FREQUENTLY ASKED QUESTIONS
.
How can I tell if Laser Vision Correction is a choice for
me?
. If you are nearsighted, farsighted or have astigmatism and are over 18 years of age, in good health, with healthy eyes and wear glasses or contact lenses most of the time and your prescription power is not changing significantly (no more than 0.50 diopters during the year previous to your pre-operative evaluation) you are a candidate for LASIK or PRK. You must also have myopia, hyperopia or astigmatism in the range for LASIK or PRK.
- Your cornea thickness must be of significant thickness for LASIK.
- You must be informed of the risks and benefits of laser vision correction and have compared them to those of other available options for correcting your nearsightedness, farsightedness and astigmatism.
- You must read, understand and sign the informed consent provided by your eye care professional.
- You must have realistic expectations about the outcome of the procedure.
- Every person's situation is unique, in order to assess whether you are a candidate, you must have a preprocedure consultation with your eye care professional.
. How can the laser improve my vision?
. Laser vision correction is the most technologically advanced method available today for treating the common vision problems of farsightedness, nearsightedness and astigmatism. Laser procedures can reduce your dependence on glasses and contact lenses, improving the quality of your life.
. Will it hurt? Is it painful?
. The procedure itself is painless and usually takes about 10 minutes. There are no needles. Anesthetic drops are used to numb the eye at the time of the procedure. During the PRK procedure a speculum will be placed to keep the eye open during the procedure. It could be a little uncomfortable while the eye is held open. Light will be shined onto the eye to permit the surgeon to work. The surgeon then gently removes the outer layer of skin (epithelium) on the cornea to prepare the surface for treatment. This layer usually grows back within 2 to 3 days. During this time patients may feel a slight irritation or scratchy feeling. After the PRK procedure you will use a combination of drops as well as a bandage contact lens which makes the eye more comfortable. After the LASIK or PRK procedures when the anesthetic drops wear off, you will have some discomfort for a few hours. The majority of patients may experience irritation or a foreign body sensation for a few hours. The amount of pain varies from person to person and drops and/or tablets will be prescribed to relieve any pain that may develop. The following day the eye will be sensitive to light and may feel irritated. This may last 3 to 4 days for PRK and 1 day for LASIK (though the majority of people do not report pain). Dryness in the eyes can last up to two days. Very rarely do patients experience pain. Most patients are able to resume normal activities within a few days.
. Has anyone ever gone blind from Excimer laser eye surgery?
. More than 1 million patients in 52 countries have improved their vision as a result of Excimer laser technology. No cases of blindness have ever been reported from either PRK or LASIK procedures.
. Will I have perfect vision after the procedure? Will I still need my contact lens or glasses?
. Experience has shown that laser vision correction has been overwhelmingly successful in reducing myopia, hyperopia and astigmatism. While vision improves following the procedure, the degree of improvement may vary from individual to individual. Overall, 98% of typical patients achieve 20/40 vision or better after one procedure (i.e. before any enhancements) which means they can drive legally, play sports and join the police and fire departments, all without their glasses. Most patients are within one or two lines on the eye chart of 20/20 vision.
Patients may receive an enhancement procedure to further improve their results if their vision is below legal driving levels. In general, there is a 10% chance that a patient will require an enhancement procedure. This chance is less in patients with mild myopia, hyperopia and astigmatism (approximately 2% chance) and greater in patients with extreme myopia, hyperopia and astigmatism (approximately 25% chance).
. When can I resume normal activities?
. The day of the procedure should be spent resting. The next few days your eyes may be sensitive to light and you may want to take it easy, though many people find themselves actively going about their normal lives. Showering is acceptable, but swimming should be avoided. Soap and water should be kept out of the eyes when showering. Your eyes need to be protected with sunglasses when outdoors and activities should allow you to follow your doctors instructions for eye drop installation. Most people return to work within 3 to 4 days after PRK and 2 days after LASIK.
. Do I need to take time off work after PRK or LASIK?
. Patients are advised to take at least 3 to 4 days off of work for PRK and 2 days for LASIK and avoid strenuous activities after the procedure. This period of time is critical to the healing and stability of the eye. Time off work will vary on the individual and occupation. Individual assessment is required to determine the time needed for recovery.
. Can I have both eyes done on the same day?
