Refractive keratotomy using a footplateless knife.

This article describes a diamond knife designed for safer, more precise extension of pre-existing refractive keratotomy incisions. The knife has a blade with a sharp vertical cutting edge whose progress is limited by a dull safety stop. The stop prevents extension of a wound by more than 500 microns at one time, minimizing the possibility of overextending the keratotomy incision into the optical zone. Because it requires no footplate, the knife improves visibility, allowing for more precise surgery.