3-1. How do I know if I am a candidate for LASIK?

You probably need to see an ophthalmologist who performs LASIK. Most will offer a free consultation, and you can learn a great deal from these visits. There is nothing wrong with seeing several doctors. After all, the consultations are free! Keep in mind that most people who need glasses or contact lenses to see well in the distance are good candidates for LASIK.

3-2. What is the difference between LASIK and PRK?

PRK, or photorefractive keratectomy, is the name of the original laser vision correction procedure. It was introduced about 12 years ago, and it is still performed today, although not as often as LASIK. PRK treats the surface the cornea (Figure 5), rather than the deeper layers. LASIK can be thought of as a modification of PRK. A “flap” is made in the cornea (Figure 6), and laser treatment is applied to the underlying bed.

Figure 5

Figure 6

3-3. How does LASIK correct someone’s vision?

LASIK uses a laser to correct abnormalities of the visual system by changing the shape of the cornea. The laser “sculpts” the cornea by dissolving small amounts of tissue. To correct nearsightedness, the laser makes the cornea flatter. This is done by removing some tissue from the steeper, central part of the cornea (Figure 7). To correct farsightedness, the laser makes the cornea steeper. This is done by removing a donut-shaped ring from the periphery of the cornea (Figure 8).

Figure 7

Figure 8

3-4. How do I choose a LASIK surgeon?

Ask your friends who have had LASIK. They are often the best source for a recommendation. Find out if they were satisfied with their doctor and the doctor’s staff, and whether they were happy with the results of their LASIK. You can find a LASIK doctor by looking in the newspaper, yellow pages, or on the Internet. But don’t be too impressed by the size of the ad or the glitziness of the web site. A personal recommendation counts for much more.

3-5. Should I ask my optometrist to recommend a LASIK surgeon?

By all means. Optometrists (O.D.’s), unlike ophthalmologists, are not medical doctors (M.D.’s), and optometrists do not perform LASIK. But, they often know the local doctors who perform LASIK. There may be a financial relationship between the optometrist and the LASIK surgeon. In some instances, the surgeon performs LASIK and the optometrist does the preoperative and followup eye exams. This arrangement is known as “co-management.” Chances are you will be charged by both doctors. So the optometrist may have a vested interest in referring you to a particular surgeon. If you want the LASIK surgeon to perform all the examinations, you should avoid co-management.

3-6. How can I tell if the LASIK surgeon has enough experience?

The best way is to ask. Most doctors are happy to tell you where they trained and how many surgeries they have performed. But keep in mind; some surgeons exaggerate their statistics! You may want to find a LASIK surgeon who has performed several hundred cases, or even a few thousand cases. You should also make sure they do at least a few cases every week to maintain their proficiency. Quantity is not necessarily a substitute for quality. You might be better off with a surgeon who does a modest number of cases very well than the busiest surgeon in town who does a large number of cases. You should look for a balance: A combination of experience and capability.

3-7. How can I tell if the LASIK surgeon is well trained?

While it is not a surefire way to assess a doctor, good doctors generally train at good institutions. You should find out where a doctor went to school and where he or she did their residency (ophthalmology training). You can learn this information by calling the doctor’s office, by checking out the doctor’s web site, or by looking at the certificates on the walls of the office. You may not think you know a good institution from a bad one. But you really do. If a university has a good reputation, it probably has good medical programs. If you have never heard of the institution, or if there are no certificates on the wall, you are right to be suspicious. If the doctor has done one or more “fellowships,” it means he or she has had additional training. If the fellowships were in cornea or refractive surgery, it emphasized the skills that are used in LASIK.

3-8. Are there any good web sites to help me learn about LASIK?

Yes. There are several. Try www.JoyOfLASIK.com, www.ascrs.org, or www.aao.org for starters.

3-9. How can I be sure LASIK will help me see better?

Your LASIK doctor can answer that question, but there is a lot you can find out on your own. You are probably a good candidate for LASIK, if:

You require glasses or contact lenses most, or all of the time, in order to see well in the distance.
Your eyes are healthy except for needing distance glasses or contact lenses.
Both of your eyes see 20/20 when you wear your glasses or contact lenses.

3-10. How can I tell if I am not a good candidate for LASIK?

You may not be a good candidate for LASIK if:

You do not need your glasses or contact lenses most of the time to see in the distance.
You see fine in the distance without glasses or contact lenses, but you need glasses in order to read.
Your eyes are not 20/20, even with your glasses or contact lenses.
You have had previous eye surgery (with some exceptions!).

3-11. How do I prepare myself for the LASIK consultation?

Do your homework. Read about LASIK on the Internet. Ask your friends about their experience. You won’t be able to keep all your questions in mind. So make a list of questions. Plan to spend an hour or so at the doctor’s office. Make sure all your questions have been answered. If you wear soft contact lenses, they should, ideally, be discontinued three days before your appointment. If you wear hard, rigid, or gas permeable lenses, try to stop them three weeks before the consultation. Contact lenses can change the shape of the cornea, and produce inaccurate measurements. Try to wear your glasses after stopping your contact lenses, and, of course, bring your glasses to the consultation. It is also helpful for the doctor to know the power of your contact lenses. The more information, the better. Your pupils may be dilated at the consultation, or at a subsequent visit. If so, you may have difficulty reading for a day or so, and you may be sensitive to lights until the drops wear off. After the consultation, and after reading the doctor’s LASIK literature, make another list of questions. You can have these questions answered at a followup visit, or over the telephone.

