An eye surgical instrument, comprising at least one optical fiber for lighting of the interior of the eye, which at least one optical fiber, at a free end thereof, is provided with a light exit and with a stop situated at a distance from the free end, which stop defines an insertion part situated between the end and the stop, and at another end is connectible to a light source, while the stop forms a separate element which is arranged so as to be slidable along the at least one fiber.