Artificial intelligence using deep learning to screen for referable and vision-threatening diabetic retinopathy in Africa: a clinical validation study de réir Valentina Bellemo, MSc, Zhan W Lim, PhD, Gilbert Lim, PhD, Quang D Nguyen, BEng, Yuchen Xie, MScPH, Michelle Y T Yip, BA, Haslina Hamzah, BSc, Jinyi Ho, DFST, Xin Q Lee, BSc (Hons), Wynne Hsu, PhD, Mong L Lee, PhD, Lillian Musonda, MD, Manju Chandran, FRCOphth, Grace Chipalo-Mutati, FCOphth (ECSA), Mulenga Muma, FCOphth (ECSA), Gavin S W Tan, MD, Sobha Sivaprasad, FRCOphth, Geeta Menon, FRCOphth, Tien Y Wong, MD, Daniel S W Ting, MD