distribution of intraocular pressure, central corneal thickness, and vertical cup to disc ratio in a healthy iranian population: the yazd eye study

purpose: to determine the distribution of intraocular pressure (iop), central corneal thickness (cct), and vertical cup-to-disc ratio (vcdr) in a healthy iranian population. methods: this cross-sectional, epidemiologic study (yazd eye study, yes) was performed on iranian adults, aged 40 to 80 years, residing in yazd, iran between 2010 and 2011. eligible subjects were selected using cluster random sampling. each participant underwent an interview and ophthalmologic examination including refraction, measurement of corrected visual acuity, pachymetry, slit-lamp examination, goldmann applanation tonometry, binocular optic disc evaluation, fundus photography and visual field. results: out of 2,320 eligible individuals, 2,098 subjects (response rate of 90.4%) participated in the study. of which, 2,262 normal eyes of 1,159 subjects were selected for evaluation. mean age was 53.1±9.6 years. mean values for iop, cct, and vcdr were 14.2±2.5 mmhg, 543±35 µm, and 0.32±0.14, respectively. multiple regression analysis showed that iop had a significant correlation with age, cct, diabetes mellitus, spherical equivalent refractive error, and smoking. conclusion: the distribution of iop, cct, and vcdr in yes was different from other studies conducted in different geographical regions; it seems advisable to employ a geographical approach for interpretation of normal variables.