Binocular Fixation Reduces Fixational Eye Movements in the Worst Eye of Patients with Center-Involving Diabetic Macular Edema

Abstract

Purpose: Treatment of diabetic maculopathy with vascular endothelial growth factor inhibitors is in some patients ineffective, and, therefore, parameters predicting visual outcome after treatment should be identified. It has been shown that fixational saccades are increased in patients with reduced visual acuity secondary to diabetic maculopathy, but it is unknown to what extent these saccades in an eye affected by diabetic maculopathy are influenced by the other eye during binocular fixation. Methods: In 57 eyes from 29 diabetic patients with clinically significant macular edema, fixational eye movements were recorded using the iView X™ video-based eye tracker, and quantitative measures of fixation with the worst eye obtained during monocular and binocular fixation were compared. Results: Fixational saccades during monocular fixation had a significantly higher frequency (p = 0.005), a larger amplitude (p = 0.03), and involved a larger retinal area (p = 0.02) than during binocular fixation. There was a significant negative correlation (r² = 0.18, p = 0.02) between visual acuity and the area of fixation during monocular but not during binocular fixation (r² = 0.007, p = 0.68). Conclusion: Binocular fixation can reduce the area of fixation and the amplitude of fixational saccades in the worst eye of patients with diabetic maculopathy. Fixational saccades in diabetic maculopathy should be studied during monocular fixation.