Presbyopia is a defect of vision that occurs due to the weakening of the ciliary muscle in old age people, which causes a decrease in the flexibility of the eye lens. As a result, people with presbyopia find it difficult to see nearby objects and have trouble reading or performing tasks that require close-up vision. Presbyopia is a natural aging process of the eye that affects a significant portion of the worlds population, particularly those over the age of 40. The causes of presbyopia include the loss of elasticity of the eye lens and the weakening of the ciliary muscles.

Presbyopia can be corrected by using suitable lenses such as bifocal lenses. Bifocal lenses have both a concave and convex surface that are part of their refractive design. The upper part of the lens is made up of a concave lens to correct myopia for distance vision, while the lower part is made up of a convex lens to correct hypermetropia for reading. Contact lenses can also be used to correct presbyopia.

In summary, presbyopia is a vision defect that occurs due to the weakening of the ciliary muscle in old age people, which causes a decrease in the flexibility of the eye lens. It can be corrected by using suitable lenses such as bifocal lenses or contact lenses.