conversion coefficients for electron exposure of the human eye lens

    NASA Astrophysics Data System (ADS)

    Behrens, R.; Dietze, G.; Zankl, M.

    2009-07-01

    Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. Two questions arise from this situation: first, which dose quantity is related to the risk of developing a cataract, and second, which personal dose equivalent quantity is appropriate for monitoring this dose quantity. While the dose equivalent quantity Hp(0.07) has often been seen as being sufficiently accurate for monitoring the dose to the lens of the eye, this would be questionable in the case when the dose limits were reduced and, thus, it may be necessary to generally use the dose equivalent quantity Hp(3) for this purpose. The basis for a decision, however, must be the knowledge of accurate conversion coefficients from fluence to equivalent dose to the lens. This is especially important for low-penetrating radiation, for example, electrons. Formerly published values of conversion coefficients are based on quite simple models of the eye. In this paper, quite a sophisticated model of the eye including the inner structure of the lens was used for the calculations and precise conversion coefficients for electrons with energies between 0.2 MeV and 12 MeV, and for angles of radiation incidence between 0° and 45° are presented. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are up to 1000 times smaller for electron energies below 1 MeV, nearly equal at 1 MeV and above 4 MeV, and by a factor of 1.5 larger at about 1.5 MeV electron energy.

  14. 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.

  15. 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.

  16. 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

    2016-01-01

    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. PMID:26984773

  17. 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®.

  18. Age-related changes in mucins from human whole saliva.

    PubMed

    Denny, P C; Denny, P A; Klauser, D K; Hong, S H; Navazesh, M; Tabak, L A

    1991-10-01

    The predominant mucins in human whole saliva, MG1 and MG2, serve to protect and to lubricate the oral cavity. In this study, both unstimulated and stimulated whole salivas were collected from two groups of subjects: young (18-35 years of age) and aged (65-83 years of age). The subjects were in apparent good health. Saliva samples from each subject were analyzed by SDS-PAGE. The gels were stained with Stains-all, and both MG1 and MG2 were quantitated by video-image densitometry. The protocol gave reproducible values for each mucin. The stimulated and unstimulated salivas from aged subjects showed significant reductions in concentrations of both MG1 and MG2, as quantitated in mucin dye-binding units. Possible associations of these reductions with the aging process are discussed. PMID:1719051

  19. Age-related changes in mucins from human whole saliva.

    PubMed

    Denny, P C; Denny, P A; Klauser, D K; Hong, S H; Navazesh, M; Tabak, L A

    1991-10-01

    The predominant mucins in human whole saliva, MG1 and MG2, serve to protect and to lubricate the oral cavity. In this study, both unstimulated and stimulated whole salivas were collected from two groups of subjects: young (18-35 years of age) and aged (65-83 years of age). The subjects were in apparent good health. Saliva samples from each subject were analyzed by SDS-PAGE. The gels were stained with Stains-all, and both MG1 and MG2 were quantitated by video-image densitometry. The protocol gave reproducible values for each mucin. The stimulated and unstimulated salivas from aged subjects showed significant reductions in concentrations of both MG1 and MG2, as quantitated in mucin dye-binding units. Possible associations of these reductions with the aging process are discussed.

  20. 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.

  1. 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 ...

  2. 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 ...

  3. 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 ...

  4. Short-latency vergence eye movements induced by radial optic flow in humans: dependence on ambient vergence level.

    PubMed

    Yang, D; Fitzgibbon, E J; Miles, F A

    1999-02-01

    Radial patterns of optic flow, such as those experienced by moving observers who look in the direction of heading, evoke vergence eye movements at short latency. We have investigated the dependence of these responses on the ambient vergence level. Human subjects faced a large tangent screen onto which two identical random-dot patterns were back-projected. A system of crossed polarizers ensured that each eye saw only one of the patterns, with mirror galvanometers to control the horizontal positions of the images and hence the vergence angle between the two eyes. After converging the subject's eyes at one of several distances ranging from 16.7 cm to infinity, both patterns were replaced with new ones (using a system of shutters and two additional projectors) so as to simulate the radial flow associated with a sudden 4% change in viewing distance with the focus of expansion/contraction imaged in or very near both foveas. Radial-flow steps induced transient vergence at latencies of 80-100 ms, expansions causing increases in convergence and contractions the converse. Based on the change in vergence 90-140 ms after the onset of the steps, responses were proportional to the preexisting vergence angle (and hence would be expected to be inversely proportional to viewing distance under normal conditions). We suggest that this property assists the observer who wants to fixate ahead while passing through a visually cluttered area (e.g., a forest) and so wants to avoid making vergence responses to the optic flow created by the nearby objects in the periphery.

  5. Complement-dependent cytotoxicity in rats bearing human adenovirus type 12-induced primary retinoblastoma-like tumor in the eye.

    PubMed

    Nishida, T; Mukai, N; Solish, S P

    1981-01-01

    Using an animal model of retinoblastoma in inbred rats and cultured human adenovirus type 12-induced retinoblastoma-like tumor cells (RAO 188), complement-dependent cytotoxicity was determined by measuring release of 3H-uridine labelled RNA. Sera from rats in which tumors did not grow after adenovirus type 12 inoculation had higher cytotoxicity against RAO 188 cells than sera from rats bearing primary adenovirus type 12-induced retinoblastoma-like tumor. These results showed that the rat which could raise antibodies against adenovirus type 12-induced retinoblastoma-like tumor cells did not allow the tumor growth in the eye after virus inoculation.

  6. 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.

  7. 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. PMID:26974795

  8. 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.

  9. [A tracking function of human eye in microgravity and during readaptation to earth's gravity].

    PubMed

    Kornilova, L N

    2001-01-01

    The paper summarizes results of electro-oculography of all ways of visual tracking: fixative eye movements (saccades), smooth pursuit of linearly, pendulum-like and circularly moving point stimuli, pursuit of vertically moving foveoretinal optokinetic stimuli, and presents values of thresholds and amplification coefficients of the optokinetic nystagmus during tracking of linear movement of foveoretinal optokinetic stimuli. Investigations were performed aboard the Salyut and Mir space stations with participation of 31 cosmonauts of whom 27 made long-term (76 up to 438 day) and 4 made short-term (7 to 9 day) missions. It was shown that in space flight the saccadic structure within the tracking reaction does not change; yet, corrective movements (additional microsaccades to achieve tracking) appeared in 47% of observations at the onset and in 76% of observations on months 3 to 6 of space flight. After landing, the structure of vertical saccades was found altered in half the cosmonauts. No matter in or after flight, reverse nystagmus was present along with the gaze nystagmus during static saccades in 22% (7 cosmonauts) of the observations. Amplitude of tracking vertically, diagonally or circularly moving stimuli was significantly reduced as period on mission increased. Early in flight (40% of the cosmonauts) and shortly afterwards (21% of the cosmonauts) the structure of smooth tracking reaction was totally broken up, that is eye followed stimulus with micro- or macrosaccades. The structure of smooth eye tracking recovered on flight days 6-8 and on postflight days 3-4. However, in 46% of the cosmonauts on long-term missions the structure of smooth eye tracking was noted to be disturbed periodically, i.e. smooth tracking was replaced by saccadic.

  10. Age-dependent fatigue behaviour of human cortical bone.

    PubMed

    Diab, T; Sit, S; Kim, D; Rho, J; Vashishth, D

    2005-01-01

    Despite a general understanding that bone quality contributes to skeletal fragility, very little information exits on the age-dependent fatigue behavior of human bone. In this study four-point bending fatigue tests were conducted on aging bone in conjunction with the analysis of stiffness loss and preliminary investigation of nanoindentation based measurements of local tissue stiffness and histological evaluation of resultant tensile and compressive damage to identify the damage mechanism responsible for the increase in age-related bone fragility. The results obtained show that there is an exponential decrease in fatigue life with age, and old bone exhibits different modulus degradation profiles than young bone. In addition, this study provides preliminary evidence indicating that during fatigue loading, younger bone formed diffuse damage, lost local tissue stiffness on the tensile side. Older bone, in contrast, formed linear microcracks lost local tissue stiffness on the compressive side. Thus, the propensity of aging human bone to form more linear microcracks than diffuse damage may be a significant contributor to bone quality, and age related fragility in bone.

  11. Aging and the human vestibular nuclei: morphometric analysis.

    PubMed

    Alvarez, J C; Díaz, C; Suárez, C; Fernández, J A; González del Rey, C; Navarro, A; Tolivia, J

    2000-04-14

    The data concerning the effects of age on the brainstem are scarce and few works are devoted to the human vestibular nuclear complex. The study of the effects of aging in the vestibular nuclei could have clinical interest due to the high prevalence of balance control and gait problems in the elderly. We have used in this work eight human brainstems of different ages sectioned and stained by the formaldehyde-thionin technique. The neuron's profiles were drawn with a camera lucida and Abercrombie's method was used to estimate the total number of neurons. The test of Kolmogorov-Smirnov with the correction of Lilliefors was used to evaluate the fit of our data to a normal distribution and a regression analysis was done to determine if the variation of our data with age was statistically significant. Aging does not affect the volume or length of the vestibular nuclear complex. Our results clearly show that neuronal loss occurs with aging in the descending (DVN), medial (MVN), and lateral (LVN) vestibular nuclei, but not in the superior (SVN). There are changes in the proportions of neurons of different sizes but they are not statistically significant. The neuronal loss could be related with the problems that elderly people have to compensate unilateral vestibular lesions and the alterations of the vestibulospinal reflexes. The preservation of SVN neurons can explain why vestibulo-ocular reflexes are compensated after unilateral vestibular injuries.

  12. 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

  13. 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

  14. 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.

  15. 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. PMID:25902704

  16. Uniquely human self-control begins at school age.

    PubMed

    Herrmann, Esther; Misch, Antonia; Hernandez-Lloreda, Victoria; Tomasello, Michael

    2015-11-01

    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 resist an impulse for immediate gratification, repeat a previously successful action, attend to a distracting noise, and quit in the face of repeated failure. Six-year-old children were more skillful than either 3-year-olds or chimpanzees at controlling their impulses. These results suggest that humans' most fundamental skills of self-control - as part of the overall decision-making process - are a part of their general great ape heritage, and that their species-unique skills of self-control begin at around the age at which many children begin formal schooling.

  17. The Bologna Process for U.S. Eyes: Re-learning Higher Education in the Age of Convergence

    ERIC Educational Resources Information Center

    Adelman, Clifford

    2009-01-01

    The title of this document is a deliberate play on the title of the biennial reports on the progress of Bologna produced by the European Students' Union, "Bologna With Student Eyes." It is a way of paying tribute to student involvement in the Bologna reforms, and marking a parallel student working participation in the state system "Tuning" study…

  18. Total body potassium in aging humans: A longitudinal study

    SciTech Connect

    Flynn, M.A.; Nolph, G.B.; Baker, A.S.; Martin, W.M.; Krause, G. )

    1989-10-01

    Total body potassium (TBK) data calculated from longitudinal measurements over 18 y of 40K by whole-body counting of 564 male and 61 female healthy humans in a 2-pi liquid scintillation counter show little change in females younger than 50 y compared with males of those ages. Males show less TBK from 41 y onward as they age, with most rapid rate of loss between 41 and 60 y. Females have a rapid loss of TBK when they are older than 60 y; the loss is at a greater rate than that of males. Percent total body fat calculated from total body weight and lean body mass (LBM) derived from TBK document greater adiposity in females at all ages except ages 51-60 y when females are similar to males in change in percent fat per year per centimeter.

  19. A network model of human aging: Limits, errors, and information

    NASA Astrophysics Data System (ADS)

    Farrell, Spencer; Mitnitski, Arnold; Rockwood, Kenneth; Rutenberg, Andrew

    The Frailty Index (FI) quantifies human aging using the fraction of accumulated age-related deficits. The FI correlates strongly with mortality and accumulates non-linearly and stochastically with age. Clinical data shows a nearly universal limit of FI <= 0 . 7 . We computationally model an aging population using a network model of interacting deficits. Deficits damage and repair at rates that depend upon the average damage of connected nodes. The model is parametrized to fit clinical data. We find that attribution errors, especially false negative, allow the model to recover the frailty limit. Mutual information allows us to assess how well the FI can predict mortality. Mutual information provides a non-parametric measure of how the FI predicts mortality. We find that attribution errors have a small effect on the mutual information when many deficits are included in the model. The mutual information of our model and of the clinical data are comparable.

