Visual Acuity in Retinal Vein Occlusion, Diabetic, and Uveitic Macular Edema: Central Subfield Thickness and Ellipsoid Zone Analysis.

PURPOSE

This study assessed relationships between best-corrected visual acuity (BCVA), central subfield thickness (CST), and ellipsoid zone (EZ) integrity in macular edema (ME) patients.

DESIGN

Post hoc analysis of 6 clinical trials, which included verified diagnoses, protocol refractions, and reading center assessment of OCT images.

PARTICIPANTS

Participants (n = 1063) were diagnosed with ME from retinal vein occlusion (RVO), diabetic retinopathy (DR; diabetic macular edema, DME), or noninfectious uveitis (NIU).

METHODS

For CST, 2 clinical trials for each disorder were analyzed. For EZ, 3 studies across 2 disorders were analyzed.

MAIN OUTCOME MEASURES

Primary outcomes were correlations between BCVA and CST, and between BCVA and 4 central subfield EZ grades.

RESULTS

For baseline BCVA and CST, Pearson correlation coefficients were: ME from RVO, -0.56 (774 eyes; 95% confidence interval [CI], -0.61 to -0.51; P < 0.001); DME, -0.50 (91 eyes; 95% CI, -0.64 to -0.33; P < 0.001); and ME from NIU, -0.38 (198 eyes; 95% CI, -0.49 to -0.26; P < 0.001). Regarding change from baseline to 24 weeks for both BCVA and CST, Pearson correlation coefficients were: ME from RVO, -0.35 (95% CI, -0.43 to -0.27; P < 0.001); DME, -0.30 (95% CI, -0.48 to -0.09; P = 0.006); and ME from NIU, -0.42 (95% CI, -0.53 to -0.29; P < 0.001). Acute and chronic ME showed similar baseline and 24-week change linear correlations. With lower baseline CST, a trend of decreased baseline and 24-week change correlations was found. For central subfield EZ at baseline, mean BCVA progressively worsened with each of 4 EZ grades in 185 eyes with gradable EZ (DME, 41 eyes; NIU, 144 eyes; P ≤ 0.050 for all pairwise comparisons except between normal and questionably abnormal EZ grades). Eyes with normal baseline central subfield EZ showed greater 24-week change in BCVA than those with abnormal baseline EZ (15.00 letters vs. 8.16 letters; P = 0.0005, with baseline BCVA, CST, and age as covariates).

CONCLUSIONS

Despite these correlations, CST and EZ integrity, as graded herein, account for the minority of BCVA variation in patients with ME resulting from RVO, DR, and NIU.