. The laser procedure is usually performed on both eyes (bilaterally), the same day. In the event that this can not be done, one eye will be treated at a time. Bilateral procedures are performed on most people because of less time off of work and you are finished with the procedure during one setting. If a patient's second eye is treated at a separate time than the first eye, one of the following two methods are used to gap the transition period:
a) the patient will wear his/her glasses with one lens covered or removed.
b) the patient will not wear glasses on the untreated eye and simply use the treated eye.
c) Do not wear your contact lens if you are going to have the other eye done.
d) The solution that is best for you will be discussed with you by your eye care professional.
. Will I still need reading glasses?
. Yes, if you are 45 years or older but you will be less dependent upon them. Many patients choose to have "monovision" which allows for good distance in one eye and good reading in the other eye, further reducing the need for reading glasses. Hyperopia is often confused with presbyopia. Presbyopia is a condition that occurs as a normal part of the aging process. The lens of the eye begins to lose it's flexibility, making it difficult to read. This typically occurs between the ages of 40 and 50, requiring the use of reading glasses or bifocals. The laser has no effect on the lens or the focusing muscles attached to the lens. Patients with hyperopia often develop presbyopia earlier and benefit greatly from hyperopic laser vision correction. In general, patients who wear bifocals prior to the procedure will only need reading glasses (non-bifocals) after their procedure.It is possible to set one eye up for distance and the other eye for near so that you can see both at distance and near.
. Is laser vision correction covered by insurance?
. Most insurance companies do not cover PRK or LASIK, but we encourage you to check with your provider. While PRK and LASIK are deemed elective and not covered, they may be tax deductible. Please consult your accountant. Some employers will set up special pre-tax dollar /medical/surgical accounts to pay for laser vision correction in conjunction with their employees. Paying for LASIK or PRK with pre-tax dollars can be of substantial savings for you. We have financing available at Denali Alaskan Federal Credit Union next door and we accept cash, check, and credit cards as payment.
. Is it a permanent correction?
. Farsightedness, myopia and astigmatism may progress with age. However, the stability results of laser vision correction have been very impressive and most experts feel these results will last a lifetime.
. What are the long-term effects of the procedure?
. The PRK excimer laser procedure has been prevalent in many countries around the world since the late 1980s. Many clinical studies have investigated the long term effects of the excimer laser on the cornea. All of these studies, without exception, have failed to demonstrate any long term negative effects on the integrity of the eye. Since LASIK is a relatively new procedure (first performed in 1991), no one knows with absolute certainty what the long term effects are. We do know that very thin corneas do not do well. The center of the cornea may bulge forward, this is called ectasia. We do know that we have to keep 250 microns of corneal tissue intact. If after calculation it shows that 250 microns or more of corneal tissue can be preserved untouched then the probability of ectasia after the LASIK procedure is much smaller. Since LASIK was first introduced clinical studies have been unable to show any other negative effects on the eye. Many patients achieve 20/20 vision after their procedure, and today, they are still 20/20 without any difficulties. Patients who require an enhancement procedure will typically do so within the first few months following the procedure, not years later.
. What are the risks of the Excimer laser procedure?
. It is essential that you understand as much as possible about the risks associated with the excimer laser procedures. The risk of having a serious vision-threatening complication is less than 1%. This is one of the safest surgical eye procedures performed today. The excimer laser procedure, however, like all surgical procedures, has limitations and risks.
The risks of PRK and LASIK are the same except for the potential flap complications of LASIK. A partial list of potential complications of PRK and LASIK are as follows:
1. overcorrection
2. undercorrection
3. perforations
4. haze
5. scarring
6. blurred vision
7. ghosting of images (double vision)
8. halos around lights
9. starburst effects emulating out of point light sources
10. decentered ablation or treatments
A partial list of potential complications of the flap in LASIK are as follows:
1. free cap/flap
2. lost cap/flap
3. folds in flap
4. interface debris or deposits
5. epithelial ingrowth
6. flap melts
7. corneal flap perforations
8. steps in flap bed
9. macerated flap
10. corneal perforations
11. inflammation under flap (shifting sands syndrome)
12. incomplete short oval flaps
13. thin flaps
14. displaced flap
The vast majority of PRK and LASIK complications can easily be treated, but up to 1% of patients may lose some visual sharpness related to poor or irregular healing. Most importantly, there has never been a case of blindness reported as a result of laser vision correction. That includes over a million procedures performed worldwide for more than 10 years.
. Are my eyes patched after the procedures?
. Your eyes are not patched after PRK or LASIK. You will be given clear plastic eye shields to wear during the first 24 hours and for 4 nights, used just while sleeping, after LASIK. Bandage contact lenses are needed for the first 2 to 4 days after PRK.
. Do I need to use eye drops after the procedure?
