context: Intacs is the brand name for a medical device that is used in the treatment of the eye disorder known as keratoconus. Keratoconus is a condition in which the cornea (the clear, central part of the front surface of the eye) bulges outward like a cone. Normally, the cornea has a dome shape, like a ball. Sometimes, however, the structure of the cornea is just not strong enough to hold this round shape. Keratoconus can cause progressive deterioration of vision. Initially, keratoconus is treated with glasses, but often, contact lenses, first soft, then gas permeable, are necessary to allow the eye to see adequately. However, because in most cases keratoconus is a degenerative disease, medical management is insufficient, and a procedure is needed to stabilize the deterioration of vision. Cornea cross-linking is a powerful procedure that can strengthen the weakened collagen fibers of the cornea (which is the cause of keratoconus) and stop it from getting worse. It's a 30-minute procedure performed in the doctors' office. Cross-linking can be performed either non-invasively (epi-on) or invasively (epi-off). Epi-off cross-linking carries many more risks the epi-on cross-linking which doesn't have any risk. Intacs are very small clear plastic arcs that are designed to be inserted into the substance of the cornea in people who have keratoconus and who can no longer see properly with glasses or contact lenses. Intacs were approved by the FDA for treatment as an alternative to corneal transplant, which used to be a standard treatment for keratoconus prior to Intacs and cross-linking. When they are inserted into the eye, Intacs reshape the cornea by flattening it closer to its original dome shape. Although the procedure usually improves uncorrected vision, the patient will often still need glasses or contact lenses after the Intacs are inserted. After the cornea has been reshaped, patients who were once unable to tolerate contact lenses may be able to return to contact lens wear and see even better than they did with the lenses prior to surgery. Some patients may even be able to see well enough to go back to simply wearing glasses. The procedure to insert Intacs is usually done in the procedure room at the doctor's office. This is what happens: The doctor numbs the patient's eye with a topical anesthetic. To keep the eye open, the doctor places a speculum in the eye. This also keeps the patient from blinking and possibly interfering with the procedure. The doctor makes a small incision in the cornea and places a centering guide on the eye to keep it steady. This also helps the doctor make sure that the Intacs will be placed properly. After separating the layers of the cornea, the doctor inserts the Intacs and then closes the incision with one suture or with tissue glue thereby making it sutureless. The procedure takes between 7-30 minutes to perform, depending on the surgeon's experience. Follow-up includes regular visits to the eye doctor to make sure the eye is healing properly and to determine if vision has improved. Possible adverse events that may occur after an Intacs procedure include the following: Eye infection Problems with night vision Seeing "halos" or glare around lights Blurry or fluctuating vision Those who should not undergo an Intacs procedure include: Pregnant women People who have other eye health problems that may cause future problems People taking certain medications that may impair healing of the eye