3-12. How soon after the consultation should I have LASIK?

Do not be in too much of a hurry. You may want to have a few visits with the doctor or visit a different LASIK surgeon. The return visits are to re-check your eye measurements. Some of these measurements are “subjective.” That is, they call for your opinion about what you see. You should do the testing when you are fresh and when your mind is at ease. Each time you perform the tests, you get a little better, and your responses become more accurate. Accuracy is the name of the game, since these measurements are programmed into the laser. It may be worth going back to the doctor’s office two or three times before surgery to repeat the measurements and make sure they are as accurate as they can possibly be.

3-13. Does my medical insurance cover LASIK?

Generally, it does not. LASIK is usually considered a cosmetic procedure, just like cosmetic plastic surgery. Still, it may be worth checking with your insurance company. Also, some employers may cover LASIK as a health benefit. Usually, you will pay out of pocket for LASIK, and often before having the surgery. Many companies have “flex-spending” plans, allowing you to use pre-tax dollars for LASIK.

3-14. How much does LASIK cost?

Fees vary, but an average cost is about $1,900 per eye. East Coast fees may be slightly higher than the rest of the country (up to $2,500 per eye). These are usually “global” fees. That is, they include everything: Surgery, the laser center’s facility fee, postoperative visits, and sometimes eyedrops and other medications. Enhancements (touchups), during the first year after surgery, should be included in the global fee. Often, there is a charge for enhancements after the first year.

3-15. Should I ask about a discount?

Absolutely. Many doctors give discounts to employees of large companies in their area, or employees of a university or clinic where LASIK is performed. There may be a discount if a friend or family member has had LASIK with your doctor. Discounts and bartering are not unknown to the medical profession. Do not be bashful about bringing up a service you might provide in exchange for a discount on LASIK surgery.

3-16. Should I wait until the technology is better to have LASIK?

You could. Technology usually advances a bit each year, but LASIK is already an extremely good procedure. It is a bit like the situation with computers. There is no doubt that the technology keeps getting better. But if you keep putting off the purchase of a computer, you miss out on a lot of benefits. Likewise, LASIK, by all measures, is good enough to have the procedure now. Yes, it will continue to improve. But it is unlikely that for most people there will be a noticeable difference in the quality of vision or the chance of success if they choose to wait.

3-17. How long after stopping my contact lenses can I have LASIK?

The rule of thumb is that soft lenses should be discontinued at least three days before LASIK, and rigid, hard, or gas permeable lenses should be discontinued three weeks before LASIK. One caveat. If the vision is still changing after the contact lenses have been discontinued, it is prudent to wait until the vision and the measurements have stabilized.

3-18. Should I have LASIK or PRK?

Both are good procedures, and most people are candidates for either.

3-19. Which procedure produces better vision, PRK or LASIK?

Most studies indicate the visual results are the same following PRK and LASIK.

3-20. Do more people have PRK or LASIK?

About 90% of people who have laser vision correction have LASIK. About 10% have PRK, or a similar procedure that treats the corneal surface. Numbers may vary widely from one practice to another.

3-21. Why do more people have LASIK than PRK?

The visual recovery is quicker with LASIK than with PRK. Vision is usually very good within a day or two after LASIK. With PRK, it may take three to seven days before vision is very good. In addition, there is more discomfort during the first 24 to 72 hours after PRK than there is with LASIK.

3-22. Why would someone choose PRK over LASIK?

Some people do not want a “cutting” procedure. In LASIK, a flap is created in the cornea with a microkeratome, or with a laser. No flap is created with PRK, so no cutting occurs. Making the cut increases the complexity of the procedure. If the cut is not done precisely, serious complications could develop. Some might even argue that making a cut in the cornea produces some permanent weakness or instability of the cornea. If the eye is ever injured, the cut could “open up” and the flap could be displaced. This has actually happened with finger, fist, and airbag injuries. Still, most people opt for LASIK because of the quick visual recovery, better comfort, and perhaps, a little bit of hype.

3-23. Are there any conditions for which the LASIK doctor would recommend PRK over LASIK?

Yes. If the cornea is too steep or too flat, it may be safer to perform PRK rather than LASIK. If the eyes are deep set, or if the patient reflexively squeezes the eyes tightly closed, it may be difficult to apply the microkeratome. If this is the case, PRK might be the better choice. Sometimes the cornea is too thin for LASIK, but thick enough for PRK. Remember, with LASIK, the laser treatment begins in the deeper layers of the cornea, about one-third into the half millimeter thick cornea. If too much corneal tissue is removed, a thin bed is left. Corneal beds thinner than 250 microns (1/4 of a millimeter) are considered potentially unstable. Therefore, if LASIK would result in a corneal bed less than 250 microns in thickness, many doctors recommend PRK over LASIK.

3-24. Are there any conditions when LASIK is recommended over PRK?

Yes. For people who need to return to work as soon as possible, and for those who do not tolerate pain very well, LASIK may be the better choice.

3-25. Do all LASIK doctors offer a choice of PRK and LASIK?

