Contact Lens Induced Infections
Despite advances in contact lens material and solutions, eye infections related to contact lens use still exist. Contact lens infections are more prevalent with extended wear lenses. This is due more to overnight wear than to the actual type of lens. Oxygen permeability is also a factor.
The most commonly found contact lens induced infections are infectious bacterial keratitis and ulcers that are related to P. aeruginosa. P. aeruginosa keratitis can lead to corneal perforation and ultimate loss of vision. Sterile keratitis is mote common with disposable extended wear lenses, where as infectious keratitis is more common with re-usable extended wear contact lenses.
The primary source of bacterial infections is poor contact lens cleansing regiments and poor hygiene of the patient. Patients who have existing blepharitis or dry eyes are more prone to infections, further complicating the situation. Disposable and frequent replacement contact lenses were developed to combat these problems. Other types of contact lens induced infections include sterile corneal infiltrates, acanthamoebic keratitis, and fungal keratitis.
Sterile corneal infiltrates occur in patients who are sensitive to the preservatives used on contact lens solutions. Symptoms include burning, itching, pain and discharge. Patients should be treated with topical antibiotics and perhaps topical steroids.
Acanathamoebic keratitis is found primarily in those patients who wear soft daily lenses and make their own saline solution. It is also common in people who swim with lenses in. This is because acanthamoeb is a pathogenic protozoan found in contaminated water, soil, dust, or may be airborne. Initially the corneal epithelium is effected. Later the corneal tissue and even the sclera are effected. Treatment can be lengthy and involves a combination of a topical antimoebic, and topical steroids. Prevention including avoiding non-sterile solution and tap water is every patient’s best choice.
Fungal keratitis occurs most often with high water content hydrogel lenses in humid climates. It appears as a superficial gray feathery infiltrate. It is associated with satellite lesions and inflammation. Again prevention with proper lens care is the best medicine.