Which defect occurs when the eye lens loses its ability to focus on near objects due to decreased flexibility?
Presbyopia results from reduced lens flexibility
Presbyopia is an age-related defect of vision in which the crystalline lens of the eye gradually hardens and the ciliary muscles weaken, so the lens can no longer change curvature enough to bring nearby objects into sharp focus.
It usually sets in after about 40 years of age and is corrected using convex (converging) lenses or bifocal spectacles that help focus near objects on the retina.
Myopia (short-sight) is caused by an elongated eyeball or too-curved lens focusing distant objects in front of the retina; hypermetropia (long-sight) is caused by a short eyeball where near objects focus behind the retina; astigmatism results from an unevenly curved cornea, not loss of flexibility.
Hence, the defect due to decreased flexibility of the eye lens is presbyopia.
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