A laser unit for performing intrastromal ophthalmic laser surgery, where a cornea defines a visual axis and has a "T" thickness, including: a means to generate a pulsed laser beam, where the duration of each pulse in the beam is less than about a PS； means for directing and focusing the beam on a series of focal points in the stroma for laser induced optical rupture (LIOB) of stromal tissue at each focal point； and a means adapted to move the focal point in the stroma to create a plurality of cuts, where each cut is made in portions of a respective cylindrical surface, where the respective cylindrical surfaces are centered on the visual axis of the cornea, and also where Each cylindrical surface has an anterior end and a posterior end, the posterior end of the cut not deeper in the stroma being located than 0.9T of an anterior surface of the eye, and the anterior end of the cylindrical cut is located in the stroma more than at least eight microns in a posterior direction of the Bowman's capsule in the cornea, characterized in that the portions of the cylindrical surfaces subjected to LIOB define diametrically opposite arc segments where each arc segment extends through an arc in a range between five degrees and one hundred sixty degrees.Una unidad láser para realizar cirugía láser oftálmica intraestromal, donde una córnea define un eje visual y tiene un grosor "T", incluyendo: un medio para generar un haz láser pulsado, donde la duración de cada pulso en el haz es inferior a aproximadamente un picosegundo； un medio para dirigir y enfocar el haz sobre una serie de puntos focales en el estroma para ruptura óptica inducida por láser (LIOB) de tejido estromal en cada punto focal； y un medio adaptado para mover el punto focal en el estroma para crear una pluralidad de cortes, donde cada corte se realiza en porciones de una superficie cilíndrica respectiva, donde las superficies cilíndricas respectivas están centradas en el eje visual de la córnea, y además donde cada sup
