Abstract
Prolonged exposure to poor optical quality gradually alters neural processing, limiting the visual benefits of advanced optical corrections. Here, we studied the underlying mechanisms of long-term neural adaptation to poor optics in keratoconus (KC), a progressive and severe corneal disease affecting normally-developed adults. We characterized contrast processing in both KC (N=5) and normal (N=5) subjects while bypassing optical factors using an adaptive optics (AO) system. Under AO correction, KC subjects showed abnormal contrast sensitivity, with impaired sensitivity at high spatial frequencies (SF) and enhanced sensitivity at low SFs. Using the Perceptual Template Model and an external noise task, we found that impaired sensitivity to high-SF was associated with reduced weighting of high-SF channels, while improved sensitivity to low-SF information was due to reduced internal noise. The more severe the optical defects, the more pronounced these effects. Our results uncover important plasticity mechanisms underlying long-term neural adaptation to severe optical defects and further our understanding of how optical and neural factors shape our visual experience.
Meeting abstract presented at the 2016 OSA Fall Vision Meeting