She told doctors that she wore disposable, soft contact lenses and that she kept them in while swimming and showering, the report said.
An eye test showed that her vision was 20/200 in her left eye, the threshold for being “legally blind” in the United States. Her right eye was not affected.
Doctors could see a cloudiness or haze in the woman’s cornea, the eye’s transparent outer covering. They performed another eye test that uses a special dye to detect damage to this covering. During this test, any damage to the cornea will appear green when doctors shine a blue light on the eye, according to the National Institutes of Health.
The doctors saw that, indeed, a defect in the woman’s cornea appeared green during the test.
Samples from her eye tested positive for Acanthamoeba keratitis, a rare parasitic infection of the cornea. The infection is known to damage a person’s vision and is tied to the use of contact lenses, according to the report, led by Lanxing Fu, of the Manchester Royal Eye Hospital in the United Kingdom.
Acanthamoeba is an amoeba that’s commonly found in water, soil and air, according to the Centers for Disease Control and Prevention. Contact lens wearers face a risk of contracting this infection if they engage in certain practices, such as disinfecting lenses with tap water or swimming or showering while wearing lenses, the CDC said.
The woman was treated with eye medications that cleared her infection. But she was left with vision loss in her left eye because of a scar on her cornea, the report said. One year later, the woman underwent a partial transplant of her cornea, which replaced part of her damaged corneal tissue with healthy tissue from a deceased donor.
After the surgery, her left eye vision improved slightly but was still impaired, although she had no pain in her eye, the report said.