Keratoconus (KC) is known to progress but not all the time. The cornea instead of being spherical, become conical. The best treatment for Keratoconus is good fitting of Rigid Gas Permeable (RGP) contact lenses. She can manage herself for decades with RGP lenses. Other modalities are considered only if contact lens fitting becomes impossible. Intacs, again is not the treatment, it only gives skeletal support to the cornea. It is again not done in the initial stages, but provides adequate support to the cornea if the KC is progressing rapidly. Collagen cross linking is a new modality, and is aimed to strengthen the corneal collagen by Riboflavin & UV light. The entire concept is in its infancy, and no one is sure about its short term or long term clinical effects. If the cone is too large, than she needs to undergo DALK. The best for your sister at this stage is to get a good pair of RGP contact lenses.