Comparison of superior and inferior laser peripheral iridotomies in primary angle closure disease – A randomized clinical trial

Aim: The purpose of this study was to assess the efficacy and side-effects of superior versus inferior laser peripheral iridotomy (LPI) in the management of primary angle-closure disease (PACD). Methods: In this prospective interventional randomized single-masked study, patients who were 30 years of age or older, diagnosed as primary angle-closure suspects (PACS) or primary angle closure (PAC) or primary angle-closure glaucoma (PACG) were randomized into two groups- superior LPI and inferior LPI. The outcome measures were patency of iridotomy, intraocular pressure (IOP), and visual side-effects at each visit during the six-month follow-up. Results: Three hundred and four eyes of 152 patients were included. The mean IOP reduced from 24.64 ± 6.35 mmHg and 24.62 ± 7.34 mmHg to 19.08 ± 2.86 mmHg and 19.07 ± 2.62 mmHg in superior and inferior LPI eyes, respectively. All LPIs were patent at six months. The mean total laser energy required to perform LPI was less in group 2 (2.8 ± 1.4 mJ) than in group 1 (4.4 ± 1.6 mJ, P < 0.01), though similar initial laser energy settings were used in both groups. The post-LPI inflammation was also lesser in inferior LPI ( P = 0.033). Two patients in both groups demonstrated dysphotopsia symptoms after LPI ( P = 1.00). Conclusion: Both superior and inferior LPIs were equally effective though inferior LPIs required lower laser power.