Measuring the Interocular Delay and its Link to Visual Acuity in Amblyopia

Area of Science:

• Ophthalmology
• Neuroscience
• Vision Science

Background:

• Amblyopia is characterized by impaired interocular synchronicity, indicating a neural processing delay between the eyes.
• Existing methods for assessing interocular delay are often costly or unsuitable for severe amblyopia cases.

Purpose of the Study:

• To adapt and assess the accessibility of a novel continuous target-tracking protocol for measuring interocular delay in a diverse range of amblyopic patients.
• To investigate the relationship between measured interocular delay and visual acuity in amblyopia.

Main Methods:

• A novel protocol involving continuous target tracking with a mouse cursor was adapted for both binocular and monocular assessments.
• Interocular delay was calculated by comparing the processing speeds of each eye using cross-correlation analysis of target and cursor velocity changes.

Main Results:

• The adapted protocol proved accessible across a wide range of amblyopes.
• A significant positive correlation was found between the magnitude of interocular delay and differences in interocular visual acuity (R² = 0.484, P = 0.0002).
• Interocular delays ranged from 0.6 to 114.0 ms, with the amblyopic eye typically showing a delay.

Conclusions:

• The novel tracking protocol is a viable and accessible tool for assessing interocular delay in amblyopia.
• The findings reinforce the connection between interocular synchronicity deficits and amblyopia.
• Interocular delay in amblyopia is likely attributable to a deficit in the temporal integration capabilities of the amblyopic eye.