Chapter Seven:
The LASIK Procedure: What to Expect

On the day of the procedure, you should arrive at the laser center as rested and relaxed as possible. You should probably allow about a two to three hour stay at the laser center. This may vary from center to center. Wear comfortable clothing. Do not wear makeup, perfume, or cologne on the day of your laser surgery. These things may interfere with the cleanliness of the procedure and the function of the excimer laser.

You should not wear contact lenses following your preoperative LASIK consultation unless it will be some time before your scheduled surgery. Soft lenses need to be out at least three to seven days prior to surgery, and gas permeable or hard lenses need to be out two to three weeks prior to surgery. It is essential that your eye be in its most natural state at the time of surgery.

With LASIK, a mild oral sedative may be administered before the procedure begins, but it is not usually necessary. During the procedure, your surgeon will constantly be talking to you. He or she will talk you through the entire procedure; you will know at all times what to expect. There will be no surprises and no pain.

Because LASIK eye surgery is more surgical in nature than PRK, sterile surgical conditions must be maintained. Your face will be cleaned with a disinfectant, and you will be asked to wear a surgical cap. You will be given an antibiotic drop and possibly an anti-inflammatory drop. These may sting for a few seconds. You will then be taken to the laser suite, positioned under the excimer laser, and given numbing drops. Your eyelashes will be taped out of the way, and an eyelid holder will be placed between your eyelids to keep you from blinking. This eye speculum can sometimes cause mild pressure or discomfort on your eyelids at first.

A suction ring is used to hold your eye in position and maintain pressure within the eye while the corneal flap is being made. This flap varies between 130 to 180 microns in thickness. The usual thickness is 160 to 180 microns, but your surgeon may choose an alternate value, depending on your refraction and the thickness of your cornea. This flap represents about twenty to thirty percent of the thickness of the cornea, which on the average is about 550 microns (about half a millimeter).

You will not feel pain or see anything while the flap is made, but environmental lighting will disappear during that time. There may also be a little pressure sensation. The flap-making process takes about thirty seconds.

When the flap is lifted back, your vision will get blurry. You will be asked to fix your vision on a target light (usually red, green, or yellow). The laser part of the procedure is then performed, taking twenty to ninety seconds. This portion of the procedure is painless, but you may notice a faint odor as the laser photoablation proceeds. You will also hear a clicking or buzzing sound with each pulse of the laser.

During the laser procedure the light will move, become a blur, or disappear. Your job will be to continue to look straight ahead at the fixation light. If your eye does start to wander, the laser will stop instantly, you will be coached to fix again on the target, and the laser procedure will resume. Some surgeons use a fixation ring to assist in the fixation of the eye, which may help to improve the accuracy of the ablation. The ring is left on the eye at very low pressure while the laser is firing. The surgeon utilizes this tool to control the position of your eye and prevent your eye from looking away from the fixation light. This ensures that the laser energy is focused precisely on the center of the cornea during the entire procedure.

After the laser treatment is completed, the hinged flap is then placed back into its original position, and the surgeon waits one to five minutes for the eye to create a natural vacuum to hold the flap down. (The cornea has the unique ability to seal itself back into place as if no flap had ever been made.)

Next, the eye is dried and the lid holder is removed, allowing you to blink normally. While a bandage contact lens is not usually required, some patients will receive one to aid in their individual healing process.

A newly created corneal flap is held down by four forces:

1. Tissues like to stick together, and within seconds hydrostatic forces between the flap and the corneal stroma create a seal between the two tissues, causing the flap to begin to readhere to the cornea.

2. The endothelial cells (inner lining of the cornea) are constantly pumping fluid out of the cornea to maintain its clarity. This pump function creates a natural vacuum that holds the flap down. This process begins working in a matter of minutes.

3. Within hours the epithelial cells grow over the edge of the flap, helping to glue it down. This process takes a few days to complete.

4. Eventually, the internal healing process allows the flap to be permanently glued down. This occurs over several months.

With LASIK, the top surface of the cornea (epithelium) and the next layer (Bowman's layer) are preserved. This is the reason the recovery time is shorter than with PRK.

A typical LASIK procedure takes between ten to fifteen minutes per eye. Because of the rapid visual recovery experienced by most LASIK patients, both eyes may undergo the procedure on the same day if your surgeon so advises and both of you are comfortable with the decision. Some surgeons only perform eyes on separate days to reduce risk or improve precision. Again, this is a patient decision to be made after appropriate consultation.

Photograph of patient under an excimer laser

Contemplating LASIK?

Marilyn was serious about having LASIK eye surgery performed on her eyes. She had this to say when asked about the experience:

"When I arrived at the doctor's office, a medical assistant took me to a prep room, gave me five milligrams of Valium (which relaxed me), and administered anesthetic eye drops. 'You're all set to go,' she told me.

I was then taken to the laser room where I laid down on a reclining chair under the laser and had my eye taped open with plastic drapes. The surgeon explained each step of the procedure as he went along.

First, he used the microkeratome to lift up a thin, cellophane-like, outer layer of the cornea (called the corneal flap) and folded it back so that the inner cornea was directly exposed. As soon as the corneal flap was lifted, everything looked extremely blurry. Then, in the course of about twenty seconds, ultraviolet light from the excimer laser reshaped the internal cornea. I could hear the laser clicking, but I felt nothing.

Finally, he folded the corneal flap back into place. 'Everything went great,' he reported. Then he proceeded to perform the procedure on the other eye.

Immediately after the procedure, my vision was a bit blurry and my eyes a bit scratchy, but I felt no pain nor any real discomfort. Before I went home, I had protective plastic shields placed on my eyes so I wouldn't rub them.

The next morning the doctor removed my eye shields and I could see 20/20 out of each eye. I now have the freedom to work, play, and ski without the bother of glasses and contact lenses. I trust my surgeon's judgment and skill and continue to recommend him to everyone I know who is interested in the procedure.

P.S. I was a very tough patient! Not only am I a physician, I am also married to an ophthalmologist.""

Pros and Cons of LASIK

Pros	Cons
Low incidence of postoperative pain Fast recovery Higher accuracy for higher degrees of correction Low probability of serious postoperative haze Ability to perform surgery to both eyes on the same day On medicated eye drops only five to seven days Architecture of cornea stays intact	Possibility of flap complications