Contact lenses can be a convenient way to switch up your look if your vision isn’t a perfect 20/20. You can wear contact lenses occasionally, like I do, or you can wear them every day. However, it’s critical to remember not to leave them in all day. And when you’re doing certain activities, like swimming or showering, leaving your contacts in can be dangerous.
A case study, published in the New England Journal of Medicine, details how a 41-year old woman developed a rare eye infection after wearing her soft, disposable contact lenses while she showered and swam, The Washington Post reports. The study shows that the infection left her legally blind in her left eye, after she experienced painful symptoms — like blurry vision and sensitivity to light — for two months. And she isn’t alone; a UK reporter lost sight in his right eye after reportedly wearing his contacts in the shower.
An eye test showed that the woman’s visual acuity was 20/200 in her left eye. The American Foundation for the Blind says that a visual acuity of 20/200 or less is considered legally blind, although both they and the Disability Evaluation Under Social Security say the “better-seeing eye” must be 20/200. The woman's right eye was not affected by the infection.
After testing, doctors confirmed that the infection in her eye was Acanthamoeba keratitis, a rare parasitic infection of the cornea. The Center for Disease Control (CDC) says that the Acanthamoeba is an amoeba found worldwide, in water and soil, and can be spread through contact lenses, cuts and wounds, or inhalation into the lungs. However, the CDC also stresses that “Most people will be exposed to Acanthamoeba during their lifetime, but very few will become sick from this exposure.”
So while you should definitely maintain safe contact lens hygiene, you shouldn’t stress out about getting this infection, because it’s very rare. You should still make sure to get any eye irritation checked out by a doctor, though. A 2015 article published in Parasite says that contact lens wearers are at higher risk of being exposed to Acanthamoeba, but that they usually seek medical help later than other patients, because they are desensitized to eye pain and may brush it off as minor. This is dangerous, as late treatment increases the risk for blindness, according to the article.
Besides taking your contacts out while you’re showering or swimming, you can wear contact lenses safely by not wearing them when you sleep and disinfecting them regularly — and properly. Overwearing your contacts — keeping them in for longer than the recommended time period — is also dangerous. Doing this not only increases your risk for infection, but it can cause your eyes to swell, leading to corneal abrasion (a scratch on your eye). So if you buy daily disposable contacts, be sure to change and discard them daily.
The woman in the case study was given anti-microbrial drops for treatment, which eliminated the infection. However, she still had impaired vision stemming from a corneal scar and a cataract. A year after being given the drops, she had eye surgery, using healthy corneal tissue from a deceased owner. Now, she feels no eye discomfort and has 20/80 vision.
This may sound like a frightening ordeal, but it’s important to remember that, like the CDC says, infections of this severity are incredibly rare. Still, it doesn’t hurt to take all the necessary precautions when it comes to contact lenses.