Anterior segment optical coherence tomography changes to the anterior chamber angle in the short-term following laser peripheral iridoplasty

Abstract

Purpose: To evaluate, by anterior segment optical coherence tomography (AS-OCT), the changes in the anterior chamber angle during the short-term postoperative period after diode laser peripheral iridoplasty (LPI). Methods: Retrospective, observational study of consecutive primary angle closure suspect, primary angle closure, or primary angle closure glaucoma patients who underwent LPI. These patients had persistent iridotrabecular contact despite the presence of a patent peripheral iridotomy. The AS-OCT images of the temporal and nasal anterior chamber angles in dark conditions before and after LPI were analyzed. The main outcome measures were changed in AS-OCT parameters such as trabecular-iris angle (TIA), angle opening distance (AOD), trabecular-iris space area (TISA), trabecular-iris contact length (TICL), iris thickness (IT), and maxi­mum iris bow height (MIBH). Secondary outcome parameters included intraocular pressure (IOP) and postlaser complications. Results: Images of 14 eyes of 14 patients were assessed. The mean time from LPI to the follow-up AS-OCT scan was 6 ± 3 weeks. The IT did not alter significantly after LPI, but there were significant increases in the TIA, AOD and TISA, as well as a significant decrease in TICL and MIBH. There were no significant postlaser complications. There was a small decrease in mean IOP from 17.1 ± 4.0 mm Hg to 14.8 ± 4.6 mm Hg (p = 0.014). Conclusion: Based on AS-OCT imaging, LPI resulted in significant angle widening and iris profile flattening during the short-term postoperative period in eyes with persistent angle closure despite the presence of a patent peripheral iridotomy.