LASIK Interface Complications: Etiology, Management, and Outcomes

Abstract

The anatomy of the LASIK interface allows for a variety of potential complications to arise, unique etiologies with overlapping clinical presentations. Primary interface complications include infectious keratitis, diffuse lamellar keratitis (DLK), central toxic keratopathy (CTK), pressure-induced stromal keratopathy (PISK), and epithelial ingrowth. Infectious keratitis is most commonly caused by Methicill in resistant S. aureus (early onset) or atypical Mycobacterium (late onset) postoperatively, and immediate treatment includes flap lift and irrigation, cultures, and initiation of broad-spectrum topical antibiotics, with possible flap amputation for recalcitrant cases. DLK is a white blood cell infiltrate that appears within the first 5 days postoperatively and is acutely responsive to aggressive topical and oral steroid use in the early stages but may require flap lift and irrigation to prevent flap necrosis if inflammation worsens. In contrast, PISK is caused by acute steroid response and resolves only with cessation of steroid use and IOP lowering. Without appropriate therapy PISK can result in severe optic nerve damage. CTK mimics stage 4 DLK but occurs early in the postoperative period is non-inflammatory. Observation is the only effective treatment, and flap lift is usually not warranted. Epithelial ingrowth is easily distinguishable from other interface complications and may be self-limited or require flap lift to treat irregular astigmatism and prevent flap melt. Differentiating between interface entities is critical to rapid appropriate diagnosis, treatment, and ultimate visual outcome. While initial presentations may overlap significantly, the conditions can be readily distinguished with close follow-up and most complications can resolve without significant visual sequelae when treated appropriately.

Therapeutic Flap Amputation for Atypical LASIK Flap and Interface Abnormalities

“…The LASIK interface, within the stromal bed, provides a novel site for infection, inflammation, and epithelial cell ingrowth. 1 Limited wound healing occurs after the creation of the flap. 2 This facilitates flap lift for re-treatments.…”

Corneal Densitometry as a Tool to Measure Epithelial Ingrowth After Laser In Situ Keratomileusis

“…A category of these complications includes those that occur within the flap interface. While the flap adheres to the stromal bed after surgery, there is a space created between the two that has potential for a number of pathologies (Randleman and Shah, 2012).…”

“…Epithelial ingrowth (EI) is the least common of the complications that can occur at the flap interface (Randleman and Shah, 2012). The incidence of epithelial ingrowth occurring after primary LASIK varies in the literature.…”

Pressure-Induced Stromal Keratopathy as a Result of Ocular Trauma After Laser In Situ Keratomileusis

“…The amount of fluid present may be relatively small, resulting in diffuse haziness in the interface, or it may be pronounced, resulting in a visible fluid cleft separating the anterior flap from the posterior residual bed. 1 Cessation of steroid use and IOP lowering are common treatments for PISK, and the results are usually good. 1,3 Here we describe the clinical features and treatment of 2 cases of PISK due to traumatic hyphema in post-LASIK eyes.…”

“…Multiple names, including pressure-induced stromal keratitis, pressureinduced interface keratitis, and interface fluid syndrome, have been given to the various manifestations of this condition. 1,2 It is usually related to increased intraocular pressure (IOP) following topical steroid treatment postoperatively, which causes marked posterior stromal edema and diffusion of aqueous humor across the stroma into the interface. The amount of fluid present may be relatively small, resulting in diffuse haziness in the interface, or it may be pronounced, resulting in a visible fluid cleft separating the anterior flap from the posterior residual bed.…”