Simple, low-cost device that affixes to a cellphone could provide quick eye tests
Wednesday, June 23, 2010 - 17:03
in Physics & Chemistry
There are two standard systems for determining a prescription for eyeglasses to correct refractive errors such as nearsightedness, farsightedness and astigmatism. One is to have the patient look through a large device called a phoropter, fitted with dozens of different lenses that can be swung into place in front of each eye in various combinations, while the patient tries to read a standard eye chart on the wall ahead. The other uses a more expensive system called an aberrometer that shines a laser into the eye and uses an array of tiny lenses to measure its characteristics, with no interaction from the patient.