Purpose: The distribution and prevalence of lens opacities and visual impairment caused by cataract were studied in an epidemiologic cross-sectional population study of inhabitants 70 years of age or older in three communities in Oulu County, Finland.
Methods: Of the 560 eligible subjects, 500 (89.3%) were examined. The best-corrected visual acuity for distance in both eyes was determined. The diagnosis of lens opacities was based on clinical biomicroscopy. The findings were compared with standardized photographs of the Lens Opacities Classification System II.
Results: One hundred sixty-five (33.0%) persons in the study population had a clear lens in both eyes. Cataract, aphakia, or pseudophakia was recorded in one or both of the eyes in 64.4% (322 persons) of the participants. The prevalence increased with age from 44.6% of persons (n = 88) in the 70- to 74-year-old age group to 97.6% of persons (n = 41) in the 85- to 89-year-old age group. A total of 56.4% of persons had cataract, aphakia, or pseudophakia in both eyes. Nuclear, cortical, and posterior subcapsular opacities were detected in 38.5%, 37.6%, and 27.7% of the participants, respectively. Exfoliation was present in one or both eyes in 22.1% of the participants. There was no difference in the prevalence of cataract between the sexes when age was considered. Visual impairment to 20/50 or worse was at least partly due to cataract in 23.8% of the right eyes and 22.4% of the left eyes. Significant risk factors for cataract were age and the presence of exfoliation in men and age, occupational exposure to sunlight, and current cigarette smoking in women.
Conclusions: Almost two thirds of the population 70 years of age or older had lens opacities, and in 23.1% of the eyes visual impairment to 20/50 or worse was at least partly due to cataract. Including the patients who had undergone surgery, 30.3% of all the eyes of persons 70 years of age or older can be considered for cataract surgery.