Near sightedness Myopia


 
 
Concept Explanation
 

Nearsightedness Myopia

Nearsightedness (Myopia):

Nearsightedness is a defect of vision due to which a person is not able to see distant objects clearly. This defect is also called shortsightedness or myopia. It arises mainly due to two reasons.

  • In certain people, the eyeball becomes elongated, i.e, longer than the normal eye. As a result, the distance of the retina from the crystalline lens increases. Then, even for the maximum focal length of the eve-lens, ie., when the cilliary muscles are most relaxed, Parallel rays of light from far away objects get focused at a point before the retina as in  Figure (a).
  •  In some cases, the curvatures of the cornea or the lens are such that the eye-lens has a shorter focal length (more power) than usual. In such cases also, the image forms short of the retina. In both cases, far away objects cannot be seen clearly, although nearby objects can.
  • .... (More Text Available, Login?)
    Sample Questions
    (More Questions for each concept available in Login)
    Question : 1

     Nearsightedness is also known as _____________________.

    Right Option : D
    View Explanation
    Explanation
    Question : 2

    Which of the following are correct ?

    (a) Nearsightedness is a defect of vision due to which a person is not able to see distant objects clearly this defect is also called myopia.

    (b) To correct the nearsightedness, a parallel beam is made divergent before it enters the eye by putting a concave lens in front of the eye .

    Right Option : C
    View Explanation
    Explanation
    Question : 3

    Which glasses or lens are used to correct the short sighted eye defect ?

    Right Option : A
    View Explanation
    Explanation
     
     


    Students / Parents Reviews [10]