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1.
Case Rep Ophthalmol ; 15(1): 648-655, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39144639

RESUMEN

Introduction: Complex corneal conditions present surgical challenges and necessitate innovation. Here, we present two cases where we performed intraocular lens trans-scleral fixation using the double-needle Yamane technique, followed by penetrating keratoplasty and vitrectomy using a temporary Landers wide-field keratoprosthesis. Case Presentation: Case 1 involved a 70-year-old man with an aphakic eye of bullous keratopathy and corneal opacity owing to multiple penetrating and endothelial keratoplasty, endophthalmitis, and herpetic keratitis. His visual acuity was counting fingers at 20 cm before surgery. Penetrating keratoplasty with vitrectomy and intraocular lens scleral fixation was performed using the double-needle Yamane technique, and 10 months postoperatively, his best-corrected visual acuity improved to 0.6, presenting a clear cornea. Case 2 involved a 62-year-old man who underwent penetrating keratoplasty twice for corneal perforation and therapeutic penetrating keratoplasty with vitrectomy for traumatic globe rupture, resulting in the loss of the intraocular lens. The patient exhibited graft failure, and his best-corrected visual acuity was 0.03. Utilizing a temporary Landers wide-field keratoprosthesis, we performed penetrating keratoplasty and intraocular lens trans-scleral fixation without complications. His final best-corrected visual acuity improved to 0.15 with a clear cornea. Conclusions: Trans-scleral fixation of intraocular lens with penetrating keratoplasty, using temporary Landers wide-field keratoprosthesis, yielded positive clinical outcomes without serious complications.

2.
Bioengineering (Basel) ; 10(10)2023 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-37892965

RESUMEN

We investigated the bioavailability and stability of a C-Clear artificial cornea in a rabbit chemical burn model. Thirty-six rabbits were divided into a control group (n = 16) and a chemical burn group that used NaOH solution (n = 20). After lamellar dissection, the central posterior lamella was excised using a 3 mm diameter trephine, and an artificial cornea was transplanted into the lamellar pocket. After 2 weeks, the central anterior lamella was excised using a 3 mm diameter trephine to secure a clean visual axis. We examined the anterior segment of the eyes weekly for 12 weeks after transplantation. Successful subjects whose artificial corneas were maintained stably for 12 weeks were euthanized and underwent histologic examinations. Artificial corneas remained stable for up to 12 weeks in 62.5 and 50% of rabbits in the control and chemical burn groups, respectively. Two rabbits in the chemical burn group showed the formation of a retroprosthetic membrane, and one rabbit with visual axis blockage underwent membrane removal using a Nd:YAG laser. In histologic examinations, adhesion between artificial cornea and peripheral corneal stoma was observed. In conclusion, we confirmed structural stability and biocompatibility of the C-Clear artificial cornea for up to 12 weeks after implantation in control and chemical burn groups.

3.
J Fr Ophtalmol ; 46(10): 1212-1221, 2023 Dec.
Artículo en Francés | MEDLINE | ID: mdl-37867123

RESUMEN

BACKGROUND/PURPOSE: To evaluate long-term visual outcomes of Boston type I keratoprosthesis (KPro) surgery and identify risk factors for visual failure. METHODS: Single surgeon retrospective cohort study including 85 eyes of 74 patients who underwent KPro implantation to treat severe ocular surface disease, including limbal stem cell deficiency, postinfectious keratitis, aniridia and chemical burns. Procedures were performed at the Centre hospitalier de l'Université de Montréal from October 2008 to May 2012. All patients with at least 5 years of follow-up were included in the analysis, including eyes with repeated KPro. Main outcome measures were visual acuity (VA), visual failure, defined as a sustained VA worse than the preoperative VA, postoperative complications, and device retention. RESULTS: Mean follow-up was 7.2±1.3 years (±SD). Mean VA was 2.1±0.7 (logarithm of minimal angle resolution) preoperatively and 1.9±1.2 at last follow-up. In total, 2.4% of patients had VA better than 20/200 preoperatively vs. 36.5% at last follow-up. Maintenance of improved postoperative VA was seen in 61.8% of eyes at 7 years. Preoperative factors associated with visual failure were known history of glaucoma (HR=2.7 [1.2 to 5.9], P=0.02) and Stevens-Johnson syndrome (HR=7.3 [2.5 to 21.4], P<0.01). Cumulative 8-year complication rates were 38.8% retroprosthetic membrane formation, 25.9% hypotony, 23.5% new onset glaucoma, 17.6% retinal detachment, 8.2% device extrusion and 5.9% endophthalmitis. The majority (91.8%) of eyes retained the device 8 years after implantation. CONCLUSION: Nearly two-thirds of patients exhibited improved VA 7 years after KPro implantation. Preoperative risk factors for visual failure were known glaucoma and Stevens-Johnson syndrome.


