That's pretty freaky body modification!!! Is it permanent?
It is permanent, as far as anyone knows at the moment, but unless the eye has some freaky healing I'd guess it will be there for life. If memory serves it's done by using a needle to inject a small amount of ink under the surface of the eyeball, repeat as needed until coverage is complete. It causes no known damage to the eye, and doesn't interfere with the eyes function.
It is however fairly untested, and I think the picture there is one person of about 3 who got it done at around the same time to see if it could be done. As such little is known about long term effects of it so there may be complications, but for the moment it seems to work.