Various conditions associated with keratoconus are as follows: Ectopia lentis Blue sclera Osteogenesis imperfecta Severe rubbing Keratoconjunctivitis sicca Retinitis pigmentosa Vernal keratoconjunctivitis  Down's syndrome Turner's syndrome Ehlers-Danlos syndrome Leber's amaurosis Marfan's syndrome Mitral valve prolapse syndrome Mental retardation Achondroplasia Aniridia Congenital cataract Retrolental fibroplasia Share your Views .