Perceptual Learning Treatment for Amblyopia

Study Overview
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Brief Summary
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Objectives. To develop a new treatment for amblyopia using a perceptual learning approach. Hypothesis to be tested. Our proposed experiments are designed to investigate whether practicing a grating detection task can improve vision in patients with amblyopia. Design and subjects. A total of 36 patients with amblyopia will be randomized allocated into two intervention groups: Group 1, perceptual learning therapy. Group 2, occlusion therapy. A control group comprising of 18 subjects with normal vision will be recruited for comparison. A battery of tests will be used to assess a range of visual functions before and after the treatment intervention. Study instruments. Grating acuity testing system Interventions. We have established a clinical protocol for acuity training. On each trial, a properly oriented stimulus will be presented randomly at one of the four locations on a flat monitor screen. The visual task is to indicate the location of the stimulus. Participants will be required to undertake 20 one-hour sessions of training. Main outcome measures. Resolution acuity, visual acuity, contrast sensitivity function

Official Title
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Towards Developing a Perceptual Learning Treatment for Amblyopia

Conditions
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Amblyopia

Intervention / Treatment
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* Other: Acuity training
* Other: Occlusion therapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Visual acuity in the amblyopic eye: 20/25 or worse Exclusion Criteria: Manifest eye disease & nystagmus

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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Accepts Healthy Volunteers

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: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Perceptual learning group - Amblyopia<br>Visual training | Other: Acuity training<br>* The intervention will be a vision therapy. On each trial, a properly oriented stimulus will be presented randomly at one of the four locations on a flat monitor screen. The visual task is to identify the location of the stimulus.<br>|
| Active Comparator: Perceptual learning group - Control<br>Visual training | Other: Acuity training<br>* The intervention will be a vision therapy. On each trial, a properly oriented stimulus will be presented randomly at one of the four locations on a flat monitor screen. The visual task is to identify the location of the stimulus.<br>|
| Placebo Comparator: Occlusion therapy - Amblyopia<br>Patching | Other: Occlusion therapy<br>* Participants will be required to patch the good eye for 20 days, 1 hour per day.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change of grating acuity | Grating acuity tests the participants' ability to resolve fine details. This study measures the change of grating acuity after 20 hours of vision training. | 20 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change of visual acuity | Visual acuity tests the participants' ability to resolve letters.This study measures the change of visual acuity after 20 hours of vision training. | 20 hours | 
| Change of contrast sensitivity | Contrast sensitivity reflects the participants' sensitivity to identify low contrast visual stimuli. This study measures the change of contrast sensitivity after 20 hours of vision training. | 20 hours | 
| Change of stereopsis | Visual acuity tests the 3-D perception. This study measures the change of stereopsis after 20 hours of vision training. | 20 hours |