A description has been provided herein of an intrastromal segment especially designed for use as a prosthesis inside the corneal tunnel of patients suffering from keratoconus. The segment consists of a lengthened body of variable dimensions in the form of an arc with noticeably rounded ends, devoid of any communicating orifice, and endowed with a transverse section that may be triangular, trapezoidal, hexagonal or oval, with at least three marks connecting to the narrowest side for which two ends aid the safe handling of the segment and the mid-section mark serves as a positional reference point. The segment will be connected to a disposable guide track along which it moves and from which it is pushed into the implantation position.