Presbyopia or tired eyesight
Also known as presbyopia, it is a defect or imperfection of vision that involves a decrease in the eye's focusing ability. It initially affects near vision while distant vision remains good, but over the years it extends to affect distant vision as well (the latter always to a lesser extent).
To clearly observe nearby objects, the eye needs to make a modification in the structure of the lens through the work of the so-called ciliary muscles. The alteration of the lens over the years decreases its adaptability (it loses flexibility) and thus cannot focus clearly on objects. This defect is corrected with converging lenses.