|Title||VALIDITY AND REPEATABILITY OF COMPUTERIZED VISUAL ACUITY DEVICES: EVA, SMART SYSTEM PC AND STIMULI ACUITY SYSTEM IN HABITUAL-CORRECTED YOUNG ADULTS|
|Author, Co-Author||Elena Zaharova|
|Abstract|| PURPOSE: The aim of this study is to evaluate the three computerized Visual Acuity charts (the EVA, the Stimuli Acuity System (SAS) by Accommodata Corporation and the Smart System PC (SS) by M&S Technologies) in terms of their accuracy of visual acuity measurements and test-retest repeatability as compared to the standardized LED back-illuminated LogMAR HOTV plastic chart using these tests under habitual-corrected conditions.
METHODS: Fully-interpolated 5 letters per line HOTV monocular visual acuities of the right eye were taken in 30 habitual-corrected young healthy adults on two visits separated by approximately 1-2 weeks. At each visit subjects were tested using EVA, SAS and SS devices against HOTV LogMAR chart. The stimulus was a single isolated standardized optotype surrounded by crowding bars. All charts were presented in random order by one masked examiner at a standard distance of 4 meters.
RESULTS: All computerized VA charts showed clinically acceptable test-retest repeatability as shown by statistically insignificant differences between VA measurements of weeks 1 and 2 (p>0.05). The 95% limits of agreement for repeatability interval was the narrowest in HOTV control chart, followed by EVA and then by SS II and SAS as analyzed by Bland-Altman methods. The mean visual acuity difference as compared to HOTV control was the most accurate in SS (MD=-0.018 +/- 0.063) with a p=0.121. The results were then followed by SAS (MD=+0.025 +/- 0.070) that had a border line p-value of p=0.058. EVA underestimated visual acuity measurements with a statistically significant difference in mean LogMAR VA of -0.087 +/- 0.073, which is not a clinically significant difference.
CONCLUSIONS: As compared to HOTV control, LogMAR visual acuity agreed the best in SS (M&S), followed by SAS and then by EVA with clinically insignificant differences in mean LogMAR VA; thus, making those tests to be good alternatives to the crowded HOTV visual acuity measurements in young healthy adults.
|Affiliation of Co-Authors|