A near sighted person wears eye glass of power 5.5D for distant vision. His doctor prescribes a correction of + 1D in near vision part of his bifocals, which is measured relative to the main part of the lens.
1. What is the focal length of his near vision part of the lens ?
(i) - 22.22 cm
(ii) -32.3 cm
(iii) -22. 22 m
2. Name the defect of vision he is suffering from.
(i) Myopia
(ii) Hypermetropia
(iii) Both A and B
3. What is the total power of this lens after the near vision is increased?
(i) -1.667 D
(ii) -4.5 D
(iii) 10 D
4. Which lens is used for correction of this defect ?
(i) Concave lens
(ii) Convex lens
5. What does the negative sign of power indicates ?
(i) Concave lens
(ii) Convex lens
