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
• • 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
• • 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
  • A61F2009/0087—Lens
• • 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
  • A61F2009/00885—Methods or devices for eye surgery using laser for treating a particular disease
  • A61F2009/00887—Cataract
• • 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
  • A61F2009/00885—Methods or devices for eye surgery using laser for treating a particular disease
  • A61F2009/00895—Presbyopia

Definitions

• the present invention relates generally to th field of photoablation of ocular tissue to correc vision deficiencies and treat other vision-impairin ocular problems, and, more particularly, to treatmen of the natural ocular lens.
• eye-*glasses i.e., spectacles
• eye-*glasses i.e., spectacles
• hyperopia wherein incident parallel rays of light converge to focus behind the retina
• myopia wherein incident parallel rays of light converge to a focus in front of the retina
• astigmatism a defect in vision ordinarily caused by irregularities in the cornea.
• contact lenses started being used as a viable alternative, at least for many individuals, to the use of spectacles for correcting vision deficiencies, and provided—often at a cost of some discomfort—freedom from many annoyances and appearance problems associated with the wearing of spectacles.
• radial keratotomy a surgic procedure on the cornea called radial keratotomy
• several slits for example abo five, are made radially inwardly toward the optic axis from the peripheral edge of the cornea.
• the radial slits enable the cornea to flatten out a bi thereby decreasing the .
• curvature of the corne Candidates for RK procedures are typically near-sight individuals who cannot or who do not want to we either spectacles or contact lenses.
• Corneal onlays or implants which may constructed of synthetic materials or from don corneas, are surgically attached to or implanted in patients' eyes, are also useful to enhance vision patients whose corneas have been damaged and/or scarr by corneal diseases, such as ulcers or cancer, or injury to the cornea.
• patent No. 4,995,913 discloses compute mapping of the cornea and computer-controlled scanni of the cornea by the laser beam.
• the laser ablation of corneal tissue is extremely painful to the patient on which the surgical procedure is performed.
• laser photoablation of th cornea it should be appreciated that although in s doing the cornea is sculpted in a manner correctin vision, it is frequently the case that the cornea i not itself responsible for the vision problems bein corrected.
• myopia may more likel be caused by an increase in lens size, usually as natural effect of the human ageing process, of th natural lens of the eye (located posteriorly of th cornea) .
• Other vision defects or deficiencies may als originate at the natural lens, while the associate cornea may itself be in a normal condition.
• th present inventor has determined that it would often b preferable to reprofile the natural lens ove reprofiling the cornea.
• Such natural lens reprofilin would eliminate many of the concerns presently raise about corneal photoablation and may result in reduce risks to patients, and since the lens has no nerv supply, the procedure should result in no sensation o pain to the patient. It is, therefore, a principl objective of the present invention to provide a metho for laser ablation of selected regions of the natura lens in order to correct vision problems and to correc problems, such as incipient cataract, on the lens.
• a method for the laser photoablation of ocula lens tissue comprising the steps o determining the region of the lens tissue to photoablated, and directing a pulsed laser beam at su region with an amount of energy effective f photoablating the region without causing substanti damage to surrounding tissue regions.
• t laser is a Nd:YLF laser having an operating frequen in the infrared spectrum and more preferably having operating frequency of about 1053 nanometers.
• T laser preferably has a repetition rate of between abo • 1 and about 1000 Hertz, and more preferably about 10 Hertz; and operates with a pulse width of between abo 1 femtosecond and about 1 millisecond and, mor preferably, about 60 picoseconds.
• the lase preferably operates at an energy level of between abou 1 nanojoule and about 50 millijou ⁇ es per pulse and more preferably, about 30 icrojoules.
• the laser preferably operates with a beam spot diamete of between about 1 micron and about 100 microns and more preferably, with a beam spot diameter of about 2 microns.
• the laser preferably operates with a zone o effect of less than about 200 microns and, mor preferably with a zone of effect of less than about 5 microns.
