Complications of laser-assisted in situ keratomileusis

Abstract

Laser-assisted in situ keratomileusis (LASIK) is one of the most commonly performed kerato-refractive surgery globally. Since its introduction in 1990, there has been a constant evolution in its technology to improve the visual outcome. The safety, efficacy, and predictability of LASIK are well known, but complications with this procedure, although rare, are not unknown. Literature review suggests that intraoperative complications include suction loss, free cap, flap tear, buttonhole flap, decentered ablation, central island, interface debris, femtosecond laser-related complications, and others. The postoperative complications include flap striae, flap dislocation, residual refractive error, diffuse lamellar keratitis, microbial keratitis, epithelial ingrowth, refractive regression, corneal ectasia, and others. This review aims to provide a comprehensive knowledge of risk factors, clinical features, and management protocol of all the reported complications of LASIK. This knowledge will help in prevention as well as early identification and timely intervention with the appropriate strategy for achieving optimal visual outcome even in the face of complications.

Keywords: Diffuse lamellar keratitis; LASIK complications; LASIK; refractive surgery; epithelial ingrowth; flap-related complications; laser in-situ keratomileusis; laser vision correction.

Figure 1

Flowchart showing the various complications of LASIK

Figure 2

(a) Slit-lamp photograph of the right eye of a patient on day one after femtosecond LASIK showing subconjunctival hemorrhage and interface bleed; (b) Intraoperative image showing a peripheral asymmetric tear meniscus during femtosecond LASIK indicating suction loss resulting in incomplete flap formation

Figure 3

Intraoperative image showing (a) a peripheral flap tear (black arrow); (b) a buttonhole flap (yellow arrow)

Figure 4

Intraoperative image showing (a) vertical gas breakthrough appearing as a dark patch (black arrow) and opaque bubble layer appearing as white stromal opacification (red arrow); (b) air bubbles in anterior chamber obscuring the pupil

Figure 5

Slit-lamp photograph showing a cotton fiber in the LASIK interface

Figure 6

Slit-lamp photograph showing (a) flap striae in the visual axis one week following LASIK; (b) resolution of flap striae after flap lift and ironing out the striae

Figure 7

(a) Slit-lamp photograph showing central circumscribed scarring with striae suggestive of central toxic keratopathy; (b) ASOCT showing an inverse dome-shaped homogenous hyperreflectivity; Slit-lamp photograph showing (c) inflammatory cells extending from periphery suggestive of diffuse lamellar keratitis (DLK) stage 1; (d) central involvement of inflammatory cells with “sands of Sahara appearance” suggestive of DLK; (e) both peripheral and central involvement of inflammatory cells suggestive of DLK stage 2

Figure 8

Slit-lamp photograph showing (a) central corneal infiltrate in the interface three weeks following LASIK suggestive of microbial keratitis; (b) signs of resolution of keratitis with residual corneal scarring after flap amputation and three months of anti-fungal therapy given based on the microbiological report that showed filamentous fungi

Figure 9

Slit-lamp photograph of (a) the right eye two years after LASIK showing white opacity extending up to 2 mm inside from the flap edge suggestive of grade 2 epithelial ingrowth; (b) ASOCT image of the same eye showing increased flap thickness with interface hyperreflectivity; (c) the left eye with white opacity extending beyond 2 mm of the flap edge suggestive of grade 3 epithelial ingrowth; (d) ASOCT image of the same eye showing increased flap thickness with interface hyperreflectivity

Figure 10

Slit-lamp photograph showing LASIK flap, steep corneal contour with central corneal thinning suggestive of post-LASIK corneal ectasia