  20. Effects of aging on the mechanical behavior of human dentin.

    PubMed

    Arola, D; Reprogel, R K

    2005-06-01

    An experimental study on the mechanical behavior of human dentin and the influence of age was conducted. Beams with rectangular cross-section were sectioned from the coronal dentin of virgin extracted molars (N = 76) that were obtained from (N = 70) patients between 17 and 80 years of age. The beams were loaded in either quasi-static 4-point flexure or 4-point flexural fatigue to failure and the stiffness, strength and fatigue properties were evaluated. In characterizing the fatigue response the beams were divided into two age groups that were regarded as young (17 < or = age < or = 30, mean +/- std. dev. = 25 +/- 5 years) and old (50 < or = age < or = 80, mean +/- std. dev. = 64 +/- 9 years) dentin. Results from monotonic loading showed that both the flexural strength and strain to fracture of dentin decreased significantly with age. The fatigue life of dentin increased with a reduction in cyclic stress amplitude and the fatigue strength of young dentin was greater than that of old dentin at all cyclic stress amplitudes. The endurance strength of young dentin (at 10(7) cycles) was approximately 44 MPa, whereas the old dentin exhibited an endurance strength of approximately 23 MPa. Based on differences in the mechanical behavior and microscopic features of the fracture surfaces from the young and old specimens, aging appears to result in an increase in both the rate of damage initiation and propagation in dentin.

  1. Adaptive Optics Analysis of Visual Benefit with Higher-order Aberrations Correction of Human Eye - Poster Paper

    NASA Astrophysics Data System (ADS)

    Xue, Lixia; Dai, Yun; Rao, Xuejun; Wang, Cheng; Hu, Yiyun; Liu, Qian; Jiang, Wenhan

    2008-01-01

    Higher-order aberrations correction can improve visual performance of human eye to some extent. To evaluate how much visual benefit can be obtained with higher-order aberrations correction we developed an adaptive optics vision simulator (AOVS). Dynamic real time optimized modal compensation was used to implement various customized higher-order ocular aberrations correction strategies. The experimental results indicate that higher-order aberrations correction can improve visual performance of human eye comparing with only lower-order aberration correction but the improvement degree and higher-order aberration correction strategy are different from each individual. Some subjects can acquire great visual benefit when higher-order aberrations were corrected but some subjects acquire little visual benefit even though all higher-order aberrations were corrected. Therefore, relative to general lower-order aberrations correction strategy, customized higher-order aberrations correction strategy is needed to obtain optimal visual improvement for each individual. AOVS provides an effective tool for higher-order ocular aberrations optometry for customized ocular aberrations correction.

  2. Telocytes and putative stem cells in ageing human heart.

    PubMed

    Popescu, Laurentiu M; Curici, Antoanela; Wang, Enshi; Zhang, Hao; Hu, Shengshou; Gherghiceanu, Mihaela

    2015-01-01

    Tradition considers that mammalian heart consists of about 70% non-myocytes (interstitial cells) and 30% cardiomyocytes (CMs). Anyway, the presence of telocytes (TCs) has been overlooked, since they were described in 2010 (visit www.telocytes.com). Also, the number of cardiac stem cells (CSCs) has not accurately estimated in humans during ageing. We used electron microscopy to identify and estimate the number of cells in human atrial myocardium (appendages). Three age-related groups were studied: newborns (17 days-1 year), children (6-17 years) and adults (34-60 years). Morphometry was performed on low-magnification electron microscope images using computer-assisted technology. We found that interstitial area gradually increases with age from 31.3 ± 4.9% in newborns to 41 ± 5.2% in adults. Also, the number of blood capillaries (per mm(2) ) increased with several hundreds in children and adults versus newborns. CMs are the most numerous cells, representing 76% in newborns, 88% in children and 86% in adults. Images of CMs mitoses were seen in the 17-day newborns. Interestingly, no lipofuscin granules were found in CMs of human newborns and children. The percentage of cells that occupy interstitium were (depending on age): endothelial cells 52-62%; vascular smooth muscle cells and pericytes 22-28%, Schwann cells with nerve endings 6-7%, fibroblasts 3-10%, macrophages 1-8%, TCs about 1% and stem cells less than 1%. We cannot confirm the popular belief that cardiac fibroblasts are the most prevalent cell type in the heart and account for about 20% of myocardial volume. Numerically, TCs represent a small fraction of human cardiac interstitial cells, but because of their extensive telopodes, they achieve a 3D network that, for instance, supports CSCs. The myocardial (very) low capability to regenerate may be explained by the number of CSCs, which decreases fivefold by age (from 0.5% to 0.1% in newborns versus adults).

  3. Vestibulosympathetic reflex during orthostatic challenge in aging humans

    NASA Technical Reports Server (NTRS)

    Monahan, Kevin D.; Ray, Chester A.

    2002-01-01

    Aging attenuates the increase in muscle sympathetic nerve activity (MSNA) and elicits hypotension during otolith organ engagement in humans. The purpose of the present study was to determine the neural and cardiovascular responses to otolithic engagement during orthostatic stress in older adults. We hypothesized that age-related impairments in the vestibulosympathetic reflex would persist during orthostatic challenge in older subjects and might compromise arterial blood pressure regulation. MSNA, arterial blood pressure, and heart rate responses to head-down rotation (HDR) performed with and without lower body negative pressure (LBNP) in prone subjects were measured. Ten young (27 +/- 1 yr) and 11 older subjects (64 +/- 1 yr) were studied prospectively. HDR performed alone elicited an attenuated increase in MSNA in older subjects (Delta106 +/- 28 vs. Delta20 +/- 7% for young and older subjects). HDR performed during simultaneous orthostatic stress increased total MSNA further in young (Delta53 +/- 15%; P < 0.05) but not older subjects (Delta-5 +/- 4%). Older subjects demonstrated consistent significant hypotension during HDR performed both alone (Delta-6 +/- 2 mmHg) and during LBNP (Delta-7 +/- 2 mmHg). These data provide experimental support for the concept that age-related impairments in the vestibulosympathetic reflex persist during orthostatic challenge in older adults. Furthermore, these findings are consistent with the concept that age-related alterations in vestibular function might contribute to altered orthostatic blood pressure regulation with age in humans.

  4. Strategies and Challenges in Clinical Trials Targeting Human Aging

    PubMed Central

    Newman, John C.; Milman, Sofiya; Hashmi, Shahrukh K.; Austad, Steve N.; Kirkland, James L.; Halter, Jeffrey B.

    2016-01-01

    Interventions that target fundamental aging processes have the potential to transform human health and health care. A variety of candidate drugs have emerged from basic and translational research that may target aging processes. Some of these drugs are already in clinical use for other purposes, such as metformin and rapamycin. However, designing clinical trials to test interventions that target the aging process poses a unique set of challenges. This paper summarizes the outcomes of an international meeting co-ordinated by the NIH-funded Geroscience Network to further the goal of developing a translational pipeline to move candidate compounds through clinical trials and ultimately into use. We review the evidence that some drugs already in clinical use may target fundamental aging processes. We discuss the design principles of clinical trials to test such interventions in humans, including study populations, interventions, and outcomes. As examples, we offer several scenarios for potential clinical trials centered on the concepts of health span (delayed multimorbidity and functional decline) and resilience (response to or recovery from an acute health stress). Finally, we describe how this discussion helped inform the design of the proposed Targeting Aging with Metformin study. PMID:27535968

  5. Human vergence eye movements to oblique disparity stimuli: evidence for an anisotropy favoring horizontal disparities

    PubMed Central

    Rambold, H. A.; Miles, F. A.

    2008-01-01

    Binocular disparities applied to large-field patterns elicit vergence eye movements at ultra-short latencies. We used the electromagnetic search coil technique to record the horizontal and vertical positions of both eyes while subjects briefly viewed (150 ms) large patterns that were identical at the two eyes except for a difference in position (binocular disparity) that was varied in direction from trial to trial. For accurate alignment with the stimuli, the horizontal and vertical disparity vergence responses (HDVRs, VDVRs) should vary as the sine and cosine, respectively, of the direction of the disparity stimulus vector. In a first experiment, using random dots patterns (RDs) with a binocular disparity of 0.2°, this was indeed the case. In a second experiment, using 1-D sine-wave gratings with a binocular phase difference (disparity) of 1/4-wavelength, it was not the case: HDVRs were maximal when the grating was vertical and showed little decrement until the grating was oriented more than ~65° away from vertical, whereas VDVRs were maximal when the grating was horizontal and began to decrement roughly linearly when the grating was oriented away from the horizontal. We attribute these complex directional dependencies with gratings to the aperture problem, and the HDVR data strongly resemble the stereothresholds for 1-D gratings, which are minimal when the gratings are vertical and remain constant for orientations up to ~80° away from the vertical when expressed as spatial phase disparities [Morgan & Castet (1997) The aperture problem in stereopsis. Vision Research, 37, 2737–2744]. To explain this constancy of stereothresholds, Morgan & Castet (1997) postulated detectors sensitive to the phase disparity of the gratings seen by the two eyes (rather than their linear separation along some fixed axis, such as the horizontal). However, because 1) our VDVR data with gratings did not show this constancy and 2) the available evidence strongly suggests that there

  6. Eye tissues study

    NASA Astrophysics Data System (ADS)

    Tuchin, Valery V.; Bashkatov, Alexey N.; Maksimova, Irina L.; Sinichkin, Yurii P.; Simonenko, Georgy V.; Genina, Elina A.; Lakodina, Nina A.

    2001-08-01

    Theoretical and in vitro and in vivo experimental study of spectral and polarization characteristics of the human and rabbit eye tissues are presented. The possibility of control of optical properties of eye cornea, lens and sclera is discussed and realized experimentally for glucose solution as the refractive index matching factor.

  7. Blue eye color in humans may be caused by a perfectly associated founder mutation in a regulatory element located within the HERC2 gene inhibiting OCA2 expression.

    PubMed

    Eiberg, Hans; Troelsen, Jesper; Nielsen, Mette; Mikkelsen, Annemette; Mengel-From, Jonas; Kjaer, Klaus W; Hansen, Lars

    2008-03-01

    The human eye color is a quantitative trait displaying multifactorial inheritance. Several studies have shown that the OCA2 locus is the major contributor to the human eye color variation. By linkage analysis of a large Danish family, we finemapped the blue eye color locus to a 166 Kbp region within the HERC2 gene. By association analyses, we identified two SNPs within this region that were perfectly associated with the blue and brown eye colors: rs12913832 and rs1129038. Of these, rs12913832 is located 21.152 bp upstream from the OCA2 promoter in a highly conserved sequence in intron 86 of HERC2. The brown eye color allele of rs12913832 is highly conserved throughout a number of species. As shown by a Luciferase assays in cell cultures, the element significantly reduces the activity of the OCA2 promoter and electrophoretic mobility shift assays demonstrate that the two alleles bind different subsets of nuclear extracts. One single haplotype, represented by six polymorphic SNPs covering half of the 3' end of the HERC2 gene, was found in 155 blue-eyed individuals from Denmark, and in 5 and 2 blue-eyed individuals from Turkey and Jordan, respectively. Hence, our data suggest a common founder mutation in an OCA2 inhibiting regulatory element as the cause of blue eye color in humans. In addition, an LOD score of Z = 4.21 between hair color and D14S72 was obtained in the large family, indicating that RABGGTA is a candidate gene for hair color.

