Seng Chee Loon, Maria Cecilia D Aquino, Joseph M Cruz, Paul TK Chew
Department of Ophthalmology, National University Hospital, Singapore

Aim: To investigate the effectiveness of 8-shot argon laser peripheral iridoplasty for treating Asian eyes with primary angle closure.
Methods: Eight laser shots, placed 2 shots per quadrant, were applied using the following parameters: power, 0.4 W to 0.7 W; duration, 150 ms to 200 ms; and spot size, 100μ to 200μ. Before treatment, all eyes had occludable angles with gonioscopic findings of grade 0 to 1 by the modified Shaffer system. Ultrasound biomicroscopy was performed to confirm angle closure in dark and light provocation tests. The degree of angle opening was measured using angle opening distance, angle recess area, and trabecular iris space area.
Results: The intraocular pressures measured by Goldmann applanation tonometry were within normal limits at 14 mm Hg to 19 mm Hg. There was strong evidence that the mean intraocular pressure was lower after the laser treatment (p < 0.001, t_{38, 0.05} = 4.699) with a mean decrease in IOP of 2.7 mm Hg. The angles opened up to an average of grade 2 at gonioscopy, and ultrasound biomicroscopy showed non-occludable angles. Ultrasound biomicroscopy images were analysed using ultrasound biomicroscopy Pro 2000 software. The majority of the ultrasound biomicroscopy measurements increased after laser treatment.
Conclusions: Eight-shot argon laser peripheral iridoplasty is effective for opening up the anterior chamber angles in Asian eyes with primary angle closure.

Key words: Glaucoma, angle-closure, Iridoplasty, Lasers

Asian J Ophthalmol. 2008;10:212-214.