Final answer:
When the lens of a person's eye is removed due to cataracts, an eyeglass lens of about 16 D (diopters) is prescribed to help restore normal vision.
Step-by-step explanation:
When the lens of a person's eye is removed due to cataracts, an eyeglass lens of about 16 D (diopters) is prescribed to help restore normal vision. This is because the cataract-clouded lens causes significant refractive error, and a lens with a power of 16 D is needed to compensate for this error and provide clear vision. The prescription of an eyeglass lens after cataract surgery helps ensure that the person can see clearly without the clouded lens.