  8. Biophysical and Morphological Evaluation of Human Normal and Dry Eye Meibum Using Hot Stage Polarized Light Microscopy

    PubMed Central

    Butovich, Igor A.; Lu, Hua; McMahon, Anne; Ketelson, Howard; Senchyna, Michelle; Meadows, David; Campbell, Elaine; Molai, Mike; Linsenbardt, Emily

    2014-01-01

    Purpose. To study melting characteristics and the morphology of human and mouse meibum. Methods. Hot stage cross-polarized light microscopy (HSPM) and immunohistochemical approaches were used. Results. Isolated human meibum, and meibum of mice (either isolated or within the meibomian ducts of mice), were found to be in liquid-crystal state at physiological temperatures. Melting of both types of meibum started at approximately 10°C and was completed at approximately 40°C. Melting curves of isolated meibum and meibum inside the meibomian ducts were multiphasic with at least two or three clearly defined phase transition temperatures, typically at approximately 12 ± 2°C (minor transition), 21 ± 3°C, and 32 ± 3°C, regardless the source of meibum. Melting was highly cooperative in nature. Samples of abnormal human meibum collected from dry eye patients with meibomian gland dysfunction often showed an increased presence of nonlipid, nonmelting, nonbirefringent, chloroform-insoluble inclusions of a protein nature. The inclusions were positively stained for cytokeratins. The presence of these inclusions was semiquantitatively characterized using a newly proposed 0 to 4 scale. In the presence of large amounts of these inclusions, melting characteristics of meibum and its structural integrity were altered. Conclusions. HSPM is an effective tool that is suitable for biophysical and morphological evaluation of meibum. Morphological properties and melting characteristics of human meibum were found to be similar to those of mice. Abnormal meibum of many dry eye patients contained large quantities of nonlipid, protein-like inclusions, which were routinely absent in meibum of normal controls. PMID:24282231

  9. Lipidomics of human brain aging and Alzheimer's disease pathology.

    PubMed

    Naudí, Alba; Cabré, Rosanna; Jové, Mariona; Ayala, Victoria; Gonzalo, Hugo; Portero-Otín, Manuel; Ferrer, Isidre; Pamplona, Reinald

    2015-01-01

    Lipids stimulated and favored the evolution of the brain. Adult human brain contains a large amount of lipids, and the largest diversity of lipid classes and lipid molecular species. Lipidomics is defined as "the full characterization of lipid molecular species and of their biological roles with respect to expression of proteins involved in lipid metabolism and function, including gene regulation." Therefore, the study of brain lipidomics can help to unravel the diversity and to disclose the specificity of these lipid traits and its alterations in neural (neurons and glial) cells, groups of neural cells, brain, and fluids such as cerebrospinal fluid and plasma, thus helping to uncover potential biomarkers of human brain aging and Alzheimer disease. This review will discuss the lipid composition of the adult human brain. We first consider a brief approach to lipid definition, classification, and tools for analysis from the new point of view that has emerged with lipidomics, and then turn to the lipid profiles in human brain and how lipids affect brain function. Finally, we focus on the current status of lipidomics findings in human brain aging and Alzheimer's disease pathology. Neurolipidomics will increase knowledge about physiological and pathological functions of brain cells and will place the concept of selective neuronal vulnerability in a lipid context.

  10. Human Ageing Genomic Resources: Integrated databases and tools for the biology and genetics of ageing

    PubMed Central

    Tacutu, Robi; Craig, Thomas; Budovsky, Arie; Wuttke, Daniel; Lehmann, Gilad; Taranukha, Dmitri; Costa, Joana; Fraifeld, Vadim E.; de Magalhães, João Pedro

    2013-01-01

    The Human Ageing Genomic Resources (HAGR, http://genomics.senescence.info) is a freely available online collection of research databases and tools for the biology and genetics of ageing. HAGR features now several databases with high-quality manually curated data: (i) GenAge, a database of genes associated with ageing in humans and model organisms; (ii) AnAge, an extensive collection of longevity records and complementary traits for >4000 vertebrate species; and (iii) GenDR, a newly incorporated database, containing both gene mutations that interfere with dietary restriction-mediated lifespan extension and consistent gene expression changes induced by dietary restriction. Since its creation about 10 years ago, major efforts have been undertaken to maintain the quality of data in HAGR, while further continuing to develop, improve and extend it. This article briefly describes the content of HAGR and details the major updates since its previous publications, in terms of both structure and content. The completely redesigned interface, more intuitive and more integrative of HAGR resources, is also presented. Altogether, we hope that through its improvements, the current version of HAGR will continue to provide users with the most comprehensive and accessible resources available today in the field of biogerontology. PMID:23193293

  11. Human Ageing Genomic Resources: integrated databases and tools for the biology and genetics of ageing.

    PubMed

    Tacutu, Robi; Craig, Thomas; Budovsky, Arie; Wuttke, Daniel; Lehmann, Gilad; Taranukha, Dmitri; Costa, Joana; Fraifeld, Vadim E; de Magalhães, João Pedro

    2013-01-01

    The Human Ageing Genomic Resources (HAGR, http://genomics.senescence.info) is a freely available online collection of research databases and tools for the biology and genetics of ageing. HAGR features now several databases with high-quality manually curated data: (i) GenAge, a database of genes associated with ageing in humans and model organisms; (ii) AnAge, an extensive collection of longevity records and complementary traits for >4000 vertebrate species; and (iii) GenDR, a newly incorporated database, containing both gene mutations that interfere with dietary restriction-mediated lifespan extension and consistent gene expression changes induced by dietary restriction. Since its creation about 10 years ago, major efforts have been undertaken to maintain the quality of data in HAGR, while further continuing to develop, improve and extend it. This article briefly describes the content of HAGR and details the major updates since its previous publications, in terms of both structure and content. The completely redesigned interface, more intuitive and more integrative of HAGR resources, is also presented. Altogether, we hope that through its improvements, the current version of HAGR will continue to provide users with the most comprehensive and accessible resources available today in the field of biogerontology.

  12. [Histological study on aging changes in the human tongue].

    PubMed

    Nakayama, M

    1991-04-01

    Dryness of the mouth, taste disturbance or misswallowing may appear due to physiological changes of tongue especially in old aged person. The purpose of this study is to investigate histological changes related to aging in the human tongue, qualitatively and quantitatively. The samples were collected from 100 autopsy-cases without any pathological changes consisting of 50 males and 50 females aged between 5 and 82. Five specimens (I-V) were obtained from each tongue by frontal section. Specimen I (anterior part of tongue), III (central part), V (posterior part) were studied. Each specimen with thickness of 4 microns were stained with Hematoxylin-Eosin and Alucian-Blue. Tongue mucosa, glands such as Blandin-Nuhn gland, von Ebner gland and those glands distributed in the root of tongue, and M. longitudinalis superior were observed histologically. The study was done quantitatively by I-BAS one picture analyzer manufactured by Zeiss Co. The results of this study are as following: 1) The epithelium of lingual mucosa The thickness of epithelium decreased with aging, rather prominent on dorsal part than the lateral. 2) lingual glands Acinar atrophy increased with aging, especially quickly in females. The atrophy of the acinus started from 40 years old in Blandin-nuhn gland and 30 in von Ebner gland. However, tongue root glandular atrophy was milder in comparison with the other two glands. 3) Lingual muscles Decrease in muscle fiber diameter with aging is also observed.

  13. [Basic principles of physics in optical imaging of the human eye].

    PubMed

    Vodicka, I

    2000-01-01

    Creation of a real picture of the observed object on the retina by optical system of the eye is the primary physical condition of the visual perception. Absorption of the light energy initiates the sequence of further physicochemical, biochemical and psychophysiological events partially taking place already in the retina but mostly in the higher cerebral and spinal centres. So the visual perception and its final evaluation is the result of a complicated complex of processes where the optical imaging itself plays the role of the starting factor. In the publication particularly the physical substance of the optical imaging on refraction surfaces between media with different refraction index has been accentuated. The laws of reflection and refraction and their origin are derived in the terms of the physical (Maxwell equations) and geometrical (Fermat principle, principle of the mutual independence of light beams) optics. In the adequate extent the development and structure of the eye and the whole visual complex, the bases of the quantification of the visual perception and contemporary opinions on mechanisms of the colour vision (trichromatic theory) have been described. The publication is completed by a mathematical appendix explaining some relations usually absent in the biomedical literature. PMID:11413677

  14. Short-latency Disparity-Vergence Eye Movements in Humans: Sensitivity to Simulated Orthogonal Tropias

    PubMed Central

    Yang, D. -S.; FitzGibbon, E. J.; Miles, F. A.

    2008-01-01

    Small disparity stimuli applied to large random-dot patterns elicit machine-like vergence eye movements at short latency. We have examined the sensitivity of these eye movements to simulated orthogonal tropias in three normal subjects by recording 1) the effects of vertical disparities on the initial horizontal vergence responses elicited by 2° crossed and uncrossed (horizontal) disparity stimuli, and 2) the effects of horizontal disparities on the initial vertical vergence responses elicited by 1.2° left-hyper and 0.8° right-hyper (vertical) disparity stimuli. Initial vergence responses were strongest when the orthogonal disparity was close to zero, and decreased to zero as the orthogonal disparity increased to 3–5°, i.e., there was only a limited tolerance for orthogonal disparity. Tuning curves describing the dependence of the initial change in the vergence angle on the orthogonal disparity were well fit by a Gaussian function. An additional subject, who had an esotropia of ~10° in our experimental setup, showed almost no horizontal vergence responses but did show vertical vergence responses to vertical disparity stimuli at short latency (albeit slightly longer than normal) despite the fact that her esotropia resulted in uncrossed disparities that would have totally disabled the vertical vergence mechanism of a normal subject, cf., anomalous retinal correspondence. PMID:12536000

  15. Successful Aging through the Eyes of Alaska Native Elders. What It Means to Be an Elder in Bristol Bay, AK

    ERIC Educational Resources Information Center

    Lewis, Jordan P.

    2011-01-01

    Purpose: Alaska Natives (ANs) view aging from a holistic perspective, which is not typical of the existing successful aging literature. One of the challenges of conducting research with cultural groups (e.g., ANs) is the lack of data, or research, on culture and aging and its impact on how we view successful aging. This research explores…

  16. Age and the transmittance of the human crystalline lens.

    PubMed Central

    Weale, R A

    1988-01-01

    1. Conflicting data both on the transmission of the human crystalline lens in the ultra-violet part of the spectrum and on its variation with age necessitate a re-examination of the subject. 2. Twenty-four excised lenses in the age range of 0-85 years were studied with a Perkin-Elmer spectrophotometer between 327 and 700 nm. 3. Some lenses were homogenized and the homogenates were similarly examined. 4. A systematic increase in absorbance with age was observed both in the visible and the ultra-violet parts of the spectrum. 5. An exponential function describes the data, facilitating comparison with, and prediction of, other values. 6. The absorbance of homogenized material was found to be predictable from that of intact lenses, and does not support the notion that mechanical trauma may account for high values in earlier studies. PMID:3411488

  17. Human mortality at very advanced age might be constant.

    PubMed

    Klemera, P; Doubal, S

    1997-11-01

    An attempt was made to identify the course of the mortality rate at the upper tail of human age. The only known data suitable for this purpose were published by Riggs and Millecchia (J.E. Riggs, R.J. Millecchia, Mech. Ageing Dev. 62 (1992) 191-199) and our analysis follows up their results. By means of mathematical elaboration it was proved that these data imply a constant mortality rate (approx. 25% per year) at ages above 113 years for men and above 116 years for women. Indirect arguments supporting the validity of the source data are discussed. Nevertheless, even if the source data are mistaken, we proved they cannot be the product of purely random errors and our results may contribute to the elucidation of the origin of those systematic errors. PMID:9379712

  18. Phase coupling between rhythmic slow activity and gamma characterizes mesiotemporal rapid-eye-movement sleep in humans.

    PubMed

    Clemens, Z; Weiss, B; Szucs, A; Eross, L; Rásonyi, G; Halász, P

    2009-09-29

    In the human sleep literature there is much controversy regarding the existence and the characteristics of hippocampal rhythmic slow activity (RSA). Generally the human RSA is believed to occur in short bursts of theta activity. An earlier study, however, reported mesiotemporal RSA during rapid-eye-movement (REM) sleep that instead of theta fell in the delta frequency band. We conjectured that if this RSA activity is indeed a human analogue of the animal hippocampal theta then characteristics associated with the animal theta should also be reflected in the human recordings. Here our aim was to examine possible phase coupling between mesiotemporal RSA and gamma activity during REM sleep. The study relied on nine epilepsy surgery candidates implanted with foramen ovale electrodes. Positive half-waves of the 1.5-3 Hz RSA were identified by an automatic algorithm during REM sleep. High-frequency activity was assessed for 11 consecutive 20 Hz-wide frequency bands between 20 and 240 Hz. Increase in high frequency activity was phase coupled with RSA in most frequency bands and patients. Such a phase coupling closely resembles that seen between theta and gamma in rodents. We consider this commonality to be an additional reason for regarding delta rather than theta as the human analogue of RSA in animals.

