Associations with Intraocular Pressure in a Large Cohort: Results from the UK Biobank

Michelle P.Y Chan,Carlota M Grossi,Anthony P Khawaja,Jennifer L.Y Yip,Kay-Tee Khaw,Praveen J Patel,Peng T Khaw,James E Morgan,Stephen A Vernon,Paul J Foster

doi:10.1016/j.ophtha.2015.11.031

Abstract

PurposeTo describe the associations of physical and demographic factors with Goldmann-correlated intraocular pressure (IOPg) and corneal-compensated intraocular pressure (IOPcc) in a British cohort.DesignCross-sectional study within the UK Biobank, a large-scale multisite cohort study in the United Kingdom.ParticipantsWe included 110 573 participants from the UK Biobank with intraocular pressure (IOP) measurements available. Their mean age was 57 years (range, 40–69 years); 54% were women, and 90% were white.MethodsParticipants had 1 IOP measurement made on each eye using the Ocular Response Analyzer noncontact tonometer. Linear regression models were used to assess the associations of IOP with physical and demographic factors.Main Outcome MeasuresThe IOPg and IOPcc.ResultsThe mean IOPg was 15.72 mmHg (95% confidence interval [CI], 15.70–15.74 mmHg), and the mean IOPcc was 15.95 mmHg (15.92–15.97 mmHg). After adjusting for covariates, IOPg and IOPcc were both significantly associated with older age, male sex, higher systolic blood pressure (SBP), faster heart rate, greater myopia, self-reported glaucoma, and colder season (all P < 0.001). The strongest determinants of both IOPg and IOPcc were SBP (partial R2: IOPg 2.30%, IOPcc 2.26%), followed by refractive error (IOPg 0.60%, IOPcc 1.04%). The following variables had different directions of association with IOPg and IOPcc: height (−0.77 mmHg/m IOPg; 1.03 mmHg/m IOPcc), smoking (0.19 mmHg IOPg, −0.35 mmHg IOPcc), self-reported diabetes (0.41 mmHg IOPg, −0.05 mmHg IOPcc), and black ethnicity (−0.80 mmHg IOPg, 0.77 mmHg IOPcc). This suggests that height, smoking, diabetes, and ethnicity are related to corneal biomechanical properties. The increase in both IOPg and IOPcc with age was greatest among those of mixed ethnicities, followed by blacks and whites. The same set of covariates explained 7.4% of the variability of IOPcc but only 5.3% of the variability of IOPg.ConclusionsThis analysis of associations with IOP in a large cohort demonstrated that some variables clearly have different associations with IOPg and IOPcc, and that these 2 measurements may reflect different biological characteristics.

Highlights

Participants had 1 intraocular pressure (IOP) measurement made on each eye using the Ocular Response Analyzer noncontact tonometer
We explore the associations of both Goldmann-correlated IOP (IOPg) and corneal-compensated IOP (IOPcc) measured by the Ocular Response Analyzer noncontact tonometer (ORA)
Left eye IOP values were chosen for the main analyses because they were measured after the right eye and were possibly less prone to artifacts with the participant more familiar with the test

Summary

Results from the UK Biobank

Michelle P.Y. Chan, FRCOphth,[1] Carlota M. PhD, FRCOphth,[2] Jennifer L.Y. Yip, PhD, MRCOphth,[2] Kay-Tee Khaw, MBBChir, FRCP,[2] Praveen J. FRCOphth, MD(Res),[1] Peng T. PhD, FRCOphth,[1] James E. DPhil, FRCOphth,[3] Stephen A. DM, FRCOphth,[4] Paul J. PhD, FRCOphth,[1] on behalf of the UK Biobank Eye and Vision Consortium*. Participants: We included 110 573 participants from the UK Biobank with intraocular pressure (IOP) measurements available. Their mean age was 57 years (range, 40e69 years); 54% were women, and 90% were white

Methods

Results

Discussion