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E. Zaharova, B. Moore, L. Mayer, L. Deng; An Evaluation of EVA, the Stimuli Acuity System and the Smart System II for HOTV Visual Acuity Measurements. Invest. Ophthalmol. Vis. Sci. 2009;50(13):2013.
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© ARVO (1962-2015); The Authors (2016-present)
The aim of this study is to evaluate the three computerized VA charts (the EVA, the Stimuli Acuity System (SAS) by Accommodata Corporation and the Smart System II (SS II) by M&S Technologies) in terms of their accuracy of visual acuity measurements and test-retest repeatability as compared to the standardized back-illuminated LogMar HOTV plastic chart using these tests under habitual-corrected and blurred conditions.
Fully-interpolated 5 letters per line monocular visual acuities of the right eye were taken under habitual-corrected and blur-induced (by a +1.25 DS) conditions in 30 young healthy adults on two separate visits separated by approximately 1-2 weeks. At each visit each subject underwent a total of 10 visual acuity measurements in which EVA, Stimuli Acuity and SS II systems were tested against ETDRS and HOTV LogMar charts in random order by one masked examiner. The order of habitual-corrected and non-blur induced tests was also randomized with setting a limit of not more than 2 tests of the same kind in a row. All charts were presented at a standard distance of 6 meters.
All computerized VA charts for both habitual-corrected condition (EVA [MD=0.01 ±0.031], SAS [MD=-0.02 ±0.059], SS II [MD=-0.152 ±0.067]) and blur-induced condition (EVA [MD=-0.03 ±0.085], SAS [MD=0.09 ± 0.17], SS II [MD=-0.004 ±0.169]) showed strong repeatability as analyzed by Bland-Altman methods and two-tail paired two-sample t-test (p>0.05). The mean visual acuity difference in habitual-correction condition as compared to HOTV control is +0.0867 for EVA, +0.258 for SAS and +0.0183 for SS II, which are statistically significant (p<0.05), but not clinically significant differences for EVA and SS II. However, in all computerized tests in blur-induced condition there is not enough evidence to conclude that the mean visual acuities were different from HOTV control measurements.
Both systems EVA and SS II showed good repeatable measurements that agreed well with LogMar HOTV chart, making it to be a good alternative to the HOTV visual acuity measurements in young healthy adults.
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