Keratoconus is usually diagnosed as an isolated disorder but there have been instances where it has been reported in association with Down Syndrome, Leber's Congenital Amaurosis, and Mitral Valve Prolapse.
It is also believed that genetics, the environment and the endocrine system all play a role in keratoconus. For example, oxidative stress, allergies and eye rubbing are known to be risk factors of developing keratoconus.