Edmund C, Sjøntoft E
Acta Ophthalmol (Copenh). 1985 Dec;63(6):670-7. doi: 10.1111/j.1755-3768.1985.tb01579.x.
Both eyes of 40 normal persons were examined with a photokeratoscope. A method for analyzing the photokeratoscopic data based on the principle of least square fitting is presented. It is demonstrated that the corneal flattening expressed as the relative change in the radius of the corneal curvature is proportional with the square of the chord distances from apex. The factor of proportionality RV is defined as the coefficient of radius variation, which, together with the radius of the apex curvature K, are characteristic constants for a given meridian in a given eye. Expressed as mean and SD, the study demonstrates for the horizontal meridian K = 7.86 mm (0.25) and RV = 0.71 X 10(-2) mm-2 (0.26 X 10(-2)), for the vertical meridian the corresponding dimension are K = 7.65 mm (0.24) and RV = 0.70 X 10(-2) mm-2 (0.38 X 10(-2)). These results imply a change in the radius of the corneal curvature 1 mm and 5 mm from apex at, respectively, 0.7% and 17.7%. The precisions expressed as SD, by which the 2 parameters may be determined, are for K 0.03 mm and RV 0.12 X 10(-2) mm-2.
用角膜镜对40名正常人的双眼进行了检查。提出了一种基于最小二乘拟合原理分析角膜镜数据的方法。结果表明，以角膜曲率半径的相对变化表示的角膜变平与距顶点弦距的平方成正比。比例系数RV被定义为半径变化系数，它与顶点曲率半径K一起，是给定眼睛中给定子午线的特征常数。以均值和标准差表示，该研究表明，水平子午线的K = 7.86 mm（0.25），RV = 0.71×10⁻² mm⁻²（0.26×10⁻²）；垂直子午线的相应尺寸为K = 7.65 mm（0.24），RV = 0.70×10⁻² mm⁻²（0.38×10⁻²）。这些结果意味着在距顶点1 mm和5 mm处角膜曲率半径的变化分别为0.7%和17.7%。以标准差表示的可确定这两个参数的精度，对于K为0.03 mm，对于RV为0.12×10⁻² mm⁻²。
