What is the effect of aging on the lens of the eye?

As individuals age, the lens of the eye undergoes several changes that impact its flexibility and overall function. The correct choice highlights the fact that the lens becomes less flexible with age. This reduction in flexibility greatly affects the eye's ability to focus on objects at various distances, a condition known as presbyopia, which is commonly experienced in middle age and beyond.

The aging process leads to biochemical changes in the lens, including an increase in the accumulation of proteins and changes in the distribution of water content. These alterations contribute to the lens becoming stiffer and less pliable over time, making it more difficult for the eye to accommodate when shifting focus from distant to near objects.

In contrast, the other choices do not accurately reflect the changes that occur with aging. The lens does not become more elastic, nor does it remain unchanged; rather, it experiences a gradual decline in flexibility. Additionally, as people age, the lens does not become thinner; in fact, it may thicken due to ongoing growth, leading to the opacification seen in cataracts if they develop. Thus, stating that the lens becomes less flexible succinctly captures the primary effect of aging on this vital structure of the eye.