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 after LASIK surgery
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 surgery but the risk increases with a second treatment.
Relifting the flap 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 undersurface of the flap to look for signs of epithelium, but still some cases of ingrowth will occur.
Sometimes, if the amount of a retreatment is low, I will choose to forgo the flap lift and simply do a direct laser treatment to the surface of the cornea itself. This method is a bit of a trade off because although it is simpler and avoids potential epithelial ingrowth, the rate of healing and vision recovery is slower. Also, blade free flap makers have a much lower incidence of epithelial ingrowth.
That would be expected because there is no physical blade traveling under the flap to potentially drag epithelium and cause ingrowth. That’s one of the reasons that I use the Intralase FS™ system to make flaps.
After the LASIK surgery
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, I think it is usually worth the attempt prior to trying more invasive methods.