7-1. What should I wear to the laser center?

Wear comfortable, loose fitting clothing. Many people wear jeans and tennis shoes. Short pants are okay. Jewelry, such as necklaces and earrings should be left at home.

7-2. What about makeup and perfume?

Eye makeup should be thoroughly removed the night before LASIK, and not reapplied the day of the procedure. Mascara and moisturizing cream should not be used. These substances can get into the tear film and contaminate the operative field. The laser is sensitive to perfumes and aftershave lotions, so these should also be avoided.

7-3. What position am I in during LASIK?

During LASIK, the patient lies on their back in a comfortable reclining chair, similar to a chair in a dentist’s office. The chair swivels out so the patient can be seated. The head of the chair then reclines, and the chair swivels in so the patient’s head is under the laser. An inflatable pillow is placed under the head. When inflated, the pillow holds the head firmly in the proper position.

7-4. How long do I have to lie still during LASIK?

LASIK takes only 5 or 10 minutes per eye. It is not difficult to remain comfortably still during the procedure. One does not have to lie motionless. The doctor will tell the patient when it is crucial to lie perfectly still. It is a good idea not to cross the feet or tap the toes during LASIK. These movements can cause head or eye movement to occur.

7-5. What is the purpose of giving a sedative prior to LASIK?

Usually, a small amount of a mild sedative, like Valium, is given by mouth before LASIK. The ideal sedative relaxes the patient, but does not make them groggy. The idea is to be alert but not anxious. If too much sedation is used, the patient may not be able to follow instructions given by the doctor or the doctor’s staff.

7-6. What is the purpose of cleansing the skin of the eyelids?

As with any operation, clean surgical technique is required with LASIK. The skin of the eyelids is cleaned, usually with a soap, alcohol or iodine solution. Cleaning does not “sterilize” the skin, but it reduces the bacteria that are always present on the skin’s surface. After cleansing the lids, it is important not to reach up and touch the skin around the eyes. Otherwise, contamination by bacteria may occur, increasing the possibility of an infection.

7-7. What is the purpose of the anesthetic eyedrops given before LASIK?

Anesthetic eyedrops are instilled in the eyes before LASIK. They numb the eye and prevent pain during the procedure. The anesthetic drops are usually one of the “caine” anesthetics, like tetracaine or proparacaine. Unlike the anesthetic the dentist uses, these “topical” anesthetics do not have to be injected. They are effective in an eyedrop form. Only a few drops are required, and they take effect within a few seconds. They may wear off in 10 or 15 minutes, so sometimes, additional drops are instilled immediately before the procedure.

7-8. What other type of eyedrops are used for LASIK?

Antibiotic eyedrops are used routinely for LASIK. Surgeons may give antibiotics surgeons give these before, during or after LASIK, or sometimes, at all three intervals. A broad-spectrum antibiotic eyedrop is usually used, often one of the fluoroquinolone antibiotics. Antibiotic drops help prevent bacterial infections from occurring.

7-9. What is the purpose of the lid drapes?

A thin piece of sterile, sticky plastic is placed over the upper and lower eyelid margins. These “lid drapes” provide a sterile barrier between the skin of the eyelids and the eye. The drapes prevent bacteria, oil and eyelashes from entering the operative field.

7-10. What is the purpose of the lid speculum?

The lid speculum holds the eyelids open. It provides “exposure,” or working room, for the surgeon. If the eyelid openings are small, the lid speculum may feel a bit tight. Thanks to anesthetic eye drops, the patient usually adjusts quickly to the stretched feeling the lid speculum produces.

7-11. What do I look at during the procedure?

Excimer lasers have a small blinking light to focus on. If the patient looks at this light throughout the procedure, the eye will be in the proper position.

7-12. What happens if I look away from the blinking light?

Probably nothing. During the LASIK procedure, the surgeon watches the eye position constantly through a microscope. If the eye begins to drift, the surgeon can ask the patient to refocus on the blinking light, or move the laser beam, in order to stay centered on the pupil. If the patient suddenly looks away from the focusing beam, the surgeon can simply stop the laser treatment by removing the foot from the foot pedal that controls the treatment.

7-13. Can I see the LASIK procedure taking place?

Some of the procedure can be seen by the patient. However, when the suction ring is applied, eye pressure rapidly increases, and vision is temporarily shut down. This is because the blood supply to the eye is temporarily cut off by the increased eye pressure. Since the eye pressure remains high during the microkeratome cut, the patient does not see the corneal flap being made. After the microkeratome pass, when the flap has been made, the suction is released, and the vision returns within a few seconds.

7-14. Can the vision be damaged when the blood supply is shut off?

