Abstract: The control arrangement (13) of this invention includes a casing on which the hand (22) of a medical practitioner may rest when the position of the point of focus of a laser beam onto a place to be surgically treated is sought. The arrangement includes a roller (20) operated by the thumb (21) and a ball (23) operated by the index finger (24), the roller and the ball respectively displacing the point of focus along a first coordinate axis (Z) and along second and third coordinate axes (X Y). A push button (25) operated by the middle finger (26) controls firing of the laser beam. The arrangement is used in ophthalmology.

Abstract: The invention concerns a contact lens for observation or treatment by irradiation of the eye, in particular the anterior chamber, outside of the optical axis of the eye. The contact lens comprises a Goldmann or Roussel lens having an entrance face which is flat or spherical, a spherical exit face which is applied to the cornea of the eye, a reflecting face and a compensating element, for example a plano-cylindrical lens. The compensating element is fixed on the reflecting face and its function is to create an astigmatism effect which is the reverse of that of the eye, for an incident light beam which enters by way of the entrance face. The contact lens permits highly accurate focusing of the beam on the apex inside the eye, which is particularly useful in ophthalmoscopy and ophthalmotherapy by means of a laser beam.

Abstract: A contact lens arrangement is described for optically examining an eye and/or treating it by light irradiation, in particular the retina, in the region of or away from the optical axis of the eye.The contact lens arrangement comprises a Goldmann lens having a plane entry surface and a spherical exit surface, applied to the cornea of the eye, and a compensating element, e.g. a prism, having an entry surface. The compensating element is fixed to the entry surface of the Goldmann lens and its function is to produce an astigmatism opposite to that of the eye with an incident light beam, entering through its entry surface.This contact lens arrangement enables very accurate focusing of the beam on to a particular point inside the eye.

Abstract: The invention concerns contact lenses for observation or irradiation of the eye. The contact lens contains, for useful radiation, an entry face (1), a surface (2) reflecting by total reflection and an approximately spherical exit surface (3). Entry face (1) constitutes a wave surface for useful radiation.

Abstract: The contact lens (1) for observation and treatment by a coherent radiation beam of a working point T of the eye comprises, for example, an entry lens (4) coupled to a contact lens (5) designed to be applied to the cornea of the eye, the optic axes (6) of said lenses being merged. The entry surface of the lens is spherical and is associated with Weierstrass points A and A' and the image of point A' by the rest of the contact lens is merged with said working point T.

Abstract: The optical head of an installation for observation and treatment by a laser beam of an eye comprises a mirror disposed between an observing microscope and a focusing lens for reflecting towards the latter a treatment and a marking laser radiation beam forming a visible envelope of the treatment beam. That mirror has an outer portion intersecting the marking beam only and an inner portion intersecting the treatment beam only. That inner portion has a reflection coefficient which is maximum for the wavelength of the treatment beam and minimum for the wavelength of the marking beam, so that the latter only is allowed to reach the observing microscope after reflection on the zone of the eye to be treated.

Abstract: A device for observing the eye in order to treat the same comprising optical elements producing optical illumination beams which issue from a light source. The beams consist of parallel rays whose axes are eccentric and parallel to the axis of the focussing lens and traverse the lens. Observation beams and illuminating beams are combined in one optical system. Beams emerging from the focussing lens or the eccentric illuminating rays exhibit a certain inclination relative to the axial observation beam.

Abstract: The invention relates to a method for the surgical treatment of the eye by perforation, by laser radiation, of a tissue or inner wall of the eyeball having a resistance to the free circulation of the aqueous humour. A laser radiation burst comprising at least one pulse of duration d comprised between 10 and 60 ns and of radiated energy comprised between 30 and 300 millijoules is produced and focussed at a determined distance p inside the wall. The radiation is focussed according to a solid angle .OMEGA. determining a density of radiated energy causing ionization of the propagation medium.A shock wave is also produced due to this ionization close to the mean direction of propagation of the radiated, thereby allowing the tissue or inner wall to be perforated.

Abstract: A pulsed infrared laser has an optical system for focusing the laser beam impulse, positioning a metallic workpiece to be drilled at the waist of the beam or at a spacing in the propagation direction in front of the waist of the laser beam, surrounding the portion of the workpiece from which metal is being removed with an atmosphere containing helium and/or hydrogen during the removal process, forming an expanding plasma in front of the portion of the workpiece to be drilled which absorbs the laser radiation at the start of the laser beam impulse by focusing the laser beam impulse at a large aperture angle and dimensioning the timewise intensity course of the laser beam impulse, and maintaining the expanding plasma only during a fraction of the laser beam impulse to remove material from the workpiece.

Abstract: Laser pulses are generated by means of a gas laser in which a gas mixture containing carbon dioxide, nitrogen and helium is at every pulse exposed to an electrical discharge. To achieve a homogeneous discharge, the vapor of a metallocene is added to the gas mixture which prior to at least a first discharge is irradiated with a pulse of ultra-violet light.

Abstract: A method of and apparatus for machining an object wherein a source of coherent radiation is pulse modulated in accordance with the desired machining and the radiation is directed to a deflecting device and deflected to the object which is moving at a controlled speed. Movement of the deflecting device is controlled to deflect the pulsed radiation on the area of the object to be machined regardless of its motion. The method is applied to engrave intaglio printing forms by using gating or pulse length modulation to reproduce accurately the large number of volume variations of the printing cells.

Abstract: A technique for ablating a metal workpiece by the use of laser beam radiation at an efficiency higher than heretofore possible and an improved regulation of the ablation process. Undesired side effects of the ablation process are eliminated by the entire and complete ejection of the molten metal at the point of beam impingement so that no material remains on the workpiece in the areas between contiguous points of ablation. The appropriate selection of beam intensity and the selection of pulse shape provide the inventive technique.