Multifocal electroretinogram changes in patients with retinal vein occlusion

Background Retinal vein occlusion (RVO) is one of the most common vascular retinal disorders that lead to macular edema. There is often discrepancy between visual prognosis and optical coherence tomography (OCT) changes. Multifocal electroretinogram (mfERG) provides useful information about retinal function in affected parts of the retina in patients with RVO. Purpose The aim of this study was to assess the functional changes in patients with RVO by mfERG and to correlate these changes with OCT findings in those patients. Patients and methods This is a prospective study of 30 eyes of patients with RVO, with their fellow eyes being taken as control. Thirteen eyes with central RVO, 12 eyes with branch RVO, and five eyes with hemi-RVO were included in the study. OCT to measure the central macular thickness was done in all patients. mfERG was also done in all patients. P wave amplitude and p wave implicit times were measured in the central area and all quadrants. Results mfERG responses were markedly affected in all quadrants in central RVO, in the affected quadrants in branch RVO, and in the affected hemiretina in hemi-RVO. The differences between the p amplitude and p implicit time between the affected eyes and the fellow eyes were statistically significant in all patients. There was a significant correlation between the central macular thickness and p amplitude in the affected half of the retina in hemi-RVO. Conclusion mfERG is a sensitive tool for assessment of retinal function in patients with RVO. mfERG can assess local retinal dysfunction in patients with RVO, which is sensitive to morphological changes detected by OCT.