Contact lens wearers are significantly more likely to be infected with microbial keratitis. This condition represents a serious infection of the cornea and is the largest single risk factor for contact lens users.
Understanding Microbial Keratitis
Microbial keratitis is an inflammation of the cornea caused by microorganisms such as bacteria, fungi, amoebae, or viruses. The cornea is the clear, outermost layer of the eye, vital for sharp vision. If left untreated, microbial keratitis can lead to severe pain, redness, blurred vision, corneal scarring, and even permanent vision loss or blindness.
Why Contact Lens Wear Increases the Risk
Wearing contact lenses, while convenient, introduces several factors that can heighten the risk of developing microbial keratitis:
- Compromised Corneal Surface: Lenses can sometimes cause microscopic abrasions on the cornea, creating entry points for microbes.
- Reduced Oxygen Flow: Lenses can restrict the amount of oxygen reaching the cornea, making it more vulnerable to infection, especially during overnight wear.
- Biofilm Formation: Microorganisms can form sticky layers (biofilms) on the surface of the lenses or inside the lens case, which are difficult to remove and can serve as a continuous source of infection.
- Improper Hygiene:
- Not washing hands before handling lenses.
- Using tap water or saliva to clean or rinse lenses.
- Not cleaning or disinfecting lens cases properly.
- "Topping off" old solution in the lens case instead of using fresh solution.
- Extended or Overnight Wear: Wearing lenses for longer durations than recommended or sleeping in them dramatically increases exposure time and reduces the eye's natural defenses.
- Contaminated Products: Using expired lenses or solutions, or solutions that have been left open and exposed to contaminants.
- Exposure to Water: Wearing lenses while swimming, showering, or using hot tubs can expose them to harmful waterborne microorganisms, such as Acanthamoeba, which can cause a particularly severe form of keratitis.
Preventing Ocular Infections in Contact Lens Wearers
Adhering to strict hygiene and care practices is crucial for minimizing the risk of microbial keratitis and other eye infections:
- Wash and Dry Hands: Always wash your hands thoroughly with soap and water and dry them with a clean, lint-free towel before touching your contact lenses or eyes.
- Use Fresh Solution: Use only fresh, sterile contact lens solution recommended by your eye care professional. Never reuse old solution or "top off" the solution in your lens case.
- Clean and Replace Lens Case: Clean your contact lens case with fresh solution, let it air dry upside down with the caps off, and replace it regularly, typically every 1 to 3 months.
- Follow Wear Schedule: Stick strictly to the wearing schedule prescribed by your eye care professional. Do not wear lenses longer than recommended, and never sleep in lenses unless specifically approved by your doctor for extended wear.
- Remove Before Water Exposure: Always remove your contact lenses before showering, swimming, or using a hot tub.
- Avoid Saliva or Tap Water: Never use saliva or tap water to wet, clean, or store your contact lenses.
- Regular Eye Exams: Schedule regular check-ups with your eye care professional to ensure your lenses are still appropriate for your eyes and that your eye health is optimal.
- Discard Expired Lenses: Do not wear contact lenses beyond their expiration date.
By following these essential guidelines, contact lens wearers can significantly reduce their susceptibility to serious eye infections and protect their vision.
