An estimated 45 million Americans wear contact lenses. They are a popular way to correct vision that won’t affect appearance or interfere with sports and activities. They are, however, medical devices that come into contact with the surface of the eyes, and poor contact lens hygiene can result in serious eye infections and possible blindness.
The inset shows an extreme example of a corneal ulcer with intraocular infection.
One contact lens hygiene issue is overwear. Contact lens overwear syndrome (OWS) can occur when you consistently wear contact lenses longer than the recommended time for that type of contact lens.
When contact lenses sit on top of your corneas for a long time they interfere with the oxygen absorption process. A properly fitted contact lens actually floats on the surface of the eye allowing enough of your tear film to get underneath the contact lens and nourish the cornea.
Your eyes need oxygen to maintain optimum health. The cornea has no blood vessels so it must get its oxygen directly from the air. The ambient oxygen enters your tear film and diffuses over your entire cornea in a continual process. Carbon dioxide is also released in this same process.
Signs of Contact Lens Overwear
Your eyes will be red and sore and there may be more blood vessels visible in the whites of your eyes. A bloodshot eye is the response of the cornea seeking another way to get more oxygen.
Bloodshot eyes occur anytime the eye is irritated and are not only a result of overwear. If you notice any of these symptoms, however, remove your contact lenses and see your eye care practitioner for an evaluation.
Is Overwear Serious?
Contact lens overwear syndrome can lead to serious eye problems.
Lack of oxygen (hypoxia) can damage the superficial lawn of cells on the cornea called the corneal epithelium. The corneal epithelium has many functions, one of which is protection from infection.
Hence, the principle issue with contact lens overwear is that it breaks down the corneal epithelium causing a corneal abrasion.
Corneal abrasions are open sores on your corneas. Infection can set in through these abrasions causing scars to form in the cornea. This can decrease and distort your vision. Sever infections can lead to blindness.
Treatment for Contact Lens Overwear
If contact lens overwear syndrome is caught early, you may only need to stop wearing your contact lenses until your corneas heal. You may also need some prescription eye drops to manage the discomfort.
If you think you have contact lens overwear syndrome you need a thorough eye exam with a high-powered microscope to examine your corneal tissue. Primary care or urgent treatment centers often do not have the specialized eye examination equipment needed for a thorough corneal examination.
If you experience any of the symptoms of OWS, remove your lenses and call your eye doctor. Do not replace your lenses without direction from your eye doctor.
Proper Fitting Lenses
Often times overwear may be caused by several factors: poor fitting lenses, old lens materials, dry eye, etc. Laser vision correction may be of benefit and is an alternative to contact lens wear.