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上海交通大学 激光与光子生物医学研究所 上海,200240
收稿日期:2006-03-16,
修回日期:2006-12-20,
网络出版日期:2007-02-20,
纸质出版日期:2007-02-20
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周传清, 余 雷, 陆培华, 等. 准分子屈光手术中非球面系数对 球差以及切削深度的影响[J]. 光学精密工程, 2007,15(2):167-172.
ZHOU Chuan-qing, YU Lei, LU Pei-hua, et al. Effect of asphericity parameter on Seidal aberration and ablation depth in laser refractive surgery[J]. Optics and precision engineering, 2007, 15(2): 167-172.
角膜前表面是人眼屈光系统的主要组成部分
屈光手术通过角膜模型定量计算角膜的修正值
因此角膜模型的精确与否直接决定了手术的效果。一般认为角膜前表面是旋转对称的二次曲面
该曲面的一个重要参数是非球面系数
Q。
目前大部分的角膜切削模型都没有考虑Q对切削深度和像差的影响
本文基于Littman-Gullstrand模型眼建立模型
分析Q值对屈光手术中透射率、球差以及切削深度的影响。模拟结果显示
Q值对球差和切削深度有显著影响
Q
绝对值逐渐增大时
球差
S
1
从正变为负
在
Q
=-0.528处
可以认为角膜前表面产生的
S
1
为零。
Q
绝对值增大时
相对切削深度增大
即角膜边缘与角膜中央切削深度差异减小。
The anterior surface of cornea is the major refracting element of human eye
which contributes over 80 per cent of the refractive power of the whole eye according to the Gullstrand Number 1 relaxed schematic model eye. Small changes in the radius at the corneal apex will greatly affect the refractive power. Corneal ablation in refractive surgery is calculated according to corneal model
it is shown that the precision of corneal model directly affects the accuracy of refractive surgery. The simplest asphericity model is to assume that the corneal is a rotationally symmetric conicoid
and
Q
is the asphericity parameter of this conicoid. The effect of
Q
on transmission rate
Seidal aberration and ablation depth based on Littman-Gullstrand model is analyzed
the results indicate that
Q
greatly affects on the Seidal aberration and the ablation depth.
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