Vision outcomes favorable after late flap dislocation

June 1, 2008

A review of four cases of trauma-induced flap dislocation occurring 8 to 10 years post-LASIK highlights the risk of this phenomenon and demonstrates the potential for good vision outcomes.

Chicago-Late LASIK flap dislocations are rare, but when they occur, outcomes generally are good, even when there is a delay in receiving medical attention, said Angie E. Wen, MD, at the annual meeting of the American Society of Cataract and Refractive Surgery.

"Flap lifts and enhancements can be performed many years after LASIK because wound healing occurs primarily at the flap edge and minimally in the lamellar interface," said Dr. Wen, instructor in clinical ophthalmology, Columbia University, New York.

"However, this also leaves LASIK patients vulnerable to flap dislocations even many years after the procedure.

"We believe patients should be counseled regarding this risk, especially if they have occupations or hobbies that place them at increased risk for ocular trauma," Dr. Wen said. She reported a case series of four eyes with late traumatic flap dislocation that presented to the Harkness Eye Institute, Columbia University, New York. The eyes were 8 to 10 years post-LASIK.

"Most LASIK flap dislocations occur within the first few days after surgery or at least within the first week," Dr. Wen said. "In a search of the literature, we found fewer than 30 cases of late flap dislocation, and most of these occurred within the first 2 to 3 years postoperatively."

The triggers for the late flap dislocations in the Harkness Eye Institute series included contact with a baby's finger or the edge of a map, falling on a deck, and alleged assault. The involved patients ranged in age from 29 to 70 years, and all had a history of bilateral myopic LASIK performed using a bladed microkeratome for flap creation.

Case history

Two patients had successful, uncomplicated outcomes after LASIK, one underwent bilateral enhancement after 1 year, and one patient remained myopic and used full-time refractive correction.

Two patients sought and received medical care within 24 hours after the flap dislocation, one patient delayed seeking care for 6 weeks, and one dislocation, which was subtle and initially missed, was treated after being referred for epithelial ingrowth noted 1 month post-trauma.

All cases were managed with lifting, debridement, stretching, and irrigation of the corneal flap.

The epithelium was recessed 1 mm in the area of the dislocation to reduce epithelial ingrowth risk.

Three of the procedures were performed at the excimer laser microscope and one at the slit lamp. The latter case involved a patient who presented to the emergency room at 1 a.m., 12 hours after the trauma that caused the flap dislocation.

"Because of the delay, we decided to attempt repositioning at the slit lamp, and this was done carefully using balanced salt solution and [cellulose sponges (Weck-Cel, Medtronic)] to edge the flap out until it unrolled," Dr. Wen said. "This patient did well, and we believe repositioning of the flap at the slit lamp can be considered in cases where access to the operating room or a laser suite would result in significant further delay and, therefore, increase the risk of fixed folds or diffuse lamellar keratitis.

"However, each case should be evaluated individually," she said.

"If the repositioning is anticipated to be complicated, the extra control afforded by the superior optics of the operating microscope may be desirable," she added.

Outcomes

Three of four eyes regained predislocation best-corrected visual acuity, including two eyes in which uncorrected visual acuity of 20/20 or better was achieved. In one patient with a history of alleged assault, vision remained counting fingers. The poor vision in the latter case was considered due to keratectasia-associated irregular astigmatism because the flap was well repositioned, and no residual striae or haze were seen.

"The relationship between ectasia and flap dislocation is unclear and requires further research," Dr. Wen said.OT