title: A pilot trial of the iPad tablet computer as a portable device for visual acuity testing.
abstract: We evaluated the accuracy of an app for the iPad tablet computer (Eye Chart Pro) as a portable method of visual acuity (VA) testing. A total of 120 consecutive patients (240 eyes) underwent visual acuity test with an iPad 2 and a conventional light-box chart. The logMAR VA results from the iPad were significantly higher than those from the light-box (P < 0.001). Bland-Altman analysis revealed a mean difference (bias) of 0.02 logMAR units between the VA results from the iPad chart and the light-box chart, with 95% limits of agreement of -0.14 to 0.19. Two groups of patients were defined: in Group 1 there were 182 eyes with VA better than 0.1 according to the light-box VA test. The median logMAR VA by the iPad was 0.54 and by the light-box chart it was 0.52; there was no significant difference between them (P = 0.69). In Group 2 there were 58 eyes with VA equal to or worse than 0.1 according to the light-box VA test. The median logMAR VA by the iPad was 1.26 and was 1.10 by the light box; the result from the iPad was significantly lower (P < 0.001). The Eye Chart Pro app installed on the iPad is reliable for VA testing only when the Snellen VA is better than 0.1 (20/200).
authors: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Centre, Sun Yat-sen University, 54S Xianlie Road, Guangzhou 510060, China.
authors: Zhao-tian
authors: ZT
authors: Zhang
authors: Shao-chong
authors: SC
authors: Zhang
authors: Xiong-gao
authors: XG
authors: Huang
authors: Ling-yi
authors: LY
authors: Liang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D034201:Computers, Handheld; D003936:Diagnosis, Computer-Assisted / Q000295:instrumentation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D012984:Software; D014786:Vision Disorders / Q000175:diagnosis*; D014787:Vision Tests / Q000295:instrumentation* / Q000379:methods; D014792:Visual Acuity