Factors affecting success and IOP rise after argon laser trabeculoplasty.

One hundred and seventeen eyes of 98 patients with open-angle glaucoma where maximum tolerable medication failed to control the intraocular pressure (IOP) were treated by argon laser trabeculoplasty. We applied multiple logistic regression analysis to the clinical data of these eyes to determine the factors which are related to the success rate and the immediate postoperative elevation of the IOP. The treatment was regarded as a success when the IOP was maintained at or below 20 mmHg during the postoperative follow-up. The treatment was judged as a failure when the IOP at two consecutive visits of the patient exceeded 20 mmHg or other surgical intervention was contemplated because of uncontrolled IOP. According to the above criteria, the success rate was found to be related to the pretreatment base line IOP, the type of glaucoma, the sex, the age and the history of previous ocular surgery. The computed logistic function could classify correctly 80% of eyes that had successful IOP control and 65% that did not. The immediate postoperative elevation of IOP was found to be related to the base line IOP, the laser power, the age and the type of glaucoma. The computed logistic function could classify correctly 74% of eyes with positive IOP rise by more than 5 mmHg and 75% with negative IOP rise.