Correlations between Corneal and Internal Wavefront Aberrations through Zernike Coefficients Analysis

Objectives: To examine corneal aberrations are offset by internal aberrations more closely, the Zernike coefficients of corneal aberrations and internal aberrations were compared and analyzed. Methods/Statistical Analysis: Measurements of higher-order aberrations were performed with KR-9000 PW (Topcon Corp., Japan), a Hartmann-Shack Wavefront aberrometer. The coefficients from the 2nd to 4th expressions on Zernike Polynomials were analyzed for cornea and internal optics within 6mm measurement zone. 342 healthy eyes of 171 young adults who have never received eye surgery and do not wear contact lenses were selected as subjects of this study. Findings: There were significant negative correlations among all Zernike coefficients of corneal and internal aberrations. In Z31(r=-0.887, p=0.00), Z4-4(r=-0.698, p=0.00), and Z44(r=-0.688, p=0.00), there were high correlations between corneal and internal aberrations. On the other hand, the correlation coefficients of Z20 and Z22 that belonged to lower-order aberration were very weak at -0.129 and -0.136 respectively, having almost no correlation. Improvements/Applications: Since some signs of their Zernike coefficients are different, it is considered necessary to analyze not the both eyes but a single eye to identify the accurate RMS values of each Zernike coefficients and not only the correlations.Keywords: Corneal Aberration, Higher-Order Aberration, Internal Aberration, Zernike Coefficients, Zernike Polynomials