CENTRAL CORNEAL THICKNESS AND INTRAOCULAR-PRESSURE IN A MONGOLIAN POPULATION

Objective: The purpose of the study was to quantify the variation of c entral corneal thickness (CCT) in an east Asian population and to exam ine its relationship to estimates of intraocular pressure (IOP) made w ith an applanation tonometer. Design: The study design was a cross-sec tional, population-based survey. Participants: One thousand two-hundre d forty-two residents of Hovsgol Province, Mongolia, 10 to 87 years of age participated. Main Outcome Measures: The CCT was measured using a n optical pachymeter in all subjects. The IOP was measured using a Gol dmann-type applanation tonometer in subjects 40 years of age and older . Results: There was a highly significant decrease in CCT with age: 5 mu m/decade in men and 6 mu m/decade in women (both, P < 0.0001). A hi ghly significant positive correlation was identified between IOP and C CT. Linear regression analysis suggests that between the ages of 40 an d 80 years, an increase in CCT of 10 mu m is associated with an increa se in IOP measurements of 0.18 mmHg in right eyes (95% confidence inte rval, 0.12-0.25) and 0.24 mmHg in left eyes (95% confidence interval, 0.17-0.31). The authors calculate that interindividual differences in CCT may produce a difference in measured IOP of between 2.3 and 3.1 mm Hg. Conclusions: Variation in CCT is a significant source of variation in IOP measurements between individuals. The authors suggest that mea surement of corneal thickness should be considered when assessing IOP as a risk factor for glaucoma in east Asians.