Predicting 1-month response of macular edema to intravitreal bevacizumab from 1-hour response

Abstract

ObjectiveTo evaluate the clinical significance of the change in central macular thickness (CMT) measured 1 h after intravitreal bevacizumab injection (IVB) for macular edema (ME) secondary to diabetic retinopathy or retinal vein occlusion (RVO). DesignRetrospective case series. ParticipantsThirty eyes with ME treated with IVB. MethodsA single IVB (1.25 mg/0.5 mL) was administered in 14 eyes with diabetic macular edema (DME) and 16 eyes with ME secondary to RVO. CMT was measured using spectral-domain optical coherence tomography before injection and again 1 hour and 1 month after injection. ResultsStatistically significant CMT reduction was observed at both time points. CMT declined from 542.3 ± 127.7 µm at baseline to 516.9 ± 123.4 µm 1 hour after injection (p < 0.001) and to 345.5 ± 110.0 µm at 1 month after injection (p < 0.001). The reduction in CMT 1 hour after injection was significantly correlated with the reduction in CMT observed at 1 month after injection, with respect to both absolute (r = 0.515, p = 0.004) and relative changes (r = 0.454, p = 0.012). The 15 eyes that had larger 1-hour CMT reductions also showed larger 1-month CMT reductions (242.9 ± 133.8 µm and 43.4% ± 16.5%) when compared with 15 eyes with smaller 1-hour CMT reductions (148 ± 130.6 µm and 25.0% ± 18.3%). This trend was the same for absolute and relative changes (p = 0.037 and 0.008). ConclusionsThe 1-month response of ME to IVB can be predicted by checking CMT 1 hour after injection.