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Histopathological analysis of post-laser-assisted in situ keratomileusis corneal ectasia with intrastromal corneal ring segments.

Keratectasia, an acquired, noninflammatory, outward bulging of the cornea, is associated with a progressive myopic shift in refraction, irregular astigmatism, corneal thinning, and scarring. It generally occurs in the thinnest portions of the cornea, with a central or inferonasal paracentral predilection; however, it may occur elsewhere. Ocular surgical procedures, particularly lamellar refractive surgery (eg, laserassisted in situ keratomileusis [LASIK]), have been known to induce corneal ectasia. Because the flap produced by LASIK never completely heals, the residual bed likely provides most of the support to maintain corneal shape and function, and keratectasia occurs when the residual bed is unable to provide this support. The 2 main risk factors for post-LASIK keratectasia are a residual corneal bed of 250 μm or less and keratoconus. Although post-LASIK corneal ectasia may be managed conservatively with rigid gas-permeable lenses, this nonsurgical treatment option may fail or may represent an unacceptable alternative for patients who underwent refractive surgery. In such cases, penetrating keratoplasty has been the principal surgical treatment. Recently, however, intrastromal corneal ring (ICR) segments have shown promise as an alternative surgical option. We describe a unique case of visually significant post-LASIK corneal ectasia initially managed with ICR segments that subsequently progressed, thus requiring penetrating keratoplasty.