Chatziralli I, Santarelli M, Patrao N, Nicholson L, Zola M, Rajendram R, Hykin P, Sivaprasad S. Identification of time point to best define ?sub-optimal response?following intravitreal ranibizumab therapy for diabetic macular edema based on real-life data. Eye. 2017;31:1594?1599.