April 2014
Volume 55, Issue 13
Free
ARVO Annual Meeting Abstract  |   April 2014
Evaluation of Tablet Computers in the Assessment of Visual Acuity: Can iPads™ Replace the Snellen Chart?
Author Affiliations & Notes
  • Conor Patrick Malone
    Ophthalmology, Royal College of Surgeons in Ireland, Dublin, Ireland
    Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin, Ireland
  • Colm McCourt
    Ophthalmology, Royal College of Surgeons in Ireland, Dublin, Ireland
  • Nawal T Al Daqqaq
    Ophthalmology, Royal College of Surgeons in Ireland, Dublin, Ireland
    RCSI-MUB, Busaiteen, Bahrain
  • Conor Murphy
    Ophthalmology, Royal College of Surgeons in Ireland, Dublin, Ireland
    Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin, Ireland
  • Footnotes
    Commercial Relationships Conor Malone, None; Colm McCourt, None; Nawal Al Daqqaq, None; Conor Murphy, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science April 2014, Vol.55, 5599. doi:
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      Conor Patrick Malone, Colm McCourt, Nawal T Al Daqqaq, Conor Murphy; Evaluation of Tablet Computers in the Assessment of Visual Acuity: Can iPads™ Replace the Snellen Chart?. Invest. Ophthalmol. Vis. Sci. 2014;55(13):5599.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose: Assessment of visual acuity (VA) is an essential clinical examination in ophthalmology and across many other specialties. In the community, primary care physicians use VA to assist in triaging patients for referral to ophthalmology. The advent of tablet computers presents an opportunity to offer physicians access to inexpensive, standardised, and accurate methods of measuring VA. Previous studies have found that glare and low baseline VA limit the reliability of tablet computers in assessing VA. This study seeks to assess the accuracy of a popular tablet application used for measuring VA and to examine the effects of decreased luminance on test validity.

Methods: 79 ambulatory care patients were recruited from a large national ophthalmology tertiary referral centre. Each patient's VA was tested twice: firstly using the established Lighthouse vision chart and secondly on an Apple iPad 2™ tablet using proprietary Kybervision Visual Acuity XL software. Phase 1 used a luminance setting of 380 cd/m2. Phase 2 used a lower luminance of 160 cd/m2. Phase 1 included 88 eyes of 46 patients. Phase 2 included 61 eyes of 33 patients. VA was recorded on the LogMAR scale.

Results: In Phase 1, at maximum device luminance of 380 cd/m2, there was a statistically significant difference between the standard chart and the tablet device for both unaided VA (p=0.0028) and best-corrected VA (p=0.0003). In Phase 2, at moderate luminance of 160 cd/m2, no statistically significant difference was found between measurements on the Lighthouse and iPad charts for either unaided VA (p=0.1008) or best-corrected VA (p=0.2849).

Conclusions: Previous studies have sought to validate the use of tablet devices for measurement of VA, but have cited glare and poor baseline VA as limiting factors. These outcomes were confirmed by Phase 1 of this study. ETDRS protocol recommends that luminance in VA assessment should be set between 80 and 320 cd/m2. Phase 2 of this study demonstrated that the use of moderate luminance (160 cd/m2) validates the use of this tablet computer and software application as an equal alternative to traditional printed or projected vision charts.

Keywords: 754 visual acuity  
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