Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F9/00—Methods or devices for treatment of the eyes; Devices for putting in contact-lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
  • A61F9/007—Methods or devices for eye surgery
  • A61F9/008—Methods or devices for eye surgery using laser
  • A61F9/00802—Methods or devices for eye surgery using laser for photoablation
  • A61F9/00817—Beam shaping with masks
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F9/00—Methods or devices for treatment of the eyes; Devices for putting in contact-lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
  • A61F9/007—Methods or devices for eye surgery
  • A61F9/008—Methods or devices for eye surgery using laser
  • A61F9/00802—Methods or devices for eye surgery using laser for photoablation
  • A61F9/00804—Refractive treatments
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
  • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
  • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
  • B23K26/066—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms by using masks
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F9/00—Methods or devices for treatment of the eyes; Devices for putting in contact-lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
  • A61F9/007—Methods or devices for eye surgery
  • A61F9/008—Methods or devices for eye surgery using laser
  • A61F2009/00861—Methods or devices for eye surgery using laser adapted for treatment at a particular location
  • A61F2009/00872—Cornea

Definitions

• the invention relates to a method for modeling or correcting optical lenses, in particular the cornea of the eye, with a pulse laser, the radiation pulses of which are directed via optical imaging means and at least one diaphragm onto the surface of the lens to be modeled, the diaphragm being successively different Covered areas of the lens surface and the laser is fired at least once after each shift of the diaphragm.
• the invention also relates to a device for carrying out this method.
• This object is achieved according to the invention in a method of the type described in the introduction in that the diaphragm steps perpendicular to the optical axis along an essentially straight displacement path of the lens. is shifted wise that the aperture opening has a greater extent in the middle in the direction of displacement than at the edge, that the step width of the aperture displacement is smaller than the extent of the aperture opening in the direction of displacement and that the start and end point of the aperture displacement are chosen in this way are that the entire aperture of the aperture covers the surface of the lens to be modeled.
• the lens surface in the form of an elongated trough which is deepest in the middle and rises on all four sides as seen from this deepest point.
• the length of the trough parallel to the direction of displacement results from the displacement path and can thus be varied
• the width of the trough transverse to the direction of displacement is determined by the expansion of the aperture opening transverse to the direction of displacement and can be chosen according to the choice of aperture can be varied.
• the boundary line of the trough at the two ends running transversely to the direction of displacement the boundary lines at the ends running parallel to the direction of displacement is a straight line which extends parallel to the direction of displacement.
• the step size is only a fraction of the greatest extent of the aperture parallel to the direction of displacement.
• the waste from the untreated lens surface to the deepest area of the trough-shaped recess is broken down into many individual stages, so that a very constant transition is obtained, both at the ends running transversely to the direction of displacement and at the ends parallel to the direction of displacement extending sides, provided the differences in expansion of the aperture in the direction of displacement are large in the central region and in the edge region.
• the displacement path of the diaphragm opening center preferably leads through the optical axis of the lens.
• the displacement path can be rotated about the optical axis if this appears necessary due to the lens surface to be modeled or corrected.
• the expansion of the diaphragm opening parallel to the direction of displacement can decrease in stages from the center to the edge. Se steps can also be smoothed, so that there is a continuous course of the edge.
• step size of the displacement movement is equal to or smaller than the smallest extension of the diaphragm opening parallel to the displacement opening. This ensures that even in the edge area, where the aperture generally has the smallest dimension, there are no "frayed" edges, but a clear transition between the modeled surface and the non-modeled surface.
• the aperture opening can be delimited by two curved pieces that bulge in the opposite direction and meet at an angle; the direction of displacement is perpendicular to the connecting line between the two points of contact of the arc pieces.
• an apparatus for carrying out the described method has the features of the characterizing parts of claims 7 to 12, these features largely correspond to the features corresponding to the method carried out.
• Fig. 4 a top view of a very simplified
• FIG. 1 the device used is shown very schematically.
