Ocular rigidity determinations were carried out in three groups of patients who were successful long-term wearers of corneal contact lenses. Group 1 consisted of those patients whose corneas showed no refractive changes upon removal of the lenses (as compared to their precontact refraction). Group 2 were patients who had developed permanent with-the-rule astigmatism. Group 3 were patients who developed keratoconus. Though our series is too small for statistical analysis, it would appear that at least one type of keratoconus may be related to the long-term wearing of corneal contact lenses on eyes that have an unusually low ocular rigidity.
Hartstein J, Becker B. Research Into the Pathogenesis of KeratoconusA New Syndrome: Low Ocular Rigidity, Contact Lenses, and Keratoconus. Arch Ophthalmol. 1970;84(6):728-729. doi:10.1001/archopht.1970.00990040730005