Table 1.

Methods of retinal image acquisition

Method	Main features	References
Stable fundus camera	Fundus camera (narrow angle) located in one place	[56–62]
Mobile fundus camera	Fundus camera (narrow angle) moved from location to location; mounted in offices; more effective	[63]
Mobile, on-vehicle hard-mounted diagnostic sets	Diagnostic sets (fundus camera [narrow- and wide-field] and software) hard-mounted on specially adapted vehicles; moved from one location to another	[22, 45, 64, 65]
Ultra-wide-field (UWF) diagnostic sets	Ultra-wide fundus cameras hard-mounted in offices or on vehicles	[36–39, 60, 61, 64, 66, 67]
OCT based diabetic retinopathy screening	Screening with use of OCT (method of choice for diabetic macular edema)	[18, 39, 53, 67–71]
Portable fundus cameras	Screening with portable handheld camera (low cost, possible in-home testing)	[27, 72–78]
Adopted smartphones	Screening with commercially available smartphones with proper adapters (low cost, possible in-home testing	[44–53, 58, 72, 79]