Historically, investigations of """"""""reduced"""""""" visual systems have made valuable contributions to our knowledge of normal vision; for example, studies of color vision anomalies were important in the development of the trichromatic basis of normal color vision. Analogously, our understanding of binocular vision processes should benefit from investigations of subjects with reduced stereopsis. The present application, therefore, proposes investigations of positional disparity processing in monkeys with stereo-deficiencies which occur as a consequence of abnormal binocular visual experience, during early life. Three experimental rearing procedures will be used, each of which causes anomalies of binocular vision without significant secondary anomalies (strabismus or amblyopia). (1) Short-term bilateral form deprivation, to uniformly prevent adequate stimulation of all disparity processing systems. (2) Short-term optical dissociation of binocular vision, which presumably alters binocular vision through suppression mechanisms. (3) Long-term unilateral, alternating, defocus to selectively degrade binocular positional disparities, without permanent alterations of monocular spatial vision. The assessment of the vision of the control and experimental monkeys will involve a series of psychophysical measurements of basic functions of monocular (spatial contrast sensitivity and the accuracy and precision of fixation) and binocular vision (interocular alignment, fusional vergence ranges, binocular summation for spatial gratings, local steropsis with narrow-band, spatially filtered stimuli, and global stereopsis with dynamic random-dot stereograms). Correlations of the results of the various functional measures should significantly increase our knowledge of normal binocular vision, with respect to the nature of the interactions between disparity vergence and stereopsis, the independence of crossed and uncrossed disparity mechanisms, the functional differentiation between fine and coarse stereopsis, and the dependence of global stereopsis on normal local stereopsis mechanisms. In addition, the results of these studies should provide new insights into the dysfunctions of binocular vision associated with strabismus and amblyopia in children.

National Institute of Health (NIH)
National Eye Institute (NEI)
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Visual Sciences B Study Section (VISB)
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University of Houston
Schools of Optometry/Ophthalmol
United States
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Patel, Nimesh; McAllister, Faith; Pardon, Laura et al. (2018) The effects of graded intraocular pressure challenge on the optic nerve head. Exp Eye Res 169:79-90
McAllister, Faith; Harwerth, Ronald; Patel, Nimesh (2018) Assessing the True Intraocular Pressure in the Non-human Primate. Optom Vis Sci 95:113-119
Patel, Nimesh B; Hung, Li-Fang; Harwerth, Ronald S (2017) Postnatal maturation of the fovea in Macaca mulatta using optical coherence tomography. Exp Eye Res 164:8-21
Ivers, Kevin M; Sredar, Nripun; Patel, Nimesh B et al. (2015) In Vivo Changes in Lamina Cribrosa Microarchitecture and Optic Nerve Head Structure in Early Experimental Glaucoma. PLoS One 10:e0134223
Patel, Nimesh B; Sullivan-Mee, Michael; Harwerth, Ronald S (2014) The relationship between retinal nerve fiber layer thickness and optic nerve head neuroretinal rim tissue in glaucoma. Invest Ophthalmol Vis Sci 55:6802-16
Patel, Nimesh B; Lim, Mimi; Gajjar, Avni et al. (2014) Age-associated changes in the retinal nerve fiber layer and optic nerve head. Invest Ophthalmol Vis Sci 55:5134-43
Luo, Xunda; Patel, Nimesh B; Rajagopalan, Lakshmi P et al. (2014) Relation between macular retinal ganglion cell/inner plexiform layer thickness and multifocal electroretinogram measures in experimental glaucoma. Invest Ophthalmol Vis Sci 55:4512-24
Hanlon, Samuel D; Smith, C Wayne; Sauter, Marika N et al. (2014) Integrin-dependent neutrophil migration in the injured mouse cornea. Exp Eye Res 120:61-70
Patel, Nimesh B; Garcia, Brenda; Harwerth, Ronald S (2012) Influence of anterior segment power on the scan path and RNFL thickness using SD-OCT. Invest Ophthalmol Vis Sci 53:5788-98
Wheat, Joe L; Rangaswamy, Nalini V; Harwerth, Ronald S (2012) Correlating RNFL thickness by OCT with perimetric sensitivity in glaucoma patients. J Glaucoma 21:95-101

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