What does presbyopia refer to?

Presbyopia specifically refers to the gradual loss of the eye's ability to focus on nearby objects, a condition that typically occurs with aging. As people age, the lens of the eye becomes less flexible, leading to difficulty in focusing on close tasks, such as reading or sewing. This is a natural part of the aging process, commonly beginning to affect individuals in their 40s or 50s.

In contrast, the other options describe different visual issues. Loss of peripheral vision may indicate conditions such as glaucoma rather than typical age-related changes. Complete vision loss refers to total blindness, which is a much more severe condition and not the same as the changes associated with presbyopia. Eye strain from screens is associated with digital eye strain or computer vision syndrome, which can occur at any age and is related to prolonged use of screens rather than the gradual aging process affecting vision.