Surgical induction of corneal astigmatism. An experimental study.

The aim of all ocular surgery is to preserve or restore optimal visual function. Reduction of excessive postoperative astigmatism after keratoplasty, cataract extraction, or other anterior segment operations has been obtained in clinical surgery by corneal wedge resection. The purpose of this experimental investigation was to quantify and evaluate the results of different microsurgical techniques in crescentic resection of a corneal wedge. Twenty-five rabbits were operated and the induced changes of corneal curvature measured by keratometry. The immediate and long-term results are presented. The effect of wedge resection was a steepening of the meridian perpendicular to the resection and a flattening of the meridian parallel to the resection. The astigmatism induced was less pronounced than the changes obtained in human surgery. There were no postoperative ocular complications and all corneas remained clear. It is suggested that the operation be performed in all cases of severe corneal astigmatism uncorrected by lenses.