Laser Surgery
What is LASIK?
LASIK, short for Laser Assisted In Situ Keratomileusis, is a surgical procedure that uses a cool (non-thermal) beam of light to gently reshape the cornea — the surface of the eye — to improve vision. The laser vaporizes tissue to flatten the cornea (for nearsightedness), steepen the cornea (for farsightedness), and/or smooth out corneal irregularities (for astigmatism). In most cases, the thickness of the layer of corneal tissue removed by the laser is less than the thickness of a human hair. The goal of any laser vision correction procedure is to reshape the cornea so it does a better job of focusing images onto the retina.
How is LASIK different from previous refractive eye surgery techniques?
Current FDA-approved laser vision correction methods, such as LASIK, have a higher predictability of the final result with a lower incidence of complications. Additionally, older non-laser techniques typically involved manually performed incisions rather than automated lasers for correction.
Is LASIK right for everyone?
Only an eye care professional can determine whether or not an individual is eligible for LASIK treatment. In general, a good LASIK candidate is at least 18 years old, has healthy corneas, and has maintained a stable eye prescription for the last 12 months. Because hormonal levels can affect the shape of the eye, women who are pregnant or nursing should not undergo LASIK treatment. The procedure should also not be performed on patients who:
- Have glaucoma, cataracts or dry eyes
- With collagen vascular, autoimmune or immunodeficiency diseases
- Show signs of keratoconus (an eye disorder in which there is thinning of the cornea that results in blurred or distorted images)
- Take medications with ocular side effects (such as Accutane® or Cordarone®).
Is LASIK Safe?
The FDA recognizes LASIK as proven, safe and effective. According to guidelines recently released by the Eye Surgery Education Council (ESEC), fewer than 1% of patients who have received LASIK to date have experienced serious, vision-threatening problems. Most LASIK complications can be treated and usually resolve within several months of surgery. There are no known cases of blindness resulting from LASIK.
What are the risks associated with LASIK?
Although no one knows the exact number of complications, studies suggest that the incidence of minor difficulties such as dry eyes and nighttime glare is around 3% to 5% from combined LASIK and PRK procedures. These minor complications include:
- Halos - Some patients will notice glare, halos or starburst around objects in low-light conditions. For the vast majority, these symptoms are temporary. However, others will continue to experience them for several months or longer. During pre-operative evaluation, the refractive surgeon can determine whether or not a person is at high risk for seeing long-term halos.
- Dry eyes - There is increased dryness of the eyes typically for several months following LASIK, though some patients may experience dryness for a longer period of time. It is important to use lubricating drops frequently. If the eyes remain dry for prolonged period, there are other drops or techniques that can help. Pre-operative evaluation will help determine whether or not a person is a likely candidate for experiencing dry eyes.
- Infection - This is an extremely rare occurrence, with a 1 in 2000-3000 chance (similar to any eye surgery). Fortunately, as the LASIK technique has developed over the years and proven to be of great benefit to millions of patients nationwide, firmly established protocols now exist which minimize the risk of infection.
- Over- or under-treatment - While the laser is very precise in the process of reshaping your cornea, we can not predict how each person will respond to the treatment. Individual healing response at times can cause an under or over correction and also the possibility of a reduction in the quality of vision possible. Any loss of best corrected vision is a very infrequent consequence and can not always be corrected. In general any under or over correction can be treated easily with an enhancement procedure.
- Your vision may change again over time - While the goal is to reduce your dependency on glasses and in many cases eliminate the need for glasses, the eye will continue to change to some degree throughout your lifetime. At the time of your visit you doctor will discuss this possibility with you and give you advice specific to your age and a reasonable estimate of what you can expect with your eyes.
Your doctor will answer all your questions honestly and in detail. All safety and risk information specific to the equipment and methods being used in the clinic will be disclosed to you.
What happens before LASIK surgery?
Before a surgeon will perform LASIK, preoperative tests are performed to screen for glaucoma, cataracts and other disqualifying conditions. The surgeon will also use an instrument called a corneal topographer to photograph and electronically map the eye in order to gather more information about the individual’s eyes prior to treatment.
Because contact lenses change the shape of the cornea, LASIK candidates are required to switch to eyeglasses before their baseline evaluation is taken and continue wearing only eyeglasses between 2-4 weeks before LASIK surgery. Not leaving contact lenses out long enough for the cornea to assume its natural shape before surgery can cause inaccurate measurements and poor vision after surgery.
What happens during the LASIK procedure?