• th method comprises the steps of determining the region o the lens tissue to be photoablated, calculating th amount of lens tissue to be photoablated from th determined region; and directing the pulsed infrare laser beam at the region with an amount of energ effective for photoablating the calculated amount o lens tissue in the determined region without causin substantial damage to lens tissue surrounding suc region.
• a metho for the laser photoablation of ocular len tissue for the removal of incipient cataract, th method comprising the steps of determining the regio of the lens tissue to be photoablated so as to remov the incipient cataract; calculating the amount of len tissue to be photoablated from the determined region s as to remove the incipient cataract; and directing th pulsed infrared laser beam at the region with an amoun of energy effective for photoablating the calculate amount of lens tissue in the determined region so as to remove the incipient cataract without causing substantial damage to lens tissue surrounding such region.
• FIG. l is a longitudinal cross sectional drawing of a representative eye showing, in simplified form, the cornea, iris, natural lens and retina, and showing the manner in which an image is focused on the retina in a normal eye.
• FIG. 2 is an enlarged, longitudinal cross sectional drawing of a normal lens showing, in simplified form, its composition
• FIG. 3 is a simplified, longitudinal cros sectional drawing—similar to FIG. l ⁇ showing th manner in which the natural lens has regions thereof photoablated using, for example, a Nd:YLF laser operating at a frequency of about 1053 nanometers and operating at a repetition rate of about 1000 pulses per second
• FIG. 3a showing the manner in which internal regions of the lens are photoablated for the purpose of correcting myopia, hyperopia or presbyopia
• FIG. 3b showing the manner in which generally surface regions of the lens are photoablated to remove incipient cataract.
• FIG. 1 a longitudinal cross sectional drawing of a typical, normal eye 10, which is generally symmetrical about an optical axis 12. Shown comprising eye 10, and in order from the front of the eye to the back, is a cornea 14, an iris 16, a natural lens 18 and a retina 20. In a normal eye, light from an object 22 is refracted by cornea 14 and lens 14 so as to form an image 24 on retina 20 (iris 16 being shown having an open central aperture 26 permitting light to pass through to the lens) . Shown more particularly in FIG.
• lens 18 is a biconvex, somewhat flexible structure which is suspended behind iris 16 and is connected to a peripheral cilary body 30 of eye 10 by zonal fibers (zonules) 32. Since lens 18 is avascular, its pathology is more simple than mos other tissues of the body; primar inflammatio processes do not occur and neoplastic growths in lens 18 are unknown. However, trauma or injury to lens 18 results in passive and degenerative changes in the lens with consequent opacification.
• Focusing of lens 18, which functions to transmit and refract light to retina 20, is (assuming the lens is in its normal, youthful condition) by contraction and relaxation of zonal fibers 32.
• lens 18 assumes its maximum convex curvature and thickness; as tension in zonal fibers increases, lens 18 is stretched and its convex curvature and thickness is decreased.
• accommodation the shape of lens 18 is physically varied in a manner causing images 22 to be correctly focused on retina 20 as the distance, D, between object 22 and cornea 14 changes between far and near.
• Lens 18 consists of about 65 percent water and about 35 percent protein (known as crystallins) , along with traces of minerals.
• Lens 18 is avascular, containing no blood vessels, and has no nerve supply, and comprises a thin, transparent capsule or bag 34, a subcapsular epithelium layer 36, a cortex 38 of soft fibres and a harder, dense nucleus 40 at the center.
• surface ectoderm invaginates to form the lens vesicle.
• the posterior cells of the lens vesicle then elongate to form the primary lens fibres, which obliterate the cavity of the vesicle and abut on the anterior (forward) epithelium layer 36. This process is completed early in fetal development.
• Lens 18 continues to grow throughout a individual's life in a process similar to that in whic the epidermal tissue of the skin renews itself. However, unlike the skin where old cells ar continually cast off from the surface, older lens cells accumulate centrally and cannot be cast off. The net result is a progressive growth of lens 18 with age, associated with a decrease in elasticity and accommodative ability. The result is that the most common degenerative condition of lens 18 is presbyopia, a condition in which loss of elasticity of the lens results in the inability of eye 10 to focus sharply for near vision, such that most individuals by about the age of forty require some visual assistance, for example, that provided by spectacles, contact lenses or RK surgery.
