Longitudinal changes in the intraocular pressure and their related factors among adults aged 40 to 64 years

To determine the five-year changes in intraocular pressure (IOP) and their related factors among individuals aged 40 to 64 years. The present report is part of the Shahroud Eye Cohort study. The sampling process for this study utilized a multi-stage cluster sampling method within Shahroud, Iran. Optometric and ophthalmologic examinations included measurement of uncorrected and best-corrected visual acuity, non-cycloplegic autorefraction and slit-lamp biomicroscope. IOP was measured using a Goldman tonometer. A total of 7384 eyes from 3855 individuals were examined in this report. The average five-year change in IOP was -0.06±2.23 mmHg (95% confidence interval: -0.14 to 0.02). The 25, 75, 95, and 99th percentiles of five-year IOP changes were -1, 1, 4, and 5 mmHg, respectively. According to the multivariate generalized estimating equation (GEE) model, the five-year changes in IOP were positively associated with female gender (coefficients(β)=0.139; P=0.036), blood pressure (β=0.40; P<0.001), diabetes (β=0.539; P<0.001), body mass index (β=0.023; P<0.001), axial length (β=0.104;P<0.007), central corneal thickness (β=0.010; P<0.001), mean keratometry (β=0.0067; P<0.001), and lens thickness at baseline (β=0.182; P<0.047). Moreover, baseline IOP exhibited an inverse association with five-year changes in IOP (β=-0.808; P<0.001). Despite a 4 mmHg increase in IOP observed in 5% of the study participants, the average change in IOP over five years was deemed not clinically or statistically significant. Nevertheless, biometric indices are important for anticipating variations in IOP.