  An acousto-optic cell was used to reduce the speckle noise that reduces the
quality of Hartmann-Shack and other wave-front sensors measuring ocular
aberrations. In the method presented here, a laser beam traverses an
acousto-optic cell, interacting with standing acoustic waves. Speckle reduction
takes place as the incoming beam is diffractively spread across the cornea. The
increased size and the wider angular spread of the incoming beam average out
the speckles, producing a more uniform response of the wave-front sensor.
