Ranibizumab Treatment for Diabetic Macular Edema in a Clinical Routine Setting: 12 Months Results

Abstract

Purpose: : To evaluate the efficacy of ranibizumab treatment in diabetic macular edema (DME) in a routine clinical setting and correlations of baseline characteristics, Spectral(SD)-OCT and visual acuity outcomes.

Methods: : Data of 30 eyes with visual impairment due to DME with a follow-up of 12 months were analyzed. All eyes were treated following a PRN regimen. Baseline characteristics, OCT results for central retinal thickness (CRT) and volume and best corrected visual acuity (BCVA) results were correlated. Absolute values and a logarithmic transformation of excess CRT were used for calculations. All calculations were performed for 3-, 6-, 9- and 12-months outcomes.

Results: : Mean values at baseline were 473µm for CRT, 8.85 mm³ for macular volume, and 0.46 for LogMAR visual acuity. During the follow-up period of 12 months a mean number of 3.9 ranibizumab injections were given, almost half of these from baseline to month 3 (1.93). CRT significantly (p<0.01) decreased by 68, 73, 85 and 85µm at months 3, 6, 9, and 12. Visual acuity significantly (p<0.01) improved to 0.31, 0.33, 0.29 and 0.30 LogMAR respectively. Greater improvement of BCVA occurred in eyes with shorter duration of macular edema and better baseline visual acuity (≤ 0.4LogMAR). No correlation was found between BCVA change and the absolute change in CRT or macular volume. However a significant correlation (p<0.05) was found between BCVA and the change in CRT based on the logarithmic calculation. No correlation of BCVA could be found with baseline CRT, baseline macular volume, pre-treatments (focal laser coagulation, intravitreal triamcinolone) or the frequency of ranibizumab injections.

Conclusions: : These results suggest that repeated intravitreal injections of ranibizumab can significantly reduce central retinal thickness and improve visual acuity in patients with DME in a clinical routine PRN regimen with a mean of 3.9 injections. Eyes with shorter history of visual impairment and better baseline BCVA seem to show better BCVA improvement. Interesting is the fact that a significant correlation was found between BCVA and excess CRT if calculated in a logarithmic transformation like LogMAR is calculated.

Keywords: diabetic retinopathy • macula/fovea • imaging/image analysis: clinical