Influence of glaucoma on corneal biomechanical properties measured with a dynamic Scheimpflug analyzer

Abstract

Purpose : To evaluate the relationship between ocular biomechanical parameters measured with a dynamic Scheimpflug analyzer and glaucoma, as well as other baseline factors such as axial length, intraocular pressure (IOP), age and central corneal thickness (CCT).

Methods : Fifty-one eyes of 51 consecutive subjects with glaucoma and 75 eyes of 75 heathy subjects who underwent measurement of biomechanical parameters with a dynamic Scheimpflug analyzer (Corvis ST) were retrospectively investigated. Twenty-nine of 36 biomechanical parameters were selected for analyses based on measurement reliability and clinical relevance. The biomechanical parameters were compared between eyes with and without glaucoma using student’s t-test. The parameters that showed nearly significant difference (P<0.1) were further evaluated with multivariable models adjusting for axial length, IOP, age and CCT.

Results : The presence or absence of glaucoma was significantly (P<0.05) correlated with 17 out of 29 biomechanical parameters in multivariable models. Glaucoma was positively correlated with delta arc length at outward applanation (A2), and deflection length, max inverse radius, integrated radius, and ratio of deformation amplitude at highest concavity (HC), and the maximum delta arc length. On the other hand, glaucoma negatively correlated with time at inward applanation, deflection area, deflection amplitude, and time at A2, radius at HC, and whole eye movement. These results consistently indicate larger deformability of the cornea in eyes with glaucoma. Many biomechanical parameters showed significant correlation with other baseline factors (15 parameters with IOP, 17 parameters with CCT, 17 parameters with age, and 10 parameters with axial length).

Conclusions : Glaucoma significantly correlated with corneal biomechanical parameters measured with a dynamic Scheimpflug analyzer. Eyes with glaucoma showed larger deformability than healthy eyes. These results suggest that the IOP measured by noncontact tonometer and Goldmann applanation tonometer were lower than the real IOP in glaucomatous eyes. Many parameters showed significant relationships with other factors, suggesting the importance of adjustment for possible confounding effects of these factors when evaluating the relationship between glaucoma and biomechanical parameters.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.