Correlation between Corneal Biomechanics and Lamina Cribrosa Curvature in Primary Open Angle Glaucoma

Abstract

Background: Primary open-angle glaucoma (POAG) is the leading cause of irreversible blindness worldwide. This condition is distinguished by progressive optic neuropathy, excavation of the optic disc, and characteristic visual field abnormalities. Intraocular pressure (IOP) elevation is the primary risk factor. Due to the same collagen makeup of the cornea and sclera, the cornea and lamina cribrosa (LC) may have similar biomechanical qualities. In the present study. This study aimed to establish the association between corneal biomechanical parameters and LC curvature in POAG-affected eyes. Methods: This prospective comparative cross-sectional investigation was conducted on sixty eyes at the Tanta University ophthalmology department. There were 30 eyes with primary open-angle glaucoma and 30 eyes with normal age, gender, and refraction. The corneal biomechanical parameters applanation 1 length and velocity (A1L, A1V), applanation 2 length and velocity (A2L, A2V), peak distance (PD), the radius of curvature (R), and deformation amplitude (DA) were measured using a non-contact Scheimpflug-based tonometer (corvids ST). LC curvature was determined by measuring the LC curvature index (LCCI) using spectral-domain optical coherence tomography B-scan pictures (OCT). The data were gathered and analyzed using a suitable statistical tool. Results: Mean A1V was significantly lower (P=0.027) in the POAG group (0.13 ± 0.02 m/sec) than the control groupn(0.14 ± 0.01 m/sec). PD was significantly increased (P=0.05) in the POAG group (4.30± 0.54 mm) than the control group (3.99± 0.66 mm). R was significantly higher (P=0.004) in the POAG group (7.90± 0.93 mm) than in the control group (7.14± 1.04 mm). DA was significantly lower (P<0.001) in the POAG group (0.95± 0.06 mm) than in the control group (1.11± 0.02 mm). LCCI was significantly higher (P<0.001) in the POAG group (10.69 ± 1.77) than in the control group (6.90 ± 0.93). LCCI showed a positive significant correlation with PD and R and a negative significant correlation with DA. Conclusions: The corneas of POAG eyes were less deformed than those of normal controls. In POAG patients, corneas with less deformability were related to a more posteriorly bent LC. This result may explain why corneal biomechanics may be utilized to evaluate and predict glaucoma risk and progression. Corvis ST is a novel non-contact tonometer that allows for simple estimation of corneal biomechanics and should be used routinely in patient monitoring.