Epidemiological studies on UV-related cataract in climatically different countries.

Area of Science:

• Ophthalmology and Environmental Health
• Epidemiological studies on solar UV radiation effects

Background:

• Cataracts are a leading cause of vision impairment globally.
• Environmental factors, particularly solar ultraviolet (UV) radiation, are implicated in cataractogenesis.
• Geographical variations in UV exposure may influence cataract prevalence and type.

Purpose of the Study:

• To investigate the influence of solar UV radiation on cataract development.
• To compare cataract prevalence and types across climatically diverse locations.
• To assess the epidemiological risk of UV exposure for different cataract formations.

Main Methods:

• Epidemiological surveys conducted in Noto and Amami (Japan), Singapore, and Reykjavik (Iceland).
• Objective assessment of lens opacity using standardized grading of lens images.
• Correlation analysis between environmental factors (solar UV exposure) and cataract characteristics.

Main Results:

• Reykjavik subjects showed significantly higher percentages of transparent lenses and lens opacification compared to Singaporeans.
• Amami and Singapore exhibited higher percentages of early cataract changes than Noto and Reykjavik.
• Singapore had the highest rate of progressed lens opacification, predominantly nuclear, while Noto and Reykjavik showed mainly cortical opacification.
• A significant correlation was observed between cortical opacification and history of time spent outdoors.

Conclusions:

• Solar UV exposure appears to influence the prevalence and type of cataracts.
• Cortical opacification shows a significant association with cumulative outdoor UV exposure.
• The epidemiological UV risk for the formation and/or progression of cortical opacification is considered acceptable.