LASIK Surgery FAQs
- What is nearsightedness?
- What is hyperopia?
- What is astigmatism?
- What is presbyopia?
- What is a diopter?
- How can these visual problems be corrected?
- Are there other non-surgical means of improving your vision?
- What is refractive surgery?
- What is laser vision correction (LVC)?
- What is the history of the excimer laser?
- What procedures are performed with the excimer laser?
- How do LASIK and PRK work?
- How long do the procedures actually take?
- Why is LASIK becoming the procedure of choice for most patients and surgeons?
- How is astigmatism corrected?
- What other surgical alternatives are there to PRK and LASIK?
- Are there other alternatives for astigmatic correction?
- What about farsightedness?
- How does LVC for hyperopia work?
- What are the results/Will my vision be 20/20 after LVC?
- Are these procedures FDA approved?
- How do I know if I’m a good candidate for laser vision correction?
- Is there a limit to how much nearsightedness LVC can correct?
- If I have had a previous corneal injury, can I have refractive surgery done?
- Will I be in any pain?
- Can I have both eyes done at the same time?
- Will I be awake as the operation is being performed?
- What if my eye moves during the procedure?
- When can I go back to work?
- Will I require eye drops after surgery?
- How many times will I be seen following surgery? And how important are these appointments?
- How long do I have to wait before I can take a bath or shower after surgery?
- When can I wear eye makeup after surgery?
- How soon after surgery can I drive?
- When can I exercise after surgery?
- If I have PRK, what kind of vision can be expected the following day?
- If I have LASIK, what kind of vision can be expected the following day?
- Will I need glasses or contacts after surgery?
- Will I need reading glasses after surgery?
- Can I wear contact lenses after laser surgery?
- Will the effects of the treatment be permanent?
- What are the side effects of this surgery?
- Is it possible to become blind with the surgery?
- What are the drawbacks of LASIK?
- How do I know LVC is safe?
DIFFERENT REFRACTIVE ERRORS
Over 60 million Americans suffer from nearsightedness, or myopia. A person is considered nearsighted when the eye has too much focusing power. This occurs when the eye is either too long or the cornea is too steep to allow light to focus directly on the retina (the film of the eye). Instead, light focuses in front of the retina causing distant images to appear blurry. A minus power lens in the form of eyeglasses or contact lenses is needed to subtract focusing power from the eye.
Learn more about myopia by clicking on the video below. In order to watch the video, you must have Adobe Flash Player. (cick here to download it).
Hyperopia is a condition where light rays entering the eye are focused behind the retina instead of directly on it, as in the normal eye. It may be present in childhood but does not usually become apparent until people are in their late 20s or 30s when they can no longer see up close. When these patients get into their 40s or 50s, they begin having difficulty seeing distant objects as well.
Learn more about hyperopia by clicking on the video below. In order to watch the video, you must have Adobe Flash Player. (click here to download it).
Astigmatism is a condition that occurs when the cornea or lens is steeper in one axis than another, similar to a football or the back of a spoon instead of completely spherical or round like a basketball. Light entering the cornea focuses on more than one point within the eye, resulting in blurring vision. Astigmatism is either regular when steep and flat axes are 90 degrees apart or irregular when they are not separated by 90 degrees.
Learn more about astigmatism by clicking on the video below. In order to watch the video, you must have Adobe Flash Player (click here to download it).
Literally “old vision”, it represents a natural aging process of the eye. It starts to affect most people around the age of 40. Normally, when a close object is viewed, the lens will change shape or “accommodate” to focus light on the retina. With presbyopia, the lens cannot sufficiently reshape and glasses are required for close viewing. If someone has laser vision correction for nearsightedness and is already presbyopic (40+ years of age), they will then need correction for reading, which is typically just the store-bought magnifying glasses.
Learn more about presbyopia by clicking on the video below. In order to watch the video, you must have Adobe Flash Player (click here to download it).
A diopter is a unit of measurement that determines your prescription. A minus sign in front of the number means you are nearsighted and a plus sign means you are farsighted.
They can be corrected with glasses, contact lenses, or surgery.
A procedure called orthokeratology has been available for many years, where a series of progressively flatter gas permeable hard contact lenses are used to flatten the cornea. When the cornea has reached its desired correction, a retainer contact must be worn for several hours per day to prevent the cornea from returning to its original shape. Therefore, it does not cause a permanent correction.
HISTORY OF REFRACTIVE SURGERY
These are a group of surgical procedures that have been designed to permanently reduce or eliminate the need for corrective eyewear to see distant objects. They include laser assisted in-situ keratomileusis (LASIK), photorefractive keratectomy (PRK), radial keratotomy and astigmatic keratotomy (RK/AK), laser thermal keratoplasty ( LTK), conductive keratoplasty (CK) to name a few. These procedures offer an alternative to glasses or contact lenses and can only improve vision if it can be improved with glasses or contact lenses.
