Senile degeneration as a cataract etiology is primarily related to what?

• A. Nutritional deficiency
• B. Trauma
• C. Infectious disease
• D. Chronic UV exposure and oxidizing stress in older animals

Answer: (D)

Age-related lens opacification results from cumulative oxidative damage and UV exposure. In aging lenses, antioxidant defenses like glutathione decline, so reactive oxygen species produced by chronic UV light accumulate and damage crystallin proteins, causing them to cross-link and aggregate into opacity. This combination of long-term UV exposure and oxidizing stress is the primary driver of senile cataracts in older animals. Traumatic, infectious, or nutritional factors can contribute to other cataract forms, but they are not the typical cause of senile cataracts.