[Results of argon laser treatment of 100 eyes with open-angle glaucoma (trabeculoplasty, trabeculoretraction)]

Abstract

One hundred phakic eyes of 76 patients with primary open angle glaucoma received argon laser therapy to the trabecular meshwork, a method, based on the works of James Wise, which we prefer to call trabecular retraction for two reasons: 1) the mechanical factor of trabecular tightening caused by the laser microscars and 2) to differentiate it from initial argon laser treatment in primary open angle glaucoma: trabeculopuncture. Argon laser trabecular retraction involves application to the entire pigmentary trabecular ring, just anterior to the scleral spur, of 100 evenly spaced non-penetrating burns, using a 50 microM. beam diameter with a pulse duration of 0,1 sec, and a power level adjusted to produce a minimum visible trabecular reaction. Laser treatment was performed on an out-patient basis using a three mirror Goldmann lens after topical anesthesia. Pre-laser anti-glaucoma medical treatment was continued unchanged during the follow-up period of this study, to assess accurately the effect of the laser treatment on intraocular pressure (IOP) without introducing the variable of changing medications. Treatment was applied to eyes with uncontrolled glaucoma on maximum tolerable medical therapy and, as such, candidates for surgery, eyes of patients unable to tolerate side effects of effective intensive medical therapy, and eyes with controlled open angle glaucoma to permit reduction of medical therapy. Mean pressure drop in the 100 eyes was 8,9 mmHg, the reduction of IOP being achieved between 3 and 6 weeks after the laser procedure. Surgery for glaucoma was avoided in 93% of the eyes. Pressure drop in 75% of treated eyes was between 4 and 11 mmHg, in 16% was 12 mmHg or more, and in 9% was 3 mmHg or less. Follow-up was for at least three months and in some cases extended to 15 months. These results and data from published reports suggest that the pressure drop obtained three months post-laser could be considered definitive, except in a very small percentage of eyes. Average intraocular pressure reduction in patients under 60 years was 8,3 mmHg and 88% of the eyes had a drop in IOP of 4 mmHg or more. In patients over 60 years, average intraocular pressure reduction was 9,3 mmHg and 93% of the eyes had a drop in IOP of 4 mmHg or more. The major complication in eyes with marked glaucomatous damage to their optic nerves is a possible rise in intraocular pressure following treatment. This post-laser increase in IOP was noted in 19 eyes but resolved either spontaneously or easily with medication. No visual field loss was observed in these eyes. Localized peripheral anterior synechiae were noted in 42 eyes, but these did not affect the success of the procedure.4