Foveal thickness reduction after anti-vascular endothelial growth factor treatment in chronic diabetic macular edema

AIM: To report foveal thickness reduction in eyes with resolution of macular edema and recovery of a foveal depression after one-year of anti-vascular endothelial growth factor (anti-VEGF) therapy for center-involving diabetic macular edema (DME). METHODS: Foveal thickness was assessed with optical coherence tomography to determine the central subfield foveal thickness (CSFT) and macular volume in 42 eyes with DME (CSFT>275 μm). Evaluations also included measurement of best-corrected visual acuity (BCVA), and were performed at baseline, and upon foveal depression recovery achieved after 12 monthly intravitreal injections of either 1.5 mg/0.06 mL bevacizumab (n=21) or 0.5 mg/0.05 mL ranibizumab (n=21). Data was compared to 42 eyes of normally sighted, non-diabetic, healthy individuals with similar age, gender and race distributions. RESULTS: Mean baseline BCVA was 0.59±0.04 and 0.32± 0.03 logMAR (P<0.001) after treatment and resolution of DME, with all, but 3 eyes, showing BCVA improvement. Mean CSFT before treatment was 422.0±20.0 μm, and after treatment, decreased to 241.6±4.6 μm (P<0.001), which is significantly thinner than CSFT found in control subjects (272.0±3.4 μm; P<0.001). Moreover, in 33/42 DM eyes (79%), CSTF was thinner than the matched control eye. Macular volume showed comparable results, but with lower differences between groups (control: 8.5±0.4 mm³; DME: 8.2±1.0 mm³; P=0.0267). CONCLUSION: DME eyes show significantly lower foveal thickness than matched controls after DME resolution achieved with one-year anti-VEGF therapy. Further investigation into the reasonsfor this presumable retinal atrophy using fluorescein angiography and functional parameters as well as establishing possible predictors is warranted. This finding should be considered during the treatment of DME.