Define presbyopia.

Presbyopia is recognized as an age-related condition that affects the eye's ability to focus on near objects. This occurs due to a gradual loss of elasticity in the lens of the eye, which makes it more difficult for the eye to accommodate or adjust focus for close-up tasks, such as reading or sewing. As individuals age, typically beginning in their 40s or 50s, this condition becomes increasingly noticeable, leading to the necessity for reading glasses or bifocals to aid in near vision tasks.

The other conditions listed do not relate to the concept of presbyopia. Increased sensitivity to light pertains to a different visual phenomenon, corneal issues describe conditions related to the shape and health of the cornea, and eye infections typically involve inflammatory processes and symptoms quite distinct from the focusing difficulties associated with presbyopia. Thus, the definition captured in the correct choice accurately reflects the primary characteristics of presbyopia.