A person needs a lens of power -4.5 D for correction of her vision. What kind of defect in vision is she suffering from?A. MyopiaB. PtosisC. PresbyopiaD. Diplopia

The power of a lens is given by the formula:
P=1fP = \frac{1}{f}
where PP is the power of the lens (in diopters, D) and ff is the focal length (in meters).
The negative value of the lens power indicates that the lens is diverging (concave lens). A concave lens is used to correct the vision defect where the image is formed in front of the retina, which is the case with myopia (nearsightedness).
Explanation:
• Myopia (nearsightedness) is a condition where the person can see nearby objects clearly, but distant objects appear blurry. This happens because the image of distant objects is focused in front of the retina. To correct myopia, a concave lens (with a negative power) is used to diverge light rays, pushing the image back onto the retina.
Thus, the person is suffering from myopia.
Correct option is A. Myopia