June 2015
Volume 56, Issue 7
Free
ARVO Annual Meeting Abstract  |   June 2015
Validation of the Dyop™ Visual Acuity Test
Author Affiliations & Notes
  • Paul Alan Harris
    Southern College of Optometry, Memphis, TN
  • Erin Keim
    Southern College of Optometry, Memphis, TN
  • Footnotes
    Commercial Relationships Paul Harris, None; Erin Keim, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science June 2015, Vol.56, 3888. doi:
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      Paul Alan Harris, Erin Keim; Validation of the Dyop™ Visual Acuity Test. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):3888.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract
 
Purpose
 

Sloan and Snellen optotypes are the global eye chart standard for visual acuity testing, but routinely patients struggle with the required endpoint of response confusion. A new Dynamic Optotype, or “Dyop”, using a dynamically sized, rotating, visual arc-area figure to measure acuity was prospectively, clinically compared to Sloan measures of visual acuity under various test conditions. The Dyop has a completely unique endpoint: the rotation animation appears to suddenly stop when threshold is reached.

 
Methods
 

Acuity was assessed with 162 subjects each randomly with the Dyop test (Konan Medical Chart2020) and Harris Stair-Step test (M&S Technologies) comparing each with the following strategies: BCVA, UCVA, + Lens (+2, +3, +4) over spectacles. The relationship between Sloan VA/20 and Dyop size in arc-minutes (both log-transformed) was investigated using correlations and repeated-measures log-log regression models.

 
Results
 

There was a strong linear relationship between Sloan and Dyop acuity measures (Pearson r=.94; p<001). In a single predictor model, the Dyop measure explained 89% of the variance in Sloan acuity. An interaction model relaxing the assumption of common slopes by testing condition indicated a significant measure X condition interaction (p=.004), and explained over 91% of the variance in Sloan acuity. Optimal conversion algorithms between Dyop and Sloan measures were developed via regression models.

 
Conclusions
 

The Dyop is a novel method of measuring visual acuity that is strongly associated with, and may offer a viable alternative to traditional visual acuity methods. Beyond high correlation with standard methods, the Dyop was observed to be advantaged by speed to threshold endpoint, finer acuity granularity compared to the typically used acuity “line” steps, and ease of endpoint interpretation by subjects.  

 
Figure 1: Plot of the log of the Dyop size in arc minutes against the log of the Sloan VA/20. <br /> Rx Corrected = Dark Gray (x)<br /> +2.00 blur = Orange (o)<br /> +3.00 blur = Red (+)<br /> +4.00 blur = Green (•)
 
Figure 1: Plot of the log of the Dyop size in arc minutes against the log of the Sloan VA/20. <br /> Rx Corrected = Dark Gray (x)<br /> +2.00 blur = Orange (o)<br /> +3.00 blur = Red (+)<br /> +4.00 blur = Green (•)
 
 
Figure 2: Scatter plots for each of the separate conditions. Correlations were significant to the p <.001 level in all conditions. Pearson correlations for each condition were: Rx Corrected r=.54, +2 blur r=.72, +3 blur r=.72, +4 blur r=.63, overall pooled r=.94.
 
Figure 2: Scatter plots for each of the separate conditions. Correlations were significant to the p <.001 level in all conditions. Pearson correlations for each condition were: Rx Corrected r=.54, +2 blur r=.72, +3 blur r=.72, +4 blur r=.63, overall pooled r=.94.

 
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