Use of the giant-pulse Nd:YAG laser for ab-externo sclerostomy in rabbits and humans.

The giant-pulse Neodymium:YAG laser, a recently developed laser source, delivers up to 200 W of peak power at pulse widths of 20 or 40 msec. The instrument can create a sclerostomy with minimal surrounding damage and, consequently, relatively little postsurgical inflammation and scarring. We tested its efficacy in performing ab-externo sclerostomy in 10 adult pigmented rabbits and in five patients with end-stage glaucoma. All of the animal eyes were hypotonus immediately after the procedure. However, the intraocular pressure increased gradually, and by the third day, returned to presurgical levels in all of the eyes. All five of the glaucoma patients treated had patent sclerostomies following the procedure. They all had early hypotony, but after 3 months, four of the five sclerostomies apparently failed. The giant-pulse Nd:YAG laser appears useful for performing sclerostomy, but modifications are needed to solve the problems of early hypotony and late closure of the fistulula.