Intraocular pressure and its relation to ocular geometry: results from the Gutenberg Health Study

Abstract

Purpose : To investigate the associations between intraocular pressure (IOP) and ocular geometry.

Methods : The Gutenberg Health Study is a population-based cohort study in Mainz, Germany including 15.010 subjects at age 35 to 74 years at baseline examination. Study participants underwent a comprehensive ophthalmologic examination including non-contact tonometry (NT 2000™, Nidek Co., Japan), objective refraction, optical biometry (LenStar, Haag-Streit, Bern, Switzerland) and Scheimpflug imaging (Pentacam, Oculus, Wetzlar, Germany) of the anterior segment at the first 5-year follow-up examination (in the year 2012-2017). Anterior chamber angle width was analyzed on Scheimpflug images using proprietary software. Multivariable linear regression analyses with generalized estimating equations were carried out to determine associations of IOP and geometric parameter, namely central corneal thickness (CCT), corneal curvature, anterior chamber depth, lens thickness and posterior segment length with adjustment for age and sex. In an additional model, anterior chamber angle width was also included.

Results : 13.280 phakic eyes of 6.640 participants (mean age 57.3 ± 10.2 years, 49.1% female) were included in this cross-sectional analysis. No included eye showed angle closure on Scheimpflug imaging. Mean IOP was 14.84±2.92 mmHg in right eyes and 14.91±2.93 mmHg in left eyes. IOP increased with higher CCT (B=0.042 per µm; 95%CI: 0.040-0.044), longer posterior segment length (B=0.20 per mm; 95%CI: 0.14-0.25), higher age (B=0.20 per 10 years; 95%CI: 0.13-0.26) (all p<0.001), thicker crystalline lens (B=0.25 per mm; 95%CI: 0.08-0.42; p=0.003) and female sex (B= 0.12; 95%CI: 0.00-0.24; p=0.05), while anterior chamber depth and corneal curvature was not associated. IOP increased with a narrower anterior chamber angle in univariate analysis (B=-0.02 per degree; 95%CI: -0.03 - -0.01; p<0.001), but not in multivariable analysis (p=0.34).

Conclusions : IOP measurement is related to the individual ocular geometry. Thus, those ocular parameters should be taken into consideration when clinically interpreting non-contact tonometric data. In eyes with an open anterior chamber angle, there is no correlation between anterior chamber angle width and IOP level in our multivariable model.

This is a 2021 ARVO Annual Meeting abstract.