Poor hygiene routines are threatening the eye health of 24 million Americans, according to the results of a new study.
This is the number of Americans who wear contact lenses - some of whom have bought them online.
Scientists from Soroka University Medical Centre in Israel studied the rate of contamination in contact lens storage cases by taking samples of the contact lens disinfection solution from lens cases belonging to candidates for refractive surgery.
In two-thirds of the storage cases, at least one health threat was detected, the most common of which was Pseudomonas, a known cause of severe corneal infections.
The authors wrote: "It seems the commonly used disinfecting solutions provide little protection from contamination of contact lens storage cases."
They also described the results as "disturbing" and urged contact lens wearers to closely follow contact lens care guidelines, including frequent cleaning and replacing their lens case regularly.
Manufacturers recommend contact lens cases themselves should be thrown away every three months.
by Alexa Kaczka