• a laser for example an excimer laser, generates radiation pulses of a certain duration, which are symbolized in Fig. 1 by an arrow.
• the radiation is directed onto the cornea 5 of the eyeball 6 via a mirror 2.
• the diaphragm 3 is mounted on a holder 7 on a drive 8 which gradually moves the diaphragm 3 in a direction arranged perpendicular to the optical axis of the eyeball 6 along an essentially straight displacement path.
• the drive 8 is actuated by a controller 9 which, at the same time, ignites the laser 1 only when the drive 8 is at rest; one or more pulses can be emitted for each position of the diaphragm.
• the aperture 4 is always shaped so that its expansion parallel to the direction of displacement is greater in the middle than at the two edges.
• this diaphragm opening comprises three regions of the same width, namely a central region 10, an edge region 12 and an intermediate region 11, each of which lies between the middle region 10 and between the two edge regions 12. These areas are delimited by edge lines 13 running transversely to the direction of displacement, the middle area is five times as long as the edge area, the intermediate areas are three times as long as the edge area.
• the A- individual areas merge into one another in stages, ie the border lines form stages. With regard to a center line running transversely to the direction of displacement, the diaphragm opening is mirror-symmetrical.
• FIGS. 2, 3 and 4 The aperture shown in FIGS. 2, 3 and 4 is shown there in different positions during the modeling process.
• the diaphragm opening occupies a lowermost position, in FIG. 3 it is shifted upwards by a distance which corresponds to the extent of the edge region 12 parallel to the direction of displacement, in FIG. 4 it is again by such an increment moved further up.
• the aperture In the starting position, the aperture is completely above the surface of the lens to be treated, as is the end position. This also results in a constant decrease in the modeling depth at the two ends of the trench described.
• the starting position eg FIG. 2
• the parts of the lens surface released by the aperture at its lower edge are only hit when laser beams are first applied, and these lowest parts are already covered when the aperture is moved for the first time.
• Multiple exposure also occurs in the middle area and in the intermediate area only in the parts at the top at the start of modeling.
• the full depth of the trench is only reached in the part of the lens surface which is arranged on the upper edge of the aperture opening at the beginning of the modeling.
• the diaphragm opening described in FIGS. 2 to 4 consists of only three areas of different dimensions in the direction of displacement, so that the trough-shaped recess (FIG. 5) that is produced only has to be composed of three layers with different depths. This results in very rough gradations. In practice, the number of stages is increased significantly. H. a much finer gradation will be carried out, if necessary the gradation can also be chosen so fine that a continuous edge line of the aperture opening is used.
• FIG. 6 An example of such an aperture is shown in FIG. 6.
• This aperture has on its front edge and on its rear edge an arcuate boundary line 14 and 15, which meet at an angle in two points of impact 16 and 17, respectively.
• a straight line passing through the two points of impact is arranged perpendicular to the direction of displacement; the direction of displacement is indicated by arrow A in FIG.
• the aperture shown in FIG. 6 is used in the same way as has been explained with reference to FIGS. 2 to 4.
• the step size of the feed can be selected to be very small, for example it can be 1/100 of the longest dimension of the diaphragm opening in the displacement direction, so that the steps of adjacent ablation layers are very close together in the trough-shaped recess in the lens surface and the height differences are small stay. In this way, an almost constant drop is obtained from the untreated lens surface to the deepest area of the trough-shaped recess.
• the step size when advancing the diaphragm opening does not necessarily have to correspond to a step, even in the case of a step-shaped diaphragm opening, in fact the displacement path by a whole step of adjacent areas is normally the greatest possible displacement path between two irradiations.
• the step size will be selected to be smaller, so that even with a step aperture, a smooth transition as possible is possible between the untreated lens surface and the bottom of the trough-shaped recess.

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• Health & Medical Sciences (AREA)
• Optics & Photonics (AREA)
• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Ophthalmology & Optometry (AREA)
• Heart & Thoracic Surgery (AREA)
• Surgery (AREA)
• Biomedical Technology (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Vascular Medicine (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Plasma & Fusion (AREA)
• Mechanical Engineering (AREA)
• Eyeglasses (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=6424447

Family Applications (1)

Country Status (2)

Cited By (4)

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Citations (2)

Family Cites Families (2)

• 1991
  • 1991-02-06 DE DE4103493A patent/DE4103493C1/de not_active Expired - Lifetime
• 1992
  • 1992-01-18 WO PCT/EP1992/000093 patent/WO1992013507A1/de unknown

Patent Citations (2)

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