Relationship between intraocular pressure and carotid intima-medial thickness: the Beaver Dam Offspring Study (BOSS)

Abstract

Purpose : It is well known that hypertension and other cardiovascular risk factors are associated with intraocular pressure (IOP) but it is not known if atherosclerosis increases IOP. We evaluated the relationship between carotid intima-medial thickness (IMT) and plaque, indicators of subclinical atherosclerosis, and IOP in a large adult cohort.

Methods : This was a cross-sectional investigation of 2769 participants (2005-2008), in the BOSS, a study of adult offspring of participants in the population-based Epidemiology of Hearing Loss Study. The mean age of participants was 48.9 years. IOP was measured using Goldmann applanation tonometry. Carotid IMT and plaque were measured using high-resolution B-mode ultrasound. Other risk factor data included refractive error, blood pressure, and laboratory measures. Generalized estimating equation models were used to test the associations of IMT and plaque with IOP.

Results : The mean IOP was 16.0 mmHg (SD 3.0). The mean IMT was 0.66 mm (SD 0.15) and 24% of the cohort had plaque in 1 or more sites.

IMT was not associated with IOP (β =-0.01 mmHg per 0.1 mm, p= 0.53), adjusting for age (β= 0.20 mmHg per 5 years, p<0.0001), sex (β= -0.44 mmHg for men v women, p <0.01), spherical equivalent ( -0.08 mmHg per diopter, p<0.001), systolic blood pressure (β= 0.25 mmHg IOP per 10 mmHg of blood pressure, p<0.0001), HbA1c (β= 0.41 mmHg per %, p<0.0001), and hematocrit (β= 0.40 per 5%, p<0.0001). In a comparable model, plaque was not associated with IOP (β= -0.03 mmHg per site, p= 0.69). Results were similar in models excluding participants with CVD, glaucoma, cataract or AMD.

Conclusions : Subclinical atherosclerosis measured by both carotid IMT and plaque was not significantly associated with IOP. Several cardiovascular disease risk factors were significantly associated with IOP, consistent with other studies, adding to the evidence that promoting cardiovascular health may benefit ocular health. However, longitudinal studies are needed to determine if atherosclerosis contributes to changes in IOP over time.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.