Full-field Electroretinography in Age-related Macular Degeneration: can retinal electrophysiology predict the subjective visual outcome of cataract surgery?

Abstract

Predicting the visual gain from cataract surgery when the main cause of vision loss is age-related macular degeneration may be difficult and warrants the need for an objective predictor of subjective outcome. Full-field electroretinography is an objective measure of overall retinal function. We therefore wanted to study if full-field electroretinography can predict subjective visual outcome using visual function questionnaire. Thirty-one patients with age-related macular degeneration operated for bilateral cataract underwent full-field electroretinography preoperatively. Full-field electroretinography was performed according to International Society for the Clinical Electrophysiology of Vision standards using a Ganzfeld bowl (RETI-port/scan 21, Roland, Berlin) and Dawson-Trick-Litzkow fibre electrodes. Vision-related quality of life was measured using the National Eye Institute Visual Function Questionnaire-39 before first-eye surgery and 4.12±2.11months after second-eye surgery. Mean change in composite visual function questionnaire score after cataract surgery was 9.2±11.9. The patients were divided into three groups: visual function questionnaire composite score increase >10 (n=17); no change (n=8); and decrease (n=6). In the dark-adapted full-field electroretinography responses, we found a significant difference between the three groups in the 0.01 b-wave amplitude (p=0.05), the 10.0 b-wave amplitude (p=0.04) and a near-significant difference in 3.0 a-wave amplitude (p=0.09). Other dark-adapted responses (the 3.0 b-wave and 10.0 a-wave) did not show any significant differences between the three groups, and neither did the light-adapted responses. Patients with low dark-adapted responses on full-field electroretinography preoperatively experience a decrease in subjective vision-related quality of life, suggesting that maintained rod function before cataract surgery may be important.