Effect of Extended Release Steroid Implants on the Contralateral Eye

PURPOSE: To investigate the contralateral effect of extended release steroid implants on cystoid macular edema (CME). METHODS: Retrospective study of patients with bilateral CME receiving intravitreal injections of long-acting intravitreal corticosteroid implants in one eye. Changes in CME and central subfield thickness (CST) in the contralateral eye on optical coherence tomography (OCT) were compared to an untreated control group. The main outcome measures were the change in central subfield thickness (CST) and the change in the macular volume. RESULTS: Thirteen study patients and 14 controls were included in the study. There was no difference in the baseline LogMAR visual acuity (0.32 ± 0.35 vs 0.43 ± 0.26, p = 0.37) or the baseline central subfield thickness (341.4 ± 76.6 vs 296.5 ± 65.0 µm, p = 0.12) between groups. In the treatment group CST remained stable in 92.3% of the patients. Of the controls, CST worsened in 21.4% and remained stable in 78.6%. The mean change in CST (6.3 ± 30.3 vs. 27.5 ± 66.1 µm, p = 0.2) and the mean change in macular volume (0.08 ± 0.34 vs. -0.05 ± 0.21 mm(3), P = 0.8) were not statistically different between the treatment group and control group. In the post-hoc analysis restricting the treatment group to patients who had not received intravitreal injections in the study eye within 6 months, CST decrement was not statistically significant (p = 0.11). CONCLUSION: In this study there was no statistically significant effect on CME of contralateral intravitreal corticosteroid implants.