Objective: To investigate the relationship between baseline center point retinal thickness measured by optical coherence tomography (OCT) and best-corrected visual acuity in eyes with macular edema associated with retinal vein occlusion and to investigate other factors associated with baseline visual acuity letter score.
Design: The Standard Care versus COrticosteroid for REtinal Vein Occlusion (SCORE) Study includes 2 multicenter, randomized clinical trials: one evaluating participants with central retinal vein occlusion (CRVO) and the other evaluating participants with branch retinal vein occlusion (BRVO).
Participants: After omitting 17 participants with missing or unreliable OCT measurements, analyses proceeded with 665 enrolled SCORE Study participants (665 eyes), including 262 with CRVO and 403 with BRVO.
Methods: At baseline, center point thickness was measured by OCT (Stratus OCT 3 [n=663] and OCT2 [n=2]; Carl Zeiss Meditech, Dublin, CA), and visual acuity was measured by the electronic Early Treatment Diabetic Retinopathy Study (E-ETDRS) methodology.
Main outcome measures: Center point thickness and best-corrected E-ETDRS visual acuity letter score.
Results: The correlation coefficient for the association between baseline OCT-measured center point thickness and best-corrected E-ETDRS visual acuity letter score is -0.27 (95% confidence limit: -0.38 to -0.16) for participants in the CRVO trial and -0.28 (95% confidence limit: -0.37 to -0.19) in the BRVO trial. Regression modeling estimated the following decrease in baseline visual acuity letter score for every 100-microm increase in OCT-measured center point thickness: 1.7 letters (P=0.0007) for CRVO and 1.9 letters (P<0.0001) for BRVO. On the basis of multivariate regression models, baseline factors significantly associated (P<0.05, after adjusting for multiple testing) with baseline visual acuity letter score include age and duration of macular edema for CRVO participants and center point thickness and presence of cystoid spaces for BRVO participants.
Conclusions: The correlation between OCT-measured center point thickness and visual acuity letter score is modest. OCT-measured center point thickness represents a useful tool for the detection and monitoring of macular edema in retinal vein occlusion, but it cannot reliably substitute for visual acuity measurements.