Longitudinal changes in intraocular pressure and association with systemic factors and refractive error: Lingtou Eye Cohort Study

OBJECTIVES: To investigate the longitudinal changes in intraocular pressure (IOP) and its associations with refractive error and systemic determinants in a Chinese geriatric population. DESIGN: Prospective cohort study. SETTING: Guangzhou Government Servant Physical Check-up Center, Guangzhou, China. PARTICIPANTS: 4413 government employees aged no less than 40 years (41.9% female) attending annual physical and eye examinations were included in this study. The inclusion criterion was having attended the 2010 follow-up examination. The exclusion criteria include glaucoma or intraocular surgery history, IOP >21 mm Hg at any visit or without available IOP data at all visits from 2010 to 2014. PRIMARY AND SECONDARY OUTCOME MEASURES: The outcome measure was IOP at each follow-up visit from 2010 to 2014. Mixed-effect model was used to assess the relationship between longitudinal changes in IOP and potential risk factors. RESULTS: For the 2653 participants who had available IOP data at both the 2010 and 2014 follow-up visits, the average change in IOP was an increase of 0.43 (95% CI 0.36 to 0.50) mm Hg. For the whole study population and in the optimised mixed model, there was a non-linear increase of IOP with age (P<0.001), with greater changes in younger subjects and in women (P<0.001 and P=0.002, respectively). Elevations in systolic blood pressure, diastolic blood pressure, body mass index (BMI) and fasting plasma glucose (FPG), as well as a myopic shift (all with P<0.001), during the follow-up were associated with an increasing trend of IOP, while serum lipids were found to be not significantly associated. CONCLUSIONS: In this cohort of elderly Chinese adults, IOP increases non-linearly with ageing. People with increasing blood pressure, BMI, FPG and myopic progression are more likely to have IOP elevation over time.