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Joshua Robinson, Rob Chun, Alex Zemke, Danielle Irvine, Vanessa Braimah, Walter M Jay; Characteristics of low vision patients that prefer reverse contrast settings on Closed Circuit Televisions (CCTVs) and iPads. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4153.
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© ARVO (1962-2015); The Authors (2016-present)
Reverse contrast is an accessibility feature generally offered on video magnifiers and tablets like the iPad. To our knowledge, no correlations have been identified between type of diagnosis (retinal versus optic nerve) and preference for reading with reverse contrast mode. The recommendation for use of reverse contrast on electronic magnifiers is driven by the patient’s subjective comfort level when reading text on an electronic device, and is not necessarily driven by the clinical findings or diagnosis of the low vision patient. The impact and its relationship to the patient’s condition have never been clinically investigated.
Analysis was completed on a previously approved IRB study where contrast sensitivity results from a prior ARVO study were not analyzed or published (Zemke A, et al. IOVS 2013;313:ARVO E-Abstract 2749). Fourteen patients, 18 years or older, with best corrected visual acuities between 20/50 and 20/200 and minimal prior experience with an iPad or CCTV were enrolled in the study. Patients were asked to read a paragraph from a newspaper article and book at their preferred magnification setting on each device. Patients were then surveyed with a questionnaire investigating subjective comfort and preference for positive (black print with white background) or negative contrast (white print with black background).
Four of the 14 patients (28.6%) preferred the reverse contrast setting. Three of these 4 patients preferred using the iPad over the CCTV. The four patients that preferred reading with reverse contrast had 4 different diagnoses including primary open angle glaucoma, retinal detachment, proliferative diabetic retinopathy, and non-arteritic ischemic optic neuropathy. A two-tailed p-value by Fisher’s exact test revealed no statistical significance when comparing patient diagnosis (retinal versus optic nerve) to patient preference for reading with reverse contrast (p = 0.5205).
The results of the study suggest that low vision practitioners may not be guided by the type of patient diagnosis when considering which patients would benefit from reading with reverse contrast. The reduced sample size was a limitation to the study and more data is needed to confirm the findings. Investigations are also needed to analyze potential relationships with baseline contrast sensitivity or symptoms of photoaversion.
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