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G Dagnelie, L Yang, F Eshraghi, NL Lewis, JC Hicks; Validated Vision Test Battery for the Home PC . Invest. Ophthalmol. Vis. Sci. 2002;43(13):3811.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To allow frequent and calibrated vision testing of clinical trial subjects between periodic clinic visits. Methods: Normally sighted and visually impaired subjects were recruited to validate 14 PC-based tests, using their home PCs to collect weekly vision measures. Home monitor screens were calibrated using a simple grayscale setting and an off-the shelf luxmeter for luminance, and a dollar bill for pixel size. NoIR U23 sunglasses and welder's goggles with ND 1.0 filters were used to reduce luminance; 2 halogen desk lamps were used as glare sources. Vision measures included: "ETDRS" visual acuity, "Pelli-Robson" contrast sensitivity, and a central visual field isopterS at 3 light levels (full, 4%, and 0.1% luminance); low contrast acuityS; glare-impaired contrast sensitivity; macular pigment densityS; 48-hue discriminationS; and primary color half-saturation setting. All letter tests converged towards threshold using 2 interspersed PEST routines; one PEST for each of 24, 12, and 12 directions was used in the visual field tests. During 3 initial sessions of tests marked "S", target size, location, contrast, and/or saturation self-adjust to each subject's vision level; the following 10-15 sessions were used to compute reproducibility. Between-sessions variability was used to compute 95% confidence intervals (CI.95) in letter size, contrast, or isopter eccentricity. Test results were compared to standard vison tests in 3-6 lab visits. Data presented here refer to all subjects who completed testing to date: 1 normally-sighted, 1 choroideremia, and 3 RP. Results: Subjects were able to perform all 14 tests in a 1-hour session every week. PC-measured vision levels corresponded well with lab-measured levels; differences were attributable to luminance differences. CI.95 were: VAfull, ±1.0 dB; VA4%, ±1.3 dB; VA0.1%, ±1.6 dB; VALC, ±0.8 dB; CSfull, ±1.0 dB; CS4%, ±1.3 dB; CS0.1%, ±1.8 dB; CSglare, ±1.5 dB; VFfull, ±1.6 dB; VF4%, ±1.9 dB; VF0.1%, ±2.1 dB. Use of dual PESTs in VA and CS tests reduced CI.95 by 0-30%. Conclusion: CI.95 values for visual acuity and contrast sensitivity tests obtained on home PCs correspond closely to those in published laboratory studies, strongly supporting the validity of PC-based tests as longitudinal measures in clinical trials. We continue to validate the remaining tests, and are collecting data in additional subjects and during a cross-over trial of lutein in RP.
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