Usually, the blood supply is cut off for a short time, perhaps 10 to 20 seconds. The eye tolerates this interruption of its blood supply well. If the suction is applied for an extended period of time, say minutes, or if the blood supply to the eye is compromised to begin with, it is possible to lose some vision permanently. This rarely happens because the surgeon tries to keep suction time to a minimum.

7-15. How long does the laser part of the procedure take?

It depends on the amount of treatment, which in turn depends on the amount of nearsightedness, farsightedness or astigmatism. For small amounts of nearsightedness, laser treatment may last only 10 seconds. For high degrees of nearsightedness, treatment may take 30 or 40 seconds. Farsighted corrections take longer, but usually no more than 1 minute.

7-16. Could I become claustrophobic or extremely anxious during the procedure?

Most people tolerate LASIK very well, often better than they expect. The procedure is quick, so time under the laser is minimal, roughly 15 minutes. The sedative helps reduce anxiety, and the surgeon and staff will “talk the patient” through the procedure. Often there is a hand to hold or a rubber ball or stuffed animal to squeeze. At some laser centers, a friend or relative is allowed to be with the patient in the laser room.

7-17. What does the laser sound like?

You will hear a series of zapping or tapping noises when the laser fires. Several pulses are fired each second. The sound is low to moderate in intensity and not particularly disturbing. Some say it sounds like a faraway machine gun.

7-18. Are there any peculiar smells during LASIK?

Many people can detect the smell of corneal tissue vaporizing when the laser is firing. The odor is suggestive of hair that has been singed by a flame. Most people do not notice any unusual smell.

7-19. What is the room temperature like during LASIK?

The room is kept a little on the cool side because lower temperatures are better for the laser’s optical system than warmer temperatures. The temperature is not uncomfortable, so no jacket is required. If someone is cold, a blanket can be used during the LASIK procedure. Most laser centers have a supply of blankets available.

7-20. Can thinner LASIK flaps be made with the IntraLase?

Yes. Typically, the IntraLase femtosecond laser is programmed to create LASIK flaps between 90 and 110 microns in thickness.

7-21. Is there an advantage to the thinner flap created by the IntraLase?

The thinner flap created by the IntraLase conserves corneal tissue. This allows treatment of higher corrections, greater ability to perform enhancements, and a more stable cornea following LASIK.

7-22. Is there an advantage of a nasal or superior hinge for the corneal flap?

Those who like a superior hinge point out that blinking and gravity reinforce and stabilize the position of the superior-hinge flap. A nasal flap could possibly be displaced by blinking. Those who prefer a nasal hinge point out that it is easy to cut a nasal flap with many currently available microkeratomes since there is no brow to obstruct the path of the instrument.

7-23. How thick should the corneal flap be?

Most microkeratomes create a flap which is 160 or 180 microns. This is about one-third of the entire corneal thickness, since the normal cornea is about 550 microns in thickness (a little more than half a millimeter). Thinner flaps can be made, but they have a tendency to wrinkle. Thicker flaps may cause the laser treatment to be too deep.

7-24. What is the diameter of the corneal flap?

Usually the diameter of the flap is between 8.5 and 9.5 mm. Since the overall corneal diameter is roughly 12 mm, the flap covers most of the central cornea, including the area in front of the pupil.

7-25. How much corneal tissue does the laser remove?

It depends on the amount of treatment required, which in turn depends on the degree of nearsightedness or farsightedness. A good rule of thumb is that the laser removes 12 microns of tissue for every diopter of treatment. So, someone who has 5 diopters of myopia (a -5.00 glasses prescription), would have 60 microns of tissue removed beneath their corneal flap. If their cornea was 530 microns before LASIK, it would be 470 microns in thickness after LASIK.

7-26. Why are ink marks placed on the eye?

Before making the LASIK flap, marks are placed on the cornea using a metal marker and blue ink. The marks are either lines or circles, and at least two or three marks are made. The ink, or dye, is methylene blue or India ink. The dye is applied to the marker with a felt tipped pen, or by placing the marker on an inkpad. When the microkeratome is activated, it cuts through the marks. At the end of the procedure, when the corneal flap is smoothed down, the marks guide the surgeon in lining up the flap with surrounding tissue. If all the marks line up, the surgeon knows the flap is in the proper position.

7-27. What happens after the laser part of the procedure?

The surgeon replaces the flap by bringing it into position and smoothing it down over the treated corneal bed. Saline irrigating solution is used to “float” the flap up before allowing it to settle into its proper position. Since the flap has a hinge, either nasally or superiorly, it naturally settles into position. The surgeon may adjust the flap slightly at this stage.

7-28. How is the flap smoothed down?

