C Perera1, R Chakrabarti2, F M A Islam3, J Crowston4. 1. 1] Journal of Mobile Technology in Medicine [2] Department of Ophthalmology, Fremantle Hospital, Western Australia, Australia. 2. 1] Journal of Mobile Technology in Medicine [2] Department of Ophthalmology, Centre for Eye Research Australia, University of Melbourne, Victoria, Australia. 3. 1] Department of Ophthalmology, Centre for Eye Research Australia, University of Melbourne, Victoria, Australia [2] Department of Psychological Sciences and Statistics, Faculty of Health, Arts and Design, Swinburne University of Technology, Victoria, Australia. 4. Department of Ophthalmology, Centre for Eye Research Australia, University of Melbourne, Victoria, Australia.
Abstract
PURPOSE: Smartphone-based Snellen visual acuity charts has become popularized; however, their accuracy has not been established. This study aimed to evaluate the equivalence of a smartphone-based visual acuity chart with a standard 6-m Snellen visual acuity (6SVA) chart. METHODS: First, a review of available Snellen chart applications on iPhone was performed to determine the most accurate application based on optotype size. Subsequently, a prospective comparative study was performed by measuring conventional 6SVA and then iPhone visual acuity using the 'Snellen' application on an Apple iPhone 4. RESULTS: Eleven applications were identified, with accuracy of optotype size ranging from 4.4-39.9%. Eighty-eight patients from general medical and surgical wards in a tertiary hospital took part in the second part of the study. The mean difference in logMAR visual acuity between the two charts was 0.02 logMAR (95% limit of agreement -0.332, 0.372 logMAR). The largest mean difference in logMAR acuity was noted in the subgroup of patients with 6SVA worse than 6/18 (n=5), who had a mean difference of two Snellen visual acuity lines between the charts (0.276 logMAR). CONCLUSION: We did not identify a Snellen visual acuity app at the time of study, which could predict a patients standard Snellen visual acuity within one line. There was considerable variability in the optotype accuracy of apps. Further validation is required for assessment of acuity in patients with severe vision impairment.
PURPOSE: Smartphone-based Snellen visual acuity charts has become popularized; however, their accuracy has not been established. This study aimed to evaluate the equivalence of a smartphone-based visual acuity chart with a standard 6-m Snellen visual acuity (6SVA) chart. METHODS: First, a review of available Snellen chart applications on iPhone was performed to determine the most accurate application based on optotype size. Subsequently, a prospective comparative study was performed by measuring conventional 6SVA and then iPhone visual acuity using the 'Snellen' application on an Apple iPhone 4. RESULTS: Eleven applications were identified, with accuracy of optotype size ranging from 4.4-39.9%. Eighty-eight patients from general medical and surgical wards in a tertiary hospital took part in the second part of the study. The mean difference in logMAR visual acuity between the two charts was 0.02 logMAR (95% limit of agreement -0.332, 0.372 logMAR). The largest mean difference in logMAR acuity was noted in the subgroup of patients with 6SVA worse than 6/18 (n=5), who had a mean difference of two Snellen visual acuity lines between the charts (0.276 logMAR). CONCLUSION: We did not identify a Snellen visual acuity app at the time of study, which could predict a patients standard Snellen visual acuity within one line. There was considerable variability in the optotype accuracy of apps. Further validation is required for assessment of acuity in patients with severe vision impairment.
Authors: Robert C Wu; Dante Morra; Sherman Quan; Sannie Lai; Samira Zanjani; Howard Abrams; Peter G Rossos Journal: J Hosp Med Date: 2010 Nov-Dec Impact factor: 2.960
Authors: Stuart Keel; Jane Scheetz; Edith Holloway; Xiaotong Han; William Yan; Andreas Mueller; Mingguang He Journal: BMJ Open Date: 2019-03-23 Impact factor: 2.692
Authors: Xiaotong Han; Jane Scheetz; Stuart Keel; Chimei Liao; Chi Liu; Yu Jiang; Andreas Müller; Wei Meng; Mingguang He Journal: Transl Vis Sci Technol Date: 2019-08-19 Impact factor: 3.283