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Accuracy, speed and repeatability of the voice assisted subjective refractor (VASR)

Authors Kabat AG, Lievens CW, Newman CM, Weber J

Received 24 April 2019

Accepted for publication 13 August 2019

Published 12 September 2019 Volume 2019:13 Pages 1807—1813


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 2

Editor who approved publication: Dr Scott Fraser

Alan G Kabat,1 Christopher W Lievens,2 Christina M Newman,2 Jacob Weber2

1Pennsylvania College of Optometry, Salus University, Elkins Park, PA, USA; 2Southern College of Optometry, Memphis, TN, USA

Correspondence: Alan G Kabat
Pennsylvania College of Optometry, Salus University, 8360 Old York Road, Elkins Park, PA 19027, USA
Tel +1 954 553 1061
Fax +1 856 433 8439

Purpose: To compare the accuracy, speed and repeatability of the voice assisted subjective refractor (VASR) to traditional refractive methods.
Methods: Fifty healthy adult subjects were examined by autorefractor, followed by subjective phoropter refinement. Subjects were then evaluated using the VASR (Vmax Vision) to obtain an objective and subjective result. Three total assessments were performed for each subject using each of the methods described. Corrected visual acuity was recorded for each eye after each procedure. The total time was measured for both the traditional and VASR refraction.
Results: A comparison of the results obtained by traditional refraction and VASR revealed no statistically significant difference from the mean in equivalent sphere measurements (P=0.1383), and the datasets were highly correlated (r=0.993). The data comparisons for cylinder power and axis were similar (cylinder: P=0.6377, r=0.864) (axis: P=0.6991, r=0.738). VASR, on average, required 71 additional seconds to complete when compared to traditional phoropter refraction. In terms of repeatability, the average difference noted upon repeat of equivalent sphere power was 0.01 D for the phoropter (P=0.98) and 0.10 D for the VASR (P=0.23). For sphere power, the average difference was 0.02 D for the phoropter (P=0.55) and 0.07 D for the VASR (P=0.58). For cylinder power, the average difference was 0.02 D for the phoropter (P=0.11) and 0.03 D for the VASR (P=0.39). For all refractive methods, the differences between measurements amounted to ≤0.10 diopters, which is neither clinically nor statistically significant.
Conclusion: Refractive error results obtained with the VASR were not statistically different from those achieved using traditional phoropter methods. Time elapsed for the VASR was slightly longer than a more traditional refractive sequence. The VASR demonstrated clinically and statistically significant repeatability of measurement, consistent with traditional refraction.

Keywords: autorefractor, subjective refraction, wavefront aberrometry, point-spread function, VASR

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