Complex sentence: Keratoconus (KC, KCN, KTCN) is a degenerative disorder of the eye in which structural changes within the cornea cause it to thin and change to a more conical shape than the more normal gradual curve.
Split into simpler sentences: Keratoconus (KC, KCN, KTCN) is a disorder of the eye which results in progressive thinning of the cornea. This results it to change to a more conical shape than the more normal gradual curve.