Symmetry in early response to intravitreal ranibizumab in bilateral diabetic macular oedema

Abstract Purpose To study the symmetry in response to bilateral diabetic macular oedema ( DME ) treated with bilateral intravitreal injections of ranibizumab ( IVR ). Methods The charts of 36 eyes of 18 patients treated with a loading dose of three monthly IVR in both eyes were retrospectively reviewed. Favourable anatomical response was defined as a decrease by more than 10% in baseline central macular thickness ( CMT ), and favourable functional response was defined as an increase in visual acuity ( VA ) ≥5 letters. A symmetric response was defined as a similar anatomical and/or functional response in the first ( FE ) and second ( SE ) treated eyes. Results The VA improved significantly after ranibizumab treatment in both eyes (p < 0.01). A statistically significant positive correlation was found for the functional response to ranibizumab between the FE and the SE ( R 2  = 0.26, p = 0.03). The mean CMT decreased significantly in both eyes (p < 0.01). A strong positive correlation was observed between the anatomical response to ranibizumab in the FE and the SE ( R 2  = 0.37, p = 0.01). Symmetric favourable anatomical and functional responses were observed in 13 patients (72%). In two additional patients, an asymmetric functional response was observed despite a decrease in retinal thickness in both eyes. Conclusion Symmetric anatomical and functional responses were observed in 72% of patients with DME after three initial IVR in each eye. This finding could be of clinical interest in the decision to treat the fellow eye, in a disease where a bilateral involvement is frequent.