The area of fixation covaries with short-term changes in visual acuity after anti-vascular endothelial growth factor treatment in patients with diabetic macular oedema.

PURPOSE: Diabetic maculopathy can be treated with intravitreal injection of vascular endothelial growth factor (VEGF) inhibitors. However, the therapy is not effective in all patients, and it would be desirable to have parameters for differentiating patients who will benefit from treatment from those who will not. Retinal fixation has been shown to be impaired in patients with low visual acuity (VA) secondary to macular disease, but the changes in fixational eye movements after anti-VEGF treatment for diabetic maculopathy have not been investigated. METHODS: Retinal fixation was studied in 29 patients with diabetic macular oedema before three monthly anti-VEGF injections, and 1 and 4 months after the last injection. The change in VA was correlated with changes in area, frequency, amplitude and total number of fixational saccades. RESULTS: During three monthly injections, best-corrected visual acuity (BCVA) increased from (mean ± SD) 74.0 ± 11.5 Early Treatment Diabetic Retinopathy Study (ETDRS) letters to 78.3 ± 9.8 ETDRS letters, (p = 0.003) and central retinal thickness (CRT) decreased from (mean ± SD) 441.7 ± 107.0 µm to 339.5 ± 74.2 µm, (p = <0.0001), which was followed by the opposite changes after treatment (BCVA reduced nonsignificantly to 77.5 ± 10.4 ETDRS letters (p = 0.06), and CRT increased to 393.0 ± 9.8 µm, p = <0.0001). Both improvement and worsening of BCVA correlated with the fixation area (r2  = 0.28, p = 0.003 and r2  = 0.14, p = 0.045, respectively), but only improvement of BCVA correlated with the frequency (r2  = 0.15, p = 0.037) and total number of saccades (r2  = 0.18, p = 0.02). BCVA showed no correlation with the amplitude and most frequently occurring saccade amplitude. CONCLUSION: Fixational eye movements may be used to monitor short-term effects of anti-VEGF treatment on diabetic macular oedema. Future studies should aim at investigating a possible predictive value of fixational eye movements for visual function in the long term.

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

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.