Visual acuity. Optometrists quantify the resolution of a patient’s vision using a concept called...

Visual acuity. Optometrists quantify the resolution of a patient’s vision using a concept called visual acuity, which is calculated as the inverse of the angular resolution of the eye measured in arc minutes (where 60 arc minutes =1°) under standard illumination. (a) What is the visual acuity of a patient who can resolve two periods separated by 1.0 mm at a distance of 35 cm from the page? (b) Another patient has a visual acuity of 0.25. Calculate the farthest distance from which she could read 12-point lettering. Assume a needed resolution of one point to be able to discern letter shapes. (In 12-point type, a period has a diameter of about 0.35 mm.)