Write the importance of ciliary muscles in the human eye. Name the defect of vision that arises due to gradual weakening of the ciliary muscles. What types of lenses are required by the person suffering from this defect to see the objects clearly?

Ciliary muscles adjust the focal length of the eye lens. This property is known as power of accommodation. Presbyopia arises due to gradual weakening of the ciliary muscles and diminishing flexibility of eye lens as increasing age of human. A common type of bi-focal lens consists of both concave and convex parts required to see objects clearly (a) Since Akshay could see only nearby objects but not the far objects, thus he is suffering from myopia. Concave lens is used to correct this defect.