In eyes with prolonged visual deprivation induced by the abnormally large optical defects such as aberrations, the actual visual performance after precise correction of remaining aberrations is significantly poorer than that predicted from optical theory and that measured in normal eyes. This unexplained vision loss suggests that the degraded image quality received by the eyes alters neural processing of images formed on the retina, which plays an important role in determining perceived visual quality. We hypothesize that the post-correction functional measurements on a given patient are biased by long-term neural adaptation to the poor retinal image quality that the patient may have progressively experienced before correction. We will test this hypothesis using a corneal disease, keratoconus as a model of long-term visual adaptation. The visual system of this unique patient group developed normally but, during adulthood, has gradually experienced severely degraded image quality by the large magnitude of aberrations for a prolonged period of time. The proposed project implements the latest tools and advances in human optics research to investigate (1) the mechanisms underlying long-term neural adaptation to degraded optical quality of the eye and (2) neural plasticity resulting from improved optics and/or visual training paradigms. We will use two innovative advanced correction tools: an adaptive optics vision simulator and a customized scleral lens for short-term and long-term precise aberration correction, respectively.
Aim 1 is designed to investigate the mechanisms that underlie long-term neural adaptation to the optically degraded retinal image quality and their impact on neural processing of image quality by (1.1) testing the hypothesis that the neural system is capable to compensate for losses in image quality due to the ocular aberration through long-term adaptation to phase spectra using broadband stimuli, acuity letters and natural images (1.2) characterizing long-term adaptation induced-changes in the key properties of basic spatial vision mechanisms using narrow band visual stimuli i.e. gratings and (1.3) examining the effects of long-term neural adaptation on the two eyes being integrated with regard to the monocular functions including visual acuity, contrast perception at and above threshold before and after aberration correction.
Aim 2 will assess the extent to which plasticity that occurs during long-term adaptation is reversible and what mechanistic changes underlie this reversal once aberration-free image quality is achieved in KC eyes. (2.1) We will first quantify the time course of "passive" neural re-adaptation to improved ocular optics achieved by wearing customized aberration correcting scleral lens daily. We will also apply different visual training paradigms based on (2.2) narrow (single spatial frequency gratings) and (2.3) broad (natural images) band visual stimuli to differentiate different mechanisms of neural plasticity and to test the hypothesis that visual performance can further be improved by the visual training. Binocular transfer of the monocular neural manipulation through visual training effects will also be examined.

Public Health Relevance

Our previous work indicates that long-term visual deprivation caused by optical defects in the eye gradually alters human visual processing. Despite vision improvement with advanced correction methods, initial visual performance after full correction is found to be considerably poorer than that predicted by optical theory or measured in normal eyes. The proposed project uses a novel optical and psychophysical approach to improving our understanding of human spatial vision by (1) providing a basis for understanding the mechanisms that underlie long-term neural adaptation to the optically degraded visual input and (2) investigating neural plasticity to improved ocular optics and visual training paradigms using narrow- and broad-band natural visual stimuli. Successful completion of specific aims will produce fundamental insights into the relationship between ocular optics and the neural adaptive process in normally developed visual systems.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
2R01EY014999-07A1
Application #
8504254
Study Section
Special Emphasis Panel (SPC)
Program Officer
Wiggs, Cheri
Project Start
2003-09-02
Project End
2017-05-31
Budget Start
2013-06-01
Budget End
2014-05-31
Support Year
7
Fiscal Year
2013
Total Cost
$356,990
Indirect Cost
$106,990
Name
University of Rochester
Department
Ophthalmology
Type
Schools of Dentistry
DUNS #
041294109
City
Rochester
State
NY
Country
United States
Zip Code
14627
Zheleznyak, Len; Jung, HaeWon; Yoon, Geunyoung (2014) Impact of pupil transmission apodization on presbyopic through-focus visual performance with spherical aberration. Invest Ophthalmol Vis Sci 55:70-7
Zheleznyak, Len; Sabesan, Ramkumar; Oh, Je-Sun et al. (2013) Modified monovision with spherical aberration to improve presbyopic through-focus visual performance. Invest Ophthalmol Vis Sci 54:3157-65
Sabesan, Ramkumar; Johns, Lynette; Tomashevskaya, Olga et al. (2013) Wavefront-guided scleral lens prosthetic device for keratoconus. Optom Vis Sci 90:314-23
Hindman, Holly B; Huxlin, Krystel R; Pantanelli, Seth M et al. (2013) Post-DSAEK optical changes: a comprehensive prospective analysis on the role of ocular wavefront aberrations, haze, and corneal thickness. Cornea 32:1567-77
Kim, Myoung Joon; Zheleznyak, Len; Macrae, Scott et al. (2011) Objective evaluation of through-focus optical performance of presbyopia-correcting intraocular lenses using an optical bench system. J Cataract Refract Surg 37:1305-12
Sabesan, Ramkumar; Yoon, Geunyoung (2010) Neural compensation for long-term asymmetric optical blur to improve visual performance in keratoconic eyes. Invest Ophthalmol Vis Sci 51:3835-9
Yadav, Rahul; Ahmad, Kamran; Yoon, Geunyoung (2010) Scanning system design for large scan depth anterior segment optical coherence tomography. Opt Lett 35:1774-6
Sabesan, Ramkumar; Yoon, Geunyoung (2009) Visual performance after correcting higher order aberrations in keratoconic eyes. J Vis 9:6.1-10
Chen, Minghan; Yoon, Geunyoung (2008) Posterior corneal aberrations and their compensation effects on anterior corneal aberrations in keratoconic eyes. Invest Ophthalmol Vis Sci 49:5645-52
Yoon, Geunyoung; Pantanelli, Seth; MacRae, Scott (2008) Comparison of Zernike and Fourier wavefront reconstruction algorithms in representing corneal aberration of normal and abnormal eyes. J Refract Surg 24:582-90

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