Longterm Treatment of Diabetic Macular Edema with Dexamethasone Im plant after Unsatisfactory Response to anti-VEGF Therapy

Abstract

Purpose: anti-VEGF drugs and triamcinolone have been established with good short- and midterm effects in diabetic maculopathy (DME). The necessity of frequent reinjections using anti-VEGF therapies and the loss of efficacy over time in some patients as well as the side effects are a concern. In this situation, the use of intravitreal dexamethasone (Ozurdex®) may be an option. Here, we wished to assess the effect of Ozurdex after several injections in difficult to treat, pretreated and vitrectomized eyes with persisting and chronic DME.

Methods: In this retrospective, interventional case series eyes with ≥ 2 Ozurdex injections with chronic and persisting DME, not responding to ≥ 3 intravitreal anti-VEGF therapies were included. All eyes were pseudophakic. Four of the eyes (44%) had undergone vitrectomy prior to their first Ozurdex injection. Best-corrected visual acuity (BCVA), intraocular pressure (mmHg) and the central retinal thickness (CRT) measurements were performed prior to Ozurdex injection, one and three months after injections as well as prior to the next intravitreal treatment. Functional and anatomical outcomes were extracted from the case records along with the time to reinjection. Informed consent was obtained from all patients.

Results: In nine eyes of seven patients 55 Dex injections were performed (mean 6.1 (2-15)) during a follow up time of 28.3±9.0 (17.3-41) months. The mean age of the patients was 63.3±10.4 years. A mean of 12.6±7.6 intravitreal injections had been performed before the first Dex injection. BCVA (logMAR) improved from 0.37±0.10 at baseline to 0.33±0.13 (1 month), 0.32±0.1 (three months) and 0.41±0.13 (before reinjection). IOP rise reached its maximum four weeks after Dex implantation. Mean pre-injection CRT decreased from 416±45 µm to 291±38 µm (one month; p=0.054) and 392±31 µm before reinjection (p=0.67). The time to reinjection was 5.8±3.1; 4.3±1.8; 4.2±1.2; and 4.1±1.7 months for the 1^st, 2^nd, 3^rd and 4^th injection, the mean duration of reffect being 6.4±5.3 months. No toxic side effects have beeen encountered

Conclusions: Dexamethasone implants may successfully be used over a period of 18-40 months in eyes with DME that were unresponsive to anti-VEGF We did not observe a shortening of the duration aof effect after several injections.