Refractometers
An autorefractor or automated refractor is a computer-controlled machine used during an eye examination to provide an objective measurement of a person's refractive error and prescription for glasses or contact lenses. This is achieved by measuring how light is changed as it enters a person's eye.
The automated refraction technique is quick, simple and painless. After application of a cycloplegic agent to keep the ciliary muscle in relaxed position and avoid the erroneous diagnosis of a pseudomyopia, the patient takes a seat and places their chin on a rest. One eye at a time, they look into the machine at a picture inside. The picture moves in and out of focus as the machine takes readings to determine when the image is on the retina. Several readings are taken which the machine averages to form a prescription. No feedback is required from the patient during this process.
