Man reports unilateral decreased vision and pain after trauma

On examination, areas of haze and focal whitening were noted under his LASIK flap.

Priti Batta

Namrata Nandakumar

A 46-year-old man was recently seen in our eye clinic for decreased vision and pain in the right eye. About 6 months prior, he was hit in the right eye with a lacrosse stick. He was evaluated at that time by another ophthalmologist, who noted a superficial corneal laceration and surrounding stromal inflammation. The ophthalmologist started the patient on hourly topical antibiotics and steroids, and the patient was soon lost to follow-up. He eventually presented to our clinic with worsening blurry vision and pain. He reported that he was still taking the drops prescribed by the previous ophthalmologist, but only as needed for pain.

The patient had a history of myopic LASIK done in both eyes 6 years prior. He had no significant medical history and no other history of surgeries. He was not taking any medications aside from occasional use of topical Zymar (gatifloxacin, Allergan) and difluprednate eye drops. He worked as a college lacrosse team coach. He denied alcohol, tobacco or illicit drug use.

On examination, his uncorrected vision was 20/200 in the right eye and 20/20 in the left eye. Manifest refraction yielded a visual acuity of 20/80 in the right eye with a –2.25 D spherical lens. His pupils were equal and reactive, with no afferent pupillary defect. Extraocular motility and confrontational visual field testing were within normal limits. IOPs were 14 mm Hg and 13 mm Hg in the right and left eyes, respectively. External examination was unremarkable.

Slit lamp examination of the anterior segment of the right eye revealed central displacement of the nasal part of the LASIK flap, as well as diffuse interface haze and a focal area of irregular whitening within the interface (Figures 1 and 2). He also had trace injection in the right eye and mild nuclear sclerotic cataracts in both eyes. His fundus examination was within normal limits.

Figures 1 & 2. Slit lamp photographs of patient’s right eye. Note the nasal LASIK flap dislocation, interface haze and focal area of whitening at the 6 o’clock position under the flap. Images: Batta P, Wu HK

What is your diagnosis?

LASIK interface haze with an area of focal whitening

It is extremely rare to have flap and interface complications so many years after LASIK, which makes this case unusual. However, when such complications do occur, they are almost always caused by direct trauma to the flap, as was the case with this patient.

Flap dislocation usually occurs within 24 hours postoperatively. The rate of immediate flap dislocation is up to 2% and typically occurs secondary to the mechanical action of the eyelids, causing displacement of the flap. Late traumatic flap dislocation is less common and usually occurs within 6 months of LASIK. On examination, the presence of flap dislocation can be easily diagnosed: The flap appears irregular, and the flap edge may be seen folded or rolled under the flap.

This patient was also noted to have an area of whitening in the interface as well as more diffuse surrounding interface haze. Several conditions may explain these findings. Diffuse lamellar keratitis is a well-known LASIK complication characterized by the accumulation of inflammatory cells within the interface. It typically appears within 1 week of LASIK surgery. The cause of diffuse lamellar keratitis is usually difficult to identify, but it is more likely to occur in the presence of an epithelial defect.

Epithelial ingrowth is another rare complication that can cause focal interface whitening. This condition is defined as an aberrant proliferation of epithelial cells in the interface. Two primary mechanisms have been proposed as the etiology: direct implantation of epithelial cells in the interface during LASIK or due to flap trauma, or postoperative migration of cells via a fistulous tract from the LASIK flap edge. Risk factors for epithelial ingrowth include epithelial compromise, flap dislocation, flap re-treatments and diffuse lamellar keratitis. On examination, epithelial ingrowth appears as focal, well-circumscribed white sheets or pearls.

Finally, infectious keratitis is relatively uncommon after LASIK. Gram-positive organisms are the most frequent cause of infectious keratitis occurring within 1 week of LASIK, while delayed cases (up to several weeks after LASIK) are often attributable to fungal or mycobacterial causes. Late infectious keratitis can occur after trauma. On examination in cases of infectious keratitis, a focal infiltrate may be seen, with or without accompanying diffuse lamellar keratitis.

Diagnosis and management

Figure 3. Slit lamp photograph of patient’s right eye after treatment. There is reduced epithelial ingrowth but persistent interface haze.

