Purpose: To evaluate the relationship between changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) in eyes from two clinical trials of dexamethasone intravitreal implant 0.7 mg for macular edema after branch or central retinal vein occlusion.
Methods: Patients with vision loss as a result of macular edema (≥6-week duration) after branch retinal vein occlusion or central retinal vein occlusion were treated with a single dexamethasone intravitreal implant or sham. Prospectively defined outcomes included BCVA and CRT (as assessed by optical coherence tomography).
Results: There was a modest but statistically significant negative linear correlation between changes in CRT and changes in BCVA in both treatment groups at Days 90 and 180 (correlation coefficient: -0.23 to -0.34; P < 0.001). Improvements in BCVA at Day 180 were significantly greater (P < 0.001) in eyes that achieved and maintained CRT ≤250 μm from Day 90 to 180 (mean BCVA improvement: 14 letters; 49% of eyes with ≥15-letter gain) than in eyes that never achieved CRT ≤250 μm (mean BCVA improvement: 2 letters; 13% of eyes with ≥15-letter gain).
Conclusion: The greatest improvements in BCVA were seen in eyes that achieved and maintained the greatest improvements in CRT.