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The Historical Development and an Overview of Contemporary Keratoprostheses. Surv Ophthalmol 2022; 67:1175-1199. [DOI: 10.1016/j.survophthal.2022.01.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/07/2022] [Accepted: 01/19/2022] [Indexed: 11/24/2022]
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Rahmani S, Kanavi MR, Javadi MA, Langroudi MM, Aski SA. Histopathologic Evaluation of Polymer Supports for Pintucci-type Keratoprostheses: An Animal Study. J Ophthalmic Vis Res 2019; 14:243-250. [PMID: 31660102 PMCID: PMC6815345 DOI: 10.18502/jovr.v14i3.4779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 10/28/2018] [Indexed: 11/30/2022] Open
Abstract
Purpose To report histopathological findings for different types of polymers proposed as support for a Pintucci-type keratoprosthesis. Methods Six polymers, including three types of polyesters (#1-3), one type of polytetrafluoroethylene (PTFE, #4), polyethylene (#5), and expanded polytetrafluoroethylene (ePTFE, #6) were evaluated. Four samples of each material were placed under the orbicularis oculi muscles of 12 rabbits. After five weeks, the samples were removed and evaluated histopathologically. Fibrovascular tissue ingrowths were investigated in terms of tissue penetration depth into the materials (graded as none, mild, moderate, and intense) and fibrovascular ingrowth area at the ultimate level of tissue penetrance. ImageJ software was used to calculate fibrovascular tissue area between the material fibers, and the mean area values were compared between the materials. Results Polyester materials #1 and #3 demonstrated intense fibrovascular tissue penetration with a large fibrovascular ingrowth area; no overt tissue ingrowth was observed into material #6. The mean area of penetrated fibrovascular tissues was significantly different between materials (P < 0.001). Materials #2, #4, and #5 showed moderate fibrovascular tissue ingrowth and the area of presented fibrovascular tissue at the paracentral parts of material #4 was significantly smaller than that of materials #1 (P = 0.02) and #3 (P = 0.01). Conclusion Two polyester materials that had relatively large pore sizes demonstrated a deep and large area of fibrovascular ingrowth. Given that material #3 is thicker and more consistent than material #1, the former can be used as the appropriate material for supporting the Pintucci-type keratoprosthesis.
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Affiliation(s)
- Saeed Rahmani
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mozhgan Rezaei Kanavi
- Ocular Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Ali Javadi
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Sasha Afsar Aski
- Ocular Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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New strategy for design and fabrication of polymer hydrogel with tunable porosity as artificial corneal skirt. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 70:665-672. [PMID: 27770940 DOI: 10.1016/j.msec.2016.09.042] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 09/02/2016] [Accepted: 09/21/2016] [Indexed: 01/01/2023]
Abstract
In order to obtain an ideal material using for artificial corneal skirt, a porous polymer hydrogel containing 2-hydroxyethyl methacrylate (HEMA), trimethylolpropane triacrylate (TMPTA) and butyl acrylate was prepared through one-step radical polymerization method and the usage of CaCO3 whisker as porogen. The physical-chemical properties of the fabricated polymer hydrogel can be adjusted by CaCO3 whisker content, such as pore size, porosity, water content of materials and surface topography. Then a series of cell biology experiments of human corneal fibroblasts (HCFs) were carried out to evaluate its properties as an artificial corneal skirt, such as the adhesion of cells on the materials with different pore size and porosity, the apoptosis on materials with different characteristics, the distribution of the cells on the material surface. The results revealed that high porosity not only could improve water content of hydrogel, but also strengthen the adhesion of HCFs on hydrogel. In addition, high porosity hydrogel with the whisker shape of pores showed much elongate spindle-like morphology than those low porosity hydrogels. MTT assay certified that the resulted polymer hydrogel material possessed excellent biocompatibility and was suitable for HCFs growing, making it promising for being developed as artificial corneal skirt.
