Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
  • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
  • G02B1/041—Lenses
  • G02B1/043—Contact lenses
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment

Definitions

• the present invention relates to improvements in artificial optical lenses such as contact lenses, intraocular lenses and intracorneal implants, and, more particularly to such optical lenses having an outermost surface of modified morphology to provide improved biological inertness.
• the morphology of the implant surface of an optical lens controls the increase in entropy and consequently the overall free energy associated with the destruction of the highly organized structure of hydrogen bonded oligomers of water molecules existing in liquid water at an implant surface immersed in an aqueous medium.
• a tissue or a biomolecule approaches the implant surface of my surface passivated optical lens immersed in an aqueous medium, water molecules which have been displaced from their stable position by the implant surface interact with the tissue surface of the biomolecule. Such interaction provides an additional site for the development of hydrogen bonded intermolecular structures.
• an optical lens body of an acrylic polymer is characterized by an outermost surface modified in morphology to possess the characteristic of low surface energy and high biological inertness.
• the outermost surface of the optical lens body is smoothed by removing only molecular level irregularities. The process of removing such irregularities involves the steps of surface preparation and surface passivation. In the surface preparation step, the surface of the lens body is treated to render it wettable by a passivation reagent in the subsequent surface passivation step.
• the optical lens body prepared by the surface preparation step to have weakly bound water molecules at its outermost surface is immersed in a silane reagent which reacts with the water molecules removing them from the outermost surface and undergoes an oligomer ization reaction.
• This process reorganises or smoothens molecular level irregularities at the surface of the optical lens body .
• the resul t ing su r f ace i s smoo t h a nd possesses a l ow s u rf ace ene rgy and supe r io r biological inertness.
• Figure 1 is a flow diagram, in block form, of my surface alteration process as it is applied to alter the surface morphology (surface passivation) of an optical lens implant to possess the desired characteristic of improved biological inertness.
• Figure 2a is a flow diagram, in block form, of the surface preparation step included in my surface alteration process.
• Figure 2b is a schematic showing the chemical reactions in the surface preparation step of Figure 2a, the surface preparation step rendering the surface of the optical lens body wettable so that the subsequent passivation process occurs uniformly over the surface of the lens body.
• Figure 2c is a flow diagram, in block form, of the surface passivation step included in my surface alteration process.
• Figure 2d is a schematic showing the chemical reaction in the surface passivation step of Figure 2c.
• my present invention provides an optical lens having a lens body of an acrylic polymer.
• the outermost surface of the lens body is altered in morphology to possess the desired characteristic of biological inertness.
• the surface alteration process is depicted in Figure 1 and is utilized to create a smoother, more regular surface morphology (surface passivation).
• the passivation process is applicable to all hydrophobic acrylic polymers, including all polymers and copolymers of alkyl acrylates and methacry lates, with the exception of those monomers, such as 2-hydroxyethyl methacrylate which impart hydrophilicity to the formulation or enhance its water solubility.
• the passivation process is shown in Figures 2c and 2d and is designed to develop a change in the organization of polymer chains only at the outermost surface of the optical lens. Accordingly, the process is carried out under conditions which do not permit invasion of the treating reagents into the bulk of the optical lens. Further, prior to the surface passivation process, it is necessary to render the lens body wettable by the passivating reagent, so that the passivation process occurs uniformly over the surface of the lens body.
• the surface preparation step is illustrated in Figures 2a and 2b.
• the surface is rendered wettable through a process of complexation of water molecules to the polymer chains at the outermost surface of the acrylic optical lens body.
• carboxylate esters pendant on polymer chains at the outermost surface of the lens body serve as sites for the binding of water molecules.
• the acrylic polymer lens body is reacted with a tetraalkylammonium hydroxide at room temperature for about 30 minutes.
• the reagent comprises a highly concentrated (e.g., 35%) aqueous solution of tetramethylammonium hydroxide.
• the lens body is immersed in such a reagent at 25oC (room temperature) for about 30 minutes.
• the lens body After immersion, the lens body is withdrawn from the solution and washed thoroughly with distilled water in order to remove any unbound reagent (base) and to allow water molecules to become hydrogen bonded to the surface.
• the acrylic optical lens body is then dried in a convection air oven for several hours at an elevated temperature.
• the organic base being volatile, is driven off leaving weakly bound water molecules at the surface of the acrylic lens body as shown in Figure 2b.
• the acrylic lens body is immersed in a methanol solution of the surface passivating reagent, as shown in Figure 2d.
• the surface passivating agent is a reactive silane which is highly reactive (attractive) towards water molecules.
• the silane reagent is a trialkoxy aminosilane.
• a silane reagent can be synthesized by reaction of
• the solution may be stored under air and water free conditions.
• the solution is diluted with 1% de ionized water volume by volume prior to use.
• the addition of water converts the alkoxysilane amide derivative to the silanol as depicted in Figure 2d.
• the silane reagent reacts with the weakly bound water molecules on the surface of the lens body and undergoes an oligomerization reaction.
• the passivating reagent increases the free energy of the surface during the period of its residence on the surface.
• the added free energy activates the polymer chain segments at the outermost surface layer and provides the chain segments with enough energy to reorganize themselves into stable conformations.
• the surface morphology becomes smooth subsequent to the passivation treatment.
• PMMA were subjected to my surface passivation treatment. Following surface passivation, the intraocular lens bodies were examined by elemental analysis and FT-IR (ATR) spectroscopy in order to determine if residual surface passivating reagents remained on the lens surface. All such measurements yielded negative results.
• the contact angle of the surface passivated implants were measured on a goniometer, using 0.1 ml drops of deionized water. The contact angles ranged from 88 to 92o, measured over 360 implants.
• my present invention provides a lens body of an acrylic polymer characterized by an outermost surface of modified morphology and possessing the characteristic of superior biological inertness, while specific examples of chemical reactions and formulations for producing such characteristics have been described in detail, the present invention is not limited to such. Rather, the invention is to be limited of scope only by the terms of the following claims.

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Optics & Photonics (AREA)
• General Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Treatments Of Macromolecular Shaped Articles (AREA)
• Materials For Medical Uses (AREA)
• Eyeglasses (AREA)

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• 1988
  • 1988-11-01 WO PCT/US1988/003876 patent/WO1989004329A1/en not_active Application Discontinuation
  • 1988-11-01 EP EP19890900968 patent/EP0343236A4/de not_active Withdrawn
  • 1988-11-01 JP JP50085489A patent/JPH02501987A/ja active Pending

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