The defect caused due to gradual weakening of ciliary muscles and diminishing flexibility of the eye lens is presbyopia. Presbyopia is the defect of eye in which a person cannot see nearby objects comfortably and distinctly without corrective eye glasses. A presbyopic eye has its near point greater than 25 cm and is gradually increases as the eye becomes older. The type of lens required by such person to improve the vision is bifocal lens. A bifocal lens consists of both convex and concave lenses. The convex lens & used in bifocal lens is used to correct hypermetropia (far sightedness) and concave lens is used to correct myopia (near sightedness).
You need to login to perform this action.
You will be redirected in 3 sec