That red eye may not be pink eye if you wear contact lenses.
Contact lenses are medical devices. You can permanently lose your vision if they aren't worn properly. Long periods of contact lens overwear and sleeping in your contact lenses can cause permanent damage to the cornea. The cornea is the clear layer in front of the colored structure of the eye and gets its oxygen from the air. If the cornea isn't getting the oxygen it needs, it starts to develop inflammation, new blood vessels, ulcers and scars. Contact lenses should be replaced as prescribed by your Optometrist. Keratitis is an inflammation of the clear tissue on the front of the eye (the cornea). Keratitis can cause holes in the cornea. A corneal ulcer is an open sore on the cornea which can also lead to scarring. Corneal scars can lead to a permanent vision loss. Corneal neovascularization is the growth of abnormal blood vessels on the corneal tissue as a result of the lack of oxygen which could lead to blindness. Contact lenses should not be purchased without a prescription whether for cosmetic use or to correct the vision. You should have an eye exam yearly with your Optometrist to update your contact lens prescription and to check the health of your eyes.