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Why Contact Lens Wearers Get Eye Infections

contact lens wearers get eye infections

It is no secret that contact lens wearers get eye infections, but what may be surprising is why. A new study presented at the American Society for Microbiology annual meeting on May 31, 2015, by NYU Langone researchers revealed that people who wear contact lenses have bacteria not usually seen in the eyes of non-wearers.


The investigative team, under direction of NYU Langone microbiologist Maria Gloria Dominguez-Bello, PhD, noted in a press release that “Our research clearly shows that putting a foreign object, such as a contact lens, on the eye is not a neutral act.” This seems like an obvious statement, but the new study sheds some light on just how “unneutral” it may be.

The researchers studied 20 individuals: 9 who wore contact lenses and 11 who did not. Hundreds of swab samples were taken from the eye conjunctiva (thin tissue that covers the outer surface of the eye) and other parts of the eye, as well as the skin immediately beneath the eye. These samples, as well as the used contact lenses, were analyzed for bacteria.

Analysis of the samples and lenses revealed the following:

  • The bacteria of the contact lens wearers more closely resembled that of their eyelid skin than did the bacteria found in the eyes of the non-wearers
  • In particular, the contact lens wearers had threefold the usual proportion of certain bacteria (e.g., Lactobacillus, Acinetobacter, Pseudomonas, Methylobacterium) on the conjunctiva than is usually found on non-wearers
  • However, the non-wearers had more Staphylococcus bacteria, which are associated with eye infections and usually found on the skin. Researchers could not explain this finding.

Overall, analysis of the samples revealed that the microoorganisms found in the eyes of lens wearers were more similar to their skin than were the bacteria found in the eyes of non-wearers. The question facing investigators now is, are these differences associated with people touching their eyes or with the pressure of the lens on the eyes, resulting in a change in the eye’s immune system and the viability of present bacteria.

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According to Jack Dodick MD, one of the study’s co-investigators and professor and chair of ophthalmology at NYU Langone, their findings may help explain the rise in corneal ulcers seen since the introduction of soft contact lenses in the 1970s. A corneal ulcer is an open sore that develops on the clear tissue at the front of the eye (the cornea).

One of the culprits in this condition is Pseudomonas. Dodick noted that the new study results suggest individuals should be more aware of hand and eyelid cleanliness to help reduce the incidence of this serious eye condition.

Contact lens risks
In addition to corneal ulcers, others eye problems that can develop among contact lens wearers include eye irritation, conjunctivitis (pink eye), and corneal abrasions. Symptoms of eye infections or other problems can include eye pain or discomfort, excess tearing or other discharge, itching, burning, unusual redness, blurry vision, swelling, hypersensitivity to light, or gritty feeling in the eye. If you experience any of these symptoms, it is best to remove your lenses and consult an eye specialist as soon as possible.

Also read about bad habits of contact lens wearers

NYU Langone Medical Center news release