Disclosed is an intrastromal insert, already preformed, of solid, transparent, impermeable, biocompatible, physiologically inert and chemically resistant material, with notches allowing the passage of metabolites, substances, cells or portions thereof, and drugs, configured to receive printing, which is adapted in the space of the corneal stroma to change the eye color and/or to solve the problem of insufficient pigmentation of the iris. The method and the related component to change, permanently and reversibly, the eye color for aesthetic purposes are described as well.