Combined intravitreal ranibizumab and posterior subtenon triamcinolone acetonide injections for patients with diabetic macular edema refractory to intravitreal ranibizumab monotherapy

Abstract

PURPOSE: The purpose of this study is to compare the efficacy of intravitreal ranibizumab (IVR) alone and concurrent IVR with posterior subtenon triamcinolone acetonide (PSTA) injection for patients with diabetic macular edema (DME) refractory to IVR monotherapy. MATERIALS AND METHODS: We enrolled 43 eyes of 43 patients with DME who received at least three times of IVR, which resulted in poor anatomical responses, with central foveal thickness (CFT) reduction <10% and postinjection CFT >300 μm. All the eyes received initial 3 monthly then pro re nata (PRN) IVR 0.5-mg injections. Twenty eyes continued PRN injections and 23 eyes received combined IVR 0.5 mg and PSTA 40 mg with at least 1-year follow-up. Best-corrected visual acuity (BCVA) and CFT were recorded from 1-month to 1-year follow-up. RESULTS: Following switch to combined therapy, the mean BCVA significantly improved from 0.61 ± 0.32 logarithm of the minimum angle of resolution (logMAR) to 0.45±0.39 logMAR at 6 month (P = 0.003), 0.43±0.35 logMAR at 9 months (P < 0.001), and 0.48±0.45 logMAR at 1 year (P = 0.03). In eyes with IVR alone, no significant VA improvement was noted throughout the year. Significantly better BCVA was noted in the combined group at 6-month, 9-month, and 1-year follow-up compared to IVR-alone group. The timing of combined therapy showed a significant association with 1-year BCVA (t = 3.25, P = 0.018). CONCLUSION: Concurrent IVR and PSTA resulted in significantly better visual outcomes in 1-year follow-up for those refractory to preceding ranibizumab monotherapy for DME. Early addition of PSTA predicted a better visual outcome.