Effect of position on the safety and efficacy of neodymium-doped: Yttrium aluminium garnet laser peripheral iridotomy in patients with primary angle-closure disease

Abstract

Purpose: The aim is to evaluate the safety and efficacy of neodymium-doped: yttrium–aluminum–garnet laser peripheral iridotomy (LPI) in the superior versus inferior quadrant in the treatment of primary angle-closure (PAC) disease. Design: Randomized, prospective, single-masked, comparative clinical study. Materials and Methods: Patients with PAC or PAC suspects were recruited and randomized to receive LPI in the superior or inferior quadrant in both eyes. Patients were masked to the location of treatment in each eye. The main outcome measures assessed were patency of iridotomy, laser parameters, complications, and visual symptoms between the two groups at 1 week and 1 month after the laser intervention. Results: A total of 100 patients were recruited, 50 into each group. The mean age was 51.46 ± 7.91 years. Average intraocular pressure (IOP) measurements before LPI was 18.24 ± 5.37 mm Hg and 18.6 ± 5.63 mm Hg in superior LPI and inferior LPI eyes, respectively. After LPI, average IOP was 17.4 ± 3.31 mm Hg and 17.1 ± 3.13 mmHg in superior LPI and inferior LPI eyes, respectively. Inferior LPIs required less use of mean total laser energy (P = 0.001) and less number of laser shots (P = 0.016) to perforate the iris tissue. There was a lower incidence of iris bleeding and focal corneal damage at the time of treatment; a lower postlaser iritis and lower need for PI enlargement in the inferior LPI group. All the iridotomies were patent at 1 month follow-up. There was no statistically significant difference between the two groups in terms of the dysphotopsias and visual symptoms experienced after the LPI (P = 0.122). Conclusions: LPI in the inferior quadrant appears to be a safe and efficient alternative to superior LPI with fewer complications in the treatment of PAC disease. Dysphotopsias and visual symptoms following inferior LPI are similar to superior LPI.