My padlet by Kashvi Tak

DEFECTS OF VISION

kashvitak — 2021-05-17 17:15:30 UTC

COMMON REFRACTIVE DEFECTS OF VISION-

kashvitak — 2021-05-17 17:16:31 UTC

(i)Myopia or near- sightedness
(ii)Hypermetropia or far-sightedness
(iii)presbyopia

MYOPIA

kashvitak — 2021-05-17 17:21:23 UTC

-Myopia is also known as near-sightedness
-A person with myopia can see nearby objects clearly but cannot see distant objects distinctly

CAUSES OF MYOPIA

kashvitak — 2021-05-17 18:15:09 UTC

-Excessive curvature of the eye lens
-elongation of the eyeball

CORRECTION OF MYOPIA

kashvitak — 2021-05-17 18:31:48 UTC

-This defect can be corrected by using a aconcave lens of suitable power
-A concave lens of suitable power will bring the image back on to the retina and thus the defect is corrected

kashvitak — 2021-05-17 19:26:26 UTC

HYPERMETROPIA

kashvitak — 2021-05-17 19:27:40 UTC

-Hypermetropia is also known as far sightedness
-A person with hypermetropia can see distant objects clearly but cannot see nearby objects clearly

kashvitak — 2021-05-17 19:36:42 UTC

CAUSE OF HYPERMETROPIA

kashvitak — 2021-05-17 19:37:51 UTC

-The focal length of the eye lens is too long
-The eyeball has become too small

CORRECTION OF HYPERMETROPIA

kashvitak — 2021-05-17 19:42:57 UTC

-This defect can be corrected by using aconvex lens of suitable power
-Eye converging lenses provide the additional focussing power required for forming the image on the retina

kashvitak — 2021-05-17 19:49:08 UTC

PRESBYOPIA

kashvitak — 2021-05-17 19:50:47 UTC

-The power of accommodation of the eye usually decreases with ageing. For most people, the near point gradually recedes away.
-They find it difficult to see nearby objects comfortably and distinctly without corrective eye-glasses. This defect is called Presbyopia.

CAUSES OF PRESBYOPIA

kashvitak — 2021-05-17 19:52:27 UTC

-It arises due to the gradual weakening of the ciliary muscles and diminishing flexibility of the eye lens

CORRECTION OF PRESBYOPIA

kashvitak — 2021-05-17 19:53:30 UTC

-This defect can be corrected by using a convex lens of appropriate power
-Glasses used to correct presbyopia may be simple reading glasses, bifocals, trifocals, or progressive lens.

kashvitak — 2021-05-17 20:01:26 UTC

-kashvi tak

kashvitak — 2021-05-17 20:04:23 UTC