Effective contrast ratio as a measure of binocular visual perception
Reviewed by Fiona Rowe

The authors used a binocular phase combination paradigm to quantitatively evaluate and compare the binocular visual perception of normal individuals and patients with different types of strabismus to understand the binocular visual perception of patients with strabismus and evaluate whether this method is effective and feasible in clinical practice. In this study, 117 patients were grouped to normal controls, exophoria, comitant exotropia, comitant esotropia and special strabismus. Effective contrast ratio (ECR) was measured to quantify binocular visual perception. Mean ECRs for groups, respectively, were 0.896 ±0.214, 0.824 ±0.234, 0.520 ±0.279, 0.261 ±0.139 and 0.461 ±0.242. Assessment was possible in about 10 minutes across a broad age range of 6-35 years. Thus, there appears to be potential for clinical application of this method. ECR was not significantly different for comitant exotropia and special strabismus types. ECR of comitant esotropia was significantly lower than that for exotropia and possibly because esotropia develops earlier. Decreased ECR relates to poor stereopsis and has a significant positive correlation with binocular fusion function.

Quantitative evaluation of binocular visual perception in patients with strabismus: an observation study.
Li Q, Fu T, Ma X, et al.
JOURNAL OF PEDIATRIC OPHTHALMOLOGY AND STRABISMUS
2023;60:120-30.