Short-term effects of intravitreal ranibizumab therapy on diabetic macular edema

BACKGROUND The short-term effects of intravitreal ranibizumab (IVR) on diabetic macular edema (DME) remains unclear. We assessed the short-term effects of IVR on DME. METHODS Eighteen eyes of 14 patients with DME were enrolled in this prospective interventional case series. After intravitreal ranibizumab was injected into treatment-naïve eyes with DME, we measured the foveal thickness (FT) before and 2 h, 1 day, 1 week, and 1 month later and the best-corrected visual acuity (BCVA) at all times except 2 h and compared the changes to baseline (ΔFT and ΔVA). RESULTS The mean FT decreased significantly (p < 0.0001) from 452 ± 77 to 429 ± 65 microns after 2 h. The mean logarithm of the minimum angle of resolution BCVA improved significantly (p = 0.032) after 1 month from 0.41 ± 0.24 to 0.32 ± 0.21 (20/51 to 20/42, Snellen equivalent). The ΔFT after 2 h was significantly (r = 0.53, p = 0.025) correlated with the ΔFT after 1 month. The ΔVA after 1 day was significantly (r = 0.59, p = 0.01) correlated with the ΔVA after 1 month. CONCLUSIONS The structural effects of IVR for DME occurred within 2 h, whereas the functional effects occurred after 1 month. The short-term effects (within 1 day) of IVR may predict the therapeutic outcome 1 month after IVR in patients with DME. TRIAL REGISTRATION The trial registration number: UMIN000026118 (Feb/13/2017). Retrospectively registered.