Once the surgeon has conducted all pre-operative examinations, the eye is anesthetized with numbing eyedrops, the area around the eye is cleaned, and an instrument called a lid speculum is used to hold the eyelids open. The surgeon will then use a specialized instrument, called a microkeratome, to cut a thin, circular flap - the outermost 20 percent of the thickness of the cornea - to expose the portion beneath. This part of the procedure is called keratectomy.
While the inner cornea (the stroma) exposed, the surgeon will ask the patient to fixate on a specific light source above the patient. This is to ensure that the laser beam is aligned precisely with the center of the patient’s eye. Once the eye is in the correct position, the laser treatment is performed. The computer-controlled excimer laser removes the tissue under the flap and reshapes the cornea of the eye. In less than 60 seconds, ultraviolet light and high-energy pulses from the excimer laser reshape the internal cornea with accuracy up to 0.25 microns, or 1/4000 of a millimeter.
After the pulses of laser energy vaporize the corneal tissue, the flap is put back into its original position. The surgeon will observe the eye for three to five minutes to ensure bonding. Because the cornea bonds quickly, healing is rapid, and the eye does not require stitches.
Is LASIK painful?
The procedure is painless, however, most people experience 4-6 hours of mild irritation after their LASIK procedure. If your treatment is PRK then, although the procedure is painless you will experience a moderate amount of discomfort as the surface of the eye is healing. This usually last 3-4 days and is managed by wearing a soft “bandage” contact lens and by using mild pain relievers through this period.
How long does the procedure take?
The laser treatment itself usually takes less than a minute, while the entire procedure takes around 15 minutes per eye.
How long must people wait to resume normal activities after LASIK treatment?
In most cases, people can return to work within 1-3 days following LASIK surgery. Excluding the day of surgery itself, people may begin driving as soon as they see well enough. Women can start wearing makeup within two to three days of treatment, however, they are advised to wear only new cosmetics in order to decrease risk of infection.
Will a person’s vision remain stable long after the procedure?
The vision correction is permanent. However, a person’s vision may change naturally with time and LASIK does not affect visual conditions that may develop with age. Also, LASIK does not prevent presbyopia and the eventual need for reading glasses. Depending on the cause, retreatment may be a viable solution to later vision changes, and other treatment options also exist.
What is PRK?
Photorefractive keratectomy, or PRK, is a type of laser eye surgery very similar to LASIK. It uses the same type of laser, and differs only in the method used to remove the top layer of the cornea (front surface of the eye) prior to the laser treatment. While in LASIK a thin flap is lifted from the cornea so the laser can treat the central corneal tissue; in PRK the top layer (epithelial layer) of the cornea is gently removed or polished from the surface prior to the laser treatment to reshape the underlying corneal surface. In both cases topical eye drops are used to anesthetize the eye so the procedures are completely painless.
Am I a candidate for PRK?
The requirements for PRK are much the same as LASIK. (See What is LASIK) In some cases PRK is the preferred method if your corneas are too thin to perform the LASIK procedure and for some types of corneal
What can I expect during this procedure?
This procedure is done under local anesthesia, using eyedrops and takes only about 10-15 minutes to complete both eyes. During PRK, your eye doctor uses a laser to reshape the cornea. This laser, which delivers a cool pulsing beam of ultraviolet light, is used on the surface of the cornea not underneath the cornea, as in LASIK.
What should I expect after surgery?
A bandage contact lens will be applied immediately after the procedure. This contact lens is usually worn for the first 3 to 4 days to allow the surface of the eye to heal. You should expect to visit you're your eye doctor at several times during the first 6 months after surgery, with the first visit being the day after surgery. These appointments are very important in monitoring your progress and the healing of your eye. Once the surface of the eye is healed, the bandage contact lens is removed.
Your vision may fluctuate between clear and blurry for the first few weeks following surgery and you may need to wear glasses for night driving or reading until your vision stabilizes. Your eyes will usually feel dry following both PRK and LASIK and your eye doctor will give you prescription eye drops to prevent infection and keep your eyes moist. These drops may cause a slight burn or momentary blurring of your vision upon using them. Your vision will gradually improve, allowing you to drive a car within one to two weeks following surgery. Your best vision, however, may not be obtained for up to 6 weeks to 6 months following surgery.
For more information associated with the risks and benefits of LASIK please visit www.fda.gov/cdhr/lasik and for more information about the risks and benefits associated with a treatment with the ALLEGRETTO WAVE system, please visit www.highperformancevision.com/information.
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