This patient experienced several unfortunate complications of LASIK related to a traumatic injury to his right eye, worsened by poor compliance and follow-up. The “corneal laceration” noted by the previous ophthalmologist was actually a dislocation of the nasal edge of the flap. The trauma led to diffuse interface inflammation, or diffuse lamellar keratitis, as well as a focal area of epithelial ingrowth at the 6 o’clock position.

Flap dislocation is an emergency, requiring flap repositioning as soon as possible to prevent further complications, such as infection, diffuse lamellar keratitis, fixed folds or loss of the flap. Prior to repositioning the flap, the flap should be carefully irrigated to remove any cells or debris. Management of diffuse lamellar keratitis can be challenging. Administration of corticosteroids, topically and/or orally, remains the first-line treatment. In more severe cases, the flap may have to be lifted, scraped and irrigated in order to remove inflammatory cells. Epithelial ingrowth, when mild and located at the flap edge, can often be asymptomatic and self-limited. If it progresses closer to the center of the visual axis, it can cause irregular astigmatism and block vision. Traditional treatment in these cases requires lifting the flap and scraping the epithelial cells, then repositioning the flap. This can be done alone or combined with alcohol application, as well as suturing or gluing the flap edges. Like diffuse lamellar keratitis, epithelial ingrowth can also be a persistent problem, with high recurrence rates after treatment.

The LASIK flap of this patient was lifted, scraped and repositioned. On the most recent follow-up visit, his uncorrected visual acuity in that eye was 20/60, with best corrected visual acuity of 20/30. Despite the improved visual acuity, he complained of distortion. On examination, he still had persistent epithelial ingrowth and interface haze, but these were improved from previous examination (Figure 3). He is currently being considered for flap amputation.

References:

• Ayala MJ, Alio JL, Mulet ME, De La Hoz F. Treatment of laser in situ keratomileusis interface epithelial ingrowth with neodymium: yttrium-aluminum-garnet laser. Am J Ophthalmol. 2008;145(4):630-634.
• Fagerholm P, Molander N, Podskochy A, Sundelin S. Epithelial ingrowth after LASIK treatment with scraping and phototherapeutic keratectomy. Acta Ophthalmol Scand. 2004;82(6):707-713.
• Kamburoglu G, Ertan A. Epithelial ingrowth after femtosecond laser-assisted in situ keratomileusis. Cornea. 2008;27(10):1122-1125.
• Knorz MC. Flap and interface complications in LASIK. Curr Opin Ophthalmol. 2002;13(4):242-245.
• Li Y, Netto MV, Shekhar R, Krueger RR, Huang D. A longitudinal study of LASIK flap and stromal thickness with high-speed optical coherence tomography. Ophthalmol. 2007;114(6):1124-1132.
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• Narváez J, Chakrabarty A, Chang K. Treatment of epithelial ingrowth after LASIK enhancement with a combined technique of mechanical debridement, flap suturing, and fibrin glue application. Cornea. 2006;25(9):1115-1117.
• Schallhorn SC, Amesbury EC, Tanzer DJ. Avoidance, recognition, and management of LASIK complications. Am J Ophthalmol. 2006;141(4):733-739.
• Tumbocon JA, Paul R, Slomovic A, Rootman DS. Late traumatic displacement of laser in situ keratomileusis flaps. Cornea. 2003;22(1):66-69.
• Vroman DT, Karp CL. Complication from use of alcohol to treat epithelial ingrowth after laser-assisted in situ keratomileusis. Arch Ophthalmol. 2001;199:1378-1379.

• Priti Batta, MD, and Helen K. Wu, MD, can be reached at New England Eye Center, Tufts University School of Medicine, 750 Washington St., Box 450, Boston, MA 02111; 617-636-4219; fax: 617-636-4866; website: www.neec.com.

• Edited by Priti Batta, MD, and Namrata Nandakumar, MD. Drs. Batta and Nandakumar can be reached at New England Eye Center, Tufts University School of Medicine, 750 Washington St., Box 450, Boston, MA 02111; 617-636-4219; fax: 617-636-4866; website: www.neec.com.