How is a normal eye able to see distinctly distant as well as nearer objects? What is the distance of distinct vision?

How is a normal eye able to see distinctly distant as well as nearer o

1.	How is a normal eye able to see distinctly distant as well as nearer objects? What is the distance of distinct vision?
Answer» Solution :Eye lens is made up of fibrous material. Its curvature can be changed by ciliary muscles which changes its FOCAL length. When muscles are relaxed, the lens becomes thin and focal length increases and the eye is able to see distant objects. Similarly when ciliary muscles CONTRACT, focal length decreases and eye is able to see nearer objects. The minimum distance at which objects can be SEEN distinctly is called distance of DISTINCT vision. It is 25 cm.