Objective: To determine the prevalence and causes of pterygium and pinguecula in the population of Tehran in 2002.

Methods: In a cross-sectional population study with cluster sampling, 6497 residents of Tehran were selected from 160 clusters. Samples were chosen according to a door-to-door head counting and were then invited for free examinations. After the interview, ophthalmic examinations were performed at an eye clinic.

Results: Of the selected sample, 4564 people (70.3%) participated in the study. The age- and gender-standardized prevalence of pterygium in this population was 1.3% (95% confidence interval (CI): 0.9-1.6%). The prevalence of pterygium was 1.4 and 1.1% in men and women, respectively (P>0.05). The prevalence of pinguecula in this study was 22.5% (95% CI: 21.1-24.0%); 27.1% in men and 17.7% in women (P<0.001). In both genders, the prevalence of pterygium and pinguecula showed a significant increase with age (P<0.001).

Conclusions: This study concerns the status of pterygium and pinguecula according to age and gender in the population of Tehran. The overall prevalence rates were 1.3 and 22.5% for pterygium and pinguecula, respectively. The comparison of the results with those reported from other areas of the world suggests lower prevalence rates in Tehran.