Abstract: Preoperative toric axis corneal marker useful for delimiting the correct position of an intraocular lens, implanting an intraestromal ring in a patient's eye, performing a limbal relaxing incision or any other type of intervention requiring a precise marking prior to an intervention on the cornea, wherein the marker incorporates an attaching means to a slit lamp and which marker comprises a generally “L”-shaped body which is anchored, by means of a first wing, to the attaching means to the slit lamp and its second wing features a hollow cylindrical shape where a tubular bushing, which presents at least a small lug radially arranged at its free base, is fitted, through which the marking on the eye will be accomplished.