The annual limit for the eye lens is commonly about how many mSv per year?

• A. Commonly 2 mSv per year.
• B. Commonly 100 mSv per year.
• C. Commonly 1 Sv per year.
• D. Commonly 20 mSv per year.

Answer: (D)

The lens of the eye is unusually sensitive to ionizing radiation, and cataracts are a key deterministic effect at relatively low doses. Because of this, the protective dose limit for the lens is kept lower than the whole-body limit. The commonly accepted occupational limit is about 20 mSv per year, averaged over five years, with no single year exceeding about 50 mSv. In practice this means the total lens dose over five years should stay around 100 mSv or less, averaging 20 mSv per year, to minimize cataract risk. This lower limit drives the emphasis on shielding, keeping a safe distance, and using eye protection and appropriate dosimetry to monitor exposure.