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阿尔贝特 达克瑟尔 - One of the best experts on this subject based on the ideXlab platform.

  • Corneal Implant for correction of impaired vision in the human eye
    2007
    Co-Authors: 阿尔贝特 达克瑟尔
    Abstract:

    The present invention relates to a Corneal Implant for introduction into the visual centre (Z) of the cornea of the human eye for the purpose of rectifying impaired vision, in particular presbyopia, or presbyopia in combination with hypermetropia or myopia. To make available a Corneal Implant which is suitable for use in the visual centre (Z) of the human eye and can be used to correct presbyopia on its own or in combination with hypermetropia or myopia, it is provided that the effective thickness (d) of the Corneal Implant (2), measured in the direction of the optic axis (5) of the eye, is more than 50mu and the maximum width (b), measured in a plane perpendicular to the direction of thickness, is less than l mm, the Corneal Implant (2) having no imaging function in relation to the human eye.

  • Corneal Implant and method for correction of impaired vision in the human eye
    2007
    Co-Authors: 阿尔贝特 达克瑟尔
    Abstract:

    Corneal Implant for introduction into the visual centre (Z) of the cornea of the human eye for the purpose of rectifying impaired vision, in particular presbyopia, or presbyopia in combination with hypermetropia or myopia. To make available a Corneal Implant which is suitable for use in the visual centre (Z) of the human eye and can be used to correct presbyopia on its own or in combination with hypermetropia or myopia, it is provided that the effective thickness (d) of the Corneal Implant (2), measured in the direction of the optic axis (5) of the eye, is more than 50[mu]m and the maximum width (b), measured in a plane perpendicular to the direction of thickness, is less than l mm, the Corneal Implant (2) having no imaging function in relation to the human eye.

Christopher N Ta - One of the best experts on this subject based on the ideXlab platform.

  • Bioactive interpenetrating polymer network hydrogels that support Corneal epithelial wound healing
    Journal of Biomedical Materials Research Part A, 2009
    Co-Authors: David Myung, Nabeel Farooqui, Jaan Noolandi, Curtis W Frank, Luo Luo Zheng, Sarita Gupta, A. Bakri, Jennifer R. Cochran, Christopher N Ta
    Abstract:

    The development and characterization of collagen-coupled poly(ethylene glycol)/poly(acrylic acid) (PEG/PAA) interpenetrating polymer network hydrogels is described. Quantitative amino acid analysis and FITC-labeling of collagen were used to determine the amount and distribution of collagen on the surface of the hydrogels. The bioactivity of the coupled collagen was detected by a conformation-specific antibody and was found to vary with the concentration of collagen reacted to the photochemically functionalized hydrogel surfaces. A wound healing assay based on an organ culture model demonstrated that this bioactive surface supports epithelial wound closure over the hydrogel but at a decreased rate relative to sham wounds. Implantation of the hydrogel into the corneas of live rabbits demonstrated that epithelial cell migration is supported by the material, although the rate of migration and morphology of the epithelium were not normal. The results from the study will be used as a guide toward the optimization of bioactive hydrogels with promise in Corneal Implant applications such as a Corneal onlay and an artificial cornea. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009

  • glucose permeable interpenetrating polymer network hydrogels for Corneal Implant applications a pilot study
    Current Eye Research, 2008
    Co-Authors: David Myung, Nabeel Farooqui, Michael R Carrasco, Jaan Noolandi, Curtis W Frank, Dale J Waters, Spencer D Schaber, Christopher N Ta
    Abstract:

    Epithelialization of a keratoprosthesis requires that the Implant material be sufficiently permeable to glucose. We have developed a poly(ethylene glycol)/poly(acrylic acid) (PEG/PAA) interpenetrating polymer network (IPN) hydrogel that can provide adequate passage of glucose from the aqueous humor to the epithelium in vivo. A series of PEG/PAA IPNs with varying PEG macromonomer molecular weights were synthesized and evaluated through swelling studies to determine their water content and diffusion experiments to assess their permeability to glucose. One of the PEG/PAA hydrogels prepared in this study had a glucose diffusion coefficient nearly identical to that of the human cornea (∼ 2.5 × 10− 6 cm2/sec). When Implanted intrastromally in rabbit corneas, this hydrogel was retained and well-tolerated in 9 out of 10 cases for a period of 14 days. The retained hydrogels stayed optically clear and the epithelium remained intact and multilayered, indicating that the material facilitated glucose transport from th...

