Table 2.
Description of smartphone ophthalmoscopy imaging techniques.
| Study author, year | Attachment used | Imaging technique | Smartphone used | Ungradable |
| Bhat, 2016 [32] | Ocular Cellscope | Up to five fields, 50°; AIa: EyeArt v1.2 software used to grade images; acquired by: medical interns and assistants. | iPhone 5S | N/Ab |
| Kim, 2017 [33] | Cellscope Retina | Both human and AI (EyeApp) graders employed. | N/A | N/A |
| Kim, 2018 [34] | Cellscope Retina | 5-field, 50°; fields imaged: central, inferior, superior, nasal, and temporal retina; images were digitally stitched, creating a 100° image; pixels per retinal degree: 52.3; acquired by: medical students or interns. | iPhone 5S | 2 (1.7%) images/eyes |
| Rajalakshmi, 2015 [35] | Remidio Fundus on Phone (FOP) | 4-field, 45°; fields imaged: macula, disc and nasal to optic disc, superior-temporal, inferior-temporal retina; autofocus function of smartphone was used. | Android phone | 0 |
| Rajalakshmi, 2018 [36] | Remidio Fundus on Phone (FOP) | 4-field, 45°; fields imaged: macula centered, disc centered, superior-temporal, and inferior-temporal retina; AI: EyeArt software used to grade images. | Android phone | 5 (1.7%) patients |
| Russo, 2015 [37] | D-Eye (Si14 SpA, Padova, Italy) | 20°; videography and digital images acquired, comprising the posterior pole, macula, optic disc, and peripheral retina; resolution: 3264×2448 pixels; pixels per retinal degree: 150; acquired by: a retinal specialist. | iPhone 5 | 9 (3.8%) eyes |
| Ryan, 2015 [38] | 20 D lens | Videography and then screenshots to obtain the best images of optic nerve and macula; resolution: 3264×2488 pixels; FilmIc Pro app used to adjust focus and zoom independently; acquired by: a medical student with limited training. | iPhone 5 | 11 (1.8%) photographs |
| Sengupta, 2018 [39] | Remidio FOP | 3-field, 45°; fields imaged: posterior pole (macula centered), nasal, and superotemporal field; resolution: 441 pixels per inch; acquired by: ophthalmic photographer without special training. | HTC One (M8) | 1.7-2.1% of images |
| Toy, 2016 [40] | Volk Digital ClearField lens mounted on Paxos Scope posterior segment hardware adapter | Variable number of fields, 45°; acquired by: an ophthalmologist. | iPhone 5S | 2 (2%) eyes |
aAI: artificial intelligence.
bN/A: not available.