Excimer laser keratoplasty. Part 2: Elliptical keratoplasty.

An excimer laser at 193 nm was used with a new "open mask system" to perform elliptical noncontact and nonthermal keratoplasties and corneal grafts in human cadaver eyes (Part 1 of this article, Ophthalmic Surg 1989; 20:262-267). By light microscopy the corneas showed sharp, unbeveled cut margins with nearly perfect apposition of the inner wound aspects. An elliptical shape may be better than a circular one, since the former closely approximates the cornea's normal elliptical outline, making it easier to fit corresponding areas of corneal graft to bed. Also, it provides a wider area of Bowman's membrane for anchoring sutures and relatively less volume of donor antigenic tissue.