Timing of Switching to Steroid Implants in Cases of Recalcitrant Diabetic Macular Edema Not Responding to Anti-vascular Endothelial Growth Factor (VEGF) Therapy: A Real-World Study.

Purpose The purpose of this study is to examine the impact of the timing of the steroid switch on both visual and anatomical outcomes in diabetic macular edema (DME) eyes that have shown an inadequate response to multiple intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections. In the treatment of DME, anti-VEGF injections are typically the initial course of action. However, in cases where DME persists despite anti-VEGF treatment, intravitreal dexamethasone implants (Ozurdex, Allergan Inc., Irvine, CA) are often utilized. Despite this, there remains a lack of consensus regarding the optimal timing for transitioning to steroid treatment. This study aims to shed light on the potential benefits of adjusting the timing of the steroid switch in cases of recalcitrant DME.  Methods The eyes (n = 105) of 77 patients with recalcitrant DME were included in this retrospective, interventional, comparative study comprising three groups: participants switched to steroid implants after three anti-VEGF injections (Group I), four to six anti-VEGF injections (Group II), and more than six anti-VEGF injections (Group III). Anti-VEGF treatment failure was defined as a central retinal thickness (CRT) of ≥300 microns and/or a lack of visual improvement (≤1 line of visual gain according to Snellen acuity). The last follow-up took place after 10-12 weeks of Ozurdex injections. Results Improvement was observed in 19 eyes (46%), 17 eyes (50%), and 10 eyes (33%) in Groups I, II, and III, respectively, after switching to dexamethasone implants. The best overall results (an improvement in vision and stabilization) were seen in Group II (32 eyes, 94%). The decrease in CRT was statistically significant in all three groups.  Conclusion Intravitreal dexamethasone implants improved functional and morphological outcomes in anti-VEGF-resistant DME eyes. After four to six anti-VEGF injections, switching to a steroid implant resulted in the best functional results.