Asunto(s)
Órganos Artificiales , Enfermedades de la Córnea , Glaucoma , Síndrome de Stevens-Johnson , Humanos , Córnea/cirugía , Prótesis e Implantes/efectos adversos , Enfermedades de la Córnea/epidemiología , Enfermedades de la Córnea/cirugía , Enfermedades de la Córnea/complicaciones , Estudios Retrospectivos , Síndrome de Stevens-Johnson/complicaciones , Órganos Artificiales/efectos adversos , Canadá , Glaucoma/epidemiología , Glaucoma/etiología , Glaucoma/cirugía , Implantación de Prótesis/efectos adversos , Implantación de Prótesis/métodos , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/cirugía , Estudios de Seguimiento
4.
Clin Pract ; 13(1): 264-279, 2023 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-36826166

RESUMEN

The cornea is a transparent avascular structure located in the front of the eye that refracts light entering the eyes and also serves as a barrier between the outside world and the internal contents of the eye. Like every other body part, the cornea may suffer insult from trauma, infection, and inflammation. In the case of trauma, a prior infection that left a scar, or conditions such as keratoconus that warrant the removal of all or part of the cornea (keratoplasty), it is important to use healthy donor corneal tissues and cells that can replace the damaged cornea. The types of cornea transplant techniques employed currently include: penetrating keratoplasty, endothelial keratoplasty (EK), and artificial cornea transplant. Postoperative failure acutely or after years can result after a cornea transplant and may require a repeat transplant. This minireview briefly examines the various types of corneal transplant methodologies, indications, contraindications, presurgical protocols, sources of cornea transplant material, wound healing after surgery complications, co-morbidities, and the effect of COVID-19 in corneal transplant surgery.

5.
Int Ophthalmol ; 43(6): 2003-2015, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36436171

RESUMEN

BACKGROUND: Many studies have been focused on the area of the artificial cornea. In our study, a bibliometric analysis was performed on the artificial cornea to identify the global key research fields and trends over the past 20 years. METHODS: Publications about artificial cornea were retrieved and downloaded from the Web of Science Core Collection from 2002 to 2021. CiteSpace and VOSviewer were used to analyze countries, institutions, authors, and related research areas. RESULTS: A total of 829 eligible publications were analyzed. The USA was the most productive country for the artificial cornea, followed by China and Canada. Harvard University was the most prolific institution in this field. Cornea published most of the studies in this area and Dohlman CH was the most cited author. CONCLUSIONS: Bibliometric analysis in our study first provides a general perspective on the artificial cornea, which can be helpful to further explore the issues in the rapidly developing area.


Asunto(s)
Bibliometría , Prótesis e Implantes , Humanos , Córnea , Canadá , China
6.
ACS Appl Bio Mater ; 5(12): 5716-5727, 2022 12 19.
Artículo en Inglés | MEDLINE | ID: mdl-36416454

RESUMEN

Despite rigorous investigations, the hydrogels currently available to replace damaged tissues, such as the cornea, cannot fulfill mechanical and structural requirements and, more importantly, cannot be sutured into host tissues due to the lack of hierarchical structures to dissipate exerted stress. In this report, solution electrospinning of polycaprolactone (PCL), protein-based hydrogel perfusion, and layer-by-layer stacking are used to generate a hydrogel-microfiber composite with varying PCL fiber diameters and hydrogel concentrations. Integrating PCL microfibers into the hydrogel synergistically improves the mechanical properties and suturability of the construct up to 10-fold and 50-fold, respectively, compared to the hydrogel and microfiber scaffolds alone, approaching those of the corneal tissue. Human corneal cells cultured on composites are viable and can spread, proliferate, and retain phenotypic characteristics. Moreover, corneal stromal cells migrate into the scaffold, degrade it, and regenerate the extracellular matrix. The current hydrogel reinforcing system paves the way for producing suturable and, therefore, transplantable tissue constructs with desired mechanical properties.