See a short video about refractive surgery by clicking on the video below. In order to watch the video, you must have Adobe Flash Player. (click here to download it).
These are refractive procedures performed with an excimer laser. The excimer generates ultraviolet light of a specific wavelength (193 nanometers) by sending high-voltage electrical energy through a cavity containing Argon Fluoride gas. The beam that is emitted has enough energy to break the bonds between the molecules that make up the tissue on your eye’s surface (the cornea). Because it is a photochemical and not a heating process, it allows the surgeon to sculpt very precise amounts of corneal tissue from above without any damaging to neighboring/adjacent tissue.
The excimer laser was developed at IBM, and was used to etch computer microchips. Its extreme precision with negligible damage to adjacent tissue made it a very attractive tool for other applications. In 1983, Stephen L. Trokel, M.D., in cooperation with R. Srinivasan, a physicist, applied it to corneal tissue in a New York laboratory. The first sighted eye was treated with the excimer laser on January 14, 1987.
LASIK, or laser in-situ keratomileusis, and PRK, or Photorefractive Keratectomy.
REFRACTIVE SURGICAL PROCEDURES AND HOW THEY WORK
In both procedures, a specially trained ophthalmologist uses the computer-guided excimer laser to gently remove a thin layer of tissue from the cornea to achieve a desired correction. Prior to the procedures, drops are placed in the eye to numb it (like the ones your eye doctor uses to check your eye pressure for a glaucoma test) and an instrument called a speculum is placed in the eye to prevent you from blinking. There are no needles and no pain.
In PRK, the surgeon first removes the surface cells of the cornea using the laser and then sculpts the underlying tissue. The surface cells regenerate over the course of 48 to 72 hours under a bandage contact lens. In LASIK, an instrument called a microkeratome, is used to lift a thin layer of the corneal tissue. This is left attached on a hinge. The laser is then used to sculpt tissue from the corneal bed and the flap is floated back into place, reattaching without the need for sutures.
During the LASIK procedure, there is no pain, however, there is about 15 seconds of firm pressure while the corneal flap is being created. Following the procedure, patients are usually more comfortable than patients undergoing PRK, experiencing only four to six hours of scratchiness in the eye.
Most patients are in the laser suite for no longer than 10 minutes. The actual laser treatment time takes just 15-90 seconds, depending on the degree of correction required. Total time at the center on the day of the procedure will be about an hour.
Because the healing occurs in the interior of the cornea, and no regrowth of surface cells are required. The corneal flap protects the treated area and there is usually little, if any, post-op discomfort. Visual rehabilitation is much quicker and regulation of the healing process with long term post-op drops is unnecessary since the center of the cornea tends to have much less of a healing reaction than the surface.
The laser treats the regions where the cornea is high or elevated. In a simple analogy- the cornea is shaped like a football with astigmatism. The laser sculpts the surface of the cornea in the shape of a baseball or basketball to correct for the astigmatism.
Radial Keratotomy (RK) is a surgical procedure that can also correct nearsightedness by changing the shape of the cornea. Microscopic incisions of 90% depth, placed in a radial pattern, like the spokes of a wagon wheel, reshape and flatten the central cornea, allowing light to focus more precisely on the retina. The length and number of incisions determine the effect of the surgery. Patients with less than 3 diopters of nearsightedness and stable prescriptions are the best candidates.
Refractive Intra Ocular Lens (RIOL) are lens implants that have recently been approved by the FDA and are usually reserved for patients with extreme myopia.
A variation of RK, called astigmatic keratotomy or AK, is a very effective means of reducing astigmatism. By making incisions in an arc-like or segmental fashion parallel to the white of the eye where the cornea is steep, it is caused to relax and become more spherical.
In the past, ALK was used where a thicker layer of the cornea was folded back with the microkeratome. Pressure inside the eye causes the corneal bed to steepen, the opposite of what occurs in LVC. The cap was placed back into position without the removal of additional tissue. Although it has been shown to effectively reduce or eliminate farsightedness in the +1.00 to +5.00 range, enough cases of corneal instability have been reported nationwide that this procedure has fallen out of favor. Now, LASIK for hyperopia is considered by most to be the best option.
Conductive Keratoplasty (CK) uses a needle-like probe to deliver radio-frequency energy to the corneal collagen in a ring of individually placed spots to steepen the cornea. Farsighted patients with a prescription between +0.75 to +3.25 and no more than 0.75 diopters of astigmatism are the best candidates for this procedure. Because of mild regression and a lack of long-term results, the procedure has been labeled as temporary.
Now, both PRK and LASIK are possible and effective for hyperopia. The procedure is identical to the myopic (nearsighted) procedure, however, by blocking the laser from treating centrally and allowing it to remove more tissue in the periphery of the cornea, a steepening rather than a flattening of the cornea is produced.
