Abstract
Purpose :
To assess changes in the position of lamina cribrosa pores (LCPs) in participants with acute intraocular pressure (IOP) elevation induced by a dark room prone provocative test (DRPPT).
Methods :
The prospective observational study included angle-closure suspects who stayed in a dark room for two hours with the forehead placed on a desk. At baseline and within 5 minutes after DRPPT end, tonometry, fundus photography and optical coherence tomography were performed. Images of the optic nerve head taken at baseline and after IOP elevation were aligned and positional changes of visible LCPs were measured, characterizing as the LCP moving distance (LCPMD), the inter-lamina range / deviation of the LCPMD, and the moving angle (LCPMA).
Results :
38 eyes from 27 participants aging 52.5±10.8 years were enrolled. The IOP rose from 16.7 ± 3.2 mmHg at baseline to 23.9 ± 4.3 mmHg after 2 hour DRPPT, with mean elevation of 7.2 ± 2.4 mmHg. The mean LCPMD was 27.5 ± 14.8 μm (5.0-77.2 μm), which increased with higher IOP rise (P=0.003) and larger vertical cup disc ratio (VCDR) (P=0.011) after multivariate analysis. The intra-lamina range of LCPMD and the intra-lamina standard deviation of LCPMD increased with younger age (P=0.027 and P=0.045, respectively), and larger VCDR (P=0.023, P=0.034, respectively). The LCPMA were directed temporally, nasally, superiorly and inferiorly in 20 (53%) eyes, 7 (18%) eyes, 5 (13%) eyes and 6 (16%) eyes, respectively.
Conclusions :
The LCPs changed in their position during a mild to moderate IOP rise lasting two hours, and the changes were not consistent within a lamina. The age and VCDR also played a role in the IOP induced movement. The findings may be of interest to elucidate the biomechanical properties of the lamina cribrosa and the pathogenesis of glaucomatous optic neuropathy.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.