Grosvenor T, Scott R
Optometry Department, University of Auckland, New Zealand.
Optom Vis Sci. 1994 Sep;71(9):573-9. doi: 10.1097/00006324-199409000-00005.
The purpose of our study was to investigate the extent to which the ratio between axial length and corneal radius (the AL/CR ratio) determines the refractive state of the human eye. Subjects for the study were 194 young adults between the ages of 18 and 30 years, whose spherical equivalent refraction ranged from +7.91 to -13.32 D. For each subject, manifest objective refraction, corneal radii, and axial ocular distances were measured. Lens power was determined using a formula proposed by Bennett and Rabbetts. The AL/CR ratio was found to be approximately 3.00 for emmetropic eyes, ranging from 2.60 for the most highly hyperopic eye to 4.10 for the most highly myopic eye. The coefficient of determination of linear regression for the AL/CR ratio as a function of spherical equivalent refraction was 0.84, suggesting that 84% of the variance in refraction could be accounted for by variance of the AL/CR ratio. The results of the study suggest that for a given amount of ametropia, an eye having a relatively high AL/CR ratio would tend to have a low-powered lens (indicating that the lens had "emmetropized"), whereas an eye having a relatively low AL/CR ratio would tend to have a high-powered lens. We conclude that the AL/CR ratio can provide information concerning the extent to which the lens has emmetropized by reducing its power concurrent with axial elongation.
我们研究的目的是调查眼轴长度与角膜半径之比（AL/CR比）在多大程度上决定人眼的屈光状态。研究对象为194名年龄在18至30岁之间的年轻成年人，其等效球镜度范围为+7.91至-13.32D。对每位受试者测量了显客观验光、角膜半径和眼轴长度。使用Bennett和Rabbetts提出的公式确定晶状体屈光力。发现正视眼的AL/CR比约为3.00，从最高远视眼的2.60到最高近视眼的4.10不等。AL/CR比作为等效球镜度函数的线性回归决定系数为0.84，这表明84%的屈光差异可由AL/CR比的差异来解释。研究结果表明，对于给定程度的屈光不正，AL/CR比相对较高的眼睛往往晶状体屈光力较低（表明晶状体已“正视化”），而AL/CR比相对较低的眼睛则往往晶状体屈光力较高。我们得出结论，AL/CR比可以提供有关晶状体通过在眼轴伸长的同时降低其屈光力而正视化程度的信息。
