Background/aims: Bevacizumab has been shown to be an effective treatment of macular edema. This study assesses the response of macular edema to bevacizumab with specific focus to the first 24 hours post-injection.
Methods: Subjects with diabetic macular edema (DME) or exudative age-related macular degeneration (ARMD) received intravitreal bevacizumab injections. ETDRS visual acuity and OCT macular thickness measurements were obtained at baseline; 1, 3, 6, 24, and 48 hours; 1 week; and 1-month post-injection.
Results: The average baseline OCT was 452.91 microns (SD = 182.96, range = 249.00 – 784.00). After injection, there was a statistically significant decrease in OCT thickness within 2 hours with a plateau phase out to 24 hours, followed by a significant drop between 24 and 48 hours, and a return towards baseline between 1 week and 1 month. Average changes in ETDRS visual acuity were not statistically significant, though many patients experienced a positive outcome.
Conclusion: While there is an immediate pressure-related effect, it appears that the anti-VEGF effects of bevacizumab require approximately 24 hours to become active and persist for 2-3 weeks. These results suggest that injections at 2-3 week intervals might provide improved clinical outcomes, compared to the currently typical four to six week interval of injections.