Apical changes and scarring in keratoconus as related to contact lens fitting techniques.

Seven keratoconus patients were fitted with gas-permeable lenses, one eye with a large apical bearing lens and the other with a small apical clearance lens. Within 12 months, 4 of the 7 eyes wearing the large flat technique developed corneal scarring, while no scarring developed in the eyes fitted with the apical clearance technique.