Paired responses to intravitreal bevacizumab in diabetic macular edema: predictors of response in the fellow eye

Abstract

Factors predictive for response of diabetic macular edema (DME) to intravitreal bevacizumab (IVB) remain unclear. In this study, we assess the predictability of DME response to IVB based on the response to IVB in a previously treated fellow eye and other known pre-injection factors in (DME). Retrospective chart review was conducted on 28 patients (56 eyes) with bilateral DME who underwent bilateral IVB therapy. Responses in both eyes were measured by change in central subfield thickness (CSFT) via optic coherence tomography (OCT), and change in visual acuity. Age, lens status, and starting macular thickness were recorded. We found 21% of the reduction in CSFT after IVB on OCT in the study eye may be explained by the percentage change in CSFT in the previously treated fellow eye [CI: 0.092-0.716; p-value = 0.0141]. Also, the pre-injection CSFT predicts 14% of the response to IVB in the same eye [R² = 9.6%, p-value = 0.018]. When combined in a multi-factorial model, 33% of the change in CSFT following IVB may be explained by these two factors. Lens status, change in visual acuity, and age were not statistically significant predictors of response. In DME, the response to IVB in an eye is partially explained by the pre-injection retinal thickness in the same eye and by the response to IVB in the previously treated fellow eye. Lens status, change in visual acuity, and age were not statistically significant predictors of response in this study.