The prevalence of lens opacities in Tehran: the Tehran Eye Study

To determine the prevalence of lens opacities and cataract surgical coverage among Tehran citizens 40 years of age and older.

The Tehran Eye Study was a population-based survey, with random sampling from Tehran household clusters. Those 40 years of age and older from that survey were included in this analysis. All participants underwent full optometric, slit lamp, and fundoscopic examinations. Lens opacity was assessed after pupil dilation using the modified Lens Opacities Classification System III (LOCS III). The main indices for prevalence of cataract were any lens changes, defined as the presence of a gradable cataract in one or both eyes, and all lens changes, defined as any lens changes plus a history of cataract surgery.

A total of 1434 participants were included in this analysis; 305 of which met the criteria for all lens changes resulting in an adjusted prevalence of 22.7% (CI95%: 20.2%-25.3%). The prevalence was 21.2% among men and 24.5% among women. The prevalence of any lens changes was 19.1% (CI95%: 16.6%-21.6%) and the prevalence was higher in women. The prevalence for both indices increased with age. Considering their better eyes, 39 people (2.7%) were shown to have low vision because of cataract and another 12 (0.8%) were classified as blind.

Cataract has affected approximately one-fifth of the Tehran population aged 40 years and over, women more than men, and has severely affected the vision of approximately 3.5% of this population. We found that access to cataract surgery facilities was not an issue.