The effects of oversize donor buttons on postoperative intraocular pressure and corneal curvature in aphakic penetrating keratoplasty.

Forty-one consecutive aphakic corneal transplants performed by the same surgeon were studied in order to determine the effects on intraocular pressure and corneal curvature of using 8.0-mm donor buttons in 7.5-mm recipient openings. One half of the grafts had oversize donor buttons, and all were followed for 13 months. The intraocular pressure in the oversize donor group was statistically significantly less during the first five days after keratoplasty, but not subsequently. Eliminating eyes with preoperative glaucoma, more transplants in the same size donor group (P = 0.08) needed glaucoma therapy 13 months after operation. The anterior corneal curvature (mean keratometry reading) was statistically significantly greater in the oversize donor group throughout the postoperative period. Concurrently, the oversize donor group was less hyperopic after all sutures were removed. There was no difference in keratometric astigmatism or corneal thickness between the two groups. Thus, the use of 0.5-mm oversize donor tissue in aphakic corneal transplants reduced the intraocular pressure and increased the central corneal curvature after keratoplasty.