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Objective: To examine risk factors for cortical and nuclear lens opacification in older citizens of Reykjavík., Material and Methods: 1045 persons, 583 females and 462 males age 50 years and older were randomly sampled and underwent detailed eye examination including slit-lamp and Scheimpflug photography of the lens and answered a questionnaire. The photographs were used for the diagnosis of lens opacification. The data was analysed using a logistic regression model., Results: An increased risk was found with ageing for developing both nuclear (OR=1.23: 95% CI 1.19-1.26: p<.001) and severe cortical lens opacification (OR=1.19: 95% CI 1.16-1.22: p<.001). Cigarette-smoking for more than 20 pack-years increased risk for nuclear lens opacification (OR=2.52: 95% CI 1.52-4.13: p<.001) as well as pipe- or cigar-smoking (OR=2.48: 95% CI 1.20-5.12: p<.05). Those who spent more than 4 hours/day outside on weekdays in their 20's - 30's and 40's and 50's were found to have increased risk of severe cortical lens opacification (OR=2.80: 95% CI 1.01-7.80: p<.05 and OR=2.91: 95% CI 1.13-9.62: p<.05, respectively). Systemic corticosteroid use was also found to be a significant risk factor for cortical lens opacification (OR=3.70: 95% CI 1.43-9.56: p<.05)., Conclusion: In our study, ageing is the main risk factor for both cortical and nuclear lens opacification. Important modifiable risk factors are smoking for nuclear lens opacification and systemic corticosteroid use and outdoor exposure for cortical lens opacification.

Objectives: Cataract is one of the most common causes for blindness in the world, though not in Iceland due to availability of cataract surgery. The aim of this study was to establish the age and sex specific prevalence of lens opacification and its severity in Iceland., Material and Methods: One thousand seven hundred citizens of Reykjavik 50 years and older were randomly selected from the national population census and offered to participate in an extensive eye study. The lenses were examined on the slitlamp microscope by two experienced ophthalmologists. Three types of lens opacification were considered separately namely cortical, nuclear and posterior subcapsular and graded according to severity using the World Health Organisation protocol. Of those randomized 68.2% of persons aged 50-79 attended and 35.8% of those 80 years and older. A total of 1045 persons; 461 males and 584 females, were examined., Results: The percentage of persons with clear lenses decreased rapidly with increasing age. Of subjects age 50-59 years 45% had clear lenses, 24% of those 60-69 years and 6% of persons 70-79 year old. No subject 80 years or older was found to have a clear lens. Concurrent with this increase in the prevalence, there was an increase in severity of lens opacification. Opacification of the cortex was most common or 67%. There was a strong correlation between opacification in one eye and opacification in the contralateral eye or 84%. Conciusions: Lens opacification is an age-related phenomenon. Early cortical opacification is common after the age of 50 years and vision-disturbing cataract is common in persons older than 70 years. In coming years considerable increase in cataract surgery may be expected because of increase in the population 70 years and older.