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Sanjeev Kasthurirangan, Carrie Garufis, Jay Rudd, Jonathan Solomon; Evaluation of an Electronic Visual Acuity and Contrast Sensitivity Test System for Use in Ophthalmic Clinical Trials. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4229.
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© ARVO (1962-2015); The Authors (2016-present)
Computer based vision testing will be preferable in ophthalmic clinical trials involving multiple visual acuity (VA) and contrast sensitivity (CS) measurements. In this study, the electronic Clinical Trial Suite (CTS) from M&S Technologies is evaluated for this purpose.
31 pseudophakic subjects were tested for uncorrected VA, best corrected VA, mesopic grating CS for 1.5, 3, 6, 12 and 18 cycles per degree (CPD) without and with glare with a chart based Vector Vision (VV) unit and the electronic CTS system. In addition, only with the CTS system, the effect of +0.25D, +0.50D and +0.75D defocus under mesopic condition was evaluated for best corrected VA, 25% contrast VA, 10% contrast VA, threshold contrast for a 20/40 letter and grating CS. Subjects included 61% females, aged 61 to 82 years and spherical equivalent refraction from -2.25D to +0.75D.
Visual acuities were within 1-line between the electronic CTS and VV systems for uncorrected VA (mean ± SD difference: -0.04 ± 0.11 logMAR) and corrected VA (difference: -0.03 ± 0.06 logMAR). Mesopic CS comparisons between VV and CTS systems showed that without glare 1.5 and 3.0 CPD were different by 0.35 logunits (p<0.05 in each case) and with glare 3.0 CPD was different by 0.16 logunits (p<0.05). For all other spatial frequencies and glare condition, the mean differences were within 0.13 logunits. CS repeatability standard deviation was up to 0.38 logunits for both VV and CTS systems across spatial frequencies and glare conditions. Defocus of +0.75D led to decline in all letter tests (p<0.0001 in all cases). For grating CS, only 6 CPD (difference: -0.18 logunit) and 12 CPD (difference: -0.21 logunit) were statistically significant (p<0.05), however this is within the repeatability of the test. Average drop with +0.75D for best corrected VA was -0.17 ± 0.13 logMAR, for 25% letter was -0.13 ± 0.10 logMAR, for 10% letter was -0.10 ± 0.11 logMAR and for contrast threshold test was -0.17 ± 0.18 logunits. The repeatability standard deviation was within 0.10 logMAR for the three acuity tests and 0.08 logunit for the contrast threshold test.
The CTS system was found to be equivalent to the currently used light box based Vector Vision system, however offers the advantage of presenting randomized letter presentation and convenience of use.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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