  19. RPE Cell and Sheet Properties in Normal and Diseased Eyes.

    PubMed

    Rashid, Alia; Bhatia, Shagun K; Mazzitello, Karina I; Chrenek, Micah A; Zhang, Qing; Boatright, Jeffrey H; Grossniklaus, Hans E; Jiang, Yi; Nickerson, John M

    2016-01-01

    Previous studies of human retinal pigment epithelium (RPE) morphology found spatial differences in density: a high density of cells in the macula, decreasing peripherally. Because the RPE sheet is not perfectly regular, we anticipate that there will be differences between conditions and when and where damage is most likely to begin. The purpose of this study is to establish relationships among RPE morphometrics in age, cell location, and disease of normal human and AMD eyes that highlight irregularities reflecting damage. Cadaveric eyes from 11 normal and 3 age-related macular degeneration (AMD) human donors ranging from 29 to 82 years of age were used. Borders of RPE cells were identified with phalloidin. RPE segmentation and analysis were conducted with CellProfiler. Exploration of spatial point patterns was conducted using the "spatstat" package of R. In the normal human eye, with increasing age, cell size increased, and cells lost their regular hexagonal shape. Cell density was higher in the macula versus periphery. AMD resulted in greater variability in size and shape of the RPE cell. Spatial point analysis revealed an ordered distribution of cells in normal and high spatial disorder in AMD eyes. Morphometrics of the RPE cell readily discriminate among young vs. old and normal vs. diseased in the human eye. The normal RPE sheet is organized in a regular array of cells, but AMD exhibited strong spatial irregularity. These findings reflect on the robust recovery of the RPE sheet after wounding and the circumstances under which it cannot recover. PMID:26427486

  20. Shack-Hartmann-based objective straylight assessment of the human eye in an increased scattering angle range

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    Objective measurement of straylight in the human eye with a Shack-Hartmann (SH) wavefront aberrometer is limited in imaging angle. We propose a measurement principle and a point spread function (PSF) reconstruction algorithm to overcome this limitation. In our optical setup, a variable stop replaces the stop conventionally used to suppress reflections and scatter in SH aberrometers. We record images with 21 diameters of the stop. From each SH image, the average intensity of the pupil is computed and normalized. The intensities represent integral values of the PSF. We reconstruct the PSF, which is the derivative of the intensities with respect to the visual angle. A modified Stiles Holladay approximation is fitted to the reconstructed PSF, resulting in a straylight parameter. A proof-of-principle study was carried out on eight healthy young volunteers. Scatter filters were positioned in front of the volunteers' eyes to simulate straylight. The straylight parameter was compared to the C-Quant measurements and the filter values. The PSF parameter shows strong correlation with the density of the filters and a linear relation to the C-Quant straylight parameter. Our measurement and reconstruction techniques allow for objective straylight analysis of visual angles up to 4 deg.

  1. Psychophysical and perceptual performance in a simulated-scotoma model of human eye injury

    NASA Astrophysics Data System (ADS)

    Brandeis, R.; Egoz, I.; Peri, D.; Sapiens, N.; Turetz, J.

    2008-02-01

    Macular scotomas, affecting visual functioning, characterize many eye and neurological diseases like AMD, diabetes mellitus, multiple sclerosis, and macular hole. In this work, foveal visual field defects were modeled, and their effects were evaluated on spatial contrast sensitivity and a task of stimulus detection and aiming. The modeled occluding scotomas, of different size, were superimposed on the stimuli presented on the computer display, and were stabilized on the retina using a mono Purkinje Eye-Tracker. Spatial contrast sensitivity was evaluated using square-wave grating stimuli, whose contrast thresholds were measured using the method of constant stimuli with "catch trials". The detection task consisted of a triple conjunctive visual search display of: size (in visual angle), contrast and background (simple, low-level features vs. complex, high-level features). Search/aiming accuracy as well as R.T. measures used for performance evaluation. Artificially generated scotomas suppressed spatial contrast sensitivity in a size dependent manner, similar to previous studies. Deprivation effect was dependent on spatial frequency, consistent with retinal inhomogeneity models. Stimulus detection time was slowed in complex background search situation more than in simple background. Detection speed was dependent on scotoma size and size of stimulus. In contrast, visually guided aiming was more sensitive to scotoma effect in simple background search situation than in complex background. Both stimulus aiming R.T. and accuracy (precision targeting) were impaired, as a function of scotoma size and size of stimulus. The data can be explained by models distinguishing between saliency-based, parallel and serial search processes, guiding visual attention, which are supported by underlying retinal as well as neural mechanisms.

  2. Change in peripheral refraction and curvature of field of the human eye with accommodation

    NASA Astrophysics Data System (ADS)

    Ho, Arthur; Zimmermann, Frederik; Whatham, Andrew; Martinez, Aldo; Delgado, Stephanie; Lazon de la Jara, Percy; Sankaridurg, Padmaja

    2009-02-01

    Recent research showed that the peripheral refractive state is a sufficient stimulus for myopia progression. This finding led to the suggestion that devices that control peripheral refraction may be efficacious in controlling myopia progression. This study aims to understand whether the optical effect of such devices may be affected by near focus. In particular, we seek to understand the influence of accommodation on peripheral refraction and curvature of field of the eye. Refraction was measured in twenty young subjects using an autorefractor at 0° (i.e. along visual axis), and 20°, 30° and 40° field angles both nasal and temporal to the visual axis. All measurements were conducted at 2.5 m, 40 cm and 30 cm viewing distances. Refractive errors were corrected using a soft contact lens during all measurements. As field angle increased, refraction became less hyperopic. Peripheral refraction also became less hyperopic at nearer viewing distances (i.e. with increasing accommodation). Astigmatism (J180) increased with field angle as well as with accommodation. Adopting a third-order aberration theory approach, the position of the Petzval surface relative to the retinal surface was estimated by considering the relative peripheral refractive error (RPRE) and J180 terms of peripheral refraction. Results for the estimated dioptric position of the Petzval surface relative to the retina showed substantial asymmetry. While temporal field tended to agree with theoretical predictions, nasal response departed dramatically from the model eye predictions. With increasing accommodation, peripheral refraction becomes less hyperopic while the Petzval surface showed asymmetry in its change in position. The change in the optical components (i.e. cornea and/or lens as opposed to retinal shape or position) is implicated as at least one of the contributors of this shift in peripheral refraction during accommodation.

  3. Associations of Mortality With Ocular Disorders and an Intervention of High-Dose Antioxidants and Zinc in the Age-Related Eye Disease Study

    PubMed Central

    2006-01-01

    Objective To assess the association of ocular disorders and high doses of antioxidants or zinc with mortality in the Age-Related Eye Disease Study (AREDS). Methods Baseline fundus and lens photographs were used to grade the macular and lens status of AREDS participants. Participants were randomly assigned to receive oral supplements of high-dose antioxidants, zinc, antioxidants plus zinc, or placebo. Risk of all-cause and cause-specific mortality was assessed using adjusted Cox proportional hazards models. Results During median follow-up of 6.5 years, 534 (11%) of 4753 AREDS participants died. In fully adjusted models, participants with advanced age-related macular degeneration (AMD) compared with participants with few, if any, drusen had increased mortality (relative risk [RR], 1.41; 95% confidence interval [CI], 1.08–1.86). Advanced AMD was associated with cardiovascular deaths. Compared with participants having good acuity in both eyes, those with visual acuity worse than 20/40 in 1 eye had increased mortality (RR, 1.36; 95% CI, 1.12–1.65). Nuclear opacity (RR, 1.40; 95% CI, 1.12–1.75) and cataract surgery (RR, 1.55; 95% CI, 1.18–2.05) were associated with increased all-cause mortality and with cancer deaths. Participants randomly assigned to receive zinc had lower mortality than those not taking zinc (RR, 0.73; 95% CI, 0.61–0.89). Conclusions The decreased survival of AREDS participants with AMD and cataract suggests that these conditions may reflect systemic rather than only local processes. The improved survival in individuals randomly assigned to receive zinc requires further study. PMID:15136320

  4. Experiments on a Model Eye

    ERIC Educational Resources Information Center

    Arell, Antti; Kolari, Samuli

    1978-01-01

    Explains a laboratory experiment dealing with the optical features of the human eye. Shows how to measure the magnification of the retina and the refractive anomaly of the eye could be used to measure the refractive power of the observer's eye. (GA)

  5. LIMNOLOGICAL OPTOMETRY: EXAMINING EARTH'S EYE

    EPA Science Inventory

    In Thoreau's Walden, a lake is described as the landscape's most expressive feature and the earth's eye. Collectively, scientists are charged by society to assess, monitor, and remedy maladies of earth's eye in the same way optometrists maintain the health of the human eye. This ...

  6. The Role of the Reactive Oxygen Species and Oxidative Stress in the Pathomechanism of the Age-Related Ocular Diseases and Other Pathologies of the Anterior and Posterior Eye Segments in Adults

    PubMed Central

    Nita, Małgorzata; Grzybowski, Andrzej

    2016-01-01

    The reactive oxygen species (ROS) form under normal physiological conditions and may have both beneficial and harmful role. We search the literature and current knowledge in the aspect of ROS participation in the pathogenesis of anterior and posterior eye segment diseases in adults. ROS take part in the pathogenesis of keratoconus, Fuchs endothelial corneal dystrophy, and granular corneal dystrophy type 2, stimulating apoptosis of corneal cells. ROS play a role in the pathogenesis of glaucoma stimulating apoptotic and inflammatory pathways on the level of the trabecular meshwork and promoting retinal ganglion cells apoptosis and glial dysfunction in the posterior eye segment. ROS play a role in the pathogenesis of Leber's hereditary optic neuropathy and traumatic optic neuropathy. ROS induce apoptosis of human lens epithelial cells. ROS promote apoptosis of vascular and neuronal cells and stimulate inflammation and pathological angiogenesis in the course of diabetic retinopathy. ROS are associated with the pathophysiological parainflammation and autophagy process in the course of the age-related macular degeneration. PMID:26881021

  7. Telocytes and putative stem cells in ageing human heart

    PubMed Central

    Popescu, Laurentiu M; Curici, Antoanela; Wang, Enshi; Zhang, Hao; Hu, Shengshou; Gherghiceanu, Mihaela

    2015-01-01

    Tradition considers that mammalian heart consists of about 70% non-myocytes (interstitial cells) and 30% cardiomyocytes (CMs). Anyway, the presence of telocytes (TCs) has been overlooked, since they were described in 2010 (visit http://www.telocytes.com). Also, the number of cardiac stem cells (CSCs) has not accurately estimated in humans during ageing. We used electron microscopy to identify and estimate the number of cells in human atrial myocardium (appendages). Three age-related groups were studied: newborns (17 days–1 year), children (6–17 years) and adults (34–60 years). Morphometry was performed on low-magnification electron microscope images using computer-assisted technology. We found that interstitial area gradually increases with age from 31.3 ± 4.9% in newborns to 41 ± 5.2% in adults. Also, the number of blood capillaries (per mm2) increased with several hundreds in children and adults versus newborns. CMs are the most numerous cells, representing 76% in newborns, 88% in children and 86% in adults. Images of CMs mitoses were seen in the 17-day newborns. Interestingly, no lipofuscin granules were found in CMs of human newborns and children. The percentage of cells that occupy interstitium were (depending on age): endothelial cells 52–62%; vascular smooth muscle cells and pericytes 22–28%, Schwann cells with nerve endings 6–7%, fibroblasts 3–10%, macrophages 1–8%, TCs about 1% and stem cells less than 1%. We cannot confirm the popular belief that cardiac fibroblasts are the most prevalent cell type in the heart and account for about 20% of myocardial volume. Numerically, TCs represent a small fraction of human cardiac interstitial cells, but because of their extensive telopodes, they achieve a 3D network that, for instance, supports CSCs. The myocardial (very) low capability to regenerate may be explained by the number of CSCs, which decreases fivefold by age (from 0.5% to 0.1% in newborns versus adults). PMID:25545142

  8. Numerical model of heat transfer in the human eye with consideration of fluid dynamics of the aqueous humour

    NASA Astrophysics Data System (ADS)

    Karampatzakis, Andreas; Samaras, Theodoros

    2010-10-01

    In this work we present a new 3D numerical model for heat transfer in the human eye, which takes into account the aqueous humour flow in the anterior chamber. We show that consideration of this phenomenon in the calculations alters the temperature distribution on the corneal and lens surfaces, without, however, noticeably changing their absolute values. The most notable effect is that the coolest area of the cornea moves at a point of 2 mm inferior to its geometric centre. The maximum velocity of the fluid in the anterior chamber was found to be 3.36 × 10-4 m s-1. The effect of the flow on displacing the cool area of the corneal surface temperature is counterbalanced by assuming anisotropic thermal conductivity. The model was implemented in the case of an artificial intraocular lens to show the resulting temperature variations.

