Effect of Initial Aflibercept, Laser, or Observation on Low-Contrast Visual Acuity in Eyes With Diabetic Macular Edema and Good Vision: Ancillary Study Within a Randomized Clinical Trial

PURPOSE: To describe 2.5% low-contrast visual acuity (VA) among eyes with good vision despite center-involved diabetic macular edema and compare changes after initial management with aflibercept, laser, or observation. METHODS: This was an ancillary study within a multicenter randomized clinical trial (DRCR Retina Network Protocol V). Participants had diabetes and 1 study eye with center-involved diabetic macular edema and a VA of 20/25 or better randomly assigned to aflibercept (n = 112), focal/grid laser (n = 146), or observation (n = 129). Eyes in the laser and observation groups received aflibercept if VA met prespecified worsening criteria. RESULTS: Participants had median age of 60 years, 37% were female and 70% were non-Hispanic White. At baseline, the mean ± standard deviation (SD) high-contrast VA was 85.2 ± 3.6 letters (Snellen equivalent 20/20), mean ± SD 2.5% low-contrast VA was 47.6 ± 18.9 letters (Snellen equivalent 20/125), and low-contrast VA letter score was 2 SDs or more below the age-specific normative values in 23%. At 2 years, the mean change ± SD in low-contrast VA in the aflibercept, laser, and observation groups was 2.7 ± 20.1, –2.0 ± 19.6, and –3.1 ± 20.8 letters (adjusted difference, aflibercept vs. laser, 5.3 [95% confidence interval, –0.2 to 10.8], P = 0.06; aflibercept vs. observation, 5.5 [95% confidence interval –0.2 to 11.2], P = 0.06; and laser vs. observation, 0.2 [95% confidence interval –4.6 to 5.0], P = 0.94). CONCLUSIONS: There was no significant difference between treatment groups in low-contrast VA change from baseline to 2 years. Considering the range of the 95% confidence intervals, however, the study may have been underpowered to detect a clinically meaningful benefit between treatment groups. TRANSLATIONAL RELEVANCE: Low-contrast VA, an important visual function, is decreased in eyes with diabetic macular edema.