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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

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

Conditions
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Amblyopia

Intervention / Treatment
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* Device: Dichoptic video game in an i-Pod touch device
* Device: Video game in an i-Pod touch device


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 7 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Sequential Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intervention (dichoptic video game play)<br>Mild amblyopic subjects will be asked to play dichoptic video game in an i-Pod touch device for 1 hour per day in 6 weeks. | Device: Dichoptic video game in an i-Pod touch device<br>* Amblyope will wear a pair of red green goggles and play the video game with 'contrast-balanced' images displayed on the screen of an i-Pod touch device. The eye with weaker eyesight will see the image with high contrast, and the good eye will see the image with low contrast. The subject will play the game one hour per day for 6 weeks.<br>|
| Placebo Comparator: Control (video game play)<br>Mild amblyopic subjects will be asked to play video game in an i-Pod touch device for 1 hour per day in 6 weeks. | Device: Video game in an i-Pod touch device<br>* Amblyope will wear a pair of red green goggles and play the video game with equal contrast images displayed on the screen of an i-Pod touch device. Both eyes will see the image of same contrast. The subject will play the game one hour per day for 6 weeks.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in fixation stability (in terms of Bivariate contour ellipse area in degree square) in the amblyopic eye after 6 weeks dichoptic video game playing in mild amblyopes | Change in fixation stability (in terms of Bivariate contour ellipse area in degree square) in the amblyopic eye after 6 weeks dichoptic video game playing in mild amblyopes. The 95% bivariate contour ellipse area will be adopted in units of degree square. | 6 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in best corrected visual acuity (in log MAR) in the amblyopic eye after 6 weeks dichoptic video game playing in mild amblyopes | Change in best corrected visual acuity (in log MAR) in the amblyopic eye after 6 weeks dichoptic video game playing in mild amblyopes. Best corrected visual acuity will be measured in log MAR unit. | 6 weeks | 
| Change in stereopsis (in arc sec) after 6 weeks dichoptic video game playing in mild amblyopes | Change in stereopsis (in arc sec) after 6 weeks dichoptic video game playing in mild amblyopes. The Titmus and Randot preschool stereopsis test will be used and the measurements are recorded in ' second of arc'. | 6 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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amblyopia, fixation stability, perceptual learning