Which of the following is a toxic etiology associated with cataracts?

• A. Lead exposure
• B. Cobalt exposure
• C. Disophenol (dewormer)
• D. Aflatoxin exposure

Answer: (C)

Toxic cataracts arise when the lens is damaged by a harmful chemical or drug, leading to denaturation of lens proteins and opacities. Disophenol, a deworming agent, has historically been linked to cataract formation with longer exposure because it can exert direct toxicity on the lens and promote oxidative stress that disrupts crystallin proteins. The other substances—lead and cobalt—are associated with various systemic toxicities but aren’t classic, well-established causes of cataracts in exam literature, and aflatoxin is more known for liver injury and carcinogenic effects than lens opacities. So the drug disophenol best represents a toxic etiology for cataracts in this context.