There are a variety of techniques to smooth the flap. The surgeon may use a cannula, a blunt needle used for irrigation. The cannula will usually have a 90-degree bend near the tip. There is also a handy device, known as a “flap applanator,” composed of a disk on the end of a metal rod. The disk has the same convex curve as the cornea, and when applied gently to the LASIK flap, the applanator squeezes out excess fluid. The surgeon may also use moist, triangular sponges, mounted on the end of small plastic sticks. These sponges, sometimes known as “Weck cells” or “Merocel sponges,” swell when wet. They are ideal for smoothing out the LASIK flap. The smoothing is done by placing the sponge near the hinge and smoothing away from the hinge. The motion is similar to using a squeegee to remove fluid and wrinkles from wallpaper.

7-29. How long does it take for the flap to dry?

Nobody knows for sure, but many surgeons allow 2 minutes for the flap to dry. Once the smoothing of the flap has been completed, the lid speculum is kept in place and the eye remains open for 2 minutes. Evaporation of fluid from the surface of the eye creates adherence of the flap to the underlying stromal bed, probably through capillary action. The flap, of course, is not very secure, or well healed, for a certain period of time. No one knows exactly what that period of time is. It seems prudent to keep the eye protected by wearing goggles or a shield the first night. It also seems reasonable to be careful about rubbing the eye for the first week or so. Even after that, vigorous eye rubbing should be avoided. There is no formula for determining the strength of the flap’s adherence. The best advice seems to be avoidance of rubbing for the first month, and only mild dabbing thereafter.

7-30. When is the LASIK flap completely healed?

This is question that is often asked. But, there is no good answer. Perhaps, a LASIK flap is never completely healed. After all, one can “lift” the LASIK flap to perform a re-treatment, even years after it was originally created.

7-31. Is there any way to promote the healing of the flap?

Air-drying is very effective in sealing the flap to the underlying cornea. Some surgeons use oxygen gas, delivered through a plastic tube, to speed up the drying process. Time is the most effective healer of the flap. Within a few days, the healing is reasonably good, and after a few weeks, the healing is very good. Eye rubbing should be avoided in the first month, and only gentle dabbing should be allowed after that.

7-32. Why is a contact lens used after LASIK?

The contact lenses used after LASIK are not typical contact lenses. Rather, they are “bandage” contact lenses. They work the same way a bandage used on the skin works. That is, they cover the eye and protect it from external trauma, such as the action of the eyelids. Contact lenses may also be used to improve comfort after LASIK. They are particularly useful if a corneal abrasion develops during the LASIK procedure. If this happens, the contact lens acts as a barrier between the cornea and the eyelid, and will lessen any discomfort that may occur with blinking. The contact lens is usually removed the day after LASIK. Some ophthalmologists routinely use a bandage contact lens after LASIK. Others use them only if a corneal abrasion occurs. Most ophthalmologists use a bandage contact lens after an enhancement. This is because a small incision must be made in the cornea to lift the edge of the LASIK flap. This process creates a defect, or abrasion, on the surface of the cornea. A bandage contact lens improves the comfort for those people who undergo an enhancement.

7-33. What happens immediately after LASIK?

A brief eye exam is performed at the slit lamp microscope. This is done to make sure the operation looks satisfactory. In particular, the ophthalmologist needs to make certain that the flap is in good position. There should be no wrinkles, or folds, in the LASIK flap. There should be no particles or debris under the flap. The “gutter,” the narrow space between the LASIK flap and the surrounding cornea, should be a uniform width in all areas. If for any reason, the LASIK flap does not appear to be perfect, the surgeon can either adjust the flap at the slit lamp microscope, or bring the patient back to the laser room and “refloat” the flap. This usually means observing the flap through the laser’s microscope, irrigating with saline underneath the flap, and smoothing the flap into its proper position. Most surgeons believe that if a problem exists, it is better to correct it before the patient leaves the operating room. It may be more difficult and more upsetting to try to correct a problem the following day.

7-34. How does the PRK procedure differ from LASIK?

PRK does not require the microkeratome, so of course, there is no cutting. The surface layer of cells, the epithelium, must be removed. First, anesthetic eye drops are instilled. Next the epithelium is removed, either by scraping with a blunt instrument, by using a round, rapidly rotating brush (an Amoils brush), or with the laser itself. We find the laser to be the most elegant way to remove the epithelium. This procedure, known as “laser scrape,” consists of setting the laser to remove 40 microns of tissue from the center of the cornea. This procedure takes only 14 seconds, and removes a nice round circle of epithelium 8.5 mm in diameter. Once the epithelium is removed, the actual laser ablation of the corneal stroma is performed.

7-35. Is there any pain during epithelial removal?

There is no pain, or any other sensation when the “laser scrape” is performed. A mild pressure sensation may be felt when a blunt instrument is used

7-36. Besides the lack of cutting, is PRK similar to LASIK?

The laser treatment of the corneal stroma is similar. With PRK, since there is no flap, there is little need to smooth out the surface, and no need whatsoever to adjust the flap or make sure it is in the proper position.

7-37. Is a bandage contact lens used after PRK?

