What is foresight and nearsightedness in these both which use concave and convex lens. PLEASE EXPLAIN TOMORROW IS MY PAPER
Dear Student,
Myopia (Nearsightedness)
- Myopia is a defect of vision in which a person clearly sees all the nearby objects, but is unable to see the distant objects comfortably and his eye is known as a myopic eye. A myopic eye has its far point nearer than infinity. It forms the image of a distant object in front of its retina as shown in the figure.
-
Myopia is caused by
- increase in curvature of the lens
- increase in length of the eyeball
- Since a concave lens has an ability to diverge incoming rays, it is used to correct this defect of vision.
Hypermetropia (Foresightedness)
- Hypermetropia is a defect of vision in which a person can see distant objects clearly and distinctively, but is not able to see nearby objects comfortably and clearly.A hypermetropic eye has its least distance of distinct vision greater than 25 cm.
- Since a convex lens has the ability to converge incoming rays, it can be used to correct this defect of vision, as you already have seen in the animation.
Regards