An example of a deterministic effect is radiation-induced cataract formation.

• A. Cancer
• B. Genetic mutations
• C. Radiation-induced cataract formation
• D. Hair loss

Answer: (C)

Deterministic effects have a dose threshold, and their severity increases with the amount of radiation absorbed. The lens of the eye is highly sensitive, and once the absorbed dose to the lens crosses a threshold, cataracts reliably develop; higher doses tend to cause earlier onset and more severe opacities. That makes radiation-induced cataract formation a classic example of a deterministic effect. In contrast, cancer and genetic mutations are stochastic effects—risk increases with dose but there isn’t a strict threshold that guarantees occurrence. Hair loss is also a deterministic effect, but cataract formation is the standard example illustrating the threshold-and-severity relationship in a specific tissue.