Question

You know that myopia is a common refractive defects of vision. A person with this defect can clearly see only objects that are near. Using concave lens of suitable power this defect is corrected.
i) Mention the other two types of defects.
ii) Explain how they can be corrected.

Answer 1

(i) Hyperopia (farsightedness)

-It is a common type of refractive error where distant objects may be seen more clearly than objects that are near.

- Hyperopia can be corrected with a convex lens. A convex lens focuses the light in addition to the natural lens and makes the image focus exactly on the retina.

(ii) Presbyopia

-It is an age-related condition in which the ability to focus up close becomes more difficult. As the eye ages, the lens can no longer change shape enough to allow the eye to focus close objects clearly.

- Presbyopia was corrected with the use of bifocal eyeglasses.