Changes in Macular Function after Ozurdex for Retinal Vein Occlusion

Purpose. To investigate changes in macular function after intravitreal dexamethasone implant (Ozurdex) for macular edema (ME) secondary to retinal vein occlusion (RVO). Methods. Nineteen treatment-naive patients with RVO-related ME were treated with intravitreal Ozurdex and followed up to 6 months to evaluate functional outcomes, by means of best-corrected visual acuity, microperimetry, and multifocal electroretinography, and their correlations with morphological parameters by enhanced depth imaging optical coherence tomography. Results. Nineteen eyes of 19 patients were included for analysis. At 1 month, mean best-corrected visual acuity, retinal sensitivity, and central macular thickness (CMT) improved from 0.50 +/- 0.34 LogMAR, 10.51 +/- 4.31 dB, and 762 +/- 259 mu m (baseline) to 0.38 +/- 0.34 LogMAR (p = 0.043), 12.28 +/- 5.06 dB (p = 0.025), and 385 +/- 191 mu m (p = 0.001), respectively. At 3 months, improvement of mean retinal sensitivity and CMT was still significant (11.62 +/- 5.05 dB [p = 0.047] and 518 +/- 251 mu m [p = 0.006]). Multifocal electroretinography measurements also showed (nonsignificant) improvement. No significant changes in choroidal thickness were recorded. Improvements recorded during the first 3 months were no longer significant from month 4. At each time point, we found a negative significant correlation between CMT and retinal sensitivity. Interestingly, 7 eyes did not undergo retreatment of less than 6 months; these eyes showed a significantly better baseline retinal sensitivity than eyes requiring retreatment of less than 6 months (12.27 +/- 3.52 dB vs. 9.48 +/- 4.53 dB [p = 0.038]). Conclusions. In eyes with ME secondary to RVO, intravitreal dexamethasone implant provides functional benefits as soon as 1 month after treatment. In most cases, the optimum retreatment interval is less than 6 months from first intravitreal Ozurdex. Microperimetry is a very useful tool to characterize macular function. Baseline macular sensitivity may predict the need for early (<6 months) retreatment.