This patient presented with an epithelial ingrowth following LASIK that was repeatedly treated by flap lifting or scraping the growing epithelium, and repeatedly relapsed after all the procedures were performed. This is typical in such cases, and the patient is lucky not to have further problems and further corneal irregularity caused by the multiple procedures that have been performed.
Fortunately, the patient has good visual acuity and the topography is not so irregular. The redness and irritation are to be attributed to the chronic irritation that the ingrowth is causing. This does not happen in all these cases but indeed it is the most probable cause of this patient's symptoms.1 The aspect of the epithelial ingrowth is the one in which mucin productive and non-productive epithelial cells are involved in the ingrowth.
The patient shows an epithelial fistula between 8 o'clock and 10:30. In this area, the repeated flap elevations have been unable to close the fistula, which can only be closed by suturing the flap. This is the reason that when a case of post-LASIK epithelial ingrowth is referred to me with a relapse affecting the vision, I always perform a maneuver in which I clean the flap with hypotonic (distilled) water to detach the epithelial cells located at the interface and to avoid the scraping, which can induce further scarring. I do not use alcohol as a cytocidal agent, and MMC is useless in these cases.
However, for this patient I do not recommend further surgery at present because the pupillary area is respected and the patient shows good vision. Corneal irregularity only affects the mid-peripheral cornea. The most adequate treatment in this case is the one we described some time ago using neodymium:YAG (Nd:YAG) laser epitheliolysis to eliminate these cells.2 The technique is as follows: the Nd:YAG laser is set to the minimum energy possible (starting from 0.1 mJ and 50 μm) and focused at the level of the corneal epithelial ingrowth. Then, the Nd:YAG laser is shot at the center of the sheet of the ingrowth cells until a small bubble is created. This marks the level of cavitation that is necessary to get into the interface. Next, I randomly create bubbles along the ingrowth epithelium starting from the periphery of the flap and the minimum energy again. The overuse of Nd:YAG energy might cause a flap perforation at the center.3 Therefore, I start with a few shots at a distance apart of 2 diameters of the initial bubble. The destructive effect on the epithelial ingrowth corresponds to the physical destruction of the cells at the impact, and then the cells are also destroyed later as they become apoptotic and disappear without the direct effect of the impact. I then put the patient on topical soft steroids (FLM or Lotemax) and schedule for another follow-up in 6 weeks. At this time, the effect is evident because all the cells surrounding the impact have disappeared and a faint leucoma is seen with biomicroscopy. After this effect is observed, the physician should decide whether it is sufficient to complete the treatment. The purpose is to eliminate the epithelial cells that are at the edge of the pupil and to close the fistula. This technique works especially well when non-mucin productive epithelium is growing at the LASIK interface, and it is less effective in cases with mucin-productive epithelium.
Since we published our report,2 we have performed this in hundreds of cases. Other surgeons are also performing it1 and even though some studies have reported complications such as flap rupture,3 this only happens when you overuse the energy. This is the best treatment and indeed this patient's symptoms and corneal regularity will improve remarkably with no further risk for complications.
Tamayo G, Castell C, Vargas P. Epithelial ingrowth. Alio JL, Azar D, editors. Management of Complications in Refractive Surgery. 2nd ed. Cham, Switzerland: Springer International; 2018: pp. 117-121.
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
Lapid-Gortzak R, Hughes JM, Nieuwendaal CP, Mourits MP, van der Meulen IJE. LASIK flap breakthrough in Nd:YAG laser treatment of epithelial ingrowth. J Refract Surg