A nearsighted person has a far point of 18 cm.What power contact lenses will allow this person to comfortably see distant objects clearly?
A)+5.6 diopters
B)-5.6 diopters
C)+0.056 diopters
D)-0.056 diopters

Question

Quizplus · Accepted Answer

A nearsighted person has difficulty seeing distant objects clearly, so they require a negative power lens to correct their vision. The power of the lens required can be calculated using the formula P = 1/f, where P is the power of the lens in diopters and f is the focal length of the lens in meters. The near point of a nearsighted person is closer than infinity, so their lens must have a negative power. The far point of a nearsighted person is the maximum distance at which they can see distant objects clearly. In this case, the far point is 18 cm away. To calculate the power of the lens required, we use the formula f = 1/d, where d is the distance between the lens and the eye. In this case, d = -18 cm (since the lens is required to correct nearsightedness), so f = -1/0.18 m = -5.56 diopters (rounded to two decimal places). Therefore, the power of the contact lenses required is -5.6 diopters.

A Nearsighted Person Has a Far Point of 18 Cm