Vision Correction Exercise Without corrective lenses, a surgeon can focus only on objects that lie at distances between 0.65 m (near point) and 8.56 m (far point) from her eye. The surgeon's eyeglasses will rest 2 cm from her eyes. (a) Find the refractive power (diopters) needed for the part of the bifocal eyeglass lenses that will give her corrected distance vision out to infinity. [answer: -0.117 diopters] (b) Find the refractive power (diopters) needed for the part of the bifocal eyeglass lenses that will give her corrected reading vision to a distance of 20 cm from her eye. [answer: +3.97 diopters; note: This is a strong prescription. For doing detailed work, this surgeon is blind as a bat without corrective lenses.] (c) Her retina of is 2.2 cm behind the lens of her eye. The lens in her eye creates a real image of the virtual object at her near point on her retina. What is the focal length of the lens in her eye when this happens? [answer: +2.1 cm

Vision Correction Exercise Without corrective lenses, a surgeon can focus only on objects that lie at distances between 0.65 m (near point) and 8.56 m (far point) from her eye. The surgeon's eyeglasses will rest 2 cm from her eyes. (a) Find the refractive power (diopters) needed for the part of the bifocal eyeglass lenses that will give her corrected distance vision out to infinity. [answer: -0.117 diopters] (b) Find the refractive power (diopters) needed for the part of the bifocal eyeglass lenses that will give her corrected reading vision to a distance of 20 cm from her eye. [answer: +3.97 diopters; note: This is a strong prescription. For doing detailed work, this surgeon is blind as a bat without corrective lenses.] (c) Her retina of is 2.2 cm behind the lens of her eye. The lens in her eye creates a real image of the virtual object at her near point on her retina. What is the focal length of the lens in her eye when this happens? [answer: +2.1 cm