Trans-Tenon's retrobulbar triamcinolone acetonide infusion for refractory diabetic macular edema after vitrectomy

Purpose To evaluate the efficacy and safety of trans-Tenon's retrobulbar triamcinolone acetonide (TA) infusion for the treatment of refractory diabetic macular edema (DME) after vitrectomy. Methods After topical anesthesia, 20 eyes from 20 patients with persistent DME after pars plana vitrectomy were treated with trans-Tenon's retrobulbar infusion of 40 mg TA through an inferotemporal approach. The mean duration (±SD) between vitrectomy and trans-Tenon's retrobulbar TA infusion was 11.4±7.9 months. The mean follow-up period (±SD) after trans-Tenon's retrobulbar TA infusion was 13.3±2.8 months. Results At 1 week after trans-Tenon's retrobulbar TA infusion, the mean central retinal thickness (±SD) measured by optical coherence tomography was 381±99 μm, which was a statistically significant decrease in comparison with the preoperative thickness (555±112 μm) (P<0.001). Additional trans-Tenon's retrobulbar TA infusions were performed in ten eyes (50%), due to the recurrence of DME at 6.6±3.0 months after the first TA infusion. At the final examination, macular edema resolved in 13 (65%), improved in four (20%), and remained unchanged in three (15%) of the 20 eyes. At 1 month after trans-Tenon's retrobulbar TA infusion, the mean laser flare value (±SD) was 9.6±3.0 photon/ms, which was a statistically significant decrease in comparison with the preoperative value (15.5±5.9 photon/ms) (P<0.01). Furthermore, in ten eyes (50%) with recurrent DME, re-elevated laser flare values were observed prior to the recurrence of DME. The final best-corrected Snellen visual acuity improved by two or more lines in nine eyes (45%), and remained unchanged in 11 eyes (55.0%). IOP elevation equal to or higher than 21 mmHg was observed in three (15%) of the 20 eyes with TA infusion, and was controlled by topical medications. No other injection-related complications were observed. Conclusion Trans-Tenon's retrobulbar TA infusion is an effective and safe method for the treatment of refractory DME, which is present even after vitrectomy.