Impact of ranibizumab on visual impairment in patients with bilateral diabetic macular edema

Diabetic macular edema (DME) frequently presents bilaterally. In case of bilateral retinal disease, the visual impairment (VI) and the visual acuity (VA) are strongly correlated to the better eye. The aim of this study was to assess the impact of ranibizumab intravitreal injections (IVR) on VI in patients with simultaneous VA loss due to DME.

This was a retrospective two-center study including consecutive DME patients with visual loss treated with ranibizumab since November 2011 and with a minimum follow-up of 6 months. Patients with bilateral visual decrease from DME undergoing IVR within 6 months of each other were included.

Twenty-nine DME patients who received bilateral IVR within a 6-month interval in the second eye were included. At baseline, 82.8% (n = 24) of patients had a VA < 20/40 in their better eye versus 44.8% (n = 13) of patients at the end of follow-up, i.e. a reduction by 45.9% of VI. In the better eye, the mean VA was 57.3, 65.0 and 65.5 ETDRS letters, respectively, at baseline, month 3 and month 6 (mean VA gain +8.2 letters). In the worse eye, the mean VA was 44.2, 53.5 and 53.8 ETDRS letters, respectively, at baseline, M3 and M6 (mean VA gain +9.6 letters).

In patients with bilateral DME, subsequent ranibizumab IVR reduced VI frequency.