The efficacy of cw Nd:YAG laser trabeculoplasty

Abstract

The long-term (mean follow up, 51 weeks) efficacy of cw Nd:YAG laser trabeculoplasty in reducing intraocular pressure (IOP) was studied in 106 eyes of 75 patients. Fifty patients (73 eyes) of this group had primary open-angle glaucoma; 11 (17), mixed glaucoma; 10 (12), pseudoexfoliation syndrome; and 4 (4), secondary glaucoma of varied etiology. Fifty laser impacts were delivered over 180 degrees of the circumference of the chamber angle with an Nd:YAG laser working in the cw mode (spot diameter, 100 microns; exposure duration, from 200 to 300 milliseconds; constant power level, 9 W, resulting in 1.8 to 2.7 J/pulse and a total energy dose/session of 90 to 135 J). In a few cases, an exposure duration of 400 milliseconds was used, corresponding to a pulse energy of 3.6 J/pulse and a total energy dose/session of 180 J. Success was defined as a reduction in IOP to 22 mm Hg or less without any further laser or surgical intervention. The cumulative success rate was 97.2% at 1 month, 93.3% at 3 months, 83.3% at 6 months, 78.7% at 12 months, and 71.5% at 24 months. Thus, the efficacy of cw Nd:YAG laser trabeculoplasty is comparable to that reported for trabeculoplasty performed using the argon laser (ALT), the Nd:YAG laser working in the free-running mode, and the diode laser. Biomicroscopy failed to reveal any serious inflammatory reactions persisting longer than 1 week. We conclude that cw Nd:YAG laser trabeculoplasty is a safe and effective alternative to ALT.