  9. Modeling of in vivo acousto-optic two-photon imaging of the retina in the human eye.

    PubMed

    Kusnyerik, Akos; Rozsa, Balazs; Veress, Mate; Szabo, Arnold; Nemeth, Janos; Maak, Pal

    2015-09-01

    Our aim is to establish a novel combined acousto-optical method for in vivo imaging of the human retina with the two-photon microscope. In this paper we present modeling results based on eye model samples constructed with parameters measured on patients. We used effectively the potential of the electronic compensation offered by the acousto-optic lenses to avoid the use of adaptive optical correction. Simulation predicted lateral resolution between 1.6 µm and 3 µm on the retina. This technology allows the visualization of single cells and promises real time measuring of neural activity in individual neurons, neural segments and cell assemblies with 30-100 µs temporal and subcellular spatial resolution. PMID:26368444

  10. Vasodilatory responsiveness to adenosine triphosphate in ageing humans

    PubMed Central

    Kirby, Brett S; Crecelius, Anne R; Voyles, Wyatt F; Dinenno, Frank A

    2010-01-01

    Endothelium-dependent vasodilatation is reduced with advancing age in humans, as evidenced by blunted vasodilator responsiveness to acetylcholine (ACh). Circulating adenosine triphosphate (ATP) has been implicated in the control of skeletal muscle vascular tone during mismatches in oxygen delivery and demand (e.g. exercise) via binding to purinergic receptors (P2Y) on the endothelium evoking subsequent vasodilatation, and ageing is typically associated with reductions in muscle blood flow under such conditions. Therefore, we tested the hypothesis that ATP-mediated vasodilatation is impaired with age in healthy humans. We measured forearm blood flow (venous occlusion plethysmography) and calculated vascular conductance (FVC) responses to local intra-arterial infusions of ACh, ATP, and sodium nitroprusside (SNP) before and during ascorbic acid (AA) infusion in 13 young and 13 older adults. The peak increase in FVC to ACh was significantly impaired in older compared with young adults (262 ± 71%vs. 618 ± 97%; P < 0.05), and this difference was abolished during AA infusion (510 ± 82%vs. 556 ± 71%; not significant, NS). In contrast, peak FVC responses were not different between older and young adults to either ATP (675 ± 105%vs. 734 ± 126%) or SNP (1116 ± 111%vs. 1138 ± 148%) and AA infusion did not alter these responses in either age group (both NS). In another group of six young and six older adults, we determined whether vasodilator responses to adenosine and ATP were influenced by P1-receptor blockade via aminophylline. The peak FVC responses to adenosine were not different in young (350 ± 65%) versus older adults (360 ± 80%), and aminophylline blunted these responses by ∼50% in both groups. The peak FVC responses to ATP were again not different in young and older adults, and aminophylline did not impact the vasodilatation in either group. Thus, in contrast to the observed impairments in ACh responses, the vasodilatory response to exogenous ATP is not

  11. Analysis of the Viscoelastic Properties of the Human Cornea Using Scheimpflug Imaging in Inflation Experiment of Eye Globes

    PubMed Central

    Lombardo, Giuseppe; Serrao, Sebastiano; Rosati, Marianna; Lombardo, Marco

    2014-01-01

    Purpose To demonstrate a Scheimpflug-based imaging procedure for investigating the depth- and time-dependent strain response of the human cornea to inflation testing of whole eye globes. Methods Six specimens, three of which with intact corneal epithelium, were mounted in a customized apparatus within a humidity and temperature-monitored wet chamber. Each specimen was subjected to two mechanical tests in order to measure corneal strain resulting from application of cyclic (cyclic regimen) and constant (creep regimen) stress by changing the intra-ocular pressure (IOP) within physiological ranges (18–42 mmHg). Corneal shape changes were analyzed as a function of IOP and both corneal stress-strain curves and creep curves were generated. Results The procedure was highly accurate and repeatable. Upon cyclic stress application, a biomechanical corneal elasticity gradient was found in the front-back direction. The average Young's modulus of the anterior cornea ranged between 2.28±0.87 MPa and 3.30±0.90 MPa in specimens with and without intact epithelium (P = 0.05) respectively. The Young's modulus of the posterior cornea was on average 0.21±0.09 MPa and 0.17±0.06 MPa (P>0.05) respectively. The time-dependent strain response of the cornea to creep testing was quantified by fitting data to a modified Zener model for extracting both the relaxation time and compliance function. Conclusion Cyclic and creep mechanical tests are valuable for investigating the strain response of the intact human cornea within physiological IOP ranges, providing meaningful results that can be translated to clinic. The presence of epithelium influences the results of anterior corneal shape changes when monitoring deformation via Scheimpflug imaging in inflation experiments of whole eye globes. PMID:25397674

  12. Acrylamide induces accelerated endothelial aging in a human cell model.

    PubMed

    Sellier, Cyril; Boulanger, Eric; Maladry, François; Tessier, Frédéric J; Lorenzi, Rodrigo; Nevière, Rémi; Desreumaux, Pierre; Beuscart, Jean-Baptiste; Puisieux, François; Grossin, Nicolas

    2015-09-01

    Acrylamide (AAM) has been recently discovered in food as a Maillard reaction product. AAM and glycidamide (GA), its metabolite, have been described as probably carcinogenic to humans. It is widely established that senescence and carcinogenicity are closely related. In vitro, endothelial aging is characterized by replicative senescence in which primary cells in culture lose their ability to divide. Our objective was to assess the effects of AAM and GA on human endothelial cell senescence. Human umbilical vein endothelial cells (HUVECs) cultured in vitro were used as model. HUVECs were cultured over 3 months with AAM or GA (1, 10 or 100 μM) until growth arrest. To analyze senescence, β-galactosidase activity and telomere length of HUVECs were measured by cytometry and semi-quantitative PCR, respectively. At all tested concentrations, AAM or GA reduced cell population doubling compared to the control condition (p < 0.001). β-galactosidase activity in endothelial cells was increased when exposed to AAM (≥10 μM) or GA (≥1 μM) (p < 0.05). AAM (≥10 μM) or GA (100 μM) accelerated telomere shortening in HUVECs (p < 0.05). In conclusion, in vitro chronic exposure to AAM or GA at low concentrations induces accelerated senescence. This result suggests that an exposure to AAM might contribute to endothelial aging.

  13. Reproductive aging patterns in primates reveal that humans are distinct

    PubMed Central

    Alberts, Susan C.; Altmann, Jeanne; Brockman, Diane K.; Cords, Marina; Fedigan, Linda M.; Pusey, Anne; Stoinski, Tara S.; Strier, Karen B.; Morris, William F.; Bronikowski, Anne M.

    2013-01-01

    Women rarely give birth after ∼45 y of age, and they experience the cessation of reproductive cycles, menopause, at ∼50 y of age after a fertility decline lasting almost two decades. Such reproductive senescence in mid-lifespan is an evolutionary puzzle of enduring interest because it should be inherently disadvantageous. Furthermore, comparative data on reproductive senescence from other primates, or indeed other mammals, remains relatively rare. Here we carried out a unique detailed comparative study of reproductive senescence in seven species of nonhuman primates in natural populations, using long-term, individual-based data, and compared them to a population of humans experiencing natural fertility and mortality. In four of seven primate species we found that reproductive senescence occurred before death only in a small minority of individuals. In three primate species we found evidence of reproductive senescence that accelerated throughout adulthood; however, its initial rate was much lower than mortality, so that relatively few individuals experienced reproductive senescence before death. In contrast, the human population showed the predicted and well-known pattern in which reproductive senescence occurred before death for many women and its rate accelerated throughout adulthood. These results provide strong support for the hypothesis that reproductive senescence in midlife, although apparent in natural-fertility, natural-mortality populations of humans, is generally absent in other primates living in such populations. PMID:23898189

  14. Eye surgery in the elderly

    PubMed Central

    Raczyńska, Dorota; Glasner, Leopold; Serkies-Minuth, Ewelina; Wujtewicz, Magdalena A; Mitrosz, Kamila

    2016-01-01

    Extending life expectancy is a human achievement. It does however entail problems. Ophthalmic treatments are widely recognized as having a low risk of general complications. A classic example is cataract surgery, considered to be one of the safest and most frequently performed surgical procedures in the world. However, advanced age brings with it risks that should be considered before surgery. Eye operations, as with procedures on other organs, are largely dependent on the quality of surgical tissues. Therefore, the elderly are at increased risk of complications. Improved general health and postoperative follow-up with the use of noninvasive technologies such as optical coherence tomography translate into lower intraoperative risk and better postoperative prognosis. In this review, we discuss the impact of general health on operational prognosis, therapeutic problems, and technical difficulties which a surgeon and anesthesiologist may encounter in the process. We also consider new technology and strategies specifically aimed at treating eye conditions in the elderly. PMID:27103794

  15. Eye Anatomy

    MedlinePlus

    ... News About Us Donate In This Section Eye Anatomy en Español email Send this article to a ... You at Risk For Glaucoma? Childhood Glaucoma Eye Anatomy Five Common Glaucoma Tests Glaucoma Facts and Stats ...

  16. Your Eyes

    MedlinePlus

    ... the eye and keeps it healthy. previous continue Light, Lens, Action These next parts are really cool, ... the eye. previous continue Rods and Cones Process Light The retina uses special cells called rods and ...

  17. Human Rights and the Ethno-Nationalist Problematic through the Eyes of Greek-Cypriot Teachers

    ERIC Educational Resources Information Center

    Zembylas, Michalinos; Charalambous, Panayiota; Charalambous, Constadina; Lesta, Stalo

    2016-01-01

    The present article aims to examine the interplay between the transnational discourses of human rights and the particularities of local constructions and conceptualisations of human rights within the context of an ethnically divided society, Cyprus. Specifically, this interplay is examined through a qualitative study of Greek-Cypriot primary…

  18. Spatial distribution of the human enamel fracture toughness with aging.

    PubMed

    Zheng, Qinghua; Xu, Haiping; Song, Fan; Zhang, Lan; Zhou, Xuedong; Shao, Yingfeng; Huang, Dingming

    2013-10-01

    A better understanding of the fracture toughness (KIC) of human enamel and the changes induced by aging is important for the clinical treatment of teeth cracks and fractures. We conducted microindentation tests and chemical content measurements on molar teeth from "young" (18 ≤ age ≤ 25) and "old" (55 ≤ age) patients. The KIC and the mineral contents (calcium and phosphorus) in the outer, the middle, and the inner enamel layers within the cuspal and the intercuspal regions of the crown were measured through the Vickers toughness test and Energy Dispersive X-Ray Spectroscopy (EDS), respectively. The elastic modulus used for the KIC calculation was measured through atomic force microscope (AFM)-based nanoindentation tests. In the outer enamel layer, two direction-specific values of the KIC were calculated separately (direction I, crack running parallel to the occlusal surface; direction II, perpendicular to direction I). The mean KIC of the outer enamel layer was lower than that of the internal layers (p<0.05). No other region-related differences in the mechanical properties were found in both groups. In the outer enamel layer, old enamel has a lower KIC, II and higher mineral contents than young enamel (p<0.05). The enamel surface becomes more prone to cracks with aging partly due to the reduction in the interprismatic organic matrix observed with the maturation of enamel.

  19. Age-dependent motor unit remodelling in human limb muscles.

    PubMed

    Piasecki, Mathew; Ireland, Alex; Jones, David A; McPhee, Jamie S

    2016-06-01

    Voluntary control of skeletal muscle enables humans to interact with and manipulate the environment. Lower muscle mass, weakness and poor coordination are common complaints in older age and reduce physical capabilities. Attention has focused on ways of maintaining muscle size and strength by exercise, diet or hormone replacement. Without appropriate neural innervation, however, muscle cannot function. Emerging evidence points to a neural basis of muscle loss. Motor unit number estimates indicate that by age around 71 years, healthy older people have around 40 % fewer motor units. The surviving low- and moderate-threshold motor units recruited for moderate intensity contractions are enlarged by around 50 % and show increased fibre density, presumably due to collateral reinnervation of denervated fibres. Motor unit potentials show increased complexity and the stability of neuromuscular junction transmissions is decreased. The available evidence is limited by a lack of longitudinal studies, relatively small sample sizes, a tendency to examine the small peripheral muscles and relatively few investigations into the consequences of motor unit remodelling for muscle size and control of movements in older age. Loss of motor neurons and remodelling of surviving motor units constitutes the major change in ageing muscles and probably contributes to muscle loss and functional impairments. The deterioration and remodelling of motor units likely imposes constraints on the way in which the central nervous system controls movements. PMID:26667009

  20. Raman spectroscopy of human skin: looking for a quantitative algorithm to reliably estimate human age

    NASA Astrophysics Data System (ADS)

    Pezzotti, Giuseppe; Boffelli, Marco; Miyamori, Daisuke; Uemura, Takeshi; Marunaka, Yoshinori; Zhu, Wenliang; Ikegaya, Hiroshi

    2015-06-01

    The possibility of examining soft tissues by Raman spectroscopy is challenged in an attempt to probe human age for the changes in biochemical composition of skin that accompany aging. We present a proof-of-concept report for explicating the biophysical links between vibrational characteristics and the specific compositional and chemical changes associated with aging. The actual existence of such links is then phenomenologically proved. In an attempt to foster the basics for a quantitative use of Raman spectroscopy in assessing aging from human skin samples, a precise spectral deconvolution is performed as a function of donors' ages on five cadaveric samples, which emphasizes the physical significance and the morphological modifications of the Raman bands. The outputs suggest the presence of spectral markers for age identification from skin samples. Some of them appeared as authentic "biological clocks" for the apparent exactness with which they are related to age. Our spectroscopic approach yields clear compositional information of protein folding and crystallization of lipid structures, which can lead to a precise identification of age from infants to adults. Once statistically validated, these parameters might be used to link vibrational aspects at the molecular scale for practical forensic purposes.

