Contact lenses are a medical device inserted directly ON the eye. Think about that for a moment. You are placing a FOREIGN BODY ON TOP OF YOUR EYEBALL. Doesn't that sound just a little insane?
It's not because contact lens technology has come a long way. But that doesn't mean that wearing contacts is without risk. Let's talk just a few of the potential issues:
Allergic reaction. The constant touching of the lens to the eye can cause an allergy to develop. You can develop an allergy to the lens material, deposits on the lenses, or the solution you use. Contact lens solution is often the culprit. Allergies to solutions present themselves as general symptoms of allergy (redness, itching, discharge). If you suspect your solution is giving you grief, try switching to a preservative-free solution. Once you find a solution that works, stick with it.
Another common cause of allergy is protein deposits on your lens. Regular enzyme cleaning of your lenses can help with this as well as changing your lenses at the times recommended by your doctor. If you wear rigid lenses, try having your lenses polished or buffed. This can usually be done in your doctor's office for a minimal charge.
Tight Lens Syndrome. Normally, a contact lens should move slightly on the surface of the eye. For different reasons (a dry environment, allergies, improper fit, hormonal changes, etc.), a lens may begin to fit more tightly. This can be because the lens was not properly fit or it may be related to increasing dryness as the day proceeds. If the lens tightens to where the eye can't move, the oxygen transmission in the cornea will drop and the cornea may swell which, of course, leads to further tightening, and so on. Symptoms of this are redness, eye irritation, burning, and dry sensation. Vision may begin to blur and halos or rainbows may be seen around light.
Rewetting drops can help prevent this cycle. Also, having the fit of the lens re-examined may eliminate problems. When a lens becomes tight like this, the lens should be removed. Use lots of rewetting drops to remove the lens. Sometimes removing a too-tight lens can cause a corneal abrasion which should be seen by your doctor.
Corneal Swelling. Corneal swelling, or edema is a result of a lack of oxygen to the cornea. Tight Lens Syndrome and sleeping in contacts are some of the most common causes of corneal edema. Symptoms include blurred or foggy vision, rainbows or halos around lights, redness, and possible pain or irritation. Don't wear your lens if you are experiencing corneal edema, and make an appointment with your eye doctor.
Corneal Ulcer: Unfortunately, corneal ulcers (an infection of the cornea) are common for contact lens wearers and we see way too many of them. Soft lenses have a higher risk of causing ulcers than rigid, but all do carry the risk. A corneal ulcer starts when a bacteria infects an area of breakdown on the surface of the cornea. Overwear of lenses, improper cleaning, sleeping in lenses, wearing overly tight lenses, and extended use of lenses may increase the risk of developing an ulcer. Normally, a corneal abrasion, even a small one, is uncomfortable, but contacts can act as a bandaid and mask some of the irritation.
Once an infection begins, most people experience severe symptoms: pain, redness, excessive tearing, sensitivity to light, blurred vision, and discharge are common. WHAT DO DO: REMOVE THE LENS AND MAKE AN APPOINTMENT WITH YOUR DOCTOR. Usually an antibiotic drop will clear it up. Contact lenses cannot be worn during this time.
Even a successfully treated ulcer can leave a scar that affects the vision. It's not impossible to go blind from improper contact lens wear. It is important to avoid situations that can lead to corneal ulcer such as overwear of lenses, poor disinfection techniques, swimming in contacts, and ignoring symptoms of pain or redness.
These are just a few of the issues that can happen from wearing contact lenses. As you can see, sharing lenses, wearing lenses that haven't been properly fitted, overwearing lenses, and not cleaning lenses properly are all contributers to major contact lens problems. PLEASE DON'T ABUSE LENSES. SAVE YOUR SIGHT: FOLLOW YOUR DOCTOR'S ADVICE, AND DON'T IGNORE ANY SIGNS OF A PROBLEM.