News of the trend among Japanese teens called oculolinctus, also known as "eyeball licking" or "worming," went viral last week after the Chinese news site Shanghaiist reported on it.
"This is a dangerous practice which has the potential to spread a number of bacteria that reside in the mouth to the eye resulting in bacterial infections such as conjunctivitis (pink eye) to styes as well as abscesses involving the lids and eye socket," Dr. Robert Glatter, an emergency medicine physician at Lenox Hill Hospital in New York, told CBSNews.com .
The Huffington Post interviewed ophthalmologists who warned of potential health risks like blindness, corneal abrasions and eye chlamydia.
Some reports say the fad was sparked by a Japanese music video from the band Born, which features an eyeball licking scene.
Japanese blog Naver Matome interviewed one concerned teacher who said that he ran into two sixth grade students licking each others' eyeballs in an equipment room. After he confronted them, they admitted it was popular in their class. His independent survey of students confirmed his fears: One-third of the children admitted to eyeball licking.
The Japanese teacher also noted with growing concern that he saw up to 10 students at a time wearing eye patches, which he realized were hiding eye ailments.
Time.com reported the fad has spread across the globe, from Japan to the U.S. Virgin Islands, and is depicted in photos, cartoons and videos on Tumblr and YouTube.
Eyeball licking comes with many risks, experts say. It's easy to spread bacteria that causes conjunctivitis with the tongue. When infected with the germs, the clear lining inside the eyelid and the white of the eye gets inflamed, giving the eye a pink or red color. Normally, pink eye will go away on its own, but in severe cases people will need antibiotics or other medical treatment.
There's also the chance that licking the eyeball could accidentally scratch it. Any cuts can become a trap for bacteria, which can lead to other problems. Dr. Philip Rizzuto, a spokesman for the American Academy of Ophthalmology, told the Huffington Post that left untreated some of these germs could also cause blindness.