The notion of a needle in the eye seems pretty horrible to most people.
In reality, though, doctors routinely give injections in the eye to deliver medicine to places where eyedrops can't reach, and they say that patients generally don't find it too painful, even though the sclera has nerve fibers in it [source: Kershner]. They lessen the discomfort by applying drops containing a chemical to numb the eye, and then inject a small amount of anesthetic into the eye itself before giving a deeper injection containing the actual medicine [source: Retina Eye Specialists]. In the late 1800s and early 1900s, eye doctors routinely injected ink into patients' eyes to cover up disfiguring corneal scars, though the practice pretty much was rendered obsolete by modern advances in reconstructive surgery [source: Pitz et al.].
Even so, getting a needle poked into your sclera, the protective outer layer of the eye, doesn't sound like something a person would choose to experience. That is, unless you're a hardcore tattoo buff who is used to enduring a little pain in order to look different from everyone else.
At a 2007 body-modification convention in Canada, three people actually volunteered to undergo a public experiment in which they had their eyes injected with ink by tattoo artists. (Doctors reportedly were consulted for advice, but none were willing to perform the procedure). The subjects used anesthetic drops to numb themselves beforehand, and it reportedly didn't hurt too badly afterward, though there was some discomfort [sources: Positano, Larratt].
The first subject tried a traditional "hand-poked" method, the process that tattoo artists used to put ink under the skin before modern electric tattoo machines. That turned out to be so cumbersome that it took 40 pokes to get the ink into the eye. After that, the experimenters switched to using a hypodermic needle, which turned out to work a little more efficiently. Even so, as one subject, Shannon Larratt, duly noted, "It is extremely difficult to get the needle into the right layer." Aftercare, he added, was antibiotic drops and a patch [sources: Positano, Larratt].