Collagen cross-linking is often applied at the same session as when the laser was performed with the intent of trying to reduce the risk of post-LASIK ectasia. In fact, collagen cross-linking originally began life as a treatment for progressive ectasia and remains so today.
In any given case during laser vision correction, surgeons may take the opinion that collagen cross-linking may either be optional or highly recommended depending on the risk profile of the patient’s eyes. In your case, it might be possible that the surgeon had deemed your eyes to be relatively safe to undergo epi-LASIK without collagen cross-linking. The best course of action would be to discuss with your surgeon the merits of collagen cross-linking in your specific case.
Dr David Chan