Iridoplasty more effective than meds in IOP reduction during first 2 hours, study says

HONG KONG — Argon laser peripheral iridoplasty is more effective than conventional systemic medications in reducing IOP levels in eyes with acute primary angle-closure glaucoma, according to a study.

Statistically significant differences existed within the first 2 hours, and became statistically insignificant after 2 hours, the authors added. Researchers suggest eliminating systemic medications and using iridoplasty as a means of controlling IOP during this crucial time.

Researchers here studied 73 eyes of 64 patients whose IOPs were 40 mm Hg or more. The eye of each patient with acute primary angle-closure glaucoma received topical pilocarpine 4% and topical timolol 0.5%.

Patients were subsequently randomized into two treatment groups. Patients in one group (33 eyes of 32 patients) were given immediate argon laser peripheral iridoplasty under topical anesthesia. Patients in the other group (40 eyes of 32 patients) were given 500 mg of intravenous acetazolamide, followed by oral acetazolamide 250 mg four times daily and an oral potassium supplement until IOP levels normalized. In the medications group, if the IOP was higher than 60 mm Hg, intravenous mannitol also was given. Both groups continued to receive topical pilocarpine 1% until peripheral iridotomy could be performed.

The iridoplasty group had lower IOP levels than the medically treated group at 15, 30 and 60 minutes after the start of treatment.

In general, argon laser peripheral iridoplasty is most useful when laser iridotomy cannot be performed because of corneal edema or a shallow anterior chamber. The usual practice is to perform the surgery 3 to 6 hours after medications fail to control IOP, the authors wrote in the September issue of Ophthalmology.