Long-term visual outcome and retinal function with and without intravitreal treatments in eyes with central retinal vein occlusion

PurposeTo investigate long-term effects of intravitreal injections on visual outcome, retinal function and structure in eyes with central retinal vein occlusion (CRVO eyes) and macular oedema and compare with untreated CRVO eyes to determine the long-term effects of anti-vascular endothelial growth factor on photoreceptor cell function.MethodsA retrospective study of 38 eyes from 38 CRVO patients. Twenty-eight patients with macular oedema received intravitreal treatments and 10 without macular oedema remained untreated. All underwent full-field electroretinography (ERG) within one month of CRVO debut (ERGI) and a follow-up (ERGII). The primary outcome was long-term change in total retinal function. Electrophysiological and clinical results of the groups were compared. Further, the treated eyes were divided into ischemic vs non-ischemic groups and compared.ResultsThe mean ETDRS letter score improved significantly in the treated group (p = 0.026). Mean central foveal thickness (CFT) decreased significantly from ERGI to ERGII and from ERGI to final visit in both the treated and non-treated groups (p < 0.001, <0.001 and p < 0.002, 0.004, respectively). The ERG results showed significantly decreased a- and b-wave amplitudes of combined rod-cone response from ERGI to ERGII in both groups (p = 0.004, 0.004 and p = 0.037 and 0.037, respectively). The non-ischemic group saw a significant decrease in the same response from ERGI to ERGII (p = 0.008, p = 0.027 respectively).ConclusionLong-term visual outcome improved in the treated group and remained unchanged in the untreated group. CFT improved in both groups, but retinal function in both was still reduced 4 years after CRVO diagnosis. This suggests that the natural course of CRVO impacts retinal function.