The prevention of an acute rise in intraocular pressure following Q-switched Nd:YAG laser iridotomy with clonidine.

We evaluated the ability of topical clonidine to suppress an acute rise in postoperative intraocular pressure (IOP) following Nd:YAG laser iridotomy. A total of 36 eyes (29 patients) with chronic primary angle-closure glaucoma underwent Q-switched Nd:YAG laser iridotomy: 18 eyes were treated topically with 0.5% clonidine ophthalmic solution prior to and immediately following the procedure, and a control group of 18 eyes underwent Nd:YAG laser iridotomy without topical clonidine. The control group was selected to match the clonidine-treated group in terms of preoperative IOP, the extent of peripheral anterior synechia, and the total amount of laser energy delivered. None of the clonidine-treated eyes experienced an IOP rise greater than 4 mm Hg over baseline, whereas 4 of the nontreated eyes (22.2%) developed an IOP rise greater than 10 mm Hg. The mean IOPs were significantly lower during the first 4 h postsurgery in the clonidine-treated eyes.