The two common defects of the eye are as follows.
1.Short Sight or Myopia
“The person having the short sight can see only the nearer object.” The eyeball of the person having short sightedness is longer than the normal sighted eye. When a parallel beam of light from the distant object is incident on the eye, the rays are brought to focus in front of the retina. Hence the image is not formed on the retina.
A concave lens of suitable focus length can rectify this defect. 2.Long Sight or Hypermetropia
1.Short Sight or Myopia
A concave lens of suitable focus length can rectify this defect. 2.Long Sight or Hypermetropia
“The person having the long sight can see only the distant object.” The eyeball of the person having long sightedness is shorter than the normal sighted eye. When the light from the nearer subject is incident on the eye, the rays are focused behind the retina. Hence, the image is not formed on the retina.
A convex lens of suitable focal length can rectify this defect.
No comments:
Post a Comment