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Duan D, Klenkler BJ, Sheardown H. Progress in the development of a corneal replacement: keratoprostheses and tissue-engineered corneas. Expert Rev Med Devices 2014; 3:59-72. [PMID: 16359253 DOI: 10.1586/17434440.3.1.59] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Rapid progress has been made in the past 5 years in the development of corneal replacements. Traditionally they are divided into two categories, keratoprostheses and tissue-engineered corneal equivalents, as replacement tissues are increasingly in demand worldwide. There are currently several different keratoprosthesis models in clinical use around the world. The most popular and most widely publicized is the AlphaCor model, which has enjoyed significant clinical success. However, improvements remain to be made, and the aim of most of the current research is to better understand the interactions between a synthetic material and the surrounding biology on a more fundamental level. This improved understanding will no doubt lead to improvements in current models and to the development of new models in the near future. While tissue-engineered corneal equivalents have been under investigation for considerably less time, there is growing evidence to suggest that a tissue-engineered corneal equivalent comprised of primarily natural materials will exist in the not too distant future. Research groups have reported strong in vitro and in vivo results. The strength of the collagen matrix and its ability to support cell infiltration have been the primary avenues of research. Various collagen crosslinking techniques have been used. Infiltration of three major cells of the cornea has been observed. Most importantly, the ability of these materials to support nerve ingrowth has been demonstrated. While challenges remain with both types of corneal replacements, the considerable progress in the recent past suggests that reliable implants for the treatment of a variety of corneal diseases will be available. This review will provide an overview of recent results, and will provide insight into the future of research on corneal replacements.
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Affiliation(s)
- Derek Duan
- McMaster University, Department of Chemical Engineering, Hamilton ON L8S 4L7, Canada
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Designing a gas foamed scaffold for keratoprosthesis. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2013; 33:3396-403. [DOI: 10.1016/j.msec.2013.04.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 03/07/2013] [Accepted: 04/10/2013] [Indexed: 11/22/2022]
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Zellander A, Wardlow M, Djalilian A, Zhao C, Abiade J, Cho M. Engineering copolymeric artificial cornea with salt porogen. J Biomed Mater Res A 2013; 102:1799-808. [DOI: 10.1002/jbm.a.34852] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Accepted: 06/05/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Amelia Zellander
- Department of Bioengineering; University of Illinois; Chicago Illinois
| | - Melissa Wardlow
- Department of Bioengineering; University of Illinois; Chicago Illinois
| | - Ali Djalilian
- Department of Ophthalmology and Visual Sciences; University of Illinois; Chicago Illinois
| | - Chenlin Zhao
- Department of Mechanical and Industrial Engineering; University of Illinois; Chicago Illinois
| | - Jeremiah Abiade
- Department of Mechanical and Industrial Engineering; University of Illinois; Chicago Illinois
| | - Michael Cho
- Department of Bioengineering; University of Illinois; Chicago Illinois
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Lee SM, Kim MK, Shin MS, Wee WR. Matrix metalloproteinase-9 expression in the Seoul-type keratoprosthesis implanted corneas with concurrent cultivated autologous oral mucosal epithelial cell transplantation. Graefes Arch Clin Exp Ophthalmol 2012; 251:619-22. [PMID: 22252113 DOI: 10.1007/s00417-011-1923-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 12/22/2011] [Accepted: 12/29/2011] [Indexed: 11/24/2022] Open
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Abstract
Previously we have found that the immobilization of Type I collagen on the
poly(vinyl alcohol)(PVA) hydrogel disc was effective in supporting adhesion and growth of the
corneal epithelium and stromal cell in vitro. But the durability of the produced corneal epithelium
layer in vivo has some problem. We hypothesized the cell construction force is much stronger than
the force of the cell adhesion on the flat modified PVA surfaces. Therefore the improvement of
mechanical anchoring force between the substrate and formed corneal cell layer maybe become one
of the solving methods. In this study, we prepared the PVA nanofiber mat by using the
electrospinning method and the surface modification of the PVA nanofiber was studied to improve
the durability of the corneal epithelium layer. The collagen-immobilized PVA nanofiber sheets
could support the adhesion and proliferation of rabbit corneal epithelial cells. And the stratified
corneal epithelium structure was observed on the PVA nanofiber sheets when the epithelium was
co-cultured with rabbit corneal stromal cells. It means that the corneal epithelium was well
differentiated on the collagen immobilized PVA nanofiber sheet. The stability of the corneal
epithelium layer on the PVA was dramatically improved; the stratified epithelium layer was kept for
two weeks after the differentiation introduction, totally after one month. A light transmittance of
these materials is not yet enough. Further study to improve the transmission of light, is required.