The results are quite remarkable. In the U.S. clinical trials for the Wavelight Allegretto for nearsightedness, 100% of the patients experienced improved, uncorrected vision six months after the treatment. 98% were returned to 20/40 sight or better — the “driving standard” in most states — and were able to enjoy life and perform most activities without glasses or contacts. 88% of the patients saw at least 20/20 and an amazing 60% of the patients saw better than 20/20.
Yes, both the PRK and LASIK procedure have been FDA approved to be safe and effective. After extensive testing, the U.S. Army has also approved laser vision correction for our soldiers.
The great majority of all nearsighted Americans are potential candidates for the laser treatment. Patients must be at least 18 years of age, have mild to moderate near sightedness with a stable prescription, and have no ocular or health issues. The best candidates tend to be people who are dissatisfied with their glasses or contact lenses and are motivated to make a change, whether it’s due to occupational or lifestyle reasons.
Although a patient’s prescription may make him or her a suitable candidate for laser vision correction procedure, it is very important that the patient have the appropriate level of expectations regarding the outcome of the procedure. Although uncorrected post-op vision (after healing) is usually excellent, no one can promise you 20/20 vision.
A person is a good candidate for Laser vision correction if he or she expresses the following sentiments in discussing whether or not to undergo the procedure:
- I dislike being dependent on glasses for clear vision.
- I was never a good contact lens candidate/wearer.
- Wearing corrective lenses restricts my participation in sports and other activities.
- My overall appearance is improved without glasses.
- I worry about losing my corrective lenses (or breaking my glasses). Without them I fear that I would be totally disabled.
- Having good vision without corrective lenses is more important than having great vision with corrective lenses.
- I would be happy if my vision was greatly improved, even if I still had to wear corrective lenses some of the time.
- I usually adjust well to change.
- I am a fairly easy-going person.
- Not wearing corrective lenses would open new career opportunities for me.
- I have often wished I did not have to wear corrective lenses.
A person is probably not a good candidate for Laser vision correction if he or she expresses the following sentiments in discussing whether or not to undergo the procedure:
- I like wearing glasses and would feel uncomfortable without them.
- I don’t mind wearing contact lenses.
- I don’t accept changes easily.
- I get upset or stressed out easily when things don’t seem to happen just the way I had planned or expected.
- I am a perfectionist and little irregularities bother me.
- I would be very upset if I did not end up with perfect vision after my procedure and would probably consider the entire experience a failure.
- If I needed more correction after my procedure, I would be devastated.
A patient is also not a good candidate for Laser vision correction, if any of the following conditions are present:
- Less than 18 years of age
- Progressive myopia/unstable refractive error(>0.50/yr)
- Keratoconus – an abnormal progressive weakening of the cornea that your doctor can detect with a sophisticated, computerized machine called a corneal topographer, as well as other tests
- Cataracts – removal of the cataract with insertion of the appropriate implant lens will greatly reduce one’s dependence on glasses
- Unwilling to commit to post-procedure and follow up-care instructions
- Pregnancy/breast feeding
- Ocular herpes
- Uncontrolled diabetes
- Uncontrolled inflammatory diseases
The corneal thickness measurement is a very important test and can be the major limitation for LASIK. This measurement is a standard test at the Atlanta Vision Institute. In these situations, PRK is an alternative to LASIK.
A full eye exam is needed in order to determine if you are a good candidate. If you have had a corneal injury, it will depend upon the size and type of injury.
WHAT TO EXPECT DURING THE PROCEDURE
There is very mild discomfort during the PRK procedure. Following the procedure, you may experience a gritty sensation, burning, tearing, and light sensitivity for the first 2-3 days.
During the LASIK procedure there is mild discomfort, no pain. Following the procedure, patients may experience some scratchiness, burning and tearing for 2-3 hours after the procedure.
Most patients undergoing LASIK and PRK prefer to have both eyes treated on the same day since it is more convenient for them, however this is a decision entirely between the patient and the doctor.
Yes. Dr Ashraf will need you to fixate on a red blinking light in the microscope during the procedure. Remember with the experience of Dr Ashraf and the speed of the Wavelight Allegretto laser, the entire LASIK procedure is completed in less than 10 minutes.
The Wavelight Allegretto laser has a tracking device. With that device the laser detects and compensates for small movements by guiding the laser beam to keep it centered precisely over the treatment area providing the highest level of precision, comfort and safety.
Most patients will be able to return to most normal activities the following day. Most patients can drive and return to work the next day after the LASIK procedure.
In PRK, because the laser removes tissue from the surface of the eye, the body will attempt to fill in the defect much like if you had a cut on your hand. Since corneal tissue has different healing properties, the process can normally be regulated with the use of topical steroid drops which patients may be required to use over a one-month period.