Not all doctors offer both. Some offer only PRK, but it is more common to offer only LASIK. This is unfortunate, since PRK is technically an easier procedure for the doctor, and a very useful alternative when LASIK would be unsafe or difficult to perform. Most doctors find a use for both procedures and can help their patients choose the procedure that is most appropriate.

3-26. If I have LASIK, will I still be able to wear contact lenses?

There is no reason you cannot wear contact lenses after LASIK, but it is very unlikely you would ever need to. The whole object of LASIK surgery is to get rid of contact lenses and glasses. If you still need contact lenses, you have not achieved the desired result. The notion that people could not wear contact lenses after LASIK probably originated with radial keratotomy, or RK, a procedure that is now rarely performed. Both RK and LASIK change the shape of the eye by flattening the apex of the cornea. This might make contact lens fitting more difficult, but not impossible. The broader point is that people simply do not need to wear contact lenses after LASIK.

3-27. Will I need to wear glasses after LASIK?

Most of the time, the answer is no, but there are some exceptions. Some people have excellent distance vision after LASIK, but their vision can be made a little sharper with a pair of glasses. These are most often used for driving, especially at night, or for the theatre, classroom, or sporting events. Most of the time, glasses would not be necessary. But, they can be worn when super sharp vision is required.

3-28. Will reading glasses be needed after LASIK?

LASIK is a procedure for distance, or far away vision. It does not usually correct close up, or reading, vision. The difficulty that people over the age of 40 have with reading vision is known as “presbyopia.” LASIK does not correct presbyopia. This is why people over age 40 who have LASIK will probably need reading glasses.

3-29. What if I don’t need reading glasses now?

Even if you do not need reading glasses now, if you are over 40, you may need reading glasses after LASIK. In fact, people with mild degrees of nearsightedness sometimes take their glasses off in order to read. This is because having a mild amount of myopia is like having “built in” reading glasses. We have all seen people in restaurants take off their glasses to read the menu. After LASIK, this optical quirk may disappear. Most probably, a 50-year-old person who has LASIK will need to put on reading glasses to see a restaurant menu.

3-30. Aren’t I just trading one pair of glasses for another if I have LASIK?

Not necessarily. It is true that people over age 40 with a small or moderate amount of myopia will probably be more dependent on reading glasses after LASIK. Those below age 40, and those with larger amounts of myopia, astigmatism, or hyperopia will not be more dependent on reading glasses. It should also be pointed out that most people would rather wear reading glasses than distance glasses.

3-31. What is “monovision?”

Monovision is a concept in which one eye is corrected for distance and the other eye is corrected for near. Monovision can be achieved with contact lenses or with LASIK. This makes most sense in people over age 40 who need a different prescription for distance than they do for reading. Usually, the dominant eye is set for distance and the nondominant eye is set for near.

3-32. How do I tell which of my eyes is dominant?

The dominant eye is the one you prefer to use for “one-eyed” tasks, such as sighting a rifle, or looking through a telescope. To tell which of your eyes is the dominant one, roll up a sheet of paper and look through it, or sight through a ring made with your thumb and index finger. It will feel comfortable to look with one eye and not the other. The comfortable eye is the dominant eye.

3-33. Why doesn’t everyone who has LASIK get monovision?

Not everyone likes monovision, in fact, only about 10% of people over age 40 like monovision. Many people do not like having one eye that is clear for distance (and blurry for near), and the other eye clear for near (and blurry for distance). Still, people who like monovision do extremely well with it. Those who adjust to monovision have the best of both worlds. No glasses for distance and no glasses for reading.

3-34. How can I tell if I will adjust to monovision?

A good way to tell if you can adjust to monovision, is to try monovision with contact lenses. This is a good simulation of what monovision LASIK will be like. You can switch the distance and near contact lenses if you are not sure which eye you prefer for distance and which eye you prefer for near. If you enjoy the kind of vision you have with monovision contact lenses, you should like the permanent results with LASIK.

3-35. What if I have monovision LASIK and then decide I really don’t like it?

If you started out nearsighted, you will need some additional laser treatment in the reading eye. This is just like having an enhancement. With monovision, the reading eye is intentionally left slightly nearsighted so you can read with it. It is usually easy to add additional laser treatment to the reading eye and make it excellent for distance vision. The situation is a bit more complicated if you started out farsighted. To make a farsighted eye suitable for reading, it must be overcorrected and made slightly nearsighted. It is still possible to reverse the monovision effect in farsighted people. But, it is not always as successful as it would be for a nearsighted person. Bottom line: If you are interested in monovision, make certain you simulate monovision with contact lenses before you have LASIK.

3-36. Won’t I need a stronger reading eye as I get older?

Yes, and this is one of the things that makes monovision tricky. The LASIK doctor will try to set the reading eye at a good working distance. But the eye cannot be adjusted each time you need a little stronger reading correction. Think of monovision as a compromise. It is not a perfect arrangement for reading, but monovision fans find it extremely useful.

3-37. What can I do if I have monovision LASIK but need both eyes for reading at work and for the computer?

Your eye doctor can prescribe reading glasses, or computer glasses, which will provide good close up vision in both eyes.

3-38. Should I have monovision LASIK if I am under 40 and I don’t need reading glasses now?