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Kim MK, Lee SM, Lee JL, Chung TY, Kim YH, Wee WR, Lee JH. Long-Term Outcome in Ocular Intractable Surface Disease With Seoul-Type Keratoprosthesis. Cornea 2007; 26:546-51. [PMID: 17525649 DOI: 10.1097/ico.0b013e3180415d35] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the long-term clinical efficacy of the Seoul-type keratoprosthesis (S-KPro). METHODS S-KPros were implanted into 4 unsighted and 5 sighted eyes in 9 patients: 6 patients were diagnosed with Stevens-Johnson syndrome, 2 had chemical burns, and 1 suffered from ocular pemphigoid. The preoperative visual acuity ranged from light perception to hand motion. The average follow-up period was 62.8 months. We evaluated several clinical factors, including visual acuity, visual field, number of additional grafting procedures, number of capsulotomy procedures, and the interval between retinal detachment and skirt exposure. RESULTS The S-KPro showed anatomic success for an average of 62.8 months in 66.7% of the eyes. The average visual acuity preservation time was 31.6 months. Localized glaucomatous visual field defect was not found in any of the sighted patients; however, diffuse visual field constriction was observed after long-term follow-up. Average time of skirt exposure and mean number of additional grafting procedures were 12.9 months and 2.44, respectively. Retinal detachments were developed in all the patients at a mean time interval of 2 months after S-KPro exchange. CONCLUSIONS S-KPro achieved visual rehabilitation for an average of 31.6 months with long-term anatomic stability in patients with severe intractable ocular surface disease.
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Affiliation(s)
- Mee Kum Kim
- Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea
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Uchino Y, Shimmura S, Miyashita H, Taguchi T, Kobayashi H, Shimazaki J, Tanaka J, Tsubota K. Amniotic membrane immobilized poly(vinyl alcohol) hybrid polymer as an artificial cornea scaffold that supports a stratified and differentiated corneal epithelium. J Biomed Mater Res B Appl Biomater 2007; 81:201-6. [PMID: 16924609 DOI: 10.1002/jbm.b.30654] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Poly(vinyl alcohol) (PVA) is a biocompatible, transparent hydrogel with physical strength that makes it promising as a material for an artificial cornea. In our previous study, type I collagen was immobilized onto PVA (PVA-COL) as a possible artificial cornea scaffold that can sustain a functional corneal epithelium. The cellular adhesiveness of PVA in vitro was improved by collagen immobilization; however, stable epithelialization was not achieved in vivo. To improve epithelialization in vivo, we created an amniotic membrane (AM)-immobilized polyvinyl alcohol hydrogel (PVA-AM) for use as an artificial cornea material. AM was attached to PVA-COL using a tissue adhesive consisting of collagen and citric acid derivative (CAD) as a crosslinker. Rabbit corneal epithelial cells were air-lift cultured with 3T3 feeder fibroblasts to form a stratified epithelial layer on PVA-AM. The rabbit corneal epithelial cells formed 3-5 layers of keratin-3-positive epithelium on PVA-AM. Occludin-positive cells were observed lining the superficial epithelium, the gap-junctional protein connexin43-positive cells was localized to the cell membrane of the basal epithelium, while both collagen IV were observed in the basement membrane. Epithelialization over implanted PVA-AM was complete within 2 weeks, with little inflammation or opacification of the hydrogel. Corneal epithelialization on PVA-AM in rabbit corneas improved over PVA-COL, suggesting the possibility of using PVA-AM as a biocompatible hybrid material for keratoprosthesis.
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Affiliation(s)
- Yuichi Uchino
- Department of Ophthalmology, Tokyo Dental College, Chiba, Japan
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Miyashita H, Shimmura S, Kobayashi H, Taguchi T, Asano-Kato N, Uchino Y, Kato M, Shimazaki J, Tanaka J, Tsubota K. Collagen-immobilized poly(vinyl alcohol) as an artificial cornea scaffold that supports a stratified corneal epithelium. J Biomed Mater Res B Appl Biomater 2006; 76:56-63. [PMID: 16044431 DOI: 10.1002/jbm.b.30332] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The cornea is a transparent tissue of the eye, which is responsible for the refraction of incoming light. Both biological corneal equivalents and synthetic keratoprostheses have been developed to replace donor tissue as a means to restore vision. However, both designs have drawbacks in terms of stability and biocompatibility. Clinically available synthetic devices do not support an intact epithelium, which poses a risk of microbial infection or protrusion of the prosthesis. In the present study, type I collagen was immobilized onto poly(vinyl alcohol) (PVA-COL) as a possible artificial cornea scaffold that can sustain a functional corneal epithelium. Human and rabbit corneal epithelial cells were air-lift cultured with 3T3 feeder fibroblasts to form a stratified epithelial layer on PVA-COL. The epithelial sheet expressed keratin 3/12 differentiation markers, the tight junction protein occludin, and had characteristic microvilli structures on transmission electron microscopy. Functionally, the stratified epithelium contained normal glycogen levels, and an apical tight-junction network was observed to exclude the diffusion of horseradish peroxidase. Furthermore, the epithelium-PVA-COL composite was suturable in the rabbit cornea, suggesting the possibility of using PVA-COL as a biocompatible material for keratoprosthesis.
