Arciniegas A, Amaya L E
Ann Ophthalmol. 1984 Dec;16(12):1155-66.
Most surgical procedures for correcting astigmatism are done on the cornea. The present article shows the modification of the corneal curvature by scleral surgery. The experiments were conducted on rabbit eyes. The most spherical eyes were chosen according to the keratometric measurements. A geometrical analysis of the astigmatism shows that beginning with an ellipse (image of an astigmatic eye in the corneascope), by modifying the main radii of the ellipse, while the perimeter is maintained constant a perfect circle is thus obtained. This analysis enables us to calculate the amount of sclera surgery required to obtain a given correction for a given degree of astigmatism. Four scleral procedures were investigated: folds, resections, imbrications, and sclerotomies; the results show that the first three procedures steepen the meridian where the surgery is performed while flattening simultaneously the ortogonal meridian. The main advantages of scleral surgery vs corneal surgery for correction of astigmatism are: (a) the cornea remains untouched, (b) the surgical area will be protected by the conjunctiva, (c) the stitches are left permanently, and (d) larger astigmatic errors can so be corrected.
大多数矫正散光的外科手术是在角膜上进行的。本文展示了通过巩膜手术对角膜曲率进行的调整。实验是在兔眼上进行的。根据角膜曲率计测量结果选择最接近球形的眼睛。对散光的几何分析表明，从一个椭圆（角膜镜中散光眼的图像）开始，通过改变椭圆的主半径，同时保持周长不变，从而可得到一个完美的圆。这种分析使我们能够计算出对于给定程度的散光，为获得特定矫正所需的巩膜手术量。研究了四种巩膜手术：折叠术、切除术、重叠术和巩膜切开术；结果表明，前三种手术会使手术进行部位的子午线变陡，同时使与之垂直的子午线变平。巩膜手术相对于角膜手术矫正散光的主要优点是：（a）角膜不受影响，（b）手术区域将受到结膜的保护，（c）缝线永久留存，（d）可以矫正更大的散光误差。
