Analysis of lens position and stability in primary angle closure disease following laser peripheral iridotomy

Abstract

Objective: This study aimed to investigate the effects of laser peripheral iridotomy (LPI) on lens position and stability in patients with primary angle-closure disease (PACD). Methods: This prospective study included 164 eyes of patients with PACD who underwent LPI (67 eyes with primary angle closure suspect [PACS], 54 with primary angle closure [PAC], and 43 with primary angle closure glaucoma [PACG]). Parameters related to the crystalline lens were collected using ultrasound biomicroscopy (UBM) and IOLMaster700® (Carl Zeiss Meditec, Jena, Germany) before and after LPI. The lens position was evaluated using lens position (LP), relative LP (RLP), and lens-axial length factor (LAF). The lens stability was assessed by calculating the differences between the maximum and minimum values of iridolenticular angle (ILA) and iridolenticular contact distance (ILCD) across the superior, inferior, nasal, and temporal quadrants. Results: Post-LPI, LP, and RLP increased in all three groups. The increase in RLP was not statistically significant in the PACS group (P > 0.05), but all other changes were statistically significant (P < 0.05). Changes in LAF were not statistically significant across all groups (P > 0.05). The differences in ILA values decreased after LPI in all three groups (PACS: pre-LPI: 9.61 ± 4.76°, post-LPI: 7.27 ± 3.95°; PAC: pre-LPI: 8.96 ± 5.29°, post-LPI: 6.47 ± 3.86°; PACG: pre-LPI: 10.61 ± 6.63°, post-LPI: 6.44 ± 3.77°), with statistically significant differences (P < 0.05). The decrease in ILA difference showed an increasing trend in all groups (PACS; 2.34 ± 4.13°, PAC; 2.49 ± 5.82°, PACG; 4.17 ± 6.43°), but was not statistically significant (P > 0.05). The ILCD differences decreased in all groups, but were not statistically significant (P > 0.05). Conclusion: LPI alters ocular structure and affects lens position, causing a relative posterior shift of the lens, which may affect intraocular lens power calculation in some patients with PACD, especially those with PACG. Furthermore, lens stability improved after LPI, with the most notable improvement observed in the PACG group.