1. The problem statement, all variables and given/known data A farsighted man uses eyeglasses with a refractive power of 2.05 diopters. Wearing the glasses 0.020 m from his eyes, he is able to read books held no closer than 0.265 m from his eyes. He would like a prescription for contact lenses to serve the same purpose. What is the correct contact lens prescription, in diopters? 2. Relevant equations 1/do+1/di=1/f 3. The attempt at a solution The image formed when wearing eyeglasses is 0.265-0.020 = 0.245 and this has to be negative because the man is using convex lenses, so d/i = -0.245 with eyeglasses. Next, I found the the object distance when wearing eyeglasses by using the formula 1/do+1/di=1/f and it turned out to be 0.163 the fact that it's positive makes sense because the object is placed in front of the lens. Now because the questions asks to find the power of the contact lenses the distance of the object when using contacts increases by 0.020m so do with lenses equals 0.183m. Finally I plugged everything into 1/do+1/di=1/f and got +1.38 diopters.