Before revision: The normal human cornea varies from around 500 to 600 micrometres in thickness; and in the LASIK procedure, the microkeratome creates an 83 to 200 micrometre thick flap.
After revision: The normal human cornea varies from around 500 to 600 μm in thickness; and in the LASIK procedure, the microkeratome creates an 83 to 200 μm thick flap.