Lamina cribrosa pore movement during acute intraocular pressure rise

Abstract

Purpose To assess changes in the position of lamina cribrosa pores (LCPs) induced by acute intraocular pressure (IOP) elevation. Methods A prospective observational study. Acute angle-closure suspects who underwent the 2-hour dark room prone provocative test (DRPPT) were included. At baseline and within 5 min after the DRPPT end, tonometry, fundus photography and optical coherence tomography were performed. Optic disc photos taken before and after the DRPPT were aligned and moving distance of each visible LCP was measured (LCPMD). Results 38 eyes from 27 participants (age: 52.5±10.8 years) were included. The IOP rose from 16.7±3.2 mm Hg at baseline to 23.9±4.3 mm Hg at the DRPPT end. The mean lateral LCPMD was 28.1±14.6 μm (range: 5.0-77.2 μm), which increased with higher IOP rise (p=0.01) and deeper optic cup (p=0.02) in multivariate analysis. The intralamina range and SD of the LCPMD increased with younger age (p=0.01 and p=0.02, respectively) and with wider optic cup (p=0.01 and p=0.02, respectively). The LCP movements were headed to the superior direction in 12 (33%) eyes, inferior direction in 10 (28%) eyes, temporal direction in 9 (25%) eyes, and nasal direction in 5 (14%) eyes. Conclusions IOP rise is associated with LCP movements in the frontal plane, which are more pronounced with higher IOP rise and deeper optic cup. The intralamina variability in the IOP rise-associated LCPMD increased with younger age and wider optic cup. IOP variation-associated lateral LCP movements may be of interest to elucidate glaucomatous optic nerve damage.