  1. Raman spectroscopy of human skin: looking for a quantitative algorithm to reliably estimate human age.

    PubMed

    Pezzotti, Giuseppe; Boffelli, Marco; Miyamori, Daisuke; Uemura, Takeshi; Marunaka, Yoshinori; Zhu, Wenliang; Ikegaya, Hiroshi

    2015-06-01

    The possibility of examining soft tissues by Raman spectroscopy is challenged in an attempt to probe human age for the changes in biochemical composition of skin that accompany aging. We present a proof-of-concept report for explicating the biophysical links between vibrational characteristics and the specific compositional and chemical changes associated with aging. The actual existence of such links is then phenomenologically proved. In an attempt to foster the basics for a quantitative use of Raman spectroscopy in assessing aging from human skin samples, a precise spectral deconvolution is performed as a function of donors' ages on five cadaveric samples, which emphasizes the physical significance and the morphological modifications of the Raman bands. The outputs suggest the presence of spectral markers for age identification from skin samples. Some of them appeared as authentic "biological clocks" for the apparent exactness with which they are related to age. Our spectroscopic approach yields clear compositional information of protein folding and crystallization of lipid structures, which can lead to a precise identification of age from infants to adults. Once statistically validated, these parameters might be used to link vibrational aspects at the molecular scale for practical forensic purposes.

  2. Retinal nerve fiber bundle tracing and analysis in human eye by polarization sensitive OCT.

    PubMed

    Sugita, Mitsuro; Pircher, Michael; Zotter, Stefan; Baumann, Bernhard; Roberts, Philipp; Makihira, Tomoyuki; Tomatsu, Nobuhiro; Sato, Makoto; Vass, Clemens; Hitzenberger, Christoph K

    2015-03-01

    We present a new semi-automatic processing method for retinal nerve fiber bundle tracing based on polarization sensitive optical coherence tomography (PS-OCT) data sets. The method for tracing is based on a nerve fiber orientation map that covers the fovea and optic nerve head (ONH) regions. In order to generate the orientation map, two types of information are used: optic axis orientation based on polarization data, and complementary information obtained from nerve fiber layer (NFL) local thickness variation to reveal fiber bundle structures around the fovea. The corresponding two orientation maps are fused into a combined fiber orientation map. En face maps of NFL retardation, thickness, and unit-depth-retardation (UDR, equivalent to birefringence) are transformed into "along-trace" maps by using the obtained traces of the nerve fiber bundles. The method is demonstrated in the eyes of healthy volunteers, and as an example of further analyses utilizing this method, maps illustrating the gradients of NFL retardation, thickness, and UDR are demonstrated.

  3. Proteomics analysis of human tears from aqueous-deficient and evaporative dry eye patients

    PubMed Central

    Perumal, Natarajan; Funke, Sebastian; Pfeiffer, Norbert; Grus, Franz H.

    2016-01-01

    Despite the high global prevalence of dry eye syndrome (DES), the fundamental processes underlying this pathology remain largely unexplored. Therefore, this study endeavoured to investigate in-depth the tear proteome of DES patients employing the mass spectrometry (MS)-based proteomic strategies. Eighty patients were recruited and subdivided into three major DES subgroups, which are the aqueous-deficient (DRYaq), evaporative (DRYlip) and a combination of the two (DRYaqlip), as well as healthy subjects (CTRL). Discovery proteomics strategy was employed to identify large number of significantly differentially expressed tear proteins in DRYlip vs. CTRL, DRYaq vs. CTRL and DRYaqlip vs. CTRL with 22, 58 and 67 proteins, respectively. Biological functional analysis demonstrated for the first time that various metabolic processes were highly expressed in DRYaq and DRYaqlip, which might modulate various other known processes, especially the inflammatory and immune processes. Targeted proteomics strategy verified that 13 major proteins were differentially expressed in specific DES subgroups, comprising of PRR4, ZG16B, SCGB2A1, DMBT1, PROL1, LACRT, ALDH3A1, ENO1, TF, S100A8, S100A9, PEBP1 and ORM1. In conclusion, this study had explored in-depth the pathology of DES by unravelling various new fundamental processes and the major proteins responsible for the maintenance of tear film stability. PMID:27436115

  4. Theoretical effect of refractive error and accommodation on longitudinal chromatic aberration of the human eye.

    PubMed

    Atchison, D A; Smith, G; Waterworth, M D

    1993-09-01

    Simple formulas based on reduced eyes have been developed to predict the variation in longitudinal chromatic aberration with variation in ametropia or accommodation. Two formulas were developed, one for axial ametropia and one for refractive ametropia. The latter also served as a model for accommodation. The results using the formulas are in close agreement with results obtained using raytracing through more sophisticated models. Combining the results of different methods gives the following predictions of change in chromatic difference of focus, between wavelengths of 400 and 700 nm, with change in each diopter of refractive error or accommodation: axial ametropia 0.012 to 0.017 D (0.6 to 0.9%), refractive ametropia 0.05 D (2.2 to 2.4%), and accommodation 0.04 to 0.05 D (2.1 to 2.6%). The chromatic aberration effects of correcting lenses with low dispersion are intermediate in effect and opposite in sign to the effects of corresponding degrees of axial ametropia and refractive ametropia. PMID:8233365

  5. Retinal nerve fiber bundle tracing and analysis in human eye by polarization sensitive OCT.

    PubMed

    Sugita, Mitsuro; Pircher, Michael; Zotter, Stefan; Baumann, Bernhard; Roberts, Philipp; Makihira, Tomoyuki; Tomatsu, Nobuhiro; Sato, Makoto; Vass, Clemens; Hitzenberger, Christoph K

    2015-03-01

    We present a new semi-automatic processing method for retinal nerve fiber bundle tracing based on polarization sensitive optical coherence tomography (PS-OCT) data sets. The method for tracing is based on a nerve fiber orientation map that covers the fovea and optic nerve head (ONH) regions. In order to generate the orientation map, two types of information are used: optic axis orientation based on polarization data, and complementary information obtained from nerve fiber layer (NFL) local thickness variation to reveal fiber bundle structures around the fovea. The corresponding two orientation maps are fused into a combined fiber orientation map. En face maps of NFL retardation, thickness, and unit-depth-retardation (UDR, equivalent to birefringence) are transformed into "along-trace" maps by using the obtained traces of the nerve fiber bundles. The method is demonstrated in the eyes of healthy volunteers, and as an example of further analyses utilizing this method, maps illustrating the gradients of NFL retardation, thickness, and UDR are demonstrated. PMID:25798324

  6. Replicative senescence: the human fibroblast comes of age.

    PubMed

    Goldstein, S

    1990-09-01

    Human diploid fibroblasts undergo replicative senescence predominantly because of arrest at the G1/S boundary of the cell cycle. Senescent arrest resembles a process of terminal differentiation that appears to involve repression of proliferation-promoting genes with reciprocal new expression of antiproliferative genes, although post-transcriptional factors may also be involved. Identification of participating genes and clarification of their mechanisms of action will help to elucidate the universal cellular decline of biological aging and an important obverse manifestation, the rare escape of cells from senescence leading to immortalization and oncogenesis.

  7. Risk Factors for Four-Year Incidence and Progression of Age-Related Macular Degeneration: The Los Angeles Latino Eye Study

    PubMed Central

    CHOUDHURY, FARZANA; VARMA, ROHIT; MCKEAN-COWDIN, ROBERTA; KLEIN, RONALD; AZEN, STANLEY P.

    2011-01-01

    PURPOSE To identify risk factors for 4-year incidence and progression of age-related macular degeneration (AMD) in adult Latinos. DESIGN Population-based prospective cohort study. METHODS Participants, aged 40 or older, from The Los Angeles Latino Eye Study (LALES) underwent standardized comprehensive ophthalmologic examinations at baseline and at 4 years of follow-up. Age-related macular degeneration was detected by grading 30-degree stereoscopic fundus photographs using the modified Wisconsin Age-Related Maculopathy Grading System. Multivariate stepwise logistic regression was used to examine the independent association of incidence and progression of AMD and baseline sociodemographic, behavioral, clinical, and ocular characteristics. RESULTS Multivariate analyses revealed that older age (OR per decade of age: 1.52; 95% CI: 1.29, 1.85) and higher pulse pressure (OR per 10 mm Hg: 2.54; 95% CI: 1.36, 4.76) were independently associated with the incidence of any AMD. The same factors were associated with early AMD, soft indistinct drusen, and retinal pigmentary abnormalities. Additionally, presence of clinically diagnosed diabetes mellitus was independently associated with increased retinal pigment (OR: 1.66; 95% CI: 1.01, 2.85), and male gender was associated with retinal pigment epithelial depigmentation (OR 2.50; 95% CI: 1.48, 4.23). Older age (OR per decade of age: 2.20; 95% CI: 1.82, 2.67) and current smoking (OR: 2.85; 95% CI: 1.66, 4.90) were independently associated with progression of AMD. CONCLUSIONS Several modifiable risk factors were associated with 4-year incidence and progression of AMD in Latinos. The results suggest that interventions aimed at reducing pulse pressure and promoting smoking cessation may reduce incidence and progression of AMD, respectively. PMID:21679916

  8. Human stem cells as targets for the aging and diseases of aging processes.

    PubMed

    Trosko, James E

    2003-03-01

    While many theories have been proposed for the aging process, and many debates on the matter of aging and the diseases of aging being either the result of the same or independent processes, most have not considered humans as a hierarchical system made up of cybernetically interacting levels of organization. To understand the aging process and the diseases of aging, one must view the human as the result of the total genomic DNA in the single fertilized egg that proliferates, differentiates and develops into an individual of about 100 trillion cells, organized by different cell types (pluri-potent stem cells, progenitor stem cells, terminally differentiated cells) into multiple tissue, organ and organ systems which interact with each other via endogenous factors and with exogenous factors. Our hypothesis is that both aging and diseases of aging are dependent of the normal functioning of the pluri-potent stem cell pool. Specifically, the concept involves the cybernetic feedback between the 'quantity' of the stem cell pool in each tissue niche with the 'quality' of the stem cells in the pool. The process of gap junctional inter-cellular communication (GJIC), which has been implicated in the evolution from the single cell organism to the multi-cellular organisms, requiring growth control, differentiation, apoptosis, adaptive response capability of differentiated cells and senescence, is speculated to be a shared mechanism in stem cell biology and in many chronic disease processes (teratogenesis; carcinogenesis, atherogenesis, diabetigenesis, etc.). Specifically, stem cells are assumed to be 'immortal' until induced to express their connexin genes and have functional GJIC, at which time they can differentiate and become 'mortal'. As long as the stem cells are communicating with their differentiated daughters via some extra-cellular soluble negative growth factor, the homeostatic control of their growth and differentiation is maintained for the organism. However, if the

  9. Sympathetic activity during passive heat stress in healthy aged humans

    PubMed Central

    Gagnon, Daniel; Schlader, Zachary J; Crandall, Craig G

    2015-01-01

    Abstract Cardiovascular adjustments during heat stress are generally attenuated in healthy aged humans, which could be due to lower increases in sympathetic activity compared to the young. We compared muscle sympathetic nerve activity (MSNA) between 11 young (Y: 28 ± 4 years) and 10 aged (A: 70 ± 5 years) subjects prior to and during passive heating. Furthermore, MSNA responses were compared when a cold pressor test (CPT) and lower body negative pressure (LBNP) were superimposed upon heating. Baseline MSNA burst frequency (Y: 15 ± 4 vs. A: 31 ± 3 bursts min−1, P ≤ 0.01) and burst incidence (Y: 26 ± 8 vs. A: 50 ± 7 bursts (100 cardiac cycles (CC))−1, P ≤ 0.01) were greater in the aged. Heat stress increased core temperature to a similar extent in both groups (Y: +1.2 ± 0.1 vs. A: +1.2 ± 0.0°C, P = 0.99). Absolute levels of MSNA remained greater in the aged during heat stress (burst frequency: Y: 47 ± 6 vs. A: 63 ± 11 bursts min−1, P ≤ 0.01; burst incidence: Y: 48 ± 8 vs. A: 67 ± 9 bursts (100 CC)−1, P ≤ 0.01); however, the increase in both variables was similar between groups (both P ≥ 0.1). The CPT and LBNP further increased MSNA burst frequency and burst incidence, although the magnitude of increase was similar between groups (both P ≥ 0.07). These results suggest that increases in sympathetic activity during heat stress are not attenuated in healthy aged humans. Key points Cardiovascular adjustments to heat stress are attenuated in healthy aged individuals, which could contribute to their greater prevalence of heat-related illnesses and deaths during heat waves. The attenuated cardiovascular adjustments in the aged could be due to lower increases in sympathetic nerve activity during heat stress. We examined muscle sympathetic nerve activity (MSNA) and plasma catecholamine concentrations in healthy young and aged individuals during whole-body passive heat stress. The main finding