Asunto(s)
Ingeniería de Tejidos , Andamios del Tejido , Humanos , Andamios del Tejido/química , Hidrogeles/farmacología , Córnea , Matriz Extracelular
7.
Vestn Oftalmol ; 138(5. Vyp. 2): 253-259, 2022.
Artículo en Ruso | MEDLINE | ID: mdl-36287164

RESUMEN

Despite the fact that various collagen biomaterials have been actively used in ophthalmology for more than 30 years, the problem of creating a material that could replace the donor cornea have not been solved. Recent advances in the field of tissue engineering and regenerative medicine have shifted the focus of approaches to solving the problem of creating an artificial cornea towards laying conditions for the restoration of its specific layers through mechanisms of its own cellular regeneration. In this regard, extracellular matrices based on collagen are gaining popularity. This review discusses general limitations and advantages of collagen for creating an artificial cornea.


Asunto(s)
Colágeno , Sustancia Propia , Ingeniería de Tejidos , Córnea , Materiales Biocompatibles
8.
J Funct Biomater ; 13(3)2022 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-35893466

RESUMEN

Corneal defects can seriously affect human vision, and keratoplasty is the most widely accepted therapy method for visual rehabilitation. Currently, effective treatment for clinical patients has been restricted due to a serious shortage of donated cornea tissue and high-quality artificial repair materials. As the predominant component of cornea tissue, collagen-based materials have promising applications for corneal repair. However, the corneal nerve repair and epithelization process after corneal transplantation must be improved. This research proposes a new collagen-based scaffold with good biocompatibility and biological functionality enhanced by surface chemical grafting of natural taurine molecular. The chemical composition of collagen-taurine (Col-Tau) material is evaluated by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, and its hydrophilic properties, light transmittance, swelling performance and mechanical tensile properties have been measured. The research results indicate that the Col-Tau sample has high transmittance and good mechanical properties, and exhibits excellent capacity to promote corneal nerve cell growth and the epithelization process of corneal epithelial cells. This novel Col-Tau material, which can be easily prepared at a low cost, should have significant application potential for the treating corneal disease in the future.

9.
Front Med (Lausanne) ; 8: 770780, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34869489

RESUMEN

Corneal diseases are a leading cause of blindness with an estimated 10 million patients diagnosed with bilateral corneal blindness worldwide. Corneal transplantation is highly successful in low-risk patients with corneal blindness but often fails those with high-risk indications such as recurrent or chronic inflammatory disorders, history of glaucoma and herpetic infections, and those with neovascularisation of the host bed. Moreover, the need for donor corneas greatly exceeds the supply, especially in disadvantaged countries. Therefore, artificial and bio-mimetic corneas have been investigated for patients with indications that result in keratoplasty failure. Two long-lasting keratoprostheses with different indications, the Boston type-1 keratoprostheses and osteo-odonto-keratoprostheses have been adapted to minimise complications that have arisen over time. However, both utilise either autologous tissue or an allograft cornea to increase biointegration. To step away from the need for donor material, synthetic keratoprostheses with soft skirts have been introduced to increase biointegration between the device and native tissue. The AlphaCor™, a synthetic polymer (PHEMA) hydrogel, addressed certain complications of the previous versions of keratoprostheses but resulted in stromal melting and optic deposition. Efforts are being made towards creating synthetic keratoprostheses that emulate native corneas by the inclusion of biomolecules that support enhanced biointegration of the implant while reducing stromal melting and optic deposition. The field continues to shift towards more advanced bioengineering approaches to form replacement corneas. Certain biomolecules such as collagen are being investigated to create corneal substitutes, which can be used as the basis for bio-inks in 3D corneal bioprinting. Alternatively, decellularised corneas from mammalian sources have shown potential in replicating both the corneal composition and fibril architecture. This review will discuss the limitations of keratoplasty, milestones in the history of artificial corneal development, advancements in current artificial corneas, and future possibilities in this field.

