However, if your eyelid tone is diminished, this can be difficult. Miniature suction cups are also available. Although many contact lenses on the market are promoted by manufacturers to be worn overnight, we do not recommend that this be done. In some severe circumstances, the infections can be so severe as to cause a penetrating hole in the cornea, with resultant blindness. In fact, the cornea normally has no blood vessels.
Contacts slightly reduce the oxygen delivered to the cornea.
When worn for days at a time, the cornea responds to this chronic oxygen deprivation by growing new, abnormal blood vessels. The chief danger of corneal neovascularization is is causing another type of cornea infection, called marginal keratitis. Although usually not as dangerous as a corneal ulcer, frequent episodes of marginal keratitis can prevent comfortable wear of contacts. Our recommendations Be smart. Don't try to be your own eye doctor and make your own diagnosis.