Editors Selection IGR 20-4

Miscellaneous: The growing role of smartphones I

Robert Chang

Comment by Robert Chang on:

82452 Smartphone use in ophthalmology: What is their place in clinical practice?, Hogarty DT; Hogarty JP; Hewitt AW, Survey of Ophthalmology, 2020; 65: 250-262

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This review article focuses on Apple iOS and Android smartphone ophthalmology-based applications (271 and 170 'apps', respectively) as of June 2019. Since 2007, smartphones have played an increasing role in global ophthalmology and telemedicine ranging from portable vision screening, picture and video sharing, online education, diagnostic decision support tools, and remote eye exams. The authors found three studies comparing distance visual acuity (VA) with Snellen and ETDRS. PEEK Acuity1 and the Snellen App2 both had a mean difference of less than one line compared with the corresponding physical chart. However, the third Eye Phone study by Perera C et al.3 found a lot of optotype sizing errors in multiple VA apps, and when the vision was worse than 6/12, the VA results were less reliable. In a 2017 trial by Rono et al.4 of PEEK Acuity App used as a vision screening tool in Kenya compared to standard tumbling E, PEEK had lower specificity and positive predictive value resulting in more unnecessary referrals. This may be due to variable test setup conditions. Given the lack of optotype accuracy standards and test re-test reliability cutoffs, no smartphone visual acuity app can be recommended currently. In terms of glaucoma, smartphone app developers have focused on fundus imaging, i.e., turning a smartphone into an ophthalmoscope, but also have begun to tackle virtual reality (VR) visual fields (VF). In optic nerve imaging, several papers4,5 have looked at grading cup-todisc (C/D) ratio from smartphone photos using an attachment such as D-Eye, demonstrating better C/D estimation from the smartphone videos. In a prototype smartphone VR, a study by Tsapakis et al. tested a custom-made VF suprathreshold algorithm compared with the Humphrey Field Analyzer. Sensitivities at various dB cutoffs for AUROC ranged from 0.762 for high threshold to 0.837 for low threshold (both P < 0.001).6 In summary, smartphone-based glaucoma apps, including VA testing, smartphone imaging, and VR VF combined with self-tonometry provide an opportunity for ubiquitous smartphone technology to be integrated into remote ophthalmic care 'from anywhere' once further validation is completed and consistent standards are set.


  1. Bastawrous A, Rono HK, Livingstone IAT, et al. Development and validation of a Smartphone-based visual acuity test (Peek Acuity) for clinical practice and community-based fieldwork. JAMA Ophthalmol. 2015;133(8):930e7.
  2. O'Neill S, McAndrew DJ. The validity of visual acuity assessment using mobile technology devices in the primary care setting. Aust Fam Physician. 2016;45(4):212e5.
  3. Perera C, Chakrabarti R, Islam FMA, Crowston J. The eye phone study: reliability and accuracy of assessing Snellen visual acuity using smartphone technology. Eye. 2015;29(7):888e94.
  4. Kim Y, Chao DL. Comparison of smartphone ophthalmoscopy vs conventional direct ophthalmoscopy as a teaching tool for medical students: the COSMOS study. Clin Ophthalmol. 2019;13:391e401.
  5. Mamtora S, Sandinha MT, Ajith A, Song A, Steel DHW. Smart phone ophthalmoscopy: a potential replacement for the direct ophthalmoscope. Eye. 2018;32(11):1766e71.
  6. Tsapakis S, Papaconstantinou D, Diagourtas A, et al. Homebased visual field test for glaucoma screening comparison with Humphrey perimeter. Clin Ophthalmol. 2018;12:2597e606.

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