A Study to Test the Potential of Brillouin Microscopy for Biomechanical Properties Measurements in Human Cornea

The purpose of this research study is to find out if the new Brillouin Ocular Scanner can
measure the variation (difference) of the corneal elastic changes involved in the onset of
corneal ectasia, induced by LASIK surgery and cornea collagen crosslinking (CXL) treatment.
Ectasia refers to the thinning and bulging of the cornea and results in severe vision
degradation (loss), which may occur because of a progressive disease (keratoconus) or because
of LASIK surgery. It is believed that the structural weakening of the cornea plays a major
role in developing ectasia. CXL is a treatment that is able to halt the progression of
ectasia.

The Brillouin Ocular Scanner is a technique based on the principles used in the laser speed
measuring of a car (radar gun). When laser light illuminates a moving sample, a portion of
the light slightly changes color. In our body, e.g in eye and corneal tissue, very weak sound
waves are naturally present and they can induce a similar color shift. Measuring this color
shift with a sensitive light color meter (spectrometer), we will measure the sound speed in
the tissue.