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Shimmura S, Miyashita H, Uchino Y, Taguchi T, Kobayashi H, Shimazaki J, Tanaka J, Tsubota K. Microkeratome assisted deep lamellar keratoprosthesis. Br J Ophthalmol 2006; 90:826-9. [PMID: 16597665 PMCID: PMC1857140 DOI: 10.1136/bjo.2006.090324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIMS To establish a keratoprosthesis (Kpro) surgical technique that maintains an intact superficial corneal layer. METHODS A manual microkeratome (Moria LSK-1) was used to create a 130 mum flap of approximately 10 mm diameter in the right eye of Japanese white rabbits. The stoma beneath the flap area was dissected before the removal of a 5.0 mm stromal disc. A 5.0 mm collagen I immobilised poly(vinyl alcohol) (COL-PVA) disc was placed on the exposed posterior stroma close to Descemet's membrane. The flap was repositioned and fixed using 10-0 nylon sutures, which were removed 2 days following surgery. The corneas were followed clinically by slit lamp microscopy and photographs. Rabbits were sacrificed after 6 months, and the transplanted corneas were examined histologically by haematoxylin and eosin staining and immunohistochemistry against vimentin and alpha-smooth muscle actin (alpha-SMA). RESULTS The transplanted COL-PVA discs remained transparent throughout the study, with no complications related to the flap or overlying epithelium. The interface between COL-PVA and Descemet's membrane remained clear without signs of opacification caused by scarring or cellular deposition. Pathology revealed the intact COL-PVA polymer in the posterior stroma, with minimal cellular infiltration along the anterior and posterior interfaces. Immunohistology shows vimentin and alpha-SMA staining at levels comparable to lamellar keratoplasty control. CONCLUSIONS Microkeratome assisted deep lamellar keratoprosthesis may be a safe technique for the transplantation of artificial hydrogels for therapeutic purposes.
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Affiliation(s)
- S Shimmura
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
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Sarayba MA, Kurtz RM, Nguyen TTB, Ignacio T, Mansoori M, Sweet PM, Chuck RS. Femtosecond Laser-Assisted Intracorneal Keratoprosthesis Implantation. Cornea 2005; 24:1010-4. [PMID: 16227853 DOI: 10.1097/01.ico.0000160975.81200.09] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To demonstrate femtosecond laser-assisted intracorneal keratoprosthesis implantation and determine the mechanical stability as a function of intraocular pressure. METHODS Eight human corneoscleral rims were mounted on an artificial anterior chamber. The femtosecond laser microkeratome was used to create a 2.5-mm diameter posterior corneal cap. A 7.2-mm-diameter lamellar stromal pocket was then created at mid-corneal depth. Finally, a 6-mm arc opening to the corneal surface was created at the periphery of the lamellar cut. The posterior lenticule was removed using corneal forceps and a 7.0-mm biopolymer keratoprosthesis was inserted into the stromal pocket. The surface wound was sealed using two 10-0 nylon sutures. A 3.0-mm anterior corneal opening was trephined to expose the keratoprosthesis. Intrachamber pressure was raised until wound leak was observed. RESULTS Seven of the 8 implants withstood pressures of at least 135 mm Hg without implant extrusion. CONCLUSION Femtosecond laser corneal dissection provides an alternative to more challenging manual dissection methods for keratoprosthesis implantation. Use of the femtosecond laser microkeratome will further refine keratoprosthesis surgical technique and may allow rapid and easy execution of the surgery.
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Affiliation(s)
- Melvin A Sarayba
- Department of Ophthalmology, University of California, Irvine, USA
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Abstract
PURPOSE OF REVIEW Diseases affecting the cornea are a major cause of blindness worldwide, second only to cataract in overall importance, with an estimated 10 to 15 million affected people. Although keratoplasty is by far the most successful transplantation surgery, the outcomes in high-risk adult patients, including those with ocular surface diseases and multiple graft rejections, and in pediatric patients with congenital corneal opacities are disappointing. RECENT DEVELOPMENTS Regrettably, no significant clinical developments have been achieved in the field of corneal transplantation since the introduction of steroids for graft rejection. Furthermore, obtaining donor corneal tissues and eye banking, particularly in the developing countries where corneal blindness is most prevalent, are problematic. Although the postoperative complications may be severe and limit the use of currently available devices, keratoprosthesis--artificial corneal implantation--has a role in the management of corneal blindness in carefully selected patients with complex ocular diseases who are at high risk for graft failure. SUMMARY This article reviews the recent ophthalmic literature published on the current concepts and techniques of keratoprosthesis surgery.
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Affiliation(s)
- Ozge Ilhan-Sarac
- The Ocular Surface Diseases and Dry Eye Clinic, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9238, USA
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