myopia is a type of defect in vision where people cannot see objects in the greater distances,but can see the objects which are near.It is also called as "nearsightedness"
1.The maximum focal length for people suffering with myopia is less than 2.5 cm.
2.The people suffering with the myopia can see objects up to a certain distance clearly, while the normal healthy person can see objects clearly all distances more than 25 cm .
3.In the defect myopia , the point of maximum distance at which the eye lens can form an image on retina is called "far point"
"Eye lens can form a clear image when any object is placed beyond near point.
hypermetropia is also called a "farsightedness".
1.the minimum focal length of the eye lens for the person suffering with hypermetropia is greater than 2.27 cm.
2.the point of minimum distance at which the eye lens can form an image on the retina is called "near point"
3.the people with hypermetropia cannot see objects placed betwwen near point and least distance of vision.
4.The least distance of vision in humans is 25cm and angle of vision is about 60degrees