[The relationship between corneal astigmatism with a vector-based method and whole eye second order wavefront aberrations].
OBJECTIVE
To investigate the relationship between corneal astigmatism and second order wavefront aberration in myopic eyes.


METHODS
The corneal astigmatism and the whole eye wavefront aberrations of both eyes of 246 subjects were measured using the Humphrey corneal topography and the WASCA wavefront analyzer. According to axial of the corneal astigmatism, the subjects were divided into five groups (WR(0), WR(180), AR, OA(45) and OA(135)). The corneal astigmatism was decomposed into J(45) and J(0) with a Vector-based method, and correlated with the 2nd order Zernike aberrations (C(3) and C(5)).


RESULTS
The mean corneal astigmatisms for the five groups were -1.34 D x 6.87 degrees, -1.03 D x 23.15 degrees, -0.48 D x 89.55 degrees, -0.91 D x 156.87 degrees and -1.02 D x 176.74 degrees respectively. Most of the corneal J(45) and J(0) components were correlated significantly with the C(3) and the C(5) aberrations in the whole eye. While the correlation coefficients (R(2)) between the J(45) and the C(3) were 0.138, 0.119, 0.090, 0.526 and 0.501, the R(2) between the J(0) and the C(5) were 0.711, 0.736, 0.864, 0.866 and 0.785 for the five groups respectively.


CONCLUSIONS
The corneal astigmatism plays an important role in determining the 2nd order wavefront aberration in the whole eye, and the combination processes between the corneal and internal astigmatism (compensation and/or addition) change with the axial of the corneal astigmatism.
Wu
Jiang-xiu
JX
School of Optometry & Ophthalmology, Wenzhou 325027, China.
Lü
Fan
F
He
Ji-cang
JC
Hu
Liang
L
Shen
Ye-yu
YY
Chen
Shi-hao
SH
Xu
Chen-chen
CC
Qu
Jia
J
D000293:Adolescent; D000328:Adult; D001251:Astigmatism / Q000503:physiopathology*; D003315:Cornea / Q000503:physiopathology*; D019781:Corneal Topography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000503:physiopathology; D012029:Refraction, Ocular / Q000502:physiology