This article is more than 5 years old. Information may no longer be current.
Epithelial ingrowth after LASIK can be treated effectively
The goal of surgical treatment is to remove the epithelial ingrowth, restore smoothness to the stromal interface and close the fistula.
Click Here to Manage Email Alerts
LASIK has transformed refractive surgery because it is safe, accurate and provides a near-instant recovery of sharp vision. But it is not without potential complications, which can happen intraoperatively as well as during the postoperative healing period.
And it is the patient’s variable healing response that determines the final status of the eye and the ultimate visual outcome. Epithelial ingrowth is a potential complication during the healing period after LASIK, but it can be effectively treated in most cases.
LASIK flap mechanics
 Uday Devgan |
When the corneal flap is made, either with a microkeratome or a femtosecond laser, a stromal plane is created and the epithelium at the flap edges is dissected. Once the excimer laser ablation is completed, the flap is replaced and it begins to heal. The epithelium regenerates and seals the flap edge; however, it can also start to grow in the stromal interface between the undersurface of the flap and the stromal bed. When the epithelial cells invade the stromal interface, they can cause a fistula to form. Clinically, there can be a sheet of cells, focal clumping of cells, epithelial pearl formation and a demarcation line in the flap, just central to the edge of the epithelial ingrowth.
Epithelial ingrowth is frequently seen after there has been trauma to the LASIK flap from patient activities in the postop period. Risk factors include epithelial basement membrane dystrophy, diabetes, older patient age, flap edema, irregular flap and flap striae. It is also more common after enhancement LASIK procedures because the epithelial layer is not as sharply demarcated as when it was cut during flap creation of the initial procedure. Any loose tags of epithelium must be carefully moved away from the flap edge when the LASIK flap is replaced to minimize the risk of future epithelial ingrowth.
Effect on vision
Mild epithelial ingrowth usually has minimal or no effect on the vision because it is far from the visual axis. With mild cases of epithelial ingrowth, careful observation and monitoring of the patient may be all that is required. In most cases, the ingrowth will not progress and it will stay locally confined. However, if these epithelial cells continue to proliferate within the stromal interface, they can lift the flap, induce astigmatism, cause corneal irregularities, invade the visual axis and cause poor quality of vision. This results in decreased visual acuity and higher risk of further issues if not appropriately addressed.
If the epithelial ingrowth appears focal and stable, the patient should be carefully evaluated for subtle refractive changes. Corneal topography and a meticulous refraction can pick up early astigmatic changes at the axis of the ingrowth. Detailed clinical drawings or slit lamp photos are done to document the extent of the ingrowth for comparison at future visits. If the epithelial ingrowth is extensive, expanding or responsible for a decrease in vision, it needs to be addressed surgically.
 This patient had recurrent, extensive epithelial ingrowth, seen best temporally, but extending all the way to the nasal cornea. This created a large degree of astigmatism and an irregular corneal surface, requiring surgical treatment. |
 After the epithelial cells were meticulously removed from the stromal bed and underside of the flap, multiple 10-0 nylon sutures were used to firmly seal the flap into position to help avoid future ingrowth. Images: Devgan U |
Surgical treatment
Small, peripheral areas of epithelial ingrowth can be treated with the Nd:YAG laser, whereas larger, more central ingrowth requires flap lifting. The goal of the surgical treatment is to remove the epithelial ingrowth, restore smoothness to the stromal interface to improve the vision and close the fistula to prevent future ingrowth. The LASIK flap edge can be seen and marked at the slit lamp before going to the operating suite for the surgical removal of the ingrowth.
The edge of the flap can then be scored using a small semi-sharp instrument such as a Sinskey hook to separate the epithelium. The flap is carefully lifted and then time is spent debriding epithelial cells from the stromal bed, as well as the underside of the LASIK flap. This can be done using a spatula, a scraping device, firm microsponges or other mechanical means. The use of caustic or chemotherapeutic agents is not typically required because these cells are of normal, not neoplastic, morphology. When the flap is repositioned, it is irrigated sufficiently and care is taken to keep any loose epithelial tags away from the interface or flap edge. A bandage contact lens can help to keep the flap held firmly in position and may serve as scaffolding for epithelial healing.
Recurrent epithelial ingrowth
If the epithelial ingrowth recurs, the treatment becomes more difficult because the fistula is still open and may be even more extensive. When the flap is lifted again, the debridement must be even more meticulous, with care taken to perform multiple passes over the stromal bed, as well as the undersurface of the flap. Epithelium can be scraped back, away from the flap edge, and then the flap can be repositioned.
To keep the stromal interface tightly sealed, sutures can be placed. These should be interrupted 10-0 nylon sutures placed in a radial manner and with a tension sufficient to keep the flap edge tightly sealed. The sutures are rotated to bury the knots and are left in position for at least a few weeks, if not longer. Because these sutures are holding the flap taut, they can induce temporary astigmatic changes, which cause blurred vision during the healing time. Once the sutures are removed, the astigmatic effect is minimized and the patient recovers sharper vision. In most cases, epithelial ingrowth after LASIK can be successfully treated, and the patient can achieve good vision as originally intended.
References:
- Agarwal A. Refractive Surgery Nightmares. Thorofare, NJ: SLACK Incorporated; 2007.
- Ayala MJ, Alió JL, Mulet ME, De La Hoz F. Treatment of laser in situ keratomileusis interface epithelial ingrowth with neodymium:yytrium-aluminum-garnet laser. Am J Ophthalmol. 2008;145(4):630-634.
- Uday Devgan, MD, FACS, is in private practice at Devgan Eye Surgery in Los Angeles, Beverly Hills, and Newport Beach, California. Dr. Devgan is Chief of Ophthalmology at Olive View UCLA Medical Center and an Associate Clinical Professor at the Jules Stein Eye Institute at the UCLA School of Medicine. Dr. Devgan can be reached at 11600 Wilshire Blvd., Suite 200, Los Angeles, CA 90025; 800-337-1969; fax: 310-388-3028; e-mail: devgan@gmail.com; Web site: www.DevganEye.com. Dr.Devgan is a consultant to Abbott Medical Optics and Bausch & Lomb, and is a stockholder in Alcon Laboratories and formerly in Advanced Medical Optics.