10.
Polymers (Basel) ; 13(24)2021 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-34960923

RESUMEN

The blindness caused by cornea diseases has exacerbated many patients all over the world. The disadvantages of using donor corneas may cause challenges to recovering eye sight. Developing artificial corneas with biocompatibility may provide another option to recover blindness. The techniques of making individual artificial corneas that fit the biometric parameters for each person can be used to help these patients effectively. In this study, artificial corneas with different shapes (spherical, aspherical, and biconic shapes) are designed and they could be made by two different hydrogel polymers that form an interpenetrating polymer network for their excellent mechanical strength. Two designed cases for the artificial corneas are considered in the simulations: to optimize the artificial cornea for patients who still wear glasses and to assume that the patient does not wear glasses after transplanting with the optimized artificial cornea. The results show that the artificial corneas can efficiently decrease the imaging blur. Increasing asphericity of the current designed artificial corneas can be helpful for the imaging corrections. The differences in the optical performance of the optimized artificial corneas by using different materials are small. It is found that the optimized artificial cornea can reduce the high order aberrations for the second case.

11.
Exp Eye Res ; 209: 108661, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34102207

RESUMEN

There is an international shortage of donor corneas for transplantation to treat the 1.5-2.0 million new cases of blindness secondary to corneal disease. Research has therefore been directed towards the development of artificial corneas using alternative materials such as collagen. The biocompatibility of an acellular collagen-based scaffold for anterior lamellar keratoplasty was investigated in vivo in a rabbit model. This scaffold has previously shown promise as a corneal substitute in vitro. Slit-lamp and Optical Coherence Tomography examinations were carried out at 2 weeks, 1, 2, 3, and 6 months post-operatively. Graft-host integration was investigated using immunohistochemistry of the cornea at 6 months. Results showed that the graft was biocompatible, supported corneal re-epithelialisation, and showed no signs of rejection. Migration of stromal cells into areas of the graft was observed, however this was accompanied by extensive graft digestion. Whilst the scaffold was biocompatible, further modifications to the material or supplementation with matrix metalloproteinase inhibitors are required to bring us closer to a stable and fully integrated corneal substitute.


Asunto(s)
Colágeno/metabolismo , Córnea/cirugía , Enfermedades de la Córnea/cirugía , Trasplante de Córnea/métodos , Ingeniería de Tejidos/métodos , Animales , Córnea/diagnóstico por imagen , Córnea/metabolismo , Enfermedades de la Córnea/diagnóstico , Enfermedades de la Córnea/metabolismo , Modelos Animales de Enfermedad , Donantes de Tejidos , Tomografía de Coherencia Óptica/métodos
12.
Am J Ophthalmol ; 231: 101-108, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34107311

RESUMEN

PURPOSE: To evaluate the incidence of vitreoretinal complications, treatment modalities, and the visual outcomes in a large cohort of eyes that underwent Boston Keratoprosthesis (KPro) implantation. DESIGN: Retrospective, interventional case series. METHODS: 132 eyes of 114 patients who underwent KPro implantation at the Centre Hospitalier de l'Université de Montréal from 2008 to 2017 were included with at least 1 year follow-up. Charts were reviewed and data was collected, including demographics, initial corneal indication for surgery, posterior segment complications, preoperative and postoperative visual acuity. RESULTS: Mean follow-up was 68.2 months and 61.4% of eyes developed postoperative vitreoretinal complications (VRC). The most common VRC was RPM formation (38.6%, n=51) followed by RD (15.2%, n=20), CME (12.1%, n=16), ERM (9.8%, n=13), endophthalmitis (9.1%, n=12), sterile vitritis (7.6%, n=10), vitreous hemorrhage (6.8%, n=9), choroidal detachment (3.0%, n=4) and central retinal vein occlusion (0.7%, n=1). BCVA improved in the no VRC group from 1.74 ± 0.33 logMAR to 1.33±0.83 logMAR and in the VRC group from 1.74±0.36 logMAR to 1.52±0.83 logMAR, without any statistically significant intergroup differences (p=0.231). RD was the only significant complication associated with poorer visual outcomes (p=0.001). CONCLUSION: Potentially blinding secondary complications occur in the majority of patients and frequent monitoring is necessary, specifically in the early and intermediate postoperative periods. This study evidenced significant improvements in visual outcomes of KPro eyes, including those that developed postoperative vitreoretinal complications.


