Training to improve contrast sensitivity in amblyopia: correction of high-order aberrations

Meng Liao,Yifeng Zhou,Haoxing Zhao,Qian Li,Yudong Zhang,Yun Dai,Longqian Liu

doi:10.1038/srep35702

Abstract

Perceptual learning is considered a potential treatment for amblyopia even in adult patients who have progressed beyond the critical period of visual development because adult amblyopes retain sufficient visual plasticity. When perceptual learning is performed with the correction of high-order aberrations (HOAs), a greater degree of neural plasticity is present in normal adults and those with highly aberrated keratoconic eyes. Because amblyopic eyes show more severe HOAs than normal eyes, it is interesting to study the effects of HOA-corrected visual perceptual learning in amblyopia. In the present study, we trained twenty-six older child and adult anisometropic amblyopes while their HOAs were corrected using a real-time closed-loop adaptive optics perceptual learning system (AOPL). We found that adaptive optics (AO) correction improved the modulation transfer functions (MTFs) and contrast sensitivity functions (CSFs) of older children and adults with anisometropic amblyopia. When perceptual learning was performed with AO correction of the ocular HOAs, the improvements in visual function were not only demonstrated in the condition with AO correction but were also maintained in the condition without AO correction. Additionally, the learning effect with AO correction was transferred to the untrained visual acuity and fellow eyes in the condition without AO correction.

Highlights

We found that the AOPL system worked well in terms of correcting HOAs, and the improvements in visual function induced by perceptual learning with adaptive optics (AO) correction were maintained in the condition with AO correction and without AO correction
In the contrast sensitivity function (CSF) measurement, seven spatial frequencies (i.e., 0.6, 1, 2, 4, 8, 16, 24 cpd) were included, whereas in the perceptual learning task, the trained spatial frequency was set at the cut-off spatial frequency in the pre-training CSF test with AO correction[18,30]
The ratio of the modulation transfer functions (MTFs) with AO correction to that without AO correction increased steadily with spatial frequency from 1.022 ± 0.002 at 0.6 cpd to 7.793 ± 1.980 at 24 cpd

Summary

Introduction

A contrast detection task conducted at the individual’s cut-off spatial frequency was used as the training protocol. This task was similar to those in previously reported studies[16,17,18,29,30,31] and enabled us to directly compare the learning benefits among different studies. We found that the AOPL system worked well in terms of correcting HOAs, and the improvements in visual function induced by perceptual learning with adaptive optics (AO) correction were maintained in the condition with AO correction and without AO correction. The possible reasons for this phenomenon and the clinical significance of HOA-corrected training in amblyopia are discussed

Methods

Results

Conclusion