. You will use medicated eye drops for one week after your LASIK treatment and three months after the PRK treatment. Artificial tears are recommended up to one month after either treatment.
. When will my vision stabilize? When will I get the crispest vision?
. After the PRK procedure, the vision will be blurry while the contact lens is in place. When the contact lens is ready to be removed the vision will start to clear. Once the contact lens is removed usually you have good functional vision (good enough to drive a car). The vision then starts to get clear and sharper over time. The sharpest vision usually occurs 1 to 2 weeks after the contact lenses have been removed. However, it can take several months for the vision to reach it's full potential.
After the LASIK procedure the vision will be blurry for the rest of the day. By the evening you will notice the vision starting to improve. The vision the following day usually is very good (sometimes good enough to drive a car). On average, vision takes a week to reach full potential and the majority of patients have vision good enough to drive within the week of the LASIK procedure. You will be acutely aware of your changing vision during the healing process and your vision may change and fluctuate after either procedure for up to 6 months.
1. How long has wavefront LASIK been available?
. The first wavefront mapping of the complete aberration profile of a human eye was performed in 1994. The first wavefront LASIK procedure was performed in 1999. The FDA approved the first commercial use of wavefront LASIK to correct nearsightedness in October 2002, and approved the VISX S4 Wavefront LASIK platform for farsighted treatment in 2004.
2. Since wavefront LASIK is a relatively new procedure, should I wait until it is more refined?
. Just as with any technology, LASIK will continue to evolve and improve. In reality you could continue to wait the rest of your life without ever having the procedure, because it will get better and better. However, given that millions of people have already had conventional LASIK and are very satisfied, and that wavefront LASIK is a huge improvement upon conventional LASIK, there seems to be no reason to wait for further refinement particularly with the following refinements already functioning. With the developments of auto centering, auto tracking and iris registration any more advances would not be as significant (see 13 below)
3. Since wavefront LASIK and PRK is the latest and greatest, shouldn't everyone having LASIK or PRK elect the custom procedure?
. While wavefront LASIK or PRK may be very appropriate for some, it may be over-doing it for others. The differentiation comes in the degree of one's pre-operative higher-order aberrations. The truth is that conventional LASIK will continue to work well for a large subset of LASIK and PRK patients. If for example you elect to have monovision (blended vision), the near eye is done by conventional laser treatments, because it makes no sense to treat higher order eye imperfections if you purposely leave one eye &endash;1.75 so that eye can read.
4. Following wavefront LASIK or PRK, will I see better than I do with contact lenses or glasses?
. In a certain percentage of wavefront LASIK and PRK cases, patients will see better than they did with their glasses or contact lenses. However, this is also true for conventional LASIK or PRK, albeit not as frequently. One needs to understand that although this vision improvement is possible, it is by no means guaranteed.
5. Is wavefront LASIK or PRK "safer" than conventional LASIK or PRK?
. When you read about claims that wavefront LASIK or PRK is "safer" than conventional LASIK or PRK, they are referring to the reduced likelihood of creating night vision or contrast sensitivity problems. While overall this may be true, it not the case for the all of patients. With appropriately selected cases, conventional LASIK or PRK provides fine night vision and contrast sensitivity. For higher risk patients, wavefront LASIK or PRK is the preferred approach.
6. For the patient, how does the wavefront LASIK or PRK experience differ from the conventional one?
. The actual surgical experience for the patient is exactly the same as conventional LASIK or PRK. The difference comes in the pre-operative measurement of the patient's lower- and higher-order aberrations. Instead of the subjective and confusing process of "which is better 1 or 2" (the better one better two test, refraction), the entire aberration profile of the eye is performed objectively, without relying on your answers, using sophisticated wavefront sensors or aberrometers.
7. Are the results of wavefront LASIK or PRK permanent?
. While we understand a great deal about the eye's lower-order aberrations and their stability, we understand far less about it's higher-order aberrations. So while the laser effects of wavefront LASIK or PRK are permanent, no one can yet predict how one's higher-order aberrations will naturally change over the years.
8. Now that my prescription can be measured without relying on my answers, does the surgeon really have to depend on me for anything?
. While it is true that wavefront refractions can objectively ascertain one's prescription (both lower- and higher-order aberrations), it is currently unable to do so in a small subset of patients. For these individuals we still have to rely on the subjective testing of "which is better 1 or 2" (refraction). Additionally, even though the laser treatments are auto-centered and pupil-tracked and auto registered, it is still necessary and helpful for the patient to maintain good fixation on the red, blinking light during treatment.
