Corneal Ulcer

Picture shows white area on the cornea (the clear window covering the eye) representing a corneal ulcer which can affect vision permanently as it heals into a scar. (picture courtesy of Rendia)

What are contact lens infections and why should I be concerned?

Contact lenses are great for many reasons. They often provide better vision than glasses, and freedom from wearing glasses. However, wearing contact lenses can increase the risk of corneal infection. The cornea is the front part of the eye that is like a window. It is clear and does not have any blood vessels in it. The cells in the cornea get some oxygen from the fluid inside the eyes, and some from the air. Contact lenses fit over your cornea and cover them. Even though contact lenses are gas permeable, there is some reduction of oxygen access from the air compared to not wearing contacts. Overtime, the corneas can get weaker since they are chronically, slightly oxygen-deprived. This is especially true if you overuse contacts by wearing them too long during the day, continuously for weeks, or overnight while sleeping. This is the case even with extended use or "overnight" contacts.

When you take your contacts off, the suction effect can sometimes pull of some of the superficial cornea cells, creating micro-abrasions or tiny scratches. Sometimes these abrasions can get infected causing a corneal ulcer, especially if the cornea is too weak to fight infection. An infection can be minor, like a warning sign, or extremely serious, such that it fogs up your vision completely and can leave a giant scar that blocks your vision. Looking through a corneal scar is like looking through a foggy or cracked window. If a scar like this damages your cornea, the only way to fix it is to replace the cornea with another one. This is called a corneal graft. Corneal tissue for grafting is obtained from the Tissue Bank Manitoba and is generously donated by people who have died and donated their eyes. This surgery can be tedious, and involve a lot of follow-ups with a Cornea Specialist (an Ophthalmologist specializing in corneal diseases).

What is "contact lens intolerance"?

When you wear contacts for long periods of time and for many years, eventually there may come a time when your eyes no longer can tolerate contacts. This is called 'contact lens intolerance". The symptoms include persistent irritation and redness whenever the contacts are worn. When they are removed, the eyes slowly get back to normal. Contact lens intolerance can lead to keratitis, which is an inflammation of the cornea or front "window" to the eyes. It also makes your eyes more vulnerable to infections. Infections like ulcers of the cornea can be difficult to treat and may leave scars that affect your vision. If you become intolerant of contacts, it may be best to stop wearing them altogether to avoid vision threatening scarring from bad infections. You will need to consult your eye doctor about this.

How should I use my contacts safely and effectively to prevent problems?

The best treatment is to PREVENT problems by using contact lenses RESPONSIBLY:

  3. CONSIDER USING DAILY DISPOSABLE CONTACTS: They are cleaner since they are single use, and do not require cleaning or storage in a reusable container that may be contaminated. Extended wear or "overnight" contacts promoted for continuous use for 2-4 weeks without taking them off, still have risk of infection and should be avoided.
  4. DO NOT OVERUSE YOUR CONTACTS: Wear them a maximum 10 hours per day and always take 1-2 days off your contacts completely per week.
  5. OWN A PAIR OF CURRENT GLASSES: You should take your contacts off in the early evening and switch to glasses.
  6. NEVER SLEEP IN YOUR CONTACTS: If you sleep in them by mistake, take them off and give your eyes time to recover - at least 1-2 days without contacts. This rule goes for ALL TYPES of CONTACTS, even extended wear or "overnight" contacts.
  7. KEEP YOUR EYES WELL MOISTURIZED: If your eyes feel dry, use lubricant drops. Some over the counter drops are useful to use about 10-15 minutes prior to putting in your contacts.
  8. RECOGNIZE THE SIGNS OF POSSIBLE INFECTION: When you have been wearing contacts for too long, without any breaks, your eyes will become red and irritated and will need a break. This redness and irritation may be a sign of an early infection, especially if there is a lot of pain, light sensitivity and tearing. If this occurs, see your Optometrist as soon as possible, or go to the emergency department. DO NOT PUT YOUR CONTACTS BACK ON until you have been cleared with an eye exam. If you force yourself to wear your contacts when your eyes are irritated, you may be promoting a bad infection that could get worse and cause vision loss.
  9. UNDERSTAND THAT CONTACTS CANNOT BE WORN FOREVER: Unfortunately, most people cannot tolerate wearing contacts for their entire lives. There comes a time when people may become intolerant of contacts such that every time they put them on, the eyes get red and irritated. This is called contact lens intolerance and happens to most contact lens users after 10-15 years of wearing contacts. You can certainly prolong your ability to tolerate contacts by using them responsibly and not over-using them (as described above).

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