Sandi Claffey, 779th Medical Group certified ophthalmic technician takes a custom wavefront WaveScan analysis of the cornea, at Joint Base Andrews, Md. The machine is used to design the patient's precise prescription and takes a fingerprint of the iris which helps to identify the patient for their laser treatment, and it displays their high order aberrations like possible glare and halos.(U.S. Air Force photo/Staff Sgt. Perry Aston)