DLK a lifelong risk in post-LASIK eyes

Miami-Although post-LASIK diffuse lamellar keratitis (DLK) typically develops in the early postoperative period, it is important to be aware that late-onset DLK can occur, said William B. Trattler, MD.

Dr. Trattler, a corneal specialist at Miami’s Center for Excellence in Eye Care, presented results from a two-center chart review that was conducted to identify cases of late DLK, defined as onset later than 1 month post-LASIK. Fifteen cases were found, including five that were stage I and 10 that were stage II, based on the Linebarger classification system. Time to presentation ranged from 43 days to 8 years after LASIK.

“The findings of this study suggest that DLK may be a lifelong risk for patients who have undergone LASIK,” Dr. Trattler said. “Awareness of this potential situation is critical both among patients who have had LASIK and the emergency room personnel who may be the first to see them in order to enable prompt referral to an ophthalmologist.

“Slit lamp exam is obviously required to identify late DLK and start treatment to minimize the risk for severe cornea damage and vision loss associated with delayed diagnosis and treatment,” he said.

Results from a study by investigators at the Emory Eye Center, Atlanta, explain the potential for the development of late DLK. Measuring cohesive tensile strength in post-LASIK and normal, unoperated cadaver eyes, the researchers found the mean peak tensile strength of the central and paracentral LASIK wounds was only about 2.4% of the controls, regardless of the time since surgery [Schmack et al. J Refract Surg 2005;21:433-445].

“Such low adhesion allows fluid and inflammatory cells to aggregate easily in the flap interface when there is trauma, inflammation, or infection,” Dr. Trattler said. “It also explains why elevated IOP is a potential cause of late DLK or the so-called pressure-induced stromal keratitis, which is characterized by fluid in the interface.”

Discerning features, outcomes

To describe the features and outcomes of eyes with late DLK, charts were reviewed from the cornea services at the Center for Excellence in Eye Care and Davis Duehr Dean, Madison, WI. Of the 15 cases identified, 12 patients had undergone surgery at a different center. The patients had an average age of 45 years (range, 31 to 62 years) and two-thirds were men.

Trauma was the most common etiology and accounted for 10 (67%) of the 15 cases. In five of the trauma-related cases, poking by a branch or plant was the inciting cause. The DLK was inflammation-related in four eyes. Two of the latter eyes were accounted for by a single patient who developed corneal abrasions while wearing contact lenses because of post-LASIK ectasia. In one eye, the DLK was associated with infection.

Intervention included combination treatment with topical antibiotics and steroids in most cases. In two eyes where trauma induced the late DLK, epithelial ingrowth developed and required surgical intervention.

Mean ± SD time to resolution of late DLK was 29 ± 22 days. Fourteen eyes recovered 20/20 or better best-corrected visual acuity (BCVA). The single eye that lost BCVA occurred in a patient who had recently sustained severe ocular trauma with vitreous hemorrhage but was lost to follow-up.

“We expected the patient would regain BCVA, but if not, that the loss would be related to retinal issues and not DLK,” Dr. Trattler concluded.OT