[Rotation auto-keratoplasty. Preoperative calculation].

A formula is given with which it is possible to calculate preoperatively the size of the eccentric trepanation in rotation autokeratoplasty and the resulting optimized visual center. On the patient's eye the position of the visual axis on the cornea, and the distance between this and the edge of the scar and the corneal limbus must be measured in the meridian where the scar extends least over the visual axis. The calculation can be performed very quickly with the aid of a diagram based on the formula r = 0.25(3R-x-2).