A woman was blinded by a shower without removing her contact lenses, according to British medical journal New England.
The 41-year-old woman used to take a bath without taking off her contact lens, which caused her cornea to suffer permanent scars.
The women did not take off their contact lenses during bathing and swimming, allowing amoeba parasites to reach the eyeball and grow there.
The stability of the microbes in the cornea caused severe pain and foggy vision, but later caused irreparable damage, with constant blindness.
New England said it was not the first time a 29-year-old British man had been blinded last year after suffering the same type of infection from bathing without taking off his lenses.
Despite the paucity of such cases, they highlight the fragile nature of the human eyeball and the risk of wearing lenses, warns John Hovanizian, a spokesman for the American Academy of Ophthalmology.
"While most people can wear contact lenses safely with simple precautions, the risk is to wear them all night or expose them to water," Huvanizian said.
According to Hovanizian, wearing lenses during bathing or swimming turns the eyeball into something like a bacterial farm.
"The contact lenses look like the small sponge you put in your eyes, sucking things and keeping them in contact with your eye. The warm, moist environment provides time for the growth of fungi and amoebas."
It shows that tap water or any stagnant water, such as pools or lakes, is full of bacteria and other small organisms.