  • histological processing of ph sensitive hydrogels used in Corneal Implant applications
    Journal of Histotechnology, 2007
    Co-Authors: Nabeel Farooqui, David Myung, Marilyn Masek, Roopa Dalal, Michael R Carrasco, Jaan Noolandi, Curtis W Frank, Christopher N Ta
    Abstract:

    Abstract Hydrogels are hydrophilic, crosslinked polymers that are being used with increasing frequency in a variety of biomedical applications. The ability to obtain high-quality histological sections, without artifacts, after in vivo Implantation is critical to their evaluation. Unfortunately, because of their high water content and environmental sensitivities, many hydrogels are unable to be successfully processed for histology using typical tissue processing methods. In this work, we present a method for successfully processing pHsensitive hydrogels for histological analysis. A modified glycol methacrylate (GMA) processing and embedding protocol is described. One cornea each from 10 New Zealand Red rabbits was Implanted with a poly(ethylene glycol) and poly(acrylic acid) interpenetrating double network hydrogel disc for 2 weeks and processed for histology. Maintaining a neutral pH during fixation with glutaraldehyde is a critical initial step for processing. In addition, typical tissue processing metho...

Margaret D. M. Evans - One of the best experts on this subject based on the ideXlab platform.

  • A perfluoropolyether Corneal inlay for the correction of refractive error
    Biomaterials, 2011
    Co-Authors: Margaret D. M. Evans, Keith M. Mclean, Timothy C. Hughes, Ruby Kala Prakasam, Pravin K. Vaddavalli, Warren Knower, John S. Wilkie, Graham Johnson, Gail A. Mcfarland
    Abstract:

    This study assessed the long-term biological response of a perfluoropolyether-based polymer developed as a Corneal inlay to correct refractive error. The polymer formulation met chemical and physical specifications and was non-cytotoxic when tested using standard in vitro techniques. It was cast into small microporous membranes that were Implanted as inlays into corneas of rabbits (n = 5) and unsighted humans (n = 5 + 1 surgical control) which were monitored for up to 23 and 48 months respectively. Overall, the inlays were well tolerated during study period with the corneas remaining clear and holding a normal tear film and with no increased vascularisation or redness recorded. Inlays in three human corneas continued past 48 months without sequelae. Inlays in two human corneas were removed early due to small, focal erosions developing 5 and 24 months post-Implantation. Polymer inlays maintained their integrity and Corneal position for the study duration although the optical clarity of the inlays reduced slowly with time. Inlays induced Corneal curvature changes in human subjects that showed stability with time and the refractive effect was reversed when the inlay was removed. Outcomes showed the potential of a perfluoropolyether inlay as a biologically acceptable Corneal Implant with which to provide stable correction of refractive error.

  • Synthetic Corneal inlays
    Clinical and Experimental Optometry, 2008
    Co-Authors: Deborah F. Sweeney, Margaret D. M. Evans, Keith M. Mclean, Timothy C. Hughes, Antti Vannas, V.k. Pravin, Ruby Kala Prakasam
    Abstract:

    This review is based on the activities of the Vision Cooperative Research Centre (previously Cooperative Research Centre for Eye Research and Technology) Corneal Implant team from 1991 to 2007. The development of a synthetic polymer of perfluoropolyether (PFPE), meeting essential physical and biological requirements, for use as a Corneal inlay is presented. Each inlay was placed in a Corneal flap created with a microkeratome and monitored over a two-year period in a rabbit model. The results indicate that the PFPE Implant shows excellent biocompatibility and biostability. As a result, a Phase 1 clinical trial is being conducted. Three years post-Implantation, the PFPE inlays are exhibiting continued excellent biocompatibility. Corneal inlays made from PFPE are biocompatible with Corneal tissue in the long term and offer a safe and biologically-acceptable alternative to other forms of refractive surgery.

