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Christopher Lievens, Christina Newman, Alan Kabat, Jacob Weber; COMPARISON OF THE VMAX VOICE ACTIV™ SUBJECTIVE REFRACTOR (VASR) AND TRADITIONAL REFRACTION IN A HEALTHY POPULATION. Invest. Ophthalmol. Vis. Sci. 2018;59(9):1283.
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© ARVO (1962-2015); The Authors (2016-present)
The Vmax VASR (Voice Activ™ Subjective Refractor) utilizes wavefront aberrometry and point spread function technology combined with artificial intelligence to conduct an objective/subjective refraction. Results with the VASR were compared to a traditional refraction.
Fifty healthy subjects were examined by a masked investigator using a standard autorefractor (Nidek TonoRef™ II), followed by subjective refinement through the phoropter (monocular subjective refraction with binocular balance). Subjects were then evaluated by a different investigator using the VASR to obtain an objective and subjective refraction result. Phoropter values were measured in 0.25 diopter steps, while VASR data was calculated to the nearest 0.01 diopter. Final corrected visual acuity was recorded for each eye after each procedure using standard Snellen targets. Time was measured via stopwatch for both the traditional refraction and the VASR refraction.
Unilateral measurements were analyzed with regard to refractive values to limit potential bias. A comparison of the results obtained by traditional refraction methods and the results of the Vmax VASR revealed no statistically significant difference from the mean in equivalent sphere measurements (p = 0.1383). Non-parametric analyses (Wilcoxon) were performed as there was a negative skew and the data was platykurtic. Dioptric values for traditional refraction ranged from +1.13 to -12.75 (95% confidence interval = -1.63 to -3.63), with a median of -2.50. For the VASR, values ranged from +1.08 to -14.39 (95% confidence interval = -1.26 to -3.46), with a median of -2.69. The spherical equivalent datasets were highly correlated (r = 0.993) as were cylinder power and axis (Cylinder: p = 0.6377, r = 0.864) (Axis: p = 0.6991, r = 0.738). Visual acuity measurements were similar for both groups: 18% of subjects had better acuity with VASR (> 1 line Snellen), 3% of subjects had worse acuity with VASR (>1 line Snellen), and 76% had less than 1 line Snellen differnece. VASR, on average, required 71 additional seconds to complete.
For spherocylindrical refractive error, the results obtained with the Vmax VASR were not statistically different from those achieved using traditional phoropter methods by an experienced optometrist. Corrected visual acuity was similar between groups and did not appear to be clinically different.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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