  10. Wave-front aberrations in the anterior corneal surface and the whole eye.

    PubMed

    He, Ji C; Gwiazda, Jane; Thorn, Frank; Held, Richard

    2003-07-01

    In order to investigate the sources of wave-front aberrations in the human eye, we have measured the aberrations of the anterior cornea and the whole eye using a topographic system and a psychophysical wave-front sensor. We have also calculated the aberrations for the internal optics of both eyes of 45 young subjects (aged 9 to 29 years). The mean rms for the anterior cornea was similar to that for the internal optics and thewhole eye when astigmatism was included, but less than that for both the internal optics and the whole eye with astigmatism removed. For eyes with low whole-eye rms values, mean rms for the anterior cornea was greater than that for the whole eye, suggesting that the anterior corneal aberration is partially compensated by the internal optics of the eye to produce the low whole-eye rms. For eyes with larger whole-eye rms values, the rms values for both the anterior cornea and the internal optics were less than that for the whole eye. Thus the aberrations for the two elements tend to be primarily additive. This pattern exists whether or not astigmatism was included in the wave-front aberration rms. For individual Zernike terms, astigmatism and spherical aberration in the anterior cornea were partially compensated by internal optics, while some other Zernike terms showed addition between the anterior cornea and internal optics. Individual eyes show different combinations of compensation and addition across different Zernike terms. Our data suggest that the reported loss of internal compensation for anterior corneal aberrations in elderly eyes with large whole-eye aberrations [J. Opt. Soc. Am. A 19, 137 (2002)] may also occur in young eyes.

  11. Eye Protection

    PubMed Central

    Pashby, Tom

    1986-01-01

    Eye injuries frequently occur in the home, at work and at play. Many result in legally blind eyes, and most are preventable. Awareness of potential hazards is essential to preventing eye injuries, particularly in children. In addition, protective devices must be used appropriately. We have developed eye protectors that have proved effective in reducing both the overall incidence and the severity of sports eye injuries. ImagesFigures 2a, bFigure 3Figures 4a, b, c, dFigure 5 PMID:21267100

  12. Does Rebound Tonometry Probe Misalignment Modify Intraocular Pressure Measurements in Human Eyes?

    PubMed Central

    Beasley, Ian G.; Laughton, Deborah S.; Coldrick, Benjamin J.; Drew, Thomas E.; Sallah, Marium; Davies, Leon N.

    2013-01-01

    Purpose. To examine the influence of positional misalignments on intraocular pressure (IOP) measurement with a rebound tonometer. Methods. Using the iCare rebound tonometer, IOP readings were taken from the right eye of 36 healthy subjects at the central corneal apex (CC) and compared to IOP measures using the Goldmann applanation tonometer (GAT). Using a bespoke rig, iCare IOP readings were also taken 2 mm laterally from CC, both nasally and temporally, along with angular deviations of 5 and 10 degrees, both nasally and temporally to the visual axis. Results. Mean IOP ± SD, as measured by GAT, was 14.7 ± 2.5 mmHg versus iCare tonometer readings of 17.4 ± 3.6 mmHg at CC, representing an iCare IOP overestimation of 2.7 ± 2.8 mmHg (P < 0.001), which increased at higher average IOPs. IOP at CC using the iCare tonometer was not significantly different to values at lateral displacements. IOP was marginally underestimated with angular deviation of the probe but only reaching significance at 10 degrees nasally. Conclusions. As shown previously, the iCare tonometer overestimates IOP compared to GAT. However, IOP measurement in normal, healthy subjects using the iCare rebound tonometer appears insensitive to misalignments. An IOP underestimation of <1 mmHg with the probe deviated 10 degrees nasally reached statistical but not clinical significance levels. PMID:24073330

  13. Mapping human resources for eye health in 21 countries of sub-Saharan Africa: current progress towards VISION 2020

    PubMed Central

    2014-01-01

    Background Development of human resources for eye health (HReH) is a major focus of the Global Action Plan 2014 to 2019 to reduce the prevalence of avoidable visual impairment by 25% by the year 2019. The eye health workforce is thought to be much smaller in sub-Saharan Africa than in other regions of the world but data to support this for policy-making is scarce. We collected HReH and cataract surgeries data from 21 countries in sub-Sahara to estimate progress towards key suggested population-based VISION 2020 HReH indicators and cataract surgery rates (CSR) in 2011. Methods Routinely collected data on practitioner and surgery numbers in 2011 was requested from national eye care coordinators via electronic questionnaires. Telephone and e-mail discussions were used to determine data collection strategies that fit the national context and to verify reported data quality. Information was collected on six practitioner cadres: ophthalmologists, cataract surgeons, ophthalmic clinical officers, ophthalmic nurses, optometrists and ‘mid-level refractionists’ and combined with publicly available population data to calculate practitioner to population ratios and CSRs. Associations with development characteristics were conducted using Wilcoxon rank sum tests and Spearman rank correlations. Results HReH data was not easily available. A minority of countries had achieved the suggested VISION 2020 targets in 2011; five countries for ophthalmologists/cataract surgeons, four for ophthalmic nurses/clinical officers and two for CSR. All countries were below target for optometrists, even when other cadres who perform refractions as a primary duty were considered. The regional (sample) ratio for surgeons (ophthalmologists and cataract surgeons) was 2.9 per million population, 5.5 for ophthalmic clinical officers and nurses, 3.7 for optometrists and other refractionists, and 515 for CSR. A positive correlation between GDP and CSR as well as many practitioner ratios was observed

  14. Gut Bifidobacteria Populations in Human Health and Aging

    PubMed Central

    Arboleya, Silvia; Watkins, Claire; Stanton, Catherine; Ross, R. Paul

    2016-01-01

    The intestinal microbiota has increasingly been shown to have a vital role in various aspects of human health. Indeed, several studies have linked alterations in the gut microbiota with the development of different diseases. Among the vast gut bacterial community, Bifidobacterium is a genus which dominates the intestine of healthy breast-fed infants whereas in adulthood the levels are lower but relatively stable. The presence of different species of bifidobacteria changes with age, from childhood to old age. Bifidobacterium longum, B. breve, and B. bifidum are generally dominant in infants, whereas B. catenulatum, B. adolescentis and, as well as B. longum are more prevalent in adults. Increasingly, evidence is accumulating which shows beneficial effects of supplementation with bifidobacteria for the improvement of human health conditions ranging from protection against infection to different extra- and intra-intestinal positive effects. Moreover, bifidobacteria have been associated with the production of a number of potentially health promoting metabolites including short chain fatty acids, conjugated linoleic acid and bacteriocins. The aim of this mini-review is to describe the bifidobacteria compositional changes associated with different stages in life, highlighting their beneficial role, as well as their presence or absence in many disease states.

  15. Gut Bifidobacteria Populations in Human Health and Aging

    PubMed Central

    Arboleya, Silvia; Watkins, Claire; Stanton, Catherine; Ross, R. Paul

    2016-01-01

    The intestinal microbiota has increasingly been shown to have a vital role in various aspects of human health. Indeed, several studies have linked alterations in the gut microbiota with the development of different diseases. Among the vast gut bacterial community, Bifidobacterium is a genus which dominates the intestine of healthy breast-fed infants whereas in adulthood the levels are lower but relatively stable. The presence of different species of bifidobacteria changes with age, from childhood to old age. Bifidobacterium longum, B. breve, and B. bifidum are generally dominant in infants, whereas B. catenulatum, B. adolescentis and, as well as B. longum are more prevalent in adults. Increasingly, evidence is accumulating which shows beneficial effects of supplementation with bifidobacteria for the improvement of human health conditions ranging from protection against infection to different extra- and intra-intestinal positive effects. Moreover, bifidobacteria have been associated with the production of a number of potentially health promoting metabolites including short chain fatty acids, conjugated linoleic acid and bacteriocins. The aim of this mini-review is to describe the bifidobacteria compositional changes associated with different stages in life, highlighting their beneficial role, as well as their presence or absence in many disease states. PMID:27594848

  16. Gut Bifidobacteria Populations in Human Health and Aging.

    PubMed

    Arboleya, Silvia; Watkins, Claire; Stanton, Catherine; Ross, R Paul

    2016-01-01

    The intestinal microbiota has increasingly been shown to have a vital role in various aspects of human health. Indeed, several studies have linked alterations in the gut microbiota with the development of different diseases. Among the vast gut bacterial community, Bifidobacterium is a genus which dominates the intestine of healthy breast-fed infants whereas in adulthood the levels are lower but relatively stable. The presence of different species of bifidobacteria changes with age, from childhood to old age. Bifidobacterium longum, B. breve, and B. bifidum are generally dominant in infants, whereas B. catenulatum, B. adolescentis and, as well as B. longum are more prevalent in adults. Increasingly, evidence is accumulating which shows beneficial effects of supplementation with bifidobacteria for the improvement of human health conditions ranging from protection against infection to different extra- and intra-intestinal positive effects. Moreover, bifidobacteria have been associated with the production of a number of potentially health promoting metabolites including short chain fatty acids, conjugated linoleic acid and bacteriocins. The aim of this mini-review is to describe the bifidobacteria compositional changes associated with different stages in life, highlighting their beneficial role, as well as their presence or absence in many disease states. PMID:27594848

  17. Aging of microstructural compartments in human compact bone

    NASA Technical Reports Server (NTRS)

    Akkus, Ozan; Polyakova-Akkus, Anna; Adar, Fran; Schaffler, Mitchell B.

    2003-01-01

    Composition of microstructural compartments in compact bone of aging male subjects was assessed using Raman microscopy. Secondary mineralization of unremodeled fragments persisted for two decades. Replacement of these tissue fragments with secondary osteons kept mean composition constant over age, but at a fully mineralized limit. Slowing of remodeling may increase fracture susceptibility through an increase in proportion of highly mineralized tissue. In this study, the aging process in the microstructural compartments of human femoral cortical bone was investigated and related to changes in the overall tissue composition within the age range of 17-73 years. Raman microprobe analysis was used to assess the mineral content, mineral crystallinity, and carbonate substitution in fragments of primary lamellar bone that survived remodeling for decades. Tissue composition of the secondary osteonal population was investigated to determine the composition of turned over tissue volume. Finally, Raman spectral analysis of homogenized tissue was performed to evaluate the effects of unremodeled and newly formed tissue on the overall tissue composition. The chemical composition of the primary lamellar bone exhibited two chronological stages. Organic matrix became more mineralized and the crystallinity of the mineral improved during the first stage, which lasted for two decades. The mineral content and the mineral crystallinity did not vary during the second stage. The results for the primary lamellar bone demonstrated that physiological mineralization, as evidenced by crystal growth and maturation, is a continuous process that may persist as long as two decades, and the growth and maturation process stops after the organic matrix becomes "fully mineralized." The average mineral content and the average mineral crystallinity of the homogenized tissue did not change with age. It was also observed that the mineral content of the homogenized tissue was consistently greater than the

  18. A randomised controlled trial investigating the effect of nutritional supplementation on visual function in normal, and age-related macular disease affected eyes: design and methodology [ISRCTN78467674

