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

Inclusion Criteria:

• Visual acuity in the amblyopic eye: 20/25 or worse

Exclusion Criteria:

• Manifest eye disease & nystagmus