VR Glasses based Measurement of Responses to Dichoptic Stimuli: A Potential Tool for Quantifying Amblyopia?

Amblyopia is a medical condition in which the visual inputs from one of the eyes is suppressed by the brain. This leads to reduced visual acuity and poor or complete loss of stereopsis. Conventional clinical tests such as Worth 4-dot test and Bagolini striated lens test can only detect the presence of suppression but cannot quantify the extent of suppression, which is important for identifying the effectiveness of treatments for amblyopia. A novel approach for quantifying the level of suppression in amblyopia is proposed in this paper. We hypothesize that the level of suppression in amblyopia can be measured by measuring the symmetry/asymmetry in the suppression experienced during a dichoptic image recognition task. Preliminary studies done on fifty one normal subjects prove that the differences between the accuracies of the left and right eyes can be used as a measure of asymmetry. Equivalence test performed using 'two-one-sided t-tests' procedure shows that the equivalence of the accuracies of left and right eyes for normal subjects is statistically significant (p = .03, symmetric equivalence margin of 5 percentage points). To validate this method, six amblyopic children underwent this test and the results obtained are promising. To the knowledge of the authors, this is the first work to make use of VR glasses and dichoptic image recognition task for quantifying the level of ocular suppression in amblyopic patients.