• cataract Another common degenerative condition of lens 18 that is generally associated with aging is cataract, which is generally defined as any opacity in the lens.
• cataract the extent of disability depends upon the location and severity of the opacity.
• a relatively small posterior (i.e., rearward) subcapsular cataract may be visually incapacitating because it is situated near the nodal point of the dioptric system, while peripheral opacities that do not impinge on optical axis 12 may cause little visual inconvenience.
• patients initially initially complain of a visual disturbance, then a diminution of vision and finally a complete failure of vision.
• the present invention relates to methods t treat presbyopia, refractive errors, and cataract b means of focusing high power pulse laser photoablatio of lens opacities and selected normal lens fibers.
• laser 50 (FIG. 3) which can advantageously be used fo such purpose is preferably, but is not limited to, quasi-continuous Nd:YLF picosecond laser which may b purchased as ISL Model 2001 MPL or 4001 CLS fro Intelligent Laser Systems, Inc. of San Diego, California:
• laser 50 produces a shoc wave in the tissue at which its beam is focused, th shock wave expanding radially from the point of focu and disintegrating the target tissue (optica breakdown) , thereby causing ionization of the maxim and the formation of a plasma.
• laser preferably has the following characteristics:
• An operating frequency preferably in t visible and infrared (IR) spectrum; mo preferably, about 1053 nanometers (nm) .
• a repetition rate preferably ranging fro about one to about 1000 Hertz; more preferably about 1000 pulses per second.
• a pulse width preferably ranging from about femtosecond to about 1 millisecond; mor preferably, about 60 picosecond.
• An energy level per pulse preferably rangin from about 1 nanojoule to about 50 millijoules more preferably, about 30 microjoules. 5.
• a focused spot size (diameter) preferabl between about 1 micron and about 100 microns; mor preferably, about 20 microns.
• a "zone of effect” preferably limited t between about 1 and about 200 microns with littl collateral effect; more preferably, the zone o effect is limited to about 50 microns.
• the procedure described hereinbelow for the lase photoablation of lens tissue ordinarily requires a initial ocular examination of the prospective patient, including refractive status, slit lamp biomicroscopy, and the measurement of axial length of lens 18 b standard applanation A-scan ultrasonography. Th accommodative amplitude of lens 18 may be measured b various techniques. For example, Adler (Moses RA "Accommodation" In: Moses RA, Hart, MA Jr. eds. Adler' Phvsiolo ⁇ v of the Eve. St. Louis, Washington, D.C. Toronto: The C.V.
• Mosby Co. Chapter 11, 1987:291-310 which is incorporated hereinto by specific reference recommends that a convex lens be moved along th optical axis in front of the patient's eye, away fro the eye, until a target object at a convenient distanc just begins to blur—it is then assumed tha accommodation is relaxed.
• the convex lens is the reduced (to a concave lens), or, alternatively, th target object is brought closer to the patient's ey until the target again starts to blur.
• the rang between the "far” .blur and the "near” blur or maximu plus (convex lens) to blur and maximum minus (concav lens) to blur is the range of accommodation i diopters.
• the amount o lens thickness to be ablated can be calculated in tw ways:
• a patient of age 60 has a lens thicknes of 4.66 mm and an accommodation amplitude of 1.2 Diopters.
• To increase the patient's accommodativ amplitude to that of a person of age 30 who has 10 lens thickness of 4.15 mm and an accommodativ amplitude of 7.5 Diopters, .51 mm (4.66 mm minu 4.15 mm) of lens tissue from the patient's lens This would represent an increase of approximatel 6.25 Diopters (7.5 Diopters minus 1.25 Diopters) 15 of accommodative amplitude. Since the maxima thickness change in the lens during accommodatio is about 0.5 mm, this change should be sufficien to restore the presbyopic 60 year old patient t an accommodative state. 20
• the amount of lens tissue to be ablated is calculated based on the work -of Koretz and
• the amount of le tissue to be ablated is calculated as described abo for presbyopia. This will increase the amplitude accommodation of the patient's lens to allow t hyperope to move the focus of distant objects up to hi or her retina 20.
