Abstract: Device and method that allows an objective measure to be taken of the size and morphological pattern of the degradation of the image in scotopic vision. It consists of a black front screen (1) which has a central luminous source (2) surrounded by a grid of circular light spots (3) which at the beginning of the test light up sequentially or at random, according to the method selected, from the nearest to the central source of glare in a centrifuge fashion to the outermost, and a trigger which the patient will press every time he can discriminate the presence of each of the spots in 12 meridians. The non-discriminated or hidden spots will border an area which is interpreted as being occupied by the light aberration and is used as a basis for calculating the glare index.

Abstract: This suction ring is composed of a ring-shaped body (1) with an incarcerated, bevelled front opening (2), with an anterolateral cannula (4) for connection to a vacuum pump and a dovetail guide (7) on which the microkeratome cutting blade moves. The lateral wall of the body (1) has a tapered truncated conical configuration, diverging backwards for adaptation to the eyeball, in order to increase the suction capacity to the eye. The front area has a wider stepped perimeter (6), which together with a bulge (8) on the outer edge and corresponding to the tips of the guide (7), increases the effective length of the latter, allowing better fixation of the cutting blade.

Abstract: A microkeratotome for the dissection of lamellae of corneal tissue includes a body (1) inside which a chassis (8) is housed where two motors (10) and (12) are installed which provide the oscillation of the corresponding cutting blade and the movement of the head (21) in which the cutting blade itself (20) is situated, all of which is combined with a suction ring (24) which immobilizes and imparts vacuum pressure to the eyeball through an orifice, the vacuum pressure being distributed simultaneously from the ring (24) through a peripheral channel situated in the same. The said ring is prevented from coming loose due to the maximum pressure reached in the eye when the unit is mounted upon it. It also includes an electronic control unit which has, according to the keratometry appropriate to the patient, several programmes which predefine cutting qualities.