degenerative eye disease
Keratoconus is a degenerative disease in which the cornea becomes cone-shaped. When the eye changes shape, it is more difficult for tears to spread over the entire eye, causing dry eyes. In fact, about 80% of patients with keratoconus suffer from dry eyes.
Many people who have keratoconus and wear contact lenses will often complain about a cloudy film that builds up over the contact lenses which causes fluctuation of vision. They may also experience itchiness and reduced comfort when wearing contacts.