Corneal tattooing

The oldest indication is the black tattooing of opacified corneas on inoperable blind eyes for aesthetic purposes, to imitate a pupil.
More recent is corneal tattooing, or keratopigmentation, of seeing eyes to repair iris defects.
This technique has the advantage of being simpler than iris suturing, rings or prostheses. It only affects the surface, by placing pigment inside a ring cut into the cornea with an overleaf cut. This surgical intervention does not even require stitches. The liquid implant placed inside allows blurry vision and photophobia to be corrected (product visible under UV light) while the iris is aesthetically corrected.
This technique is currently used for purely aesthetic purposes to change eye colour. For this purpose, its use in combination with surface tattooing using a dermograph can obtain a natural multi-coloured appearance. Some kinds of refractive surgery could benefit from being used in combination with corneal tattooing.