Definition The clear covering of the eyeball is called the cornea. Surgery is performed on the cornea for two main reasons. One is to remove scarring and clouding that interferes with vision. The other purpose of surgery is to change the curve of the cornea to correct vision problems such as nearsightedness or farsightedness. Operations on the cornea can performed either with traditional surgical tools or as laser surgery.
Who is a candidate for the procedure? The best candidates for this type of surgery are people whose vision can't be corrected by wearing glasses, or contact lenses. However, many people opt to have corneal surgery for convenience and cosmetic reasons.
How is the procedure performed? Several procedures can be performed on the cornea to restore its clarity and allow more light to pass through. Common procedures include:
corneal transplant, in which a person's cloudy, diseased cornea is replaced with a cornea from donor eye.
scraping the surface layers of the cornea that have become rough or cloudy. This allows normal tissue to grow in its place.
removal of a membrane-type growth on the surface of the cornea called a pterygium.
repair of corneal lacerations. Small nylon stitches are used to reattach the cut edges of the cornea.
A procedure called a conjunctival flap is done when the cornea is diseased and painful. It can also be done when there is danger of the cornea tearing because it is too thin. The mucous membrane that covers the white portion of the eye, called the conjunctiva, is brought over the cornea and stitched in front of it. This provides comfort and protection for the eye. However, the eye will no longer be able to see.
In the last decade, procedures have been developed to correct nearsightedness, farsightedness, and astigmatism. These are termed refractory surgery. One of the first of the procedures was radial keratotomy (RK). This operation consists of spoke-like cuts in the edges of the cornea. The cuts do not extend over the area covering the pupil. The cuts allow the edges of the cornea to weaken and bow. This causes the area of the cornea over the pupil to flatten, and decreases the person's nearsightedness. While this operation is still performed today, is has been almost completely replaced by a procedure called LASIK.
LASIK, or LAser in-SItu Keratomileusis, is usually done on both eyes at once. It can be used to correct nearsightedness with or without astigmatism, and farsightedness. In this technique, a thin flap of the cornea is lifted. Then a laser is used to dissolve very thin layers of corneal tissue under the flap and create a flatter surface over the pupil. Following the laser treatment, the flap is repositioned.
What happens right after the procedure? The procedure is usually done on an outpatient basis in a same day surgery center. An eye patch may be put on after surgery. The person will be taken to the surgery recovery room after the surgery. Once all the effects of anaesthesia have worn off, and the person is able to drink fluids without nausea, he or she will be discharged home.
What happens later at home? The main complication to be avoided after surgery is infection. For this reason, individuals need to use antibiotic eye drops. Steroid drops are often prescribed to promote healing, as well. In addition, people who have refractive surgery may need to use artificial teardrops to make the eyes more comfortable. These do not contain any medication. Many people have their vision completely corrected with this surgery. Others may need to continue to wear corrective lenses. Recovery can take several months.
What are the potential complications after the procedure? There are complications with any surgery or anaesthesia. These include bleeding, infection, and reactions to the anaesthesia medications. The major risks of corneal surgery are over correction and under correction of the vision problem. Under correction can be treated with further surgery.
Author: Reviewer: eknowhow Medical Review Panel Editor: Dr John Hearne Last Updated: 15/03/2005 Contributors Potential conflict of interest information for reviewers available on request
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