Glaucoma is a disease of the eye which can lead to the optic nerve becoming damaged. This is usually due to excessively high intraocular pressure (IOP). If the pressure in the eye is not treated, optic nerve damage can cause permanent vision loss, which begins with unnoticeable blind spots, followed by tunnel vision, and eventual blindness. If you suffer from glaucoma, you will not be a suitable candidate for laser eye surgery.