Senescent changes in human ? vision have been well documented, but the factors responsible for these changes ? are only partially understood. The proposed research is intended to provide ? fundamental data on aging of the human visual system using psychophysical ? methods that separate the relative contributions of optical and neural ? mechanisms. Because much of the sensitivity loss of cone pathways occurs at ? early stages of processing, we will examine age-related losses in cone ? photopigment optical density in the central 10 degree of retina for normal and ? sex-linked dichromats whose genes have been sequenced to look for genetic ? correlates of photopigment optical density and receptor """"""""longevity."""""""" It is ? hypothesized that senescent changes in cone photopigment density will not be ? uniform with retinal eccentricity, and the outcome of this experiment will be ? important for theoretical and practical reasons.
A second aim of the proposed ? research is to quantify senescent changes in the temporal properties of ? isolated color mechanisms through measurements of the temporal contrast ? sensitivity function and the impulse response function.
The third aim i s to ? determine senescent changes in spatial properties of isolated color mechanisms ? through measurements of the area of complete spatial summation (Ricco's area). ? Age-related changes in spatial summation are predicted based on our previous ? work, and documented losses of retinal ganglion cells with age, but we do not ? know whether this will be found in all color pathways.
The fourth aim i s also ? concerned with spatial properties of rod and cone pathways, but will measure ? spatial contrast sensitivity functions for isolated mechanisms.
The final aim ? is based on our previous work showing that, at a perceptual level, the visual ? system employs mechanisms that compensate, in part, for losses in sensitivity ? at lower levels. Color appearance mechanisms will be proved by measurements of ? age-related changes in chromatic perceptive fields over areas of retina ? associated with different relative losses of cones and ganglion cells. ? Sensitivity of isolated cone mechanisms and color appearance will be measured ? for individuals before and after cataract extraction and implantation of ? intra-ocular lenses. These experiments will provide new information on ? mechanisms that promote color constancy despite substantial variations in the ? retinal image due to lenticular senescence. Each of these alms will include ? detailed tests of individual younger and older observers, and measurement on ? selected conditions with a large group of individuals ranging in age from ? approximately 12 to 85 years. In addition to providing basic data on the aging ? visual system, the experiments will provide probes for models of how the visual ? system adapts and compensates for degradations in the optical and neural images ? that occur with senescence and disease.
| Panorgias, Athanasios; Tillman, Megan; Sutter, Erich E et al. (2017) Senescent Changes and Topography of the Dark-Adapted Multifocal Electroretinogram. Invest Ophthalmol Vis Sci 58:1323-1329 |
| Shinomori, Keizo; Panorgias, Athanasios; Werner, John S (2016) Discrimination thresholds of normal and anomalous trichromats: Model of senescent changes in ocular media density on the Cambridge Colour Test. J Opt Soc Am A Opt Image Sci Vis 33:A65-76 |
| Tregillus, Katherine E M; Werner, John S; Webster, Michael A (2016) Adjusting to a sudden “aging” of the lens. J Opt Soc Am A Opt Image Sci Vis 33:A129-36 |
| Winkler, Alissa D; Spillmann, Lothar; Werner, John S et al. (2015) Asymmetries in blue-yellow color perception and in the color of 'the dress'. Curr Biol 25:R547-8 |
| Panorgias, Athanasios; Zawadzki, Robert J; Capps, Arlie G et al. (2013) Multimodal assessment of microscopic morphology and retinal function in patients with geographic atrophy. Invest Ophthalmol Vis Sci 54:4372-84 |
| Parkosadze, Khatuna; Kalmakhelidze, Teona; Tolmacheva, Marina et al. (2013) Persistent biases in subjective image focus following cataract surgery. Vision Res 89:10-7 |
| O'Neil, Sean F; McDermott, Kyle C; Mizokami, Yoko et al. (2012) Tests of a functional account of the Abney effect. J Opt Soc Am A Opt Image Sci Vis 29:A165-73 |
| Elliott, Sarah L; Werner, John S; Webster, Michael A (2012) Individual and age-related variation in chromatic contrast adaptation. J Vis 12:11 |
| Shinomori, Keizo; Werner, John S (2012) Aging of human short-wave cone pathways. Proc Natl Acad Sci U S A 109:13422-7 |
| Werner, J S; Keltner, J L; Zawadzki, R J et al. (2011) Outer retinal abnormalities associated with inner retinal pathology in nonglaucomatous and glaucomatous optic neuropathies. Eye (Lond) 25:279-89 |
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