A rare tumor has caused hair follicles to grow on an Iranian man’s eyeball, and researchers have informally called his condition “hairy eyeball.”

The New England Journal of Medicine said in its Jan. 2 issue that the case involves a 19-year-old man who was born with a limbal dermoid tumor. Although the tumor was benign, it eventually grew to just under a quarter of an inch at 5mm, the medical journal said. Nejm.org has photos of the man's “hairy eyeball tumor.”

According to researchers from the Tabriz University of Medical Sciences in Iran, the limbral dermoid tumor eventually caused several black hairs to start growing on the man’s eyeball. While the patient “did not have pain” and only suffered from mild vision loss, he decided to undergo surgery for cosmetic reasons, they said; however, the removal of the hairy eyeball tumor led to “little improvement in visual acuity” because of amblyopia vision deficiency and astigmatism, the researchers said.

While limbal dermoid tumors are very rare, eye doctors do typically see one to two cases in their tenure, according to Mark Fromer, of Fromer Eye Centers, in New York City. Fromer, who did not treat the Iranian man, told Yahoo that limbal demoids typically contain tissue found in other parts of the body. In this case, and frequently seen in similar cases  hair follicles are present and eventually grow hair directly on the tumor in the eyeball. Fromer said the tumors can also contain cartilage and sweat glands instead of hair follicles.

Fromer added that this type of tumor can cause blurred vision, but it typically do not cover the cornea, which can lead to blindness. People generally remove the limbal dermoids not for improved eyesight, but rather for cosmetic purposes.

Fromer also said he has a female patient suffering from a similar “hairy eyeball tumor,” and she does not want to have it removed.

"It hasn’t grown or changed and it doesn't physically bother her," Fromer said.