    PubMed Central

    Bartlett, Hannah; Eperjesi, Frank

    2003-01-01

    Background Age-related macular disease is the leading cause of blind registration in the developed world. One aetiological hypothesis involves oxidation, and the intrinsic vulnerability of the retina to damage via this process. This has prompted interest in the role of antioxidants, particularly the carotenoids lutein and zeaxanthin, in the prevention and treatment of this eye disease. Methods The aim of this randomised controlled trial is to determine the effect of a nutritional supplement containing lutein, vitamins A, C and E, zinc, and copper on measures of visual function in people with and without age-related macular disease. Outcome measures are distance and near visual acuity, contrast sensitivity, colour vision, macular visual field, glare recovery, and fundus photography. Randomisation is achieved via a random number generator, and masking achieved by third party coding of the active and placebo containers. Data collection will take place at nine and 18 months, and statistical analysis will employ Student's t test. Discussion A paucity of treatment modalities for age-related macular disease has prompted research into the development of prevention strategies. A positive effect on normals may be indicative of a role of nutritional supplementation in preventing or delaying onset of the condition. An observed benefit in the age-related macular disease group may indicate a potential role of supplementation in prevention of progression, or even a degree reversal of the visual effects caused by this condition. PMID:14594455

  19. Maladaptive bias for extrahippocampal navigation strategies in aging humans.

    PubMed

    Wiener, Jan M; de Condappa, Olivier; Harris, Mathew A; Wolbers, Thomas

    2013-04-01

    Efficient spatial navigation requires not only accurate spatial knowledge but also the selection of appropriate strategies. Using a novel paradigm that allowed us to distinguish between beacon, associative cue, and place strategies, we investigated the effects of cognitive aging on the selection and adoption of navigation strategies in humans. Participants were required to rejoin a previously learned route encountered from an unfamiliar direction. Successful performance required the use of an allocentric place strategy, which was increasingly observed in young participants over six experimental sessions. In contrast, older participants, who were able to recall the route when approaching intersections from the same direction as during encoding, failed to use the correct place strategy when approaching intersections from novel directions. Instead, they continuously used a beacon strategy and showed no evidence of changing their behavior across the six sessions. Given that this bias was already apparent in the first experimental session, the inability to adopt the correct place strategy is not related to an inability to switch from a firmly established response strategy to an allocentric place strategy. Rather, and in line with previous research, age-related deficits in allocentric processing result in shifts in preferred navigation strategies and an overall bias for response strategies. The specific preference for a beacon strategy is discussed in the context of a possible dissociation between beacon-based and associative-cue-based response learning in the striatum, with the latter being more sensitive to age-related changes.

  20. Establishing Age-Adjusted Reference Ranges for Iris-Related Parameters in Open Angle Eyes with Anterior Segment Optical Coherence Tomography

    PubMed Central

    Peterson, Jeffrey R.; Blieden, Lauren S.; Chuang, Alice Z.; Baker, Laura A.; Rigi, Mohammed; Feldman, Robert M.; Bell, Nicholas P.

    2016-01-01

    Purpose Define criteria for iris-related parameters in an adult open angle population as measured with swept source Fourier domain anterior segment optical coherence tomography (ASOCT). Methods Ninety-eight eyes of 98 participants with open angles were included and stratified into 5 age groups (18–35, 36–45, 46–55, 56–65, and 66–79 years). ASOCT scans with 3D mode angle analysis were taken with the CASIA SS-1000 (Tomey Corporation, Nagoya, Japan) and analyzed using the Anterior Chamber Analysis and Interpretation software. Anterior iris surface length (AISL), length of scleral spur landmark (SSL) to pupillary margin (SSL-to-PM), iris contour ratio (ICR = AISL/SSL-to-PM), pupil radius, radius of iris centroid (RICe), and iris volume were measured. Outcome variables were summarized for all eyes and age groups, and mean values among age groups were compared using one-way analysis of variance. Stepwise regression analysis was used to investigate demographic and ocular characteristic factors that affected each iris-related parameter. Results Mean (±SD) values were 2.24 mm (±0.46), 4.06 mm (±0.27), 3.65 mm (±0.48), 4.16 mm (±0.47), 1.14 (±0.04), 1.51 mm2 (±0.23), and 38.42 μL (±4.91) for pupillary radius, RICe, SSL-to-PM, AISL, ICR, iris cross-sectional area, and iris volume, respectively. Both pupillary radius (P = 0.002) and RICe (P = 0.027) decreased with age, while SSL-to-PM (P = 0.002) and AISL increased with age (P = 0.001). ICR (P = 0.54) and iris volume (P = 0.49) were not affected by age. Conclusion This study establishes reference values for iris-related parameters in an adult open angle population, which will be useful for future studies examining the role of iris changes in pathologic states. PMID:26815917

  1. Effects of Long-Term Exposure to 60 GHz Millimeter-Wavelength Radiation on the Genotoxicity and Heat Shock Protein (Hsp) Expression of Cells Derived from Human Eye.

    PubMed

    Koyama, Shin; Narita, Eijiro; Shimizu, Yoko; Suzuki, Yukihisa; Shiina, Takeo; Taki, Masao; Shinohara, Naoki; Miyakoshi, Junji

    2016-01-01

    Human corneal epithelial (HCE-T) and human lens epithelial (SRA01/04) cells derived from the human eye were exposed to 60 gigahertz (GHz) millimeter-wavelength radiation for 24 h. There was no statistically significant increase in the micronucleus (MN) frequency in cells exposed to 60 GHz millimeter-wavelength radiation at 1 mW/cm² compared with sham-exposed controls and incubator controls. The MN frequency of cells treated with bleomycin for 1 h provided positive controls. The comet assay, used to detect DNA strand breaks, and heat shock protein (Hsp) expression also showed no statistically significant effects of exposure. These results indicate that exposure to millimeter-wavelength radiation has no effect on genotoxicity in human eye cells. PMID:27509516

  2. Effects of Long-Term Exposure to 60 GHz Millimeter-Wavelength Radiation on the Genotoxicity and Heat Shock Protein (Hsp) Expression of Cells Derived from Human Eye.

    PubMed

    Koyama, Shin; Narita, Eijiro; Shimizu, Yoko; Suzuki, Yukihisa; Shiina, Takeo; Taki, Masao; Shinohara, Naoki; Miyakoshi, Junji

    2016-01-01

    Human corneal epithelial (HCE-T) and human lens epithelial (SRA01/04) cells derived from the human eye were exposed to 60 gigahertz (GHz) millimeter-wavelength radiation for 24 h. There was no statistically significant increase in the micronucleus (MN) frequency in cells exposed to 60 GHz millimeter-wavelength radiation at 1 mW/cm² compared with sham-exposed controls and incubator controls. The MN frequency of cells treated with bleomycin for 1 h provided positive controls. The comet assay, used to detect DNA strand breaks, and heat shock protein (Hsp) expression also showed no statistically significant effects of exposure. These results indicate that exposure to millimeter-wavelength radiation has no effect on genotoxicity in human eye cells.

  3. Effects of Long-Term Exposure to 60 GHz Millimeter-Wavelength Radiation on the Genotoxicity and Heat Shock Protein (Hsp) Expression of Cells Derived from Human Eye

    PubMed Central

    Koyama, Shin; Narita, Eijiro; Shimizu, Yoko; Suzuki, Yukihisa; Shiina, Takeo; Taki, Masao; Shinohara, Naoki; Miyakoshi, Junji

    2016-01-01

    Human corneal epithelial (HCE-T) and human lens epithelial (SRA01/04) cells derived from the human eye were exposed to 60 gigahertz (GHz) millimeter-wavelength radiation for 24 h. There was no statistically significant increase in the micronucleus (MN) frequency in cells exposed to 60 GHz millimeter-wavelength radiation at 1 mW/cm2 compared with sham-exposed controls and incubator controls. The MN frequency of cells treated with bleomycin for 1 h provided positive controls. The comet assay, used to detect DNA strand breaks, and heat shock protein (Hsp) expression also showed no statistically significant effects of exposure. These results indicate that exposure to millimeter-wavelength radiation has no effect on genotoxicity in human eye cells. PMID:27509516

  4. Rejuvenation of senescent cells-the road to postponing human aging and age-related disease?

    PubMed

    Sikora, Ewa

    2013-07-01

    Cellular senescence is the state of permanent inhibition of cell proliferation. Replicative senescence occurs due to the end replication problem and shortening telomeres with each cell division leading to DNA damage response (DDR). The number of short telomeres increases with age and age-related pathologies. Stress induced senescence, although not accompanied by attrition of telomeres, is also attributed to the DDR induced by irreparable DNA lesions in telomeric DNA. Senescent cells characterized by the presence of γH2AX, the common marker of double DNA strand breaks, and other senescence markers including activity of SA-β-gal, accumulate in tissues of aged animals and humans as well as at sites of pathology. It is believed that cellular senescence evolved as a cancer barrier since non-proliferating senescent cells cannot be transformed to neoplastic cells. On the other hand senescent cells favor cancer development, just like other age-related pathologies, by creating a low grade inflammatory state due to senescence associated secretory phenotype (SASP). Reversal/inhibition of cellular senescence could prolong healthy life span, thus many attempts have been undertaken to influence cellular senescence. The two main approaches are genetic and pharmacological/nutritional modifications of cell fate. The first one concerns cell reprogramming by induced pluripotent stem cells (iPSCs), which in vitro is effective even in cells undergoing senescence, or derived from very old or progeroid patients. The second approach concerns modification of senescence signaling pathways just like TOR-induced by pharmacological or with natural agents. However, knowing that aging is unavoidable we cannot expect its elimination, but prolonging healthy life span is a goal worth serious consideration. PMID:23064316

  5. Long-Term Visual Outcomes for a Treat and Extend Anti-Vascular Endothelial Growth Factor Regimen in Eyes with Neovascular Age-Related Macular Degeneration

    PubMed Central

    Mrejen, Sarah; Jung, Jesse J.; Chen, Christine; Patel, Samir N.; Gallego-Pinazo, Roberto; Yannuzzi, Nicolas; Xu, Luna; Marsiglia, Marcela; Boddu, Sucharita; Freund, K. Bailey

    2015-01-01

    With the advent of anti-vascular endothelial growth factor (VEGF) therapy, clinicians are now focused on various treatment strategies to better control neovascular age-related macular degeneration (NVAMD), a leading cause of irreversible blindness. Herein, we retrospectively reviewed consecutive patients with treatment-naïve NVAMD initially classified based on fluorescein angiography (FA) alone or with an anatomic classification utilizing both FA and optical coherence tomography (OCT) and correlated long-term visual outcomes of these patients treated with an anti-VEGF Treat-and-Extend Regimen (TER) with baseline characteristics including neovascular phenotype. Overall, 185 patients (210 eyes) were followed over an average of 3.5 years (range 1–6.6) with a retention rate of 62.9%, and visual acuity significantly improved with a TER that required a mean number of 8.3 (±1.6) (± standard deviation) intravitreal anti-VEGF injections/year (range 4–13). The number of injections and the anatomic classification were independent predictors of visual acuity at 6 months, 1, 2, 3 and 4 years. Patients with Type 1 neovascularization had better visual outcomes and received more injections than the other neovascular subtypes. There were no serious adverse events. A TER provided sustained long-term visual gains. Eyes with Type 1 neovascularization had better visual outcomes than those with other neovascular subtypes. PMID:26239682

  6. Long-Term Visual Outcomes for a Treat and Extend Anti-Vascular Endothelial Growth Factor Regimen in Eyes with Neovascular Age-Related Macular Degeneration.

    PubMed

    Mrejen, Sarah; Jung, Jesse J; Chen, Christine; Patel, Samir N; Gallego-Pinazo, Roberto; Yannuzzi, Nicolas; Xu, Luna; Marsiglia, Marcela; Boddu, Sucharita; Freund, K Bailey

    2015-01-01

    With the advent of anti-vascular endothelial growth factor (VEGF) therapy, clinicians are now focused on various treatment strategies to better control neovascular age-related macular degeneration (NVAMD), a leading cause of irreversible blindness. Herein, we retrospectively reviewed consecutive patients with treatment-naïve NVAMD initially classified based on fluorescein angiography (FA) alone or with an anatomic classification utilizing both FA and optical coherence tomography (OCT) and correlated long-term visual outcomes of these patients treated with an anti-VEGF Treat-and-Extend Regimen (TER) with baseline characteristics including neovascular phenotype. Overall, 185 patients (210 eyes) were followed over an average of 3.5 years (range 1-6.6) with a retention rate of 62.9%, and visual acuity significantly improved with a TER that required a mean number of 8.3 (±1.6) (± standard deviation) intravitreal anti-VEGF injections/year (range 4-13). The number of injections and the anatomic classification were independent predictors of visual acuity at 6 months, 1, 2, 3 and 4 years. Patients with Type 1 neovascularization had better visual outcomes and received more injections than the other neovascular subtypes. There were no serious adverse events. A TER provided sustained long-term visual gains. Eyes with Type 1 neovascularization had better visual outcomes than those with other neovascular subtypes. PMID:26239682