The apparatus uses infrared light to measure the wavefront aberration of the system plus the eye with a Hartmann-Shack wavefront sensor.
Defocus is added (or removed) with a computer- controlled, motorized optometer, while higher order aberrations are introduced by a 37-channel
membrane deformable mirror. A parallel viewing channel is used for visual testing with the instrument. Visual acuity, contrast sensitivity, and other visual tests are performed under normal viewing for each desired aberration profile.