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Lei Shi, E E. Hartmann, Naser T. Naser, J W L. Lewis, Ying-Ling Chen, Ming Wang; Pilot Study of a Dynamic Binocular Photoscreening Device. Invest. Ophthalmol. Vis. Sci. 2011;52(14):2516.
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© ARVO (1962-2015); The Authors (2016-present)
To design an objective, binocular, and friendly/relaxed testing method to estimate refractive errors. Two major challenges that cannot be ignored in photorefraction measurements are pupil size and retinal stray-light scattering, both of which vary considerably among individuals. The former is also age-related, and the later is ethnicity-correlated.
This method utilizes the infrared dynamic photoscreening method with multiple meridians and eccentricities. The quantitative analysis of refractive status uses the relative signal ratio of each illuminating measurement to the coaxial illumination. The defocus along a meridian is proportional to the width of the fitted ratio curve, and the width increases with the pupil size. The retinal scattering property is identified through the correlation between the photorefraction patterns of the same eccentricity. We tested the analysis method on an artificial eye with various refractive errors and pupil settings. A pilot study of 47 optometry students and volunteers (94 eyes; +1 to -8.75 diopters) under three lighting conditions was also performed to evaluate the design. Total data points used are n=251. Standard eye examinations were performed for all test subjects for comparison.
From the comparison between the artificial eye and human tests, significant retinal scattering difference is present. Bland-Altman analysis shows standard deviations of the spherical equivalent SE and crossed cylinder values J0 and J45 in human eyes are 0.64, 0.26, and 0.18 diopters, respectively (n=251).
The pilot study on cooperative adults shows promising results and areas of potential improvements. Testing on children is important in the near future.
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