| How To Combat Epithelial Ingrowth After A Lasik Surgery
June 10, 2009 at 3:21 pm
|
| One well known complication of Lasik Surgery is Epithelial Ingrowth. Epithelium is the very fast growing cell layer that covers the eye. Actually, there is an epithelium that covers every part of the outside of your body. It is rapidly growing and constantly shedding and renewing itself throughout your lifetime. The epithelium should remain on the very outer surface of the body, but at times we can see it grow beneath the surface where it becomes trapped and cannot properly shed and renew itself. On the skin, epithelial ingrowth appears as a cyst or bump and has only a cosmetic consequence.
Epithelial ingrowth can happen on the eye after Lasik surgery as well. The act of creating the flap creates a space beneath the corneal surface into which epithelium can potentially grow. Epithelial ingrowth is actually very uncommon after an initial Lasik surgery but the risk increases with a second treatment. Lifting the flap again generally requires more manipulation of the flap edge which may lead to the increased risk of introducing epithelial cells beneath the flap. Surgeons are generally very careful to examine the cornea bed and under-surface of the flap to look for signs of epithelium, but still some cases of ingrowth will occur.
If there is significant epithelium growing beneath the flap, it may have to be removed. The traditional way to remove epithelium is to lift the flap and use a surgical spatula to scrape it out. Some surgeons use alcohol to treat the area as well to kill any microscopic remnants. If the epithelial ingrowth has a tendency to recur, it may be necessary to place sutures in the area to try and seal off a tract or pathway that has formed where epithelium is passing under the flap. Unfortunately, the act of lifting the flap itself is a source for potentially more epithelium ingrowth in the same or other spots.
Sometimes, there is a simpler method to kill the epithelium even without lifting the flap. Laser energy from a YAG or Argon laser can be directed at the area of the ingrowth. The epithelium absorbs the laser energy and is disrupted by it. In many cases, depending on the amount of epithelial ingrowth, it can be disrupted enough to cause it to stabilize or regress entirely. These lasers are different than the lasers used for the actual Lasik surgery and have been around for many decades before Lasik was even conceived.
The technique of using laser energy on epithelium is actually many decades old and was used as a method to whiten or delineate epithelial ingrowth in cases when it grew deep inside the eye itself rather than only beneath a corneal flap. The advantage of using a laser technique to treat the epithelial ingrowth is that no flap lifting is required. This tends to be gentler on the flap keeping it smoother and more regular in appearance. It also minimizes the risk of new ingrowth at other adjacent areas. Although the laser technique doesn't always work, because of its simplicity, it is usually worth the attempt prior to trying more invasive methods.Dr. John Suson MD is an ophthalmologist and a clinical instructor at the Medical College of Wisconsin. Currently, Dr. Suson is in private practice with his sister at their Suson Eye Specialists Clinic. Laser eye surgery is only one of the many procedures that Dr. Suson offers. Eye health and care are both a family tradition and lifelong passion for Dr. Suson. Article Source: ArticleSpan |
| Explaining The Flap In Lasik Eye Surgery
June 10, 2009 at 3:00 pm
|
| Refractive surgery has evolved greatly over several decades. Surgery to correct nearsightedness first took root and began to flourish as Radial Keratotomy (RK) during the 1970s and 1980s in the United States. This surgery required full thickness cuts with a diamond blade through the cornea. As technology developed, the laser was developed and the era of refractive surgery was born.
Today, Laser refractive surgery has reached its pinnacle in Lasik. Lasik has been termed the "flap-and-zap" surgery because it requires the creation of a flap of corneal tissue. This flap is gently lifted out of the way and the laser "zaps" the remaining cornea to reshape it and eliminate the patient's nearsightedness, farsightedness, or astigmatism.
Although, Lasik surgery has now become the most common refractive eye surgery, many people do not understand why the flap is so important and how it came into practice. Originally, Laser refractive surgery came into being as PRK (Photorefractive Keratectomy). PRK is simply Lasik without a flap. To perform PRK, the outer cellular layer (epithelium) of the cornea is stripped off of the eye by mechanical or laser scraping, or by use of alcohol. Over the course of a few days after the procedure, this epithelium grows back to provide a protective layer and a smooth optical surface.
Lasik was developed in order to avoid stripping off the epithelium by creating a flap of surface tissue that is lifted out of the way and then replaced after the laser reshaping. Although it adds an additional surgical step, it provides significantly faster healing, less pain, and a much speedier recovery of vision for the patient.
The original tool to create the flap is called a microkeratome and was used for many years in a surgery called Automated Lamellar Keratoplasty (ALK). In ALK surgery, the microkeratome was used to create a tissue flap and then a second microkeratome cut was made to remove corneal tissue to eliminate nearsightedness. The microkeratome uses a high speed vibrating razor blade and plates of varying thickness to make cuts in the cornea. The concept was very similar to Lasik except that there was no laser involved. In ALK, a mechanical microkeratome was used both to create the flap and also to make a "refractive cut," thus altering the optics of the eye. The marriage of the ALK flap making microkeratome with the PRK laser technology is what gave genesis to Lasik surgery.
ALK lacked the precision for the optics that could only be achieved with a laser. By uniting the flap technology and the laser technology, we were able to have surgical outcomes that were both relatively precise as well as fast healing.
Most recently, we have been able to do away with the mechanical microkeratomes entirely. The development of the femtosecond lasers like the Intalase FS Laser allowed us to have the same laser precision and safety for the creation of the Lasik flap as well as for the laser optical correction. The same logic that lead surgeons to abandon the ALK technology for the excimer laser also lead us to abandon the ALK technology for flap creation once the laser technology was fully developed.
Today, we are able to perform a "flap-and-zap" technique which is fully laser based without the imprecise mechanical razor bladed microkeratomes of old. This pinnacle of technology allows us to treat with a level of confidence and precision that was never dreamed of in the ALK era and could never be accomplished using that old style equipment. The benefits to patients are impressive. The all Laser era has truly delivered a faster healing, more precise, and safer refractive eye surgery.Dr. John Suson MD is an ophthalmologist and a clinical instructor at the Medical College of Wisconsin. Currently, Dr. Suson is in private practice with his sister at their Suson Eye Specialists Clinic. Laser eye surgery is only one of the many procedures that Dr. Suson offers. Eye health and care are both a family tradition and lifelong passion for Dr. Suson. Article Source: ArticleSpan | | | 
|
No comments:
Post a Comment