Ocular Biometric Determinants of Intraocular Pressure and Risk Factors for Ocular Hypertension: The Chinese American...

Angle width and iris area measured by anterior OCT are increasingly predictive of intraocular pressure and ocular hypertension below parameter-specific angle width cutoffs. Cumulative gonioscopy score is weakly predictive below all score cutoffs.

To assess ocular biometric determinants of intraocular pressure (IOP) and risk factors for ocular hypertension (OHTN).

CHES participants underwent Goldmann applanation tonometry, gonioscopy, ultrasound A-scan, and anterior segment OCT (AS-OCT) imaging. Biometric data from one eye per participant were used to develop linear and logistic regression models of IOP and OHTN (IOP >21 mm Hg), respectively, below different angle width cutoffs adjusted for central cornea thickness (CCT).

A total of 2360 eyes of 2360 eligible participants (1518 female, 842 male) were analyzed. Mean age was 60.2±7.8 years. Multivariable stepwise linear regression models and change-point analysis showed that below a trabecular iris space area (TISA 750 ) measurement of 0.08 mm 2 , models became increasingly predictive of IOP up to an adjusted R 2 of 0.84. Smaller TISA 750 and iris area (IA) were the only parameters consistently associated ( P ≤0.04) with higher IOP for TISA 750 below 0.20, 0.10, and 0.05 mm 2 . In multivariable models of OHTN (AUC≤0.95), smaller TISA 750 was associated with OHTN for TISA 750 <0.20, 0.10, and 0.05 mm 2 ( P ≤0.03), while IA was associated with OHTN for TISA 750 <0.05 mm 2 ( P ≤0.03). Cumulative gonioscopy score (sum of gonioscopy grades) was weakly predictive of IOP at all cutoffs (adjusted R 2 ≤0.08).

TISA 750 and IA become strongly predictive of IOP when angle width decreases below a TISA 750 cutoff of 0.08 mm 2 . The relationship between cumulative gonioscopy score and IOP is weak below all gonioscopy score cutoffs. AS-OCT measurements could supplement gonioscopy by helping identify individuals at higher risk for elevated IOP from angle closure.