What are the three defects of eye????.....with causes and correction.....
Answers
Answer:
the ans is here
Explanation:
the three defects of eye are myopia ,hypermetropia and presbiopia....
myopia is defect in which eye cannot see distant objects clearly and image of distant obj forms in front of retina .it is also called near sightedness...
now the cause of myopia....
1 . excessive curvature of eye lens .
2. elongation of eyeball.
correction _
use of concave lens can correct the defect..
hypermetropia is also called far sightedness...
in which eye can't see distant objects clearly and image of close by object forms behind retina .
cause_
focal length of eye lens is too long and also eyeball becomes small
correction _
we should use convex mirror ..
presbiopia....
in this eye suffers from myopia as well as hypermetropia......
reasons ..?...
it is due to gradual weakening of ciliary muscles and diminishing flexibility of eye lens...
correction...
bifocal lens { concave plus convex lenses}...
#hope it will be helpful to u