Probably not. Most people below age 40 who try monovision do not like it.

3-39. Can I have both eyes corrected for distance with LASIK, and then wear a contact lens in my nondominant eye for reading?

Yes. A reading contact lens can be used in the nondominant eye for periodic monovision.

3-40. Can I get monovision glasses instead of contact lenses or monovision LASIK?

Yes, but they do not seem to work very well. Most people detect a different image size, and a type of double vision with monovision glasses. This does not usually occur with contact lenses, because contact lenses tend to equalize the size of the image.

3-41. If I have dry eyes, can I still have LASIK?

Mild dryness of the eyes is common. It can be associated with aging or with taking certain medications, such as antihistamines and diuretics. Severe dry eye can be a sign of a systemic condition, like rheumatoid arthritis or Sjögren’s Syndrome. Dry eye is considered a “relative contraindication” for LASIK. In other words, it is not ideal to have this preexisting condition, but it does not completely rule out LASIK. People with mild to modest dry eyes often do quite well with LASIK, especially since they have difficulty wearing contact lenses. Your LASIK doctor can advise you as to whether or not the eyes are too dry for LASIK.

3-42. Can I have LASIK if I have diabetes?

Diabetes is also a “relative contraindication” for LASIK. It is thought that people with diabetes can sometimes have trouble healing. By now, thousands of diabetics have had LASIK, and there does not appear to be any higher incidence of complications than with non-diabetics.

3-43. Are there any conditions in which LASIK is not recommended?

LASIK is not recommended for people with keratoconus, a condition in which the cornea is thin and slightly cone-shaped. The results of LASIK are unpredictable in people with keratoconus. Many people with keratoconus would love to have their vision corrected with laser surgery. They often have a lot of nearsightedness and astigmatism. Many wear rigid contact lenses. Unfortunately, it is not safe for people with keratoconus to have LASIK. In fact, LASIK surgeons perform a number of tests, like corneal topography, largely to rule out subtle cases of keratoconus.

3-44. What is “form fruste” keratoconus?

This is a mild or early form of keratoconus. It can usually be identified by corneal topography. Like more advanced keratoconus, it is a contraindication for LASIK.

3-45. Can LASIK be done during pregnancy or while nursing?

It is not ideal to perform LASIK during pregnancy, or while nursing. Occasionally, vision may fluctuate, possibly due to fluid retention, and it is undesirable to prescribe eyedrops and other medications during pregnancy that are not entirely necessary. Usually women who are pregnant or nursing are advised to defer LASIK until a few months after pregnancy and nursing have been completed.

3-46. Are there any personality types that are not suitable for LASIK?

Yes. People who are perfectionists may not be the best LASIK candidates. LASIK results are usually very good, but no doctor can guarantee they will be perfect. If someone cannot cope with a less than perfect outcome, they should probably stick with glasses or contact lenses. People with psychiatric disorders must be considered on an individual basis, but many doctors will not operate unless there are no apparent psychological problems. This is not to say individuals with high standards and high expectations should not have LASIK. But they must also realize that there is no way to guarantee a perfect result.

3-47. Are there any professions that are not compatible with LASIK surgery?

There are no definite rules about this. Boxers, wrestlers, and those who play contact sports, might be better off with PRK than LASIK. Since PRK does not require a flap, the cornea is more stable in case of injury. Lawyers, engineers, accountants, professional athletes, doctors, and even LASIK surgeons, are usually good candidates for LASIK.

3-48. Can airline pilots and military personnel have LASIK?

Yes. Requirements vary, depending on the certifying agency. The military offers LASIK to their pilots and other personnel. It is important to familiarize yourself and your LASIK doctor with any special aviation or military requirements for vision before having LASIK.

3-49. What amount of nearsightedness, farsightedness, and astigmatism can be corrected with LASIK?

The rule of thumb is up to 10 diopters of myopia, up to 5 diopters of farsightedness, and up to 6 diopters of astigmatism. But, there are no hard and fast rules. Sometimes higher degrees of correction are possible if the cornea is of adequate thickness.

3-50. Is there any lower limit for LASIK correction?

Not really. Refractive errors even less than 1 diopter can be corrected with LASIK. The important consideration is to decide if it is worth going through an operation in order to correct a small visual disturbance.

3-51. Will vision be better after LASIK than with glasses or contact lenses?

Vision may be as good or better after LASIK than with glasses or contact lenses, but it is not a certainty. Vision could, in fact, be worse after LASIK. Here is why. Glasses and contact lenses have a lot of flexibility. If vision with them is not 20/20, a doctor can prescribe a slightly different lens. With LASIK, we try to achieve 20/20 based on several measurements of the eyes and expectations about the response of the cornea to laser treatment. But there is still some guesswork in how the cornea responds to the laser. Granted, we usually achieve 20/20 vision with one treatment. But probably only 90% of the time. If vision is not 20/20, we can go back and do a touch up, or enhancement. But, this requires a second, smaller procedure. Because of the flexibility we have with glasses and contact lenses, and because of an element of uncertainty in how the cornea heals, glasses or contact lenses may be considered the “gold standard” and LASIK may be considered the “silver standard.”

3-52. Isn’t the quality of vision different with LASIK than with glasses and contact lenses?

