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
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/14—Eye parts, e.g. lenses, corneal implants; Implanting instruments specially adapted therefor; Artificial eyes
  • A61F2/16—Intraocular lenses
  • A61F2/1613—Intraocular lenses having special lens configurations, e.g. multipart lenses; having particular optical properties, e.g. pseudo-accommodative lenses, lenses having aberration corrections, diffractive lenses, lenses for variably absorbing electromagnetic radiation, lenses having variable focus
  • A61F2/1616—Pseudo-accommodative, e.g. multifocal or enabling monovision
  • A61F2/1618—Multifocal lenses
• • G—PHYSICS
  • G02—OPTICS
  • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
  • G02C7/00—Optical parts
  • G02C7/02—Lenses; Lens systems ; Methods of designing lenses
  • G02C7/04—Contact lenses for the eyes
  • G02C7/041—Contact lenses for the eyes bifocal; multifocal

Definitions

• Intraocular lens Intraocular lens
• the invention relates to an intraocular lens to be fitted inside the eye.
• the lens of the eye is usually removed in connection with a cataract operation.
• the function of the lens has to be compensated for by means of, for example, spectacles or contact lenses.
• the spectacles are very.strong and therefore thick and heavy.
• the use of contact lenses is often also difficult, and owing to the irritation caused by them they are not suitabl for all cataract operation patients.
• the lenses are classified for example on the basis of the location of the lens, in which case the lense are called chamber angle supported lenses, iris supported lenses, and posterior chamber supported lenses.
• the attaching means fitted to the lens is supported by the respective chamber.
• the optical part of the lens is usually made of polymethyl methacrylate (perspex) , either by turning or by casting.
• the lenses can also be classifie on the basis of the material and design of the supporting loops or feet.
• the supporting loop or foot may be of polypropylene, either clear or colored, usually blue.
• All previously known lenses are characterized by spherical optics, realized by means of convexity of the front surfac or the back surface of the lens.
• These spherical intraocul lenses have the disadvantage that they form a sharp image at only one distance.
• the lens can be designed to correct the patient's near vision, if the patient uses most of his time in, for example, reading, writing, or similar close work.
• the object of the invention is to provide an intraocular lens which corrects the patient's visual acuity, both near and distant.
• a bifocal intraocular lens (BIOL) is produced according to the invention by dividing the lens into at least two parts with different refractive powers
• the lens is made up of two parts, the first and the second part, the second part can be located in, for example, the center of the len on its main axis, in which case the first part is made up of the peripheral part of the lens.
• the diameter of the lens is about 6 mm.
• the central part is 1.8-2.3 mm.
• the first part of the lens is of a first material and the second lens of a second material, the refractive coefficient of the second materi being different from that of the first.
• the second part of the lens is in this case advantageously a hole, cavity or depression formed in the center of the lens.
• the hole may extend through the lens, whereby a so-called pinhole is obtained.
• the central part refracts close-distance light and the peripheral part longer-distance light, or vice versa. By changing the size of the central part it is possible to accomplish an optimal balance between the simultaneously visible long-distance and close-distance images.
• the lens may also be made aspherical, in which case the first part of the lens has a different refractive power from its second part.
• Figure 1 depicts an eye with a conventional intraocular lens
• Figure 2 depicts an eye with a bifocal intraocular lens
• Figures 3-12 depict bifocal intraocular lenses which are divided into two or several parts having different refractive powers.
• Figure 1 the eye has been fitted with a conventional intraocular lens 2 designed for distant vision.
• rays of light 6, 6' coming from a long distance are refracted correctly to one point 3 on the retina of the eye.
• rays of light 7 and 7' coming from a close distance are refracted to point 4 and form a blurred image in area 5 on the retina of the eye.
• Figure 2 shows how the intraocular lens 2, which is divided into two parts 8 and 9, refracts both rays 6 and 6 ' coming from a long distance and rays 7 and 7' coming from a close distance, in areas 8 and 9, respectively, to one point 3 on the retina of the eye 1.
• the brain can emphasize either the close-distance image or the long ⁇ distance image, both of them being seen sharp.
• Figures 3 and 4 depict a bifocal intraocular lens which is aspherical, the peripheral part 8 of the lens having a certain focal distance and the central part 9 of the lens a different focal distance. Thus, also, two images are produced on the retina.
• Figure 5 shows a lens in which a piece of a material having greater refractive ower than the peripheral part 8 has been fitted in the central area 9.
• Figure 6 depicts a lens with a so-called pinhole fitted in its central area. This can be accomplished either by simpl making a small hole through the lens, whereupon ⁇ this hole serves as a lens in the manner familiar from the pinhole camera.
• the peripheral part 8 constitutes the second part of the lens, having a different focal distance.
• the pinhole. can also be produced by means of a tube 10 inserted in the center of the lens, the tube delimiting the pinhole area 9.
• the lens according to Figure 7 is divided into many parts which are located concentrically around the axis of the lens.
• every second part 11 has mutually the same focal distance and every second part 12 mutually the same focal distance.
• the parts 11 can be fitted for near vision and the parts 12 for distant vision.
• the lens in Figure 8 is also divided into several areas, these areas being in alternation radially.
• area 11 can be fitted for distant vision and area 12 for near vision.
• Figure 9 depicts a lens in which the curvature of the lens changes continually. Thereby a continual focussing precision at different distances is accomplished.
• Figure 10 depicts a diffraction-type lens.
• concentric rings are formed in the lens, the thickness of the rings decreasing by an amount which corresponds to the optical distance of half a wavelength.
• the semi-wave areas 13 and the whole-wave areas 14 produce two different images on the retina of the eye.
• Fresnel concentric Fresnel prisms 15 are used, their prismatic refractive power increasing outwards in the lens.
• the lens according to Figure 12 is divided into two parts 16 and 17 having different focal distances, the parts bein located in such a way that the lens is divided radially into two parts.

Landscapes

• Health & Medical Sciences (AREA)
• Ophthalmology & Optometry (AREA)
• Physics & Mathematics (AREA)
• General Health & Medical Sciences (AREA)
• Vascular Medicine (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Transplantation (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• Engineering & Computer Science (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Cardiology (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Prostheses (AREA)

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• 1984
  • 1984-12-31 FI FI845177A patent/FI79619C/fi not_active IP Right Cessation
• 1985
  • 1985-12-30 EP EP19860900672 patent/EP0243365A1/de active Pending
  • 1985-12-30 WO PCT/FI1985/000103 patent/WO1986003961A1/en unknown
  • 1985-12-31 AU AU53158/86A patent/AU5315886A/en not_active Abandoned

Non-Patent Citations (1)

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