A patient is going to be prescribed bifocals which will be 2.50 cm from the eye. The prescribed powers (in diopters) for the bifocals are +1.60 and -0.40, and these bifocals give the patient normal vision.

(a) Without the bifocals, what is the patient's near point?
cm
(b) Without the bifocals, what is the patient's far point?

To find the patient's near point and far point, we need to understand how the power of the lenses affect the patient's vision. The power of a lens is measured in diopters (D) and determines how much the lens bends light.

(a) To find the patient's near point without the bifocals, we need to consider the power of the lens that corrects for near vision. In this case, the near power of the bifocals is +1.60 D. The near point is the closest distance at which the eye can see objects clearly.

To calculate the near point, we can use the formula:

Near point (in meters) = 1 / Near power (in diopters)

Converting 2.50 cm to meters:

2.50 cm = 0.025 m

Calculating the near point:

Near point = 1 / 1.60 D = 0.625 m

Therefore, the patient's near point without the bifocals is 0.625 meters.

(b) To find the patient's far point without the bifocals, we need to consider the power of the lens that corrects for distance vision. In this case, the distance power of the bifocals is -0.40 D. The far point is the farthest distance at which the eye can see objects clearly.

To calculate the far point, we can use the formula:

Far point (in meters) = 1 / Far power (in diopters)

Calculating the far point:

Far point = 1 / (-0.40 D) = -2.5 m

Therefore, the patient's far point without the bifocals is 2.5 meters.