Correlation of visual acuity and macular thickness measured by optical coherence tomography in patients with persistent macular edema.

PURPOSE

The purpose of this study was to evaluate the correlation between best-corrected visual acuity (BCVA) and macular thickness in patients with persistent macular edema treated with a dexamethasone intravitreal drug delivery system (dexamethasone DDS).

METHODS

In a randomized, multicenter, controlled, parallel-group, dose-ranging study, patients with macular edema lasting at least 90 days despite treatment were randomized to observation or treatment with 350- or 700-microg dexamethasone DDS. Macular thickness was assessed in 80 patients using optical coherence tomography. Best-corrected visual acuity was measured using Early Treatment Diabetic Retinopathy Study methodology.

RESULTS

At baseline, macular thickness was significantly inversely correlated with BCVA (r = -0.406, P < 0.001). Patients treated with 350- or 700-microg dexamethasone DDS showed a significant decrease in macular thickness from baseline to Day 90 (P = 0.002). In the 700-microg dexamethasone DDS treatment group, there was a modest inverse correlation between changes in macular thickness from baseline to Day 90 and improvement in BCVA (r = -0.530, P = 0.009). In the 350-microg dexamethasone DDS treatment group, the correlation was weaker and not statistically significant (r = -0.206, P = 0.304).

CONCLUSION

The correlation between baseline BCVA and macular thickness in patients with persistent macular edema was modest. Improvement in BCVA after treatment with 700-microg dexamethasone DDS was consistent with changes in macular thickness measured using optical coherence tomography.