Vision after LASIK is somewhat different from vision with glasses, and more like contact lens vision. Glasses enlarge the image slightly for nearsighted people and diminish the image slightly for farsighted people. In addition, the glasses frame interferes slightly with peripheral vision. Vision after LASIK is similar to vision with contact lenses in terms of image size and peripheral vision. However, without the muss and fuss of contact lenses, and without the eye irritation contact lenses often produce, vision after LASIK is usually much more pleasant experience for former contact lens wearers.

3-53. How long does the effect of LASIK last?

The vision achieved with LASIK can be considered permanent, unless some unrelated eye condition develops. What are the chances of an unrelated sight-threatening condition? Well, almost everyone develops cataracts later in life. Cataracts interfere with vision, but they can be treated surgically with great success. Glaucoma affects about 2% of the population but can usually be controlled with eyedrops. Macular degeneration is a disease of older eyes, which can interfere seriously with vision. LASIK does not protect the eyes against any of these conditions.

3-54. Does having LASIK make me more likely to develop other eye diseases?

No. LASIK does not make the eyes more susceptible to other eye diseases.

3-55. Does having LASIK make it more difficult to treat other eye conditions?

Although there may be some rare exceptions, treatment of other eye diseases is not usually compromised by having LASIK.

3-56. Can someone with early cataracts have LASIK?

Yes. Cataracts are opacities of the crystalline lens, the main lens of the eye’s internal optical system. Just about everyone develops cataracts if they live long enough. Cataracts are a natural aging change of the lens in which the appearance of the lens changes from clear to yellow, brown, or white. But this change happens slowly, rather than suddenly. Mild cataracts may not reduce vision for many years. Therefore, it is possible to have LASIK, even in the presence of mild cataracts.

3-57. When should someone with cataracts
not have LASIK?

People with advanced cataracts should not have LASIK. This is not because LASIK would be harmful. Rather, it is because cataract surgery can usually accomplish the same thing LASIK can. That is, elimination, or reduced dependency, on distance glasses or contact lenses. So, if cataract surgery needs to be done in the near future, LASIK should not be undertaken.

3-58. Is LASIK sometimes performed after cataract surgery?

Yes. If distance vision is not adequate after cataract surgery, and if distance vision can be improved with glasses or contact lenses, LASIK may be a reasonable way to improve distance vision.

3-59. If the vision is not perfect after cataract surgery, why not just exchange the intraocular lens, rather than perform LASIK?

Intraocular lens exchange is an option for obtaining better vision when the intraocular lens correction is not satisfactory. However, it may be technically more difficult to perform a “lens exchange,” especially if months of years have elapsed since the original surgery. This is because healing and scar formation can seal the lens in place, and make it more difficult to remove an intraocular lens. In such situations, LASIK may be a better way to “fine tune” the vision after cataract surgery.

3-60. Can I have laser vision correction if my glasses prescription is over 10 diopters?

PRK is a good procedure for higher levels of myopia. PRK, or photorefractive keratectomy, is the original excimer laser procedure for correcting nearsightedness, farsightedness, and astigmatism. While largely supplanted by LASIK, PRK is useful when corrections are high, when the cornea is too thin, and when there are surface irregularities in the cornea. PRK works well for higher corrections because the treatment begins at the corneal surface, rather than one third of the way into the cornea. The laser still removes about 12 microns of tissue for each diopter of correction. But, since the tissue is removed from the corneal surface, rather than center of the cornea, there is little or no destabilization of the cornea. PRK also avoids thinning the posterior cornea to less than 250 microns, the minimum thickness most LASIK surgeons believe necessary for corneal stability.

3-61. What is meant by the terms, “All Laser LASIK” and “Intralasik?”

The terms, “All laser LASIK” and “Intralasik,” refer to LASIK procedures using the femtosecond laser (IntraLase®) to create the LASIK flap. The microkeratome flap is “meniscus-shaped.” That is, it is thicker in the center, and thinner in the periphery (Figure 9). The IntraLase flap has the same thickness in the center and the periphery. Every LASIK procedure makes use of the excimer laser to shape the cornea. The femtosecond laser is an alternative to the microkeratome for making the corneal flap. If the femtosecond laser is used to make the flap, the procedure can be said to be “all-laser LASIK.” Of course, there are many aspects of LASIK which do not depend on a laser, such as irrigating and smoothing the flap. Furthermore, it is unclear whether creating a flap with a laser is better, worse or the same as creating the flap with a microkeratome. The terms, “All laser LASIK” and “Intralasik,” may have a certain marketing appeal, since some consumers may think that if one laser is good, two lasers must be even better.

Figure 9

3-62. What is LASEK?

LASEK is similar to LASIK, but instead of creating a corneal flap with a microkeratome, an even thinner flap, consisting of the most superficial layers of the cornea, is fashioned. This outer layer of cells, known as the “epithelium,” is lifted and the underlying bed is treated with the excimer laser. LASEK is an acronym for “laser assisted epithelial keratomileusis.” Some authorities say LASEK is not significantly different that PRK. Both procedures are considered “surface ablation,” and the corneal epithelium is replaced in both.

3-63. What are the most important factors in selecting a surgeon for laser vision correction?

The most important factor is the doctor and the doctor’s staff. If you have confidence in the doctor and the doctor’s staff, you have accomplished the most important step in choosing the setting for your laser vision correction.

