Since LASIK was approved by the FDA in the early 1990s, the procedure has grown to become the most widely-performed eye surgery in the United States. LASIK is a surgical procedure performed on the eye to correct an individuals vision and reduce dependency on eyeglasses or contact lenses. LASIK stands for Laser-Assisted In-Situ Keratomileusis, which literally means to “reshape the cornea from within using a laser. The procedure has broad applications to treat refractive errors of the eye and can be used to treat myopia (nearsightedness), hyperopia (farsightedness), and astigmatism (an elongated cornea).
LASIK works by improving the ability of the eye to properly focus light. In a perfectly formed eye light entering the eye bends and directly hits retina, allowing the eye to produce a clear image. The majority of people, though, have imperfectly shaped corneas. Imperfectly shaped corneas do not properly refract the light on the retina, with the result that the viewed image is blurry and distorted. LASIK can correct these refractive errors by permanently changing the shape of the cornea. Once reshaped, the cornea is able to better focus light, eliminating the need for glasses or contacts.
LASIK patients will be given a detailed set of instructions to follow, beginning a few weeks before the procedure is to take place. It is critical that these instructions are followed if the surgery is to be a success. Patients wearing contact lenses will be advised to stop wearing their lenses anywhere from 2-4 weeks before the procedure, to give their eyes a chance to resume their natural shape. Certain foods, vitamins, beauty products, and medication can also affect the health of your eyes and may need to be avoided prior to LASIK. Failure to follow pre-operative instructions may result in a failed LASIK procedure, or the need to completely redo the surgery.
Patients remain awake and alert during surgery, although the doctor may administer a mild sedative to help keep the patient calm and relaxed. Numbing eye drops will be applied to the eye to serve as a local anesthetic. Since the eyes natural tendency is to blink when it comes into contact with foreign items, it is necessary to secure the eyelids to keep them out of the way of the laser. This is done using an instrument called a lid speculum. Once the speculum is in place and the eye is cleaned, a small ring is placed on the cornea to apply a strong suction to the cornea. This part of the procedure can be a bit uncomfortable, but the strong suction ensures that the eyes remain immobile throughout the rest of the surgery.
Next a flap is cut into the cornea, leaving a small hinge to keep it attached to the eye. This flap may be made using a small razor sharp knife called a microkeratome, or by using a laser also called IntraLase. The suction ring serves as a precise guide for the microkeratome to ensure that the flap is made cleanly and accurately. After the cut has been made the suction ring is removed and the flap is gently teased away from the cornea and peeled back (towards the hinge) to reveal the underlying stroma.
The doctor will then dry the eye and ask the patient to stare at a fixed light, without moving, until the end of the procedure. Once the eye is in the proper position, the excimer laser will be activated. The surgeon will have already programmed the laser to remove the precise amount of tissue from the exact location(s) on your eye before the start of the procedure. More severe refractive errors will require a longer laser treatment, since more corneal tissue will need to be removed. As the laser pulses a beam of light into the eye to remove the excess tissue from the eye, the patient will hear a ticking or zapping sound and may smell an odor similar to that of burning hair. Once the laser has ceased pulsing, the surgeon will replace the corneal flap on the eye and smooth it out to ensure no surface wrinkles develop.
Since an eye is vulnerable after LASIK, it is very important to take extra precautions to protect the eye during the healing process. The doctor will give the patient an eye shield to wear immediately after the LASIK procedure. This shield should be worn while sleeping to prevent a person from rubbing their eye and dislodging the flap. The eye shield also prevents a person from inadvertently putting any pressure on the eye. Antibiotic ointment should be used to prevent infection from forming, while eye drops may be used to keep dry and scratchy eyes well-lubricated as they heal.
The doctor will make a follow-up appointment to evaluate the patients eyes within 24-48 hours from the time of surgery. This will allow the physician to monitor the healing process, evaluate the eyes for any potential problems, and begin accessing the success of the LASIK procedure. After the initial follow-up appointment, the patient will be asked to return for regular visits every few weeks, then every few months, until such time that the surgeon is confident that the procedure was successful.
Keep in mind that LASIK is not a risk-free procedure and that not all individuals are good candidates for LASIK. If you are interested in finding more about this procedure, contact your ophthalmologist and request an appointment.