• the amount of le tissue to be ablated can be calculated based on th refractive status of the eye and the measured len thickness as set forth above in paragraph 2.
• beam 52 from a HeNe focusing laser 54 (FIG. 3a) i focused, by an associated lens or lens system 56 through cornea 14 (which is transparent to the focusin beam) and iris opening 26, to a region 56 to b photoablated by Nd:YLF laser 50 for correction of th specific vision problem under treatment.
• a HeNe focusing laser 54 (FIG. 3a) i focused, by an associated lens or lens system 56 through cornea 14 (which is transparent to the focusin beam) and iris opening 26, to a region 56 to b photoablated by Nd:YLF laser 50 for correction of th specific vision problem under treatment.
• the more centrall located, older cortical and/or nuclear fibers b ablated since the width of nucleus 40 (FIG. 2) remain relatively constant with age, whereas that of cortex 3 increases.
• a laser beam 60 from Nd:YLF laser 5 is focused by an associated focusing lens or len system 66 through cornea 14 (which is transparent t the laser beam) and iris opening 26, onto region 5 which is to be photoablated by the Nd:YLF laser beam
• the amount of lens tissue to be ablated (i.e. decomposed) to achieve the desired vision correctio is determined in the manner described above.
• Th optical zone equatorial diameter
• region 56 b selected so that nucleus 40 and/or centrally locate older fibers in cortex 38 are ablated using a smalle optical zone so as to decrease the curvature of a anterior (forward) surface 62 of lens 18.
• Such lase ablation of lens 18 to correct myopia, presbyopia an hyperopia may be termed "photorefractive phacoplasty” or "phototherapeutic phacoplasty.”
• beam 52 from HeNe focusing laser 54 may be directly focused by lens or. lens system 56 (with the beam passing through cornea 14 and iris opening 26) onto an area or region 64 of small lenticular opacity. Then beam 60 from Nd:YLF laser 50 is focused, by lens or lens system 62 onto area or region 64 and the laser is pulsed until the opacity is ablated (as determined, for example, by visual observation through cornea 12 and iris opening 26) .
• opacity area or region 64 is adjacent to lens capsule 18 (FIG. 2) , aiming beam 52 from HeNe laser 52 is focused more centrally to the opacity to account for shock wave expansion.
• Such treatment i.e., photoablative removal
• phototherapeutic phacoablation or "photo-therapeutic phacoectomy.”
• Nd:YLF laser 5 Care is taken in the operation of Nd:YLF laser 5 not to rupture lens capsule 34 by expansion of lase shock wave. Moreover, if excessive bubbles are forme at the ablation site, as detected, for example, b viewing, with a slit lamp (not shown) the ablatio region through cornea 14 and iris opening 26, the lase ablation procedure is discontinued and additiona treatment is performed at a later date, for example, i one or two weeks.
• the natural lens i an eye can be photoablated by pulsed energy from laser—preferably a Nd:YLF laser—in a manne correcting myopia, presbyopia and hyperopia and in manner removing incipient cataracts.
• laser preferably a Nd:YLF laser
• the natural lens i an eye can be photoablated by pulsed energy from laser—preferably a Nd:YLF laser—in a manne correcting myopia, presbyopia and hyperopia and in manner removing incipient cataracts.
• laser-ablative procedures ar relatively non-invasive (as compared, for example t laser photoablation of the cornea to correct visio problems or the surgical removal of a natural lens i the case of cataract) and because lens 18 is non vascular and contains no nerve supply, no post-ablatio inflammation or wound-healing problems are anticipate and the use of steroids--commonly used after cornea laser photoablation—is not indicated.
• lens 18 is no expected to revert—with time—to its pre-

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Cited By (13)

• 1992
  • 1992-08-26 CA CA002122373A patent/CA2122373C/fr not_active Expired - Lifetime
  • 1992-08-26 WO PCT/US1992/007228 patent/WO1993008677A2/fr active Application Filing

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