LONG-TERM FOLLOW-UP OF DIODE-LASER TRABECULOPLASTY FOR PRIMARY OPEN-ANGLE GLAUCOMA AND OCULAR HYPERTENSION

Background. Initial studies of laser trabeculoplasty using infrared en ergy (810 nm) emitted by diode semi-conductor lasers have been encoura ging. A 2-year study of diode laser trabeculoplasty (DLT) in the contr ol of primary open-angle glaucoma (POAG) and ocular hypertension has b een completed. Methods: Patients with uncontrolled POAG or ocular hype rtension were treated with DLT to one half of the trabecular meshwork using a trabeculoplasty lens. Spot size was 100 mum, exposure time was 0.2 second, and mean power was 1096 mW (+/- 46.5 mW). The desired end point was a mild blanching of the meshwork only. Results: Twenty-five eyes of 16 patients were treated. Mean intraocular pressure reduction was 9.24 mmHg (+/- 3.4 mmHg) at 6 weeks, 9.32 mmHg (+/- 3.6 mmHg) at 3 months, 9.34 mmHg (+/- 3.8 mmHg) at 6 months, 8.42 mmHg (+/- 2.62 mmH g) at 12 months, 8.14 mmHg (+/- 3.42 mmHg) at 18 months, and 7.9 mmHg (+/- 3.63 mmHg) at 24 months. No pressure peaks (> 5 mmHg) were record ed after therapy. Inflammation and discomfort were minimal after laser treatment. Of 16 eyes examined at 2 years, there were no peripheral a nterior synechiae. During the course of the study, six eyes became unc ontrolled, despite one session of DLT. Four eyes regained control with a further session of DLT, but two required trabeculectomy. Conclusion : Diode laser trabeculoplasty is an effective form of therapy in POAG and ocular hypertension. Hypotensive effects and success rates are com parable with argon laser trabeculoplasty (ALT). Reduced inflammation a fter laser treatment may be due to reduced absorption of infrared ener gy by the melanin of the anterior segment. The portable nature of thes e lasers may allow for laser delivery in developing countries and remo te situations.