Home-based binocular serious games in virtual reality to treat visual acuity and stereovision in residual amblyopia: AMBER study

Objectives

Amblyopia is a pediatric visual disorder traditionally treated by patching the fellow eye, though many patients retain residual amblyopia post-treatment. Increasing evidence suggests that visual plasticity allows treatment beyond the classical therapeutic window. AMBER evaluated the efficacy of binocular serious games in virtual reality (VR) in residual amblyopia.

Methods and Analysis

The monocentric, prospective, randomized, crossover trial (reported as case series) included 14 anisometropic, strabismic, or mixed residual amblyopia patients (6-35 years; 5 children, 9 adults). Participants underwent two 2-month intervention phases: optical correction (standard care) and standard care plus VR games (2.5 h/week), each with a 2-month follow-up. Best-corrected visual acuity (BCVA), stereoacuity, and reading speed were assessed (5 timepoints) using the Sloan and Landolt charts, the Titmus, TNO, Lang II, Asteroid, and Mnread tests. Compliance and adverse events (AE) were recorded.

Results

VR training improved BCVA in 10 amblyopic eyes (Landolt and Sloan), with more pronounced effects in anisometropic patients. Six patients showed improved stereoacuity (Titmus; 4x mixed, 1x anisometropic, 1x strabismic amblyopia), persistent only in children (1x strabismic, 1x mixed amblyopia). Four improvements were observed with TNO (1x), Lang II (1x), Asteroid (0x), and MNread (1x). Despite positive trends, when comparing results of individual patients, between both eyes, and with standard treatment, consistency of improvements cannot be conclusively demonstrated. One non-severe AE (dizziness) was reported.

Conclusions

Following individual cases, VR training improved BCVA and stereoacuity, particularly in children and patients with high compliance. However, considering the cohort as a whole, consistency of effects has to be confirmed in larger groups. Thus, the methodologically sophisticated AMBER study revealed differences in VR treatment efficacy between amblyopia types, children/adults, endpoints and tests, offering precious data for the design of meaningful future studies. It shows that neurovisual plasticity gauged by VR-games offers safe, engaging treatment options for residual amblyopia.

What is already known on this topic

• Binocular treatment approaches have shown promise in efficiently treating amblyopia for which the standard treatment, patching, is effective but is limited by factors such as poor compliance and a narrow treatment window.

What this study adds

• The study investigated the benefits of binocular serious games in virtual reality for both children and adults with residual amblyopia and compared various tests to assess outcomes. This comprehensive approach allowed for a comparison of treatment efficacy across different age groups and types of amblyopia, as well as an evaluation of the suitability of the various tests for determining treatment outcomes.

How this study might affect research, practice or policy

• The findings support the hypothesis that binocular training can effectively treat amblyopia demonstrating highest safety and benefits even beyond the classical treatment window, and in residual amblyopia, which could affect clinical practice of ophthalmologists who offer such therapies, at least as a supplement to standard treatment.

• Assessment of various tests will help uniformize future studies, thus, increase studies’ comparability and, finally, allow conclusive analyses and formulation of treatment recommendations.