Abstract
Highly aberrated keratoconic (KC) eyes do not elicit the maximum visual advantage from a customized optical correction. This is attributed to the neural insensitivity arising from chronic visual experience with poor retinal image quality, dominated by low spatial frequencies. The goal of this study was to investigate if targeted perceptual learning with adaptive optics (AO) can stimulate neural plasticity in these highly aberrated eyes. The worse eye of 2 KC subjects was trained in a contrast threshold test under AO correction. Prior to training, tumbling visual acuity and contrast sensitivity at 4, 8, 12, 16, 20, 24 and 28 c/deg were measured in both eyes of subjects with their routine prescription and with AO correction for a 6mm pupil. The spatial frequency requiring 50% contrast for detection with AO correction was picked as the training frequency. Subjects were required to train on a contrast detection test with AO correction for 1 hour each for 5 consecutive days. During each training session, 800 trials of threshold contrast sensitivity measurement at the training frequency with AO were conducted. Pre-training measures were repeated after the 5 training sessions. After training, contrast sensitivity with AO improved by a factor of 1.91 (range: 1.77 — 2.04) and 1.75 (1.22 — 2.34) on average over spatial frequencies in the two subjects. This improvement in contrast sensitivity transferred to visual acuity with the two subjects improving by 1.5 and 1.3 lines respectively with AO following training. These improvements in visual performance after training with AO denoted an improvement in neural sensitivity as they were not accompanied with any change in optical quality. Therefore, visual training with AO has the potential to enhance neural function in abnormal corneal patients.
Meeting abstract presented at OSA Fall Vision 2012