The surgical management of corneal astigmatism after penetrating keratoplasty.

Seventeen patients with high astigmatism ranging from 5.63 to 19.50 diopters after penetrating keratoplasty had further surgery performed to reduce the astigmatism. Twelve patients had a mean reduction of 4.70 diopters ranging from 1.75 to 10.50 diopters. Four patients had a mean increase of 4.81 diopters with a range from 2.13 to 9.00 diopters. We have found that large amounts of astigmatism can be corrected with relaxing incisions within or circumferential to the graft-host interface but the predictability of the surgical outcome is not satisfactory in all cases.