Yes. A bandage contact lens is routinely used for comfort and to promote healing. It remains in place for about three days. This is considerably longer than when a contact lens is worn after LASIK. PRK produces a relatively large defect in the surface of the cornea. A small corneal abrasion will heal within 24 hours, but a large, 8.5 mm defect will take about 3 days to heal.

7-38. Is there pain during the healing process?

There may be mild, moderate, and occasionally, even severe pain after PRK. The pain is usually at its worst within the first 24 hours following PRK. It may last longer, sometimes up to 3 days. Vision may be blurry during this time. After PRK, it may take 4 or 5 days to achieve good vision, and sometimes, as long as a week. Pain, and delayed visual recovery, are the two main reasons most people opt for LASIK rather than PRK.

7-39. Is there a way to control the pain after PRK?

Yes. We often give a pain medication by mouth before the procedure, usually one of the over-the-counter agents like Advil or Motrin. Sometimes, a prescription pain medication, like Celebrex, is used before and after PRK. After PRK, we may use a stronger pain medication, like Vicodin or Darvocet. Occasionally, anesthetic eyedrops will be given during the first few postoperative days. These are used sparingly, since excessive use can delay healing.

7-40. What if the contact lens falls out during the 3-day healing period?

The contact lens can be reinserted, but often it is not. Healing will continue to take place at a rapid rate, even without a contact lens. It may be more comfortable for the patient to stay at home with the eyes closed as much as possible rather than come into the office for a replacement contact lens.

7-41. How thick is the corneal epithelial flap in LASEK?

About 40 microns in thickness.

7-42. How is the LASEK flap made?

The corneal epithelium is loosened with a 20% ethyl alcohol solution, applied to the cornea for 10 to 60 seconds. The epithelial layer is then lifted away from the underlying corneal tissue with a spatula. Laser treatment is performed and the flap is repositioned over the bed.

7-43. Is LASEK similar to PRK?

Some experts think there is no significant difference between LASEK and PRK. This is another reason why many ophthalmologists have not switched to LASEK. They think PRK accomplishes the same result as LASEK, but is easier to perform. With PRK, the epithelial cells are removed, either by scraping with a spatula, or with the laser, a technique known as “laser scrape.”

7-44. Can LASIK be performed after corneal transplant surgery?

Yes. Corneal transplants are one of the most commonly performed transplant operations, and about 30,000 are performed in the United States every year. Corneal transplants replace a damaged cornea with a human cornea obtained from an eye bank. A network of eye banks throughout the world collects corneas from organ donors, with permission of their family, immediately after death. The corneas are either preserved in tissue culture fluid, and used within a week of the donor’s death, or they may be frozen and used at a later time. Corneal transplants are sewn into the recipient’s eye using very fine sutures. This technique is a remarkable way of restoring vision, however, it can create moderate, or large amounts of nearsightedness and astigmatism. These refractive errors can be reduced or eliminated with laser vision correction.

7-45. How long after a corneal transplant should laser vision correction be performed?

The cornea must be completely healed before considering laser vision correction. This means waiting at least 6 to 12 months after the transplant operation.

7-46. Are there potential complications from laser vision correction after corneal transplantation?

Yes. The usual complications, such as undercorrection and overcorrection can occur. These complications may require repeat laser treatment. Infections and persistent inflammation can occur, but they are rare. Because corneal transplants may have an unusual shape, cutting a LASIK flap can be tricky. Irregular flaps and buttonholes can occur. These problems can be avoided by using PRK instead of LASIK.

7-47. Can LASIK or PRK lead to corneal transplant rejection?

Yes. While corneal transplants reject far less often than other types of transplants, any significant disturbance of the eye may lead to rejection. A cornea specialist should monitor a corneal transplant patient, especially after laser vision correction.

7-48. Can laser vision correction be performed after cataract surgery?

Yes. Cataract surgery is a procedure in which a cloudy lens inside the eye, known as the crystalline lens, or simply “the lens,” is removed. The natural lens is almost always replaced by a clear, synthetic lens which has just the right amount of focusing power to produce good vision. The power of the lens must be calculated before the operation. While the calculations are usually quite precise, they may be inaccurate enough that glasses are required after cataract surgery. Nearsightedness, farsightedness, or astigmatism following cataract surgery can be reduced or eliminated by laser vision correction.

7-49. Can the need for reading glasses after cataract surgery be eliminated after cataract surgery?

Usually, it cannot. Laser vision correction is mainly used to correct distance vision. Sometimes, it can be used to create monovision, that is, one eye for distance and one eye for reading. This can be done in people who have had cataract surgery as well as in those who have not had cataract surgery. Only about 10% of people seem to prefer monovision over having both eyes corrected for distance. When both eyes are corrected for distance, drugstore reading glasses are usually adequate.