  • A review of the development of a synthetic Corneal onlay for refractive correction
    Biomaterials, 2001
    Co-Authors: Margaret D. M. Evans, Keith M. Mclean, Timothy C. Hughes, Deborah F. Sweeney
    Abstract:

    A synthetic Corneal onlay, or Implantable contact lens, could obviate the need for spectacles or conventional contact lenses in patients who seek convenient, reversible correction of refractive error. Several research groups have attempted to develop such a product in the past but much of the data from these studies remains unpublished due to commercial interests. This article reviews relevant papers and patents in the Corneal Implant field and discusses our efforts to develop a synthetic Corneal onlay using a perfluoropolyether-based polymer.

Walter D. Furlan - One of the best experts on this subject based on the ideXlab platform.

  • Imaging Performance of a Diffractive Corneal Inlay for Presbyopia in a Model Eye
    IEEE Access, 2019
    Co-Authors: Diego Montagud-martínez, Vicente Ferrando, Federico Machado, Juan A. Monsoriu, Walter D. Furlan
    Abstract:

    In this work we evaluated the imaging properties of the Diffractive Corneal Inlay (DCI), a novel type of Corneal Implant working by diffraction that we proposed for the treatment of presbyopia. ZEMAX OpticStudio software was employed for the numerical assessment, with simulations performed in a human-based eye model. In the ray tracing analysis, we used the Modulation Transfer Function (MTF), the Area under the MTF (AMTF), and the Point Spread Function (PSF). The theoretical performance of the DCI under different situations was evaluated in comparison with a commercially available pinhole based Corneal inlay. Finally, real images were obtained experimentally in vitro in a model eye with inlays prototypes. The obtained results allow to state that the DCI exhibits a very high light throughput, improved imaging capabilities for far and near objects, and robustness against decentrations.

Deborah F. Sweeney - One of the best experts on this subject based on the ideXlab platform.

  • Synthetic Corneal inlays
    Clinical and Experimental Optometry, 2008
    Co-Authors: Deborah F. Sweeney, Margaret D. M. Evans, Keith M. Mclean, Timothy C. Hughes, Antti Vannas, V.k. Pravin, Ruby Kala Prakasam
    Abstract:

    This review is based on the activities of the Vision Cooperative Research Centre (previously Cooperative Research Centre for Eye Research and Technology) Corneal Implant team from 1991 to 2007. The development of a synthetic polymer of perfluoropolyether (PFPE), meeting essential physical and biological requirements, for use as a Corneal inlay is presented. Each inlay was placed in a Corneal flap created with a microkeratome and monitored over a two-year period in a rabbit model. The results indicate that the PFPE Implant shows excellent biocompatibility and biostability. As a result, a Phase 1 clinical trial is being conducted. Three years post-Implantation, the PFPE inlays are exhibiting continued excellent biocompatibility. Corneal inlays made from PFPE are biocompatible with Corneal tissue in the long term and offer a safe and biologically-acceptable alternative to other forms of refractive surgery.

  • A review of the development of a synthetic Corneal onlay for refractive correction
    Biomaterials, 2001
    Co-Authors: Margaret D. M. Evans, Keith M. Mclean, Timothy C. Hughes, Deborah F. Sweeney
    Abstract:

    A synthetic Corneal onlay, or Implantable contact lens, could obviate the need for spectacles or conventional contact lenses in patients who seek convenient, reversible correction of refractive error. Several research groups have attempted to develop such a product in the past but much of the data from these studies remains unpublished due to commercial interests. This article reviews relevant papers and patents in the Corneal Implant field and discusses our efforts to develop a synthetic Corneal onlay using a perfluoropolyether-based polymer.