If the patient opts to have only one eye treated at a time, a contact lens maybe needed for the untreated eye until the second eye undergoes the procedure. Most patients can do this, even if they have not been able to tolerate contacts in the past. Keep in mind the optics of removing the glass in front of the treated eye in the spectacles, while giving clearer vision to each eye individually, will often cause disorientation and headaches due to image size discrepancy--unless the original prescription was less than -3.00.