Long-term effect of lens extraction on anterior angle morphology in primary angle closure glaucoma

Abstract

Background To evaluate dynamic changes in anterior segment biometric parameters after lens extraction (LE) in different subtypes of primary angle-closure glaucoma (PACG). Methods We conducted a prospective cohort study in 35 eyes of 27 patients with PACG who were enrolled between October 2019 and January 2021. Patients underwent ultrasound biomicroscopy before and after LE surgery. All enrolled eyes were classified into two subgroups according to their angle morphology: pure pupillary block group (PPB) and non-pure pupillary block group (NPPB). Follow-up examinations were performed postoperatively (at 1, 3, and 6 months) to observe dynamic changes in the anterior chamber angle. Results PPB was identified in 11 eyes (31%) and NPPB was identified in 24 eyes (69%). The change in anterior chamber depth was similar in both groups, while improvements in the angle opening distance at 500 µm and the trabecular-iris angle were larger in the PPB group than those in NPPB group at 1-month, 3-month, and 6-month follow-up. The trabecular ciliary process distance and the trabecular ciliary angle increased statistically significantly after surgery in both groups. Ciliary body thickness at the scleral spur and iris thickness showed no statistically significant changes postoperatively in either group. Conclusions LE has a weaker long-term effect in widening the anterior chamber angle in eyes with non-pure pupillary block mechanism than in eyes with pure pupillary block mechanism. LE cannot eliminate the configuration of the anterior ciliary position. Clinicians should perform individualized treatments for PACG according to the relevant angle-closure mechanisms.