Wide field of view handheld smart fundus camera for telemedicine applications.

Purpose: We report that a large field-of-view (FOV) retinal image can be acquired by a smart fundus camera. Approach: This handheld system consists of a Raspberry Pi board, a touch screen display, a customized optical lens group, a ring light-emitting diode, and a Li-battery. Results: Wide FOV of ∼ 57 deg is observed with proper lens configuration and can be expanded using image stitching algorithms. Conclusions: This customized handheld fundus camera provides better image quality than cellphone-based fundus imaging solutions and offers more operational features than traditional portable fundus cameras. It may benefit field-portable ophthalmic diagnostic applications.