9. If I have large pupils is it required that I have wavefront LASIK or PRK?
. While there is a tendency for those with larger pupils to have a larger degree of higher-order aberrations, this is not always the case. Pre-operative wavefront measurements will determine this degree and whether wavefront LASIK or PRK would be recommended over conventional LASIK or PRK.
10. I have already had LASIK (or PRK) and experience night vision and/or contrast sensitivity disturbances. Can wavefront LASIK or PRK help me?
. Wavefront refractions of post-operative LASIK or PRK patients with such quality of vision complaints often demonstrate large degrees of higher-order aberrations. Preliminary studies suggest that wavefront LASIK or PRK retreatments can reduce these aberrations, as well as subjectively improve these night vision and contrast sensitivity problems.
11. What is CustomVue individualized laser vision correction? Is it the same as wavefront LASIK or PRK? -Yes
. CustomVue (wavefront LASIK or PRK) procedures differ from conventional laser vision correction by using a WaveScan (wavefront) machine to measure the unique imperfections (Wavefront) of your eye&emdash;25 times more accurately than standard methods (the better one better two test, refraction). This creates a map and a set of computer commands (algorithm) that directs the laser treatment spots to be placed at the precise locations on the cornea. This map and your treatment algorithm of your eye is as unique as your fingerprint. Dr Grendahl then transfers this precise information to a VISX S4 IR laser, and uses it to custom-tailor your individualized treatment.
12. Why is WaveScan technology so important?
. Until now, physicians were forced to practice one- size- fits- all vision. An off the shelf lens corrects an individual's vision fairly well, but it is not uniquely tailored to "The fingerprint of your vision". Now, with WaveScan technology, we can custom tailor a correction for the unique characteristics of each individual's vision.
13. What is Iris Registration Technology?
. It's the first fully automated method of aligning and registering wavefront corrections for CustomVue treatments. It's normal for the pupil to shift positions from the point of wavefront measurement to the point of treatment. Iris Registration Technology centers the treatment correctly, independent of changes in the pupil center from measurement to treatment. It also torsional (clockwise or counterclockwise) aligns the treatment automatically. Auto registration relies on computer programs and infrared cameras that take pictures of the iris when the wavefront measurement takes place in the office setting. In addition the VISX S4 IR laser has infrared cameras and computer programs to match the VISX S4 IR laser captured iris image to that of the wavefront machine's previously taken in the office. This assures that when a person lies down under the laser when there eye cyclo torts (rotation of the eye in the socket clockwise or counterclockwise) that the laser head optically rotates to realign perfectly with the eyes position present in the office wavefront measurement setting. With auto tracking if you move your eye while the laser (VISX S4 IR) is on the laser head follows the movement. With auto centering the laser (VISX S4 IR) treatment is automatically aligned with the center of the pupil that was measured at the time when the person had the wavefront measurement in the office setting, This is why I said, "With the developments of auto centering, auto tracking and iris registration any more refinements would not be as significant".
14. What is the centroide shift of the pupil?
. The center of the pupil, measured at the time when the wavefront measurement was done is not necessarily the center of the pupil when the person lies down under the laser. This is because, under different lighting conditions and different physiologic tone of the pupil, the pupil is a different size and shape. When the pupil dilates or constricts the center of the pupil shifts ever so slightly, because the iris fibers do not contract symmetrically. This results in .1 to .5 mm. shifts in the center of the pupil. Because of these pupil shifts and the movement of the iris it is necessary to reference to a fixed and unchanging structure. This reference is chosen as the limbus. The limbus is the outer most part of the cornea were it meets the white of the eye (sclera). The computer in the laser calculates the centroide shift relative to the limbus. To do this the laser computer compares the center of the pupil when at the wavefront measurement setting to the center of the pupil when under the laser (VISX S4 IR). All of these measurements are referenced to the limbus. Then the laser's computer program shifts the laser head the correct amount and in the right direction and location so treatment is perfectly matched to the eye's measured wavefront and centered perfectly (this is part of auto regisration, see # 13 above).
15. I don't understand the above answers to iris registration. Can you try to explain it to me by an analogy?
. The simple analogy of a Pringles potato chip container and the potato chips in side will do very well. The reason why you can fit so many potato chips into the container is because every potato chip is perfectly aligned up with all the other potato chips (registration). Consider just three of the chips. The top one is the wavescan of the cornea, the center chip represents the treatment algorythium (computer list of instruction to the laser head) and the chip at the bottom represents the cornea. The treatment algorythium aligns perfectly with the wavescan and the cornea like Pringles Potato Chips lining up. The computer automatically lines up all the potato chips called auto registration.
