Will Perceptual Learning Via Video Game Playing Improve Visual Acuity Stereopsis & Fixation Stability in Mild Amblyopes?

Will Perceptual Learning Via Video Game Playing Improve Visual Acuity, Stereopsis and Fixation Stability in Mild Amblyopes? Part 2 Study

Contrast balanced dichoptic videogame training has been found to improve sensory functions in adults with amblyopia; best corrected distance visual acuity (BCVA) and stereopsis, but its effect on motor function, namely amblyopic eye fixation stability, is unknown. Furthermore, the effect of treatment in cases of mild amblyopia is not well understood. The aim of this study is to find out the difference on fixation stability, BCVA and stereopsis in mild amblyopes after 6 weeks' contrast balanced dichoptic video game training.

Objectives: To assess the change of fixation stability as well as visual acuity and stereopsis before and after training mild amblyopia by perceptual learning through dichoptic video game playing.

Hypothesis: It has been shown that the visual acuity, stereopsis and fixation stability are compromised in amblyopic eye. Perceptual learning via video game playing has been found effective in improving visual acuity and stereoacuity in moderate and severe amblyopic eyes, but there is no study on such treatment in mild amblyopia. In this study, we hypothesize that fixation stability, visual acuity and stereopsis will be improved after training by dichoptic video game playing in mild amblyopia.

Methods: Participants (aged 7 or above) with Best Corrected Visual Acuity (BCVA) ≤ 0.28 logMAR in the amblyopic eye and an interocular acuity difference ≥ 0.2 logMAR will be recruited. An anaglyphic, contrast balanced dichoptic video game will be provided on an i-Pod Touch (Apple Inc.) for 6 weeks of home-based training (60 mins per day). Fixation stability quantified using bivariate contour ellipse area (BCEA by micro-perimeter (MP) Nidek MP-1), BCVA and stereopsis will be assessed before and after treatment.

Inclusion Criteria:

• Best corrected VA in amblyopic eye ≤ 0.28 log MAR, fellow eye VA with an interocular VA difference ≥ 0.20 log MAR;
• Amblyopia could be in form of strabismic, anisometropic and mixed (both strabismic and anisometropic)
• Able to complete 3 successful measurements (each with 30 seconds fixation) of BCEA by the MP-1 systems in each eye
• Able to align the nonius cross (≤10mm horizontal error and 5mm vertical error) in the i-Pod game

Exclusion Criteria:

• Myopia of spherical equivalent power > -6.0 diopter in either eye
• Previous intraocular surgery
• any types of ocular pathology (e.g. media opacities or retinal lesion)
• Previous or current history of neurological problem