cisis

Special case: Keratoconus after LASIK

One complication of LASIK surgeries which are used to treat regular myopia is post-LASIK keratectasia. During LASIK surgery the cornea is weakened, because of the open flap creation and the removal of tissue by the Laser. Thus, the cornea starts bulging and thinning exactly the same way which can be observed in keratoconus.

Most frequently, given the lack of available alternatives, surgeons tend to recommend crosslinking for the treatment of post-LASIK keratactasia. In this very specific case, CISIS / MyoRing keratoplasty is, however, clearly the first choice of treatment

Why?

While Crosslinking can stop the progression of a “normal” keratoconus, this does not apply in the same way to post-LASIK keratectasia. This difference in therapy options is caused by the flap which is created during LASIK treatment and which does heal completely anymore. Even after 8 - 10 years the flap can be lifted simply by a spatula. Thus, the free flap does not fully contribute to the biomechanics anymore. Merely the remaining fraction of the cornea under the flap (residual stromal bed = anatomic corneal thickness without the thickness of the flap) adds to the cornea’s stability. However, during Crosslinking mainly the anatomic frontal section of the cornea, in the case of post-LASIK keratectasia the free flap is stiffened. This does not make much sense since the residual stromal bed is, practically, not treated. Thus, MyoRing implantation into the stromal bed is, in fact, the only reasonable therapy for stopping the progression of post-LASIK keratectasia.

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