In LASIK, these drops are only used for a week. These drops will rarely cause any problems. However, eyes must be monitored on a monthly basis to fine tune the drop dosage and check for any unwanted side effects such as delayed or too rapid healing and elevation in eye pressure (glaucoma). Antibiotic drops are also used for about a week with both procedures. Please see – Post Operative Instructions.
Plan on about 3 short visits in the first three months following surgery. Even if you are seeing well, there are things that must be monitored during the first few months following your procedure to ensure that you achieve the best possible outcome for your vision.
You can shower or bathe the day after surgery. Avoid getting soap or water in the eyes or immersing in the ocean, in a pool or in a Jacuzzi for al least 1 week after the surgery.
It is a good idea to buy new mascara after surgery to avoid infection and it is best to wait 1-2 weeks before using eye makeup.
You can resume driving as you feel comfortable with your vision. Majority of patients are able to drive on their own on the day following LASIK. With PRK, it usually takes about 4-5 days to feel comfortable.
You may resume exercises as you wish. Don’t get sweat in your eyes. Try to keep your hands clean and away from your eyes and avoid rubbing the eyes for the first few weeks after surgery. Swimming, however, should also be avoided for at least two weeks.
WHAT TO EXPECT AFTER SURGERY
Vision is greatly improved but typically blurry immediately after the procedure (20/80-20/200). It generally starts to improve once the surface layer of the cornea (epithelium) has grown back, which in most cases takes 3 to 4 days (approximately 20/40). Vision typically starts to get good within 7-10 days (usually 75-85% improvement) but can continue to improve weeks afterwards. The healing process varies for each patient, and it is difficult to predict precisely when you will achieve your best visual acuity. However, most patients who have both eyes treated at the same time report that they are able to drive a car safely and resume their normal activities between 3-5 days following PRK.
The first day after LASIK, most patients have experienced a large improvement in their vision, usually 20/40 or better. This greatly depends on your preoperative prescription. You can expect to regain approximately 90-95% percent of your vision in the first two to three days after LASIK. The remainder of your vision will improve gradually over several weeks. If you have significant astigmatism, or are very near sighted/far sighed sight recovery and stabilization are slower.
If the patient opts to have only one eye treated at a time, a contact lens maybe needed for the untreated eye until the second eye is done. This can be done in almost all cases, even if you have not been able to tolerate contacts in the past. The optics of removing the glass in front of your treated eye in your spectacles, while giving clearer vision to each eye individually, will often cause disorientation and headaches due to image size discrepancy, unless your original prescription was less than -3.00.
As people enter their 40s, they start to develop presbyopia (see #4). Regardless of whether or not you’ve had Laser vision correction, this process will happen to you. Dr Ashraf can create an effect known as monovision. This means that one eye will be left slightly nearsighted, thus allowing you to focus on print such as labels and menus without reading glasses, and perhaps allowing you to read into your 50s. As one gets older, it will be necessary to wear reading glasses. Furthermore, if you are over the age of 40 and are used to removing your glasses to read, you must realize that this will no longer be an option following a full correction of your nearsightedness with the surgery.
Shortly after you have had the procedure, it is possible that you may require a temporary pair of reading glasses if you are approaching your 40th birthday since the laser, by design, causes an early over-correction that normally goes away with time.
If you were able to wear contacts prior to surgery, you should be able to wear contacts afterwards.
Given the results of the U.S. clinical trials and the results reported internationally, the treatment appears to be permanent, however LVC will not prevent age related conditions such as cataracts, glaucoma, macular degeneration, or presbyopia.
SAFETY AND LVC
The vast majority of patients have no side effects, however the most common complaint after laser vision correction is dry eyes. The patients at particular risk are the ones that have dry eyes prior to vision correction. Dr Ashraf will perform a complete eye exam and in some cases he may initiate dry eye treatments prior to laser surgery.
The majority of cases of dry eyes usually resolve within a few weeks after the surgery. Another complaint after surgery is the “halo” effect and some glare at night around lights. However, these problems are no worse than what most contact lens and eyeglass wearers often experience and the majority of patients function without any visual impairment at night. Using the Wavelight Allegretto laser we can expand the treatment areas thereby reducing the risk of the side effects in patients with larger pupils.
As with any surgery any complication could potentially occur. In over 3 million laser vision correction procedures performed in the United States, no cases of blindness have been reported.
While more comfortable and yielding quicker rehabilitation of vision, LASIK is technically more difficult to perform than PRK. There is an extra step involved – the creation of the corneal flap. This is rarely associated with any considerable or permanent vision loss, however, there are occasional circumstances which could cause flap complications. Fortunately, most of these can be corrected with additional procedures.
In the U.S. clinical trials’ 3-year follow-up, no sight-threatening complications were reported. And with over three million treatments performed nationwide, very few sight-threatening complications have occurred.
I WOULD LIKE TO HAVE LVC