The optical prescription of a pair of spectacle is
Right eye: - 3.5 D Left eye: - 4.00 D

i) Name the defect of the eye

ii) Are these lenses thinner at the middle or at the edges?

iii) Which lens has a greater focal length?

Question

Philoid · Accepted Answer

i) The person is suffering from myopia i.e. he has a difficulty in seeing distant objects.

ii) The corrective lens used in treating myopia is concave lens. These lenses are thicker at the edge and thinner at the middle.

iii) The power of the corrective lens is

a) For the right eye:

Power = -3.5D

b)For the left eye:

Power = -4.00 D

This are the required focal length of the corrective concave lenses.

The optical prescription of a pair of spectacle isRight eye: - 3.5 D Left eye: - 4.00 Di) Name the defect of the eyeii) Are these lenses thinner at the middle or at the edges?iii) Which lens has a greater focal length?