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 μm (baseline) to 0.38 ± 0.34 LogMAR (p = 0.043), 12.28 ± 5.06 dB (p = 0.025), and 385 ± 191 μm (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 μm [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.