As, discussed earlier, “A contact lens is a foreign, plastic object placed on the ocular surface, therefore, patients must be instructed properly in effective lens care & in the necessity of follow-up visits.
A contact lens may be considered to be an optical patch & bandage. As a patch it reduces the availability of oxygen and the dissipiration of carbon dioxide from the cornea. As a bandage it creates pressure on the underlying tissue & reduces wetting of the ocular surface & dissipation of material from between the contact lens & the cornea.
Dry eye is the leading cause of contact lens discomfort or intolerance. Soft contacts in particular, rapidly evaporates the tears from the eye, causing irritation, protein deposits, infection and pain.
Contact lenses may become contaminated with organic & inorganic deposits, & become scratched, clipped or ripped. This lead to corneal edema.