Correlation of Change in Macular Thickness With Change in Visual Acuity in Diabetic Macular Edema: Post Hoc Analysis of VISTA and VIVID Trials

Purpose: To assess the correlation between the change in central subfield thickness (CST) and change in best-corrected visual acuity (BCVA) in eyes with diabetic macular edema (DME) treated with fixed-dosing intravitreal aflibercept injection (IAI). Methods: This post hoc analysis of the VISTA and VIVID randomized controlled clinical trials, in which 862 eyes with central-involved DME were randomly assigned to IAI 2 mg every 4 weeks (2q4; 290 eyes), IAI 2 mg every 8 weeks after 5 initial monthly doses (2q8; 286 eyes), or macular laser (286 eyes) and followed through 100 weeks. Correlations between the change in CST and change in BCVA from baseline to weeks 12, 52, and 100 were assessed using the Pearson correlation. Results: The respective correlations (r [95% CI]) at weeks 12, 52, and 100 were −0.39 (−0.49 to −0.29), −0.27 (−0.38 to −0.15), and −0.30 (−0.41 to −0.17) in the 2q4 arm and −0.28 (−0.39 to −0.17), −0.29 (−0.41 to −0.17), and −0.33 (−0.44 to −0.20) in the 2q8 arm. Linear regression analysis of the correlation at week 100, adjusted for relevant baseline factors, showed CST changes accounted for 17% of the variance in BCVA changes; every 100-µm decrease in CST was associated with a 1.2-letter increase in BCVA (P = .001). Conclusions: Correlations between the change in CST and change in BCVA after 2q4 or 2q8 fixed-dosing IAI for DME were modest. Although a change in CST might be important in determining the need for antivascular endothelial growth factor for DME at follow-up, it was not a good surrogate for VA outcomes.