Casteldaccia eye study: prevalence of cataract in the adult and elderly population of a Mediterranean town.

Prevalence of cataract was studied in a population based survey performed in adults aged 40 years or more living in Casteldaccia, a small Sicilian town. Lens opacities of moderate or severe grade (type II or worse, according to the Lens Opacity Classification System II) were found at the following rates: nuclear opalescence in 18.5%, cortical cataract in 12.9%, posterior subcapsular cataract in 10.8%. All these types of cataract were much more frequent in the elderly population and were about 1.5 times more common in women than in men. Late cataract was found in about 1/3 of subjects aged 60 to 69 years, in 2/3 of subjects aged 70 or more, but rarely under 60 years of age. However, early cataract was rather common among younger subjects. Cataracts causing a reduction of visual acuity under 0.7 in the worst eye were found in 4%, 8.7% and 21.5% respectively in the three age groups ranging from 40 to 49, 50 to 59 and 60 to 69 years and in 54.4% of subjects 70 years old or over.