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DLK not just an early complication
Dry eye and recurrent corneal erosions may contribute to late-onset DLK.
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KOLOA, Hawaii — Though widely considered an early complication of LASIK, diffuse lamellar keratitis can also occur long after the procedure, according to anecdotal reports.
“Diffuse lamellar keratitis (DLK) may occur beyond the acute postoperative period for months or years. Minimal surface disruption, with or without antecedent trauma, including dry eye and recurrent erosions, may contribute to late-onset DLK.” said Helen K. Wu, MD, an assistant professor of ophthalmology at Tufts University in Boston.
Dr. Wu described two cases of late-onset DLK here at Hawaii 2001, the Royal Hawaiian Eye Meeting, sponsored by Ocular Surgery News in conjunction with the New England Eye Center.
She said it is important to treat LASIK patients who have corneal abrasions with extra care.
“I think it's important to remember that they can develop this complication long after the initial postoperative period. Monitor them more closely for signs of DLK, and we need to be very aggressive again about treating dry eye and possibly recurrent erosions as well to prevent this,” she said.
Etiology unclear
According to Dr. Wu, DLK, also known as sands of the Sahara syndrome, can be caused by an infiltration into the interface of polymorphonuclear leukocytes, as well as multiple other causative agents.
“In terms of clinical signs, the corneal infiltrates are focal and multifocal. They're confined, by definition, to the lamellar interface, and there's no anterior or posterior extension into the stroma. There's no anterior chamber reaction, and it's typically seen in the first postoperative week.” she said.
Dr. Wu said DLK is an uncommon event that has an uncertain cause.
“The etiology is not clear, but it's felt to be a secondary inflammatory response to a variety of agents within the potential space of the flap interface,” she said. “Surface disruption may lead to a potentially severe inflammatory reaction underneath the flap. Typical DLK can be seen anecdotally even up to 2 years following LASIK.”
Two cases
Dr. Wu presented data on two cases of late-onset DLK. The first case was a 48-year-old woman with a history of hypothyroidism who underwent bilateral sequential LASIK.
“We used the (Bausch & Lomb) Hansatome and the (Alcon) Summit Apex Plus excimer laser,” she said. “In each separate eye she had a 50% epithelial defect and she actually did have the typical DLK in the left eye present on postoperative day 1. These defects healed well with bandage soft contact lens wear after a couple of days, and her DLK in the left eye resolved after 1 week of intensive topical fluorometholone treatment.”
One month after the procedure, the patient lost some of her best corrected vision and attributed it to dry eye.
“She had mild punctate epitheliopathy and was noncompliant with her drops, but she didn't want to have lower lid punctal plugs,” Dr. Wu said.
Two months postoperatively, the patient had a sudden onset of redness and foreign body sensation in her left eye. She was found to have a focal 2-mm by 2-mm non-suppurative infiltrate in the lamellar area inferocentrally and mild flap edema.
“We lifted her flap and debrided the infiltrate. We sent the scrapings for cultures and irrigated the interface with fortified vancomycin and tobramycin drops, and a bandage contact lens was applied,” Dr. Wu said. She was treated with hourly topical steroids and antibiotics.
Three weeks after the episode, the patient's uncorrected visual acuity had increased to 20/60, but her best corrected visual acuity had decreased to 20/30 and she had a mild stromal scar and mild flap edema.
“About a year later she remains about like this with best corrected visual acuity between 20/25 and 20/30 with a hyperopic shift,” Dr. Wu said. “In her other eye, 3 months after LASIK, she developed a non-traumatic epithelial abrasion without keratitis and 3 days later this abrasion healed. She also had a diffuse mild interface opacity. She was diagnosed again with DLK, treated with hourly prednisolone and ofloxacin and she resolved without any loss of best corrected vision.”
The second case was a 51-year-old hyperthyroid woman, seen by Roger F. Steinert, MD, who had bilateral LASIK for high myopia. Seven months postoperatively she had a superior conjunctival resection for superior limbal keratoconjunctivitis.
“Three days after this conjunctival resection, she had worsening pain and blurry vision and she had what appeared to be classic DLK,” Dr. Wu said. The patient was treated with hourly prednisolone and ofloxacin and did well, she said.
For Your Information:
- 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) 636-5784; fax: (617) 636-4866.