Rodrigo Fernando dos Santos, a tattoo artist, has paid nearly £350 to cover the whites of his eyes with a solid, dark colour.
The 39-year-old has covered 70 percent of his body covered in tattoos and is the 13th person in Brazil to have the procedure.
"I cried ink for two days," he told Brazil's The Local.
"Only now is the colour of my tears lightening up. I think they are still half grey."
Rafael Leao Dias, who tattooed dos Santos's eyes, explained that procedure uses a special syringe-like needle that injects ink into the eyeball permanently.
He also revealed that he had to go over the area three times to obtain an opaque result.
"There is no drilling," Dias told MyHealthBowl.com. However, he did not say whether the procedure was painless.
"We apply the ink between the conjunctiva and sclera layer that protects the eye," he said. "I studied the procedure for two years and performed my first application in October 2012. There is no risk or discomfort due to the use of specific eyewash.
"The law does not prohibit this, here [in Brazil] or abroad. There is no risk or discomfort due to the use of specific eyewash."
There have been reports of eyeball tattoos up to 2,000 years ago, according to the BME.com website, which says blindness is a potential risk.
Body modification artist Russ Fox says the injection method originated in Toronto around six years ago.
"The contrast and relationship between a person's natural iris color and the scleral tattoo can create all sorts of amazing and beautiful effects," he told The Huffington Post.
"For example, tattooing the sclera solid black will have differing effects if a person has crystal blue irises as opposed to dark brown irises. Brighter colours have drastically different effects."
According to Dr. Lewis Ziegler in Transactions of the American Ophthalmological Society, corneal tattooing was practised as early as the first century AD. He reports that prominent Roman physician Galen attempted to improve the appearance of patient's eyes by using a heated metal rod to cauterise the surface of the eyeball, after which he applied powdered nutgalls or pomegranate bark mixed with a copper salt to the area.
"Cosmetic tattooing of the cornea can be extremely dangerous," Dr. Sandra Belmont, a clinical associate professor of ophthalmology at Weill Cornell Medical Centre, told Open Salon. "Infection, loss of vision, blindness, perforation and haemorrhage are among the potential complications.
"And it's bizarre and creepy to look at too."