Purpose: Current treatment paradigms for macular edema associated with retinal vein occlusions (RVO) often involve initial treatment with anti-vascular endothelial growth factor (VEGF) agents, then switching to intravitreal dexamethasone implant (IDI; Ozurdex, Allergan, Parsippany, NJ) for poor responders. However, many patients undergo multiple injections prior to being declared a nonresponder. We devised a method for prediction of poor anti-VEGF response after one injection, and show that these patients subsequently respond well to IDI.
Methods: This study is a retrospective consecutive interventional case series of patients with RVO receiving anti-VEGF agents that were switched to IDI. Patients were categorized as nonresponders to anti-VEGF agents (edema did not improve) or responders (edema improved, but switched to IDI for longer treatment duration). Receiver operating characteristics (ROC) curve analysis was used to determine cutoffs of reduction in central retinal thickness (CRT) to predict poor response to anti-VEGF treatment.
Results: Twenty-three patients met inclusion criteria. There were 14 nonresponders and 9 responders. The ROC curve analysis found that the maximal sensitivity and specificity in correctly identifying responders to anti-VEGF therapy was those with >25% reduction in CRT 1 month after 1 anti-VEGF treatment (sensitivity 0.89, specificity 0.79, area under the curve 0.93). After IDI placement, anti-VEGF nonresponders showed significant improvement in visual acuity (VA) (p = 0.02) and CRT (p = 0.01).
Conclusions: In patients with macular edema secondary to RVOs, a reduction in CRT by ≤25%, 1 month after 1 anti-VEGF injection, is predictive of poor response to anti-VEGF treatment. These patients may benefit from earlier conversion to IDI treatment, which in our study, resulted in improved VA and CRT.