Comparison of Refractive Errors measured using Auto-Refractometer and calculated using Zernike Coefficients
Sang-Deok Lee

Sang-Deok Lee, Department of Optometry, Gimcheon University,  Daehak-Ro Gimcheon-Si Gyeongbuk-Do, Korea, East Asian. 

Manuscript received on 10 June 2019 | Revised Manuscript received on 17 June 2019 | Manuscript Published on 22 June 2019 | PP: 754-757 | Volume-8 Issue-8S2 June 2019 | Retrieval Number: H11250688S219/19©BEIESP

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Abstract: This research aims to identify the relationship between refractive errors measured by a refractometer and refractive errors using Zernike coefficients measured by an aberrometer. Methods/Statistical analysis: This study measured Zernike coefficients C_2^0,C_2^2, and C_2^(-2) of 6mm and 4mm-pupil areas using a wave-front aberrometer. They compared and analyzed sphere, cylinder, and cylindrical axes calculated by the coefficients and the values measured by the auto-refractometer. Findings: The study showed that the average difference between the sphere value measured by refractometer and 4mm-aberrometer was -0.03D, smaller than the difference of 0.15D between the sphere values measured by the refractometer and 6mm-aberrometer. The difference between the refractometer and 4mm-aberrometer was 0.12D for the cylinder, smaller than the difference of 0.17D between the refractometer and 6mm-aberrometer; next, as in sphere and cylinder, the difference between the refractometer and 4mm aberrometer was smaller than difference between the refractometer and 6mm-aberrometer for SE values. The correlation analyses showed that the correlation between the refractometer and 4mm-aberrometer was higher than correlation between the refractometer and the 6mm-aberrometer in all of sphere, cylinder, and SE values. Improvements/Applications: When simple refraction values of lower-order aberration replaced values measured using wave-front aberrometer, it seems adequate to set the measuring range as 4mm of pupil diameter than 6mm.

Keywords: Refractive Error, Zernike Coefficients, Sphere, Cylinder, Cylindrical Axis.
Scope of the Article: Analysis of Algorithms and Computational Complexity