3-64. How can I tell if the doctor and the doctor’s staff are right for me?

It helps to have a recommendation from someone who has been through the experience of laser vision correction. If your friends or colleagues had a positive experience, chances are you will too. You can also evaluate the doctor and staff during a free consultation. You are under no obligation after this visit. And, virtually all doctors who perform LASIK offer free consultations. You can even obtain a few consultations before making your final decision.

3-65. Who are the best candidates for LASEK?

The best candidates for LASEK are people who might be exposed to eye injuries, those with thin or irregular corneas, and those with high corrections. These are the same people who would be better candidates for PRK than LASIK. Boxers and other athletes who play contact sports should consider LASEK or PRK. People with corneas which are too thin for LASIK, or with certain surface irregularities, may also be better candidates for LASEK or PRK.

3-66. Is there an advantage to LASEK over PRK or LASIK?

While LASEK is a recent modification of LASIK, it is not clear that it offers any advantages. At this point, a relatively small number of ophthalmologists have chosen to perform LASEK. Those who perform LASEK, feel it is more flexible, offers better safety and less pain than LASIK or PRK.

3-67. In what way is LASEK safer than LASIK?

Since no cutting is required with a microkeratome, there is no risk of creating a poor corneal flap. Thus, the potential problems of striae, epithelial ingrowth, and DLK are avoided.

3-68. In what way is LASEK more flexible?

Because laser treatment starts near the most superficial part of the cornea, higher amounts of myopia can be treated without making the posterior bed of the cornea too thin. In order to maintain stability of the cornea, the thickness of the corneal bed should be at least 250 microns after laser treatment. This means that the average cornea can accommodate a correction of about 10 diopters. But with LASEK, a much thicker corneal bed is available. Higher corrections can be performed, and thinner corneas can be treated.

3-69. Why do some ophthalmologists prefer to perform LASEK rather than PRK?

Some ophthalmologists feel that LASEK is associated with quicker visual recovery, less pain, and a lower risk of corneal haze. Others think there is no difference in visual recovery, pain, or haze. If there is an advantage of one procedure over the other, it must be very small.

3-70. What is “advanced surface ablation?”

Surface ablation refers to laser treatment of the corneal surface, in other words, PRK and LASEK. The “advanced” part refers to a variety of improvements that have been made since laser vision correction was first introduced. These advances might include improved methods for evaluating the corneal surface, better techniques for anesthesia and pain control, improved laser hardware and software, and even, LASEK, itself.

3-71. What laser vision correction therapy does the military use?

The military uses LASIK and PRK. LASIK is used 2.5 times more often than PRK. At this time, aviators and divers in the military can have PRK, but they cannot have LASIK.

3-72. Do law enforcement agencies allow vision correction with LASIK?

Many law enforcement agencies allow LASIK and PRK, but rules vary from one agency to the next. Since vision requirements and alternatives for correction change from time to time, it is advisable to check the guidelines for the agency in question.

3-73. What are some common misunderstandings about the outcome of LASIK?

Some people believe their vision will be better after LASIK than it was with glasses or contact lenses before having LASIK. While this is sometimes true, it is not always the case. Vision after LASIK may be better, the same, or even slightly worse than “corrected” vision before surgery. Patients should also understand that they may require a “touch-up” procedure, or enhancement, after LASIK, in order to achieve the best possible vision. They should also understand that, despite their doctor’s best efforts, there can occasionally be an unexpected complication of LASIK. Most of the time, these complications can be corrected, and the vision will be fine. But, it is important for the patient to understand they will have to work with their doctor, and possibly, undergo additional procedures.

3-74. Can people with glaucoma have LASIK?

Some people with glaucoma are good candidates for LASIK, while others are not. If a person has glaucoma, it does not rule out the possibility of having LASIK.

3-75. What is glaucoma?

Glaucoma is an eye condition that runs in families and affects 2% of the population. Most glaucoma is associated with elevated pressure within the eye. If eye pressure remains high for too long, usually a matter of months or years, the optic nerve can be damaged. The optic nerve is the nerve that connects the eye with the brain. When the nerve is damaged, vision becomes impaired.

3-76. Why is glaucoma an important consideration when having LASIK?

Glaucoma is an important consideration because during LASIK surgery, eye pressure is greatly increased for several seconds. The increased pressure occurs when the suction ring of the microkeratome is placed on the eye. When suction is activated, eye pressure increases to 70 or 80 mm Hg, about four times the normal eye pressure. An optic nerve already damaged by glaucoma could be further damaged by the brief, but extreme, increase in eye pressure that occurs during LASIK.

3-77. How can someone with glaucoma determine whether or not they are a candidate for LASIK?

An ophthalmologist can tell whether LASIK will be a safe procedure for someone with glaucoma. In general, if the optic nerve is healthy, and has little or no damage from glaucoma, LASIK should not pose a significant risk.

3-78. Is there a safe alternative to LASIK for someone with glaucoma?

Yes. PRK is often safer than LASIK in someone with glaucoma. This is because PRK does not require a microkeratome or suction ring. Unlike LASIK, there is no increase in eye pressure during PRK

3-79. Can people who have had glaucoma surgery undergo LASIK?

