Dichoptic Game Training in Strabismic Amblyopia Improves the Visual Evoked Response

Abstract

Dichoptic video gaming offers an alternative approach in amblyopia treatment by allowing different information to be presented in the two eyes, resulting to reduced suppression and/or enhanced fusion. The aim of this case report series is to evaluate the outcome of supervised dichoptic training, with the use of video games in a virtual reality (VR) system, on far and near visual acuity (VA), stereoacuity, and the visual evoked response of an adult and two children with strabismic amblyopia. Results suggest that despite the absence of improvement in VA following supervised dichoptic training, a remarkable increase in stereoacuity was evident with a concurrent decrease in phorias. Moreover, an improvement in the P100 latency of the pattern visual evoked potentials (VEPs) in the amblyopic eye was observed in all participants. Finally, at least two sessions per week were completed for each patient under continuous supervision, implying sufficient compliance and treatment efficiency with dichoptic video gaming. Supervised dichoptic training, consisting of at least 20 hours of video gaming using a VR system, improves stereoacuity and the latency of the visual evoked response in the amblyopic eye. This probably occurs by overcoming its suppression, indicating that the speed of visual processing, as evaluated by pattern VEPs, may precede improvements in VA.

Keywords: amblyopia; dichoptic training; strabismus; vep; vision training.

Figure 1. Grand-averaged (64 epochs) monocular pVEP waveforms for case 1 at 15 arcmin (left) and 40 arcmin (right) size, elicited using 2 Hz-reversing check pattern of 100% contrast for the amblyopic eye (black line) and the fellow eye (gray line), before treatment (baseline), and after 20 hours (eight weeks) of dichoptic training. P100 latency is indicated in ms.

Figure 2. Grand-averaged (64 epochs) monocular pVEP waveforms for case 2 at 15 arcmin (left) and 40 arcmin (right) size, elicited using 2 Hz-reversing check pattern of 100% contrast for the amblyopic eye (black line) and the fellow eye (gray line), before treatment (baseline), and after 20 hours (eight weeks) of dichoptic training. P100 latency is indicated in ms.

Figure 3. Grand-averaged (64 epochs) monocular pVEP waveforms for case 3, elicited using 2 Hz-reversing 10 arcmin checks of 100% contrast for the amblyopic eye (black line) and the fellow eye (gray line) before treatment (baseline), after 20 hours (five weeks), and 50 hours (12 weeks) of dichoptic training. P100 latency is indicated in ms.