Contact lenses are corrective plastic discs that are inserted on the eye's cornea to correct the wearer's vision. In some instances, people use contact lenses for cosmetic purposes, such as changing their eye color from, for example, gray to blue. Contact lenses have the same function as eyeglasses. Unlike eyeglasses, however, they are worn directly on the eye, are lightweight and almost invisible. Some side effects are occasionally associated with use of contact lenses.
Deposits of intraocular fluid (or aqueous humor) on the contact lenses are a possible side effect. These deposits can result in the contact lenses being uncomfortable to wear. They can also raise the chance of developing an eye infection. Deposits have a higher chance of developing with soft contact lenses as opposed to hard contact lenses, as soft lenses are more flexible and therefore more susceptible to having eye fluids stick to them.
Problems with the cornea also sometimes result from wearing contact lenses, such as vision haziness and swelling of the eyes. This is caused by lower amounts of oxygen being delivered to the corneas, which is a condition known as hypoxia. Scrapes and scratches to the corneas can also occur. The cornea's shape can also be changed by contact lens wear. Corneal infections such as bacterial keratitis are also possible.
Inflammation of the eyelids is also possible with wearing contact lenses. Some people might experience small, inflammatory bumps that appear under their eyelids, which can make wearing contact lenses painful and uncomfortable.
One common side effect of wearing contact lenses is developing dry eyes. This condition results from having insufficient tears. Dry eyes can occur in wearers of soft and hard contact lenses, alike. People with dry eyes might experience symptoms such as the eyes feeling hot, a sensation of something stuck inside the eye, redness, and burning or tearing.
Some people might experience allergic reactions from wearing contact lenses. One common type of allergic reaction is the eyes turning very red whenever contact lenses are inserted. This type of hypersensitivity or allergic reaction often comes from the preservative in the contact lens solution. In these situations, your optometrist can usually prescribe a contact lens solution with a different preservative.