Yes. Many people who have had glaucoma surgery have undergone LASIK with great success. The condition of the eye, especially the optic nerve, must be evaluated to determine whether it is safe to perform LASIK. It should also be decided if PRK is a safer procedure for the person who has had glaucoma surgery.

3-80. Are there any special considerations about medications for the glaucoma patient undergoing LASIK?

Glaucoma patients should continue their glaucoma medications before and after LASIK surgery unless instructed otherwise by their doctor. Steroid eye drops, used after LASIK or PRK can increase eye pressure in some people. This is especially true for people with glaucoma. When steroids are taken, it is important that they be used only for brief periods of time. The eye pressure should be closely monitored.

3-81. Should LASIK be done if an optic nerve problem is present?

There is concern that a damaged optic nerve can be further damaged during LASIK. Increased intraocular pressure related to the application of the suction ring can interfere with the blood supply to the optic nerve. A damaged optic nerve is more susceptible to further damage than a healthy optic nerve.

3-82. Can LASIK cause a retinal detachment?

There is no evidence that LASIK can cause a retinal detachment. However, it is worth noting that nearsighted people, the people most likely to undergo LASIK, have a higher incidence of retinal detachment than the general population.

3-83. What is the risk of retinal detachment for a LASIK patient?

The incidence of retinal detachment in the general population is 1.2 per 10,000 people per year. For nearsighted people, the lifetime incidence of retinal detachment is between 0.7% and 6.0%. In nearsighted people, with 1 to 3 diopters of myopia, there is a four-fold increase in the incidence of retinal detachment. If myopia is greater than 3 diopters, the incidence is 10-fold greater than the general population. After LASIK, the incidence of retinal detachment is 0.05% over a two-year period. In other words, the risk of retinal detachment after LASIK, is about 1 in 2,000.

3-84. Is there a way to determine if a LASIK patient is at risk for a retinal detachment?

There are certain risk factors for retinal detachment that should be taken into account before undergoing LASIK. These include a history of retinal detachment in one or both eyes, a history of a retinal hole or tear, and thinning of the peripheral retina.

3-85. Are there any special examinations that should be carried out if any of these risk factors are present?

If any risk factors for a retinal detachment are present, a careful retina exam should be carried out before undergoing LASIK. If there is any doubt about the findings, it may be helpful to have an examination with a retina specialist. Small holes or tears in the retina can then be repaired prior to LASIK.

3-86. Are there any other retina problems associated with LASIK?

Very rarely, a retinal blood vessel may show evidence of bleeding after LASIK. This event is thought to be caused by sudden changes in eye pressure related to the suction ring. Occasionally, a retinal blood vessel can occlude, or close off during LASIK, producing a “mini-stroke” in the retina. Either a bleeding or occluded blood vessel can lead to mild or even severe vision loss. In general, small hemorrhages in the retina absorb without any loss of vision.

3-87. Are there any medical conditions that make it unsafe to have LASIK?

There are a few medical conditions in which LASIK is contraindicated, or unsafe. Some of these relate to an underlying eye condition, like keratoconus. Keratoconus, a defect in the collagen of the cornea, may be associated with defects in collagen elsewhere in the body, particularly the spine and the joints. Rare medical conditions, like Marfan’s syndrome (Abe Lincoln’s skeletal condition), and pseudoxanthoma elasticum (a rubbery skin condition), may coexist with keratoconus.

3-88. Are there eye conditions in which LASIK should not be done?

Other eye conditions in which LASIK is contraindicated include herpes simplex corneal infection, pellucid marginal degeneration, and corneal keloids. The excimer laser may reactivate corneal herpes. Pellucid marginal degeneration is an unusual and rare thinning of the peripheral cornea. LASIK can cause corneal thinning to become worse, leading to instability of the cornea, and progressive astigmatism. Corneal keloids are growths of fibrous tissue on the cornea, which occur in response to cuts or surgical incisions. While corneal keloids are extremely rare, they should be looked for and asked about when laser vision correction is being considered.

3-89. Should LASIK be done in people who form keloids on the skin?

Keloid formation on the skin should be considered a “relative” contraindication. In other words, there is no absolute reason to avoid laser vision correction in keloid-formers. However, the patient and surgeon should be aware of keloid-forming tendencies because of the remote possibility that a corneal keloid could develop after LASIK surgery.

3-90. Can laser vision correction be done in someone with rheumatoid arthritis?

Rheumatoid arthritis and related conditions, known as “collagen-vascular diseases,” or “autoimmune diseases,” are considered “relative contraindications to LASIK. The reason for caution with these conditions is that they occasionally have corneal complications. These include inflammation and thinning of the cornea. If these corneal complications of rheumatoid conditions occur just before or after LASIK, the results of laser vision correction may be unexpectedly poor. Some recent studies show that LASIK appears to be safe in rheumatoid arthritis, as long as there is no sign of inflammation in the eyes.

3-91. Can people with diabetes have laser vision correction?

Many people with diabetes have had successful laser vision correction. However, caution should be exercised in diabetics because they are prone to healing problems and infection. Diabetics are prone to develop defects in the surface of the cornea during any kind of eye surgery, and LASIK incisions may heal more slowly in diabetics. People with diabetes may also be more susceptible to infection, so antibiotics should always be used after laser vision correction.

