Contact Lens Induced Corneal Problems
Physiological changes occur in the cornea as a direct result of contact lens use. These changes lead to epithelial, stromal and endothelial damages, as well as disorders of the ocular surface. Complications from the damages run from simple to severe. Some of the complications are red eye, tight lens syndrome, hypoxia or corneal edema, and microbial keratitis. These disorders are due primarily to poor contact lens care.
Red eye is exactly as the name implies, corneal infiltrates cause acute red eyes. Other symptoms include discomfort and the sense that something is in the eye. Treatment usually involves cessation of contact lens use until there is complete healing which is approximately two weeks. Usually no medications are prescribed.
Tight lens syndrome occurs when the contact lens dries and no longer fits properly, squeezing the eye. The lens no longer moves on blinking. Tight lens syndrome results in infiltrates, anterior chamber reaction, corneal staining, epithelial damage and conjunctival injection. Symptoms include irritation, pain, blurred vision and photophobia. Topical antibiotics and steroids as well as cyclopedic agents are used in treatment.
Hypoxia is insufficient oxygen flow to the cornea. This results in stromal swelling. Causes of hypoxia can be the type of lens used, or tight lens syndrome.
Microcystic epithelial changes occur during acute edema, which can lead to cell death. Symptoms include pain, tearing, reduced tolerance of contact lenses, reduced vision and photophobia.
Chronic edema occurs with extended contact lens use. In this case there is the presence of epithelial microcysts, increase stromal thickness and neovascularization. Symptoms of chronic edema are subtler than that of acute edema. There is no pain and minimal vision problems.
Microbial keratitis is the most severe corneal damage that can occur from contact lens use. It can lead to permanent vision loss. While occurrence of the disorder is low, its serious complications make it noteworthy.
Gram-negative pseudonomas aeruginosa and gram positive staphylococcus are the organisms responsible for microbial keratitis. Risk factors include hypoxia and the presence of organisms adhered to corneal epithelium. Improper care and use of contacts also play a role in microbial keratitis.
Symptoms of microbial keratitis include moderate to severe pain, tearing, foreign body sensation, and photophobia. Consequences of infection other than loss of vision include irregular astigmatism, corneal scarring, and low visual acuity. Treatment includes fortified topical antibiotics. The type of antibiotic used is dependent on which organism is the cause of infection. In some cases corneal transplant is required.
With all the corneal complications listed, the patient can return to contact lens use under doctor supervision.