Plain English Meaning
As people get older, their eyes have a harder time focusing on things up close, like a chart or instrument panel. It's a normal part of aging, not a disease.
Full Definition
An age-related vision change in which the lens of the eye gradually loses flexibility, reducing the eye's ability to focus on close objects. It typically becomes noticeable after age 40 and is corrected with reading glasses, bifocals, or progressive lenses.
Context Anchor
Seen in night vision and pilot health discussions, especially when reading cockpit information in low light.
Derivation
From Greek 'presbys' meaning 'old man' and 'opia' meaning 'sight' or 'vision.' Literally 'old-person sight,' which describes exactly what it is: the change in close-up vision that comes with age.
Why Pilots Care
It impairs reading plates, , and instruments at or in dim cockpit lighting, raising the chance of misreading information.