3-92. How good are the visual results of laser vision correction in people with diabetes?

The visual results in diabetics who have had LASIK are excellent, and probably as good as any other group of people who have LASIK. Planning for LASIK in diabetic patients may take some extra time. If diabetes has not been in good control, vision may fluctuate, and it may be difficult to obtain a good refraction. It may be useful to repeat the refraction a few times over a period of at least a few months. If blood sugar and vision are stable over a three-month period, it is probably safe to proceed with LASIK. Keep in mind that people with diabetes have a greater tendency to develop cataracts, glaucoma, and retinal problems, so diabetics often require closer follow up than the average LASIK patient.

3-93. What is the best advice for people with diabetes, rheumatoid arthritis, and other conditions, which are considered “relative contraindications” to LASIK?

The best advice for people with “relative contraindications” is to “proceed with caution.” LASIK is a very safe procedure, and people who have relative contraindications have had extremely good results. If severe complications exist, especially those that affect the eye, it may be safer to postpone LASIK, or avoid it all together. Your doctor can help guide you in this decision. On the other hand, if the systemic disease is well controlled, and vision has been stable, it is probably safe to undergo LASIK.

3-94. What is a “lazy” eye, and can it be treated with LASIK?

A “lazy” eye is a layman’s term for a weak eye, that is, an eye that does not fully develop its visual potential. The medical term for this condition is “amblyopia.” There are several reasons why amblyopia occurs. The most common is an early childhood condition called “strabismus.” With strabismus, one eye may turn out (exotropia), in (esotropia), up (hypertropia), or down (hypotropia). Strabismus is usually inherited, and often, more than one family member has a similar condition. Since only one eye focuses straight ahead, the turned eye can become amblyopic, or “lazy.” LASIK may sometimes improve the vision in a lazy eye, but often, the vision cannot be made perfect.

3-95. If the vision in a lazy eye cannot be made perfect, what is the point of having LASIK?

Although LASIK may not produce perfect vision in a lazy eye, it can often lead to a vast improvement in vision. Lazy eyes may be nearsighted, farsighted, or astigmatic. LASIK can correct these problems just about as well as glasses or contact lenses. What LASIK cannot do is make the vision better than it would be with glasses or a contact lens.

3-96. How can I tell if LASIK will improve vision in my lazy, or amblyopic, eye?

The ophthalmologist will be able to evaluate the amblyopic eye and help you decide if it is worth doing LASIK. A good test is to place a contact lens (or glasses) over the lazy eye and see if overall vision is improved. If vision is not improved in the amblyopic eye, LASIK will probably not help.

3-97. Is there any treatment that will improve vision in a lazy eye?

There is usually no way to produce perfect vision in a lazy eye. However, vision can often be made better with a contact lens, glasses, or LASIK.

3-98. Is there a treatment for a turned eye, or “strabismus?”

Strabismus is usually treated surgically, by moving the position of the extraocular muscles, the muscles that move the eyes. There are six extraocular muscles attached to the outside of each eye. Repositioning these muscles can usually straighten the eyes.

3-99. Are there any complications of doing LASIK for strabismus?

The same risks that apply to LASIK in any other eye apply to the eye with strabismus. In addition, there is a possibility that double vision could occur after surgery.

3-100. Why would double vision occur after LASIK?

If each eye is looking in a different direction than the other, each eye sees a different image. This can produce double vision. Sometimes the brain “suppresses” one of the two images, and this eliminates double vision. When the vision in the turned eye is made better by LASIK, or a contact lens, double vision may be more noticeable than before correction.

3-101. Should the strabismus or the LASIK operation be done first?

The strabismus operation should be done first. That way, any problem with potential double vision can be addressed and treated before having LASIK.

3-102. Is there any treatment for the double vision caused by strabismus other than surgery?

Occasionally, prisms are put in glasses or contact lenses to eliminate double vision. Occasionally, eye exercises may be of some benefit.

3-103. What if I have LASIK and then develop double vision?

The reason for the double vision has to be determined. If the reason is strabismus, more eye muscle surgery may be performed. Other causes of double vision include diabetes, cardiovascular disease, autoimmune disease, injury, and neurologic diseases like stroke, multiple sclerosis, and brain tumors. Obviously, these problems require extensive investigation, and this can be done with the help of the neurologist, internist, and ophthalmologist.

3-104. Is everyone capable of achieving 20/20 vision after LASIK?

Most people, but not everyone, are capable of achieving 20/20 vision after LASIK. There are many reasons for this. If some type of eye pathology is present, such as a cataract, corneal scar, or macular degeneration, vision after LASIK will not be perfect. If amblyopia, also known as a “lazy eye,” has been present since childhood, vision after LASIK will be limited. LASIK does not address these eye problems. It can only correct nearsightedness, farsightedness, and astigmatism. Vision is processed in the brain by the cerebral cortex, and sometimes the brain may be “wired” in a way that does not allow a person to see 20/20.

3-105. Why do people have LASIK?

According to people who have LASIK, the four most common reasons are:

LASIK simplifies life, since there is usually no further need to wear glasses or contact lenses.
Freedom from dependency on contact lenses or glasses.
Improved ability to play sports.
The desire to have good vision, day or night, seven days a week.