Quantitative Analysis of Strabismus Misalignment

Abstract

Strabismus is a binocular misalignment disorder in which the two eyes are not focused at the same target. Strabismus affects approximately 1 of 50 people, causing blurry and double vision as a result of the brain’s reception of differing images from the affected and non-affected eyes. Superior oblique palsy (SOP) occurs due to weakening of the superior oblique muscle and is a common cause of vertically-imbalanced strabismus. SOP is treated surgically. However, a lack of quantitative, long-term analysis results in lesser knowledge about the regression of strabismus post-surgery. Throughout this study, Hess Screen Charts, which mapped SOP-affected patients’ misaligned vision at 21 standardized eye positions, were translated digitally to obtain measured eye position angles and then analyzed at three time periods in the treatment process. These samples included pre-surgery, immediately post-surgery, and a post-post surgery period ranging from approximately 5-208 weeks. Then, the error between each standardized and actual eye position was calculated using three metrics: horizontal, vertical, and composite. Finally, these errors were averaged for each of the patients to examine the effects of the corrective surgery and regression of SOP misalignment post-operatively.