“Galen is said to have been the first to tattoo the cornea for disguising opacities. He is said to have cauterized the opacity and then applied a paste composed of powder of gall-nut, pomegranate bark and a salt of copper. This, according to Panas, was the origin of tattooing. Anagostakis states that the ancient Greeks had a method of tattooing the eye.” The Opthalmic Record, 1902
The above quoted treatise goes on to talk about a Dr. De Wecker who, in 1869, did the first modern eye tattooing, and who documented his methods for others. I’ll get into the methods in a bit, but first let’s talk about corneal opacity. Have you ever seen a movie where a blind person was shown having white eyes? That’s a film representation of corneal opacity. In real life it looks more like a white stain on the eye, and it’s usually the result of trauma. It’s also the fourth leading cause of blindness after glaucoma, cataracts and something else. I forgot the other thing, but just know that corneal opacity is #4.
This is where Galen comes in. Born in 130 AD, this Greek physician basically was a miracle worker in his time. He was so influential that his work was still being used as a primary reference into the 1600s. Also, he did a lot of bloodletting, but no one is perfect. Galen had experience with tattoos because they were widely used in slavery at the time and Galen also pioneered tattoo removal, for when people were no longer slaves and wanted their slave tattoos gone.
So it’s the 2nd century CE, and some folks came to Galen with a corneal opacity in just one eye (super common) and Galen was like, “What if I tattoo that?”. And they were probably like, “Cool, how does that work?” and Galen was like, “Definitely not with me sticking a needle dipped in gall-nuts in your eye a bunch of times. That would be weird.”
But even in 1869 when De Weeker was doing the operation, it was noted how little pain and irritation the patients faced, and how well they healed with minimal risk of infection.
They would start by tattooing the pupil (Using a sterile needle dipped in “Chinese ink in stick” made at the Imperial factory at Peking [Beijing] or Shanghai) by making a series of dots. For the lines of the iris, the needle would be inserted sideways and when pulled out it made a faint line in the white tissue of the eye. More lines = darker eye, less = lighter. The doctor would just get as close to the shade of the other eye as possible, but in grayscale. Using this method, they could make the white scar tissue of the opacity look more or less like the patient’s matching eye, particularly at a distance.
Now, this is different from the modern tattooing of the sclera, which you may or may not have seen examples of online. That’s where the white of the eye is tattooed to make it another color. I’ve reached out to some folks who do sclera tattooing for details, and that’ll be the subject of another blog.
But for corneal tattoos we need to fast forward to today, because surprise! This is still totes a thing you can have done at your eye doctor’s office. It turns out that modern doctors eschew the use of Chinese or India inks, both popular in the 19th century, for the procedure since those can cause more toxicity and irritation than modern inks.
So what do they use?
According to Dr. Keith Walter and the American Academy of Ophthalmology, the answer is lasers. For those faint of heart or stomach, I don’t recommend googling “femtosecond laser” because you will see pics and video of people getting their eyes lasered. What is cool is that the femtosecond laser is far, far more accurate at eye cutting than what a human can accomplish with their own hands (In my interview with Lunacobra, inventor of the modern sclera tattoo, he actually talks about the procedure and why it should be the only way to tattoo an eye going forward. But that’s another blog.)
A pocket is created beneath the clear coating of the eye (Called the “clear part” – just kidding, it’s the conjunctiva), pigment is matched to the iris color and then “impregnated” beneath the surface. This produces a very solid likeness of the original eye color. Still, the procedure isn’t widely used, with other therapies taking the forefront, including simply wearing colored contacts.