Contact lenses can be used to correct visual acuity in people who are nearsighted (myopic), farsighted (hyperopic) and have irregular corneas (astigmatism). According to the Association of Contact Lens Manufacturers, there are 31 million people in the United States that wear contact lenses. With so many people wearing these devices, some people are going to wear them improperly by not cleaning them properly or wearing the lenses too long. Improper wear increases the risk of complications to the eye of the contact lens wearer. Some of the complications can be corrected by stopping contact lens wear temporarily; for other conditions, medications may be required. In some cases, the eye doctor may discontinue the contact lens wear permanently.
Dry Eyes
Mezu-Nnabue states in the winter 2009 QEI Newsletter that wearing contact lenses can increase dry eye symptoms—some patients who may have had mild dry-eye symptoms before wearing contact lenses may find that the symptoms increase greatly when wearing contact lenses. The symptoms may hinder the lenses wearer from using the contacts at all (contact-lens intolerant). Using rewetting drops or soaking the lenses during the day may relieve some of the complaints; changing the lenses or increasing the amount of blinking during the day may also help.
Giant Papillary Conjuncitivitis (GPC)
Giant papillary conjuncitivitis (GPC) is a reaction of the conjunctiva under the eyelids to the contact lenses and the deposits on the lenses. Symptoms include itching, a stringy discharge and some discomfort while wearing the contact lens. The patient would need to stop wearing the lenses until the condition completely resolves. This doesn't mean that the patient cannot wear contacts again; the doctor may try a lens made of different material to see if the problem is resolved.
Corneal Neovascularization
Corneal neovascularization is the growth of fine blood vessels at the edge of the cornea—usually caused by the cornea being constantly deprived of oxygen. This condition is more commonly seen in patients who wear extended-wear contact lenses and those people who wear daily lenses for long periods of time. The doctor may change the contact lens material or decrease the wearing time.
Corneal Abrasions
A corneal abrasion is an area of injury to the corneal epithelium, which is typically caused in contact lens wearers by a foreign body (e.g., dirt) on the contact lenses or torn edges of lenses. The injured areas could become infected without proper care, and patients would have to stop wearing the lenses, using antibiotic drops or ointments frequently. Eye doctors would also want to examine abrasions patients every 24 hours to make sure conditions are improving.
Cornal Infecton (Ulcer)
Corneal ulcers are infections of the cornea that can be caused by bacteria, fungi or parasites. Ulcers usually occur if there are injuries to the corneal epithelium as in an abrasion. These infections can be visually devastating. To treat corneal ulcers, the patients have to discontinue contact lens wear; and eye doctors will take scrapings of the infections to try to find out what types of organisms are causing the infection and place the patients on antibiotic eye drops. Doctors will also evaluate the patients every 24 hours to make sure that their infections are improving.
Acanthamoeba Keratitis
Acanthamoeba is a small, one-celled animal that can cause a difficult but rare infection in contact lens wearers. Bennett on AllAboutVision.com notes that these infections tend to be caused by contaminated water or contact lens solutions, or wearing the lens in the hot tub. Prevention is the best strategy against this infection.