Asunto(s)
Órganos Artificiales , Enfermedades de la Córnea , Córnea/cirugía , Enfermedades de la Córnea/cirugía , Estudios de Seguimiento , Humanos , Complicaciones Posoperatorias , Prótesis e Implantes , Implantación de Prótesis , Estudios Retrospectivos
13.
ACS Appl Nano Mater ; 4(11): 12650-12662, 2021 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-35252778

RESUMEN

Despite rigorous research, inferior mechanical properties and structural homogeneity are the main challenges constraining hydrogel's suturability to host tissue and limiting its clinical applications. To tackle those, we developed a reverse solvent interface trapping method, in which organized, graphene-coated microspherical cavities were introduced into a hydrogel to create heterogeneity and make it suturable. To generate those cavities, (i) graphite exfoliates to graphene sheets, which spread at the water/ heptane interfaces of the microemulsion, (ii) heptane fills the microspheres coated by graphene, and (iii) a cross-linkable hydrogel dissolved in water fills the voids. Cross-linking solidifies such microemulsion to a strong, suturable, permanent hybrid architecture, which has better mechanical properties, yet it is biocompatible and supports cell adhesion and proliferation. These properties along with the ease and biosafety of fabrication suggest the potential of this strategy to enhance tissue engineering outcomes by generating various suturable scaffolds for biomedical applications, such as donor cornea carriers for Boston keratoprosthesis (BK).

14.
Transl Vis Sci Technol ; 9(12): 10, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-33200051

RESUMEN

Purpose: To benchmark the optical performance of Boston Keratoprosthesis (B-KPro). Methods: Back focal lengths (BFL) of B-KPros for various eye axial lengths were measured using an optical bench, International Organization for Standardization-certified for intraocular lens characterization, and compared against manufacturer's specification. The modulation transfer function (MTF) and the resolution efficiencies were measured. The theoretical geometry-dependent higher-order aberrations (HOA) were calculated. The devices were characterized with optical profilometry for estimating the surface scattering. Aberration correction and subsequent image quality improvement were simulated in CODE-V. Natural scene-imaging was performed in a mock ocular environment. Retrospective analysis of 15 B-KPro recipient eyes were presented to evaluate the possibility of achieving 20/20 best-corrected visual acuity (BCVA). Results: BFL measurements were in excellent agreement with the manufacturer-reported values (r = 0.999). The MTF specification exceeded what is required for achieving 20/20 visual acuity. Astigmatism and field curvature, correctable in simulations, were the primary aberrations limiting imaging performance. Profilometry of the anterior surface revealed nanoscale roughness (root-mean-square amplitude, 30-50 nm), contributing negligibly to optical scattering. Images of natural scenes obtained with a simulated B-KPro eye demonstrated good central vision, with 10/10 visual acuity (equivalent to 20/20). Full restoration of 20/20 BCVA was obtainable for over 9 years in some patients. Conclusions: Theoretical and experimental considerations demonstrate that B-KPro has the optical capacity to restore 20/20 BCVA in patients. Further image quality improvement can be anticipated through correction of HOAs. Translational Relevance: We establish an objective benchmark to characterize the optics of the B-KPro and other keratoprosthesis and propose design changes to allow improved vision in B-KPro patients.


Asunto(s)
Órganos Artificiales , Astigmatismo , Astigmatismo/cirugía , Córnea/diagnóstico por imagen , Humanos , Estudios Retrospectivos , Agudeza Visual
15.
Exp Eye Res ; 200: 108256, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32971095

RESUMEN

Bio-engineering technologies are currently used to produce biomimetic artificial corneas that should present structural, chemical, optical, and biomechanical properties close to the native tissue. These properties are mainly supported by the corneal stroma which accounts for 90% of corneal thickness and is mainly made of collagen type I. The stromal collagen fibrils are arranged in lamellae that have a plywood-like organization. The fibril diameter is between 25 and 35 nm and the interfibrillar space about 57 nm. The number of lamellae in the central stroma is estimated to be 300. In the anterior part, their size is 10-40 µm. They appear to be larger in the posterior part of the stroma with a size of 60-120 µm. Their thicknesses also vary from 0.2 to 2.5 µm. During development, the acellular corneal stroma, which features a complex pattern of organization, serves as a scaffold for mesenchymal cells that invade and further produce the cellular stroma. Several pathways including Bmp4, Wnt/ß-catenin, Notch, retinoic acid, and TGF-ß, in addition to EFTFs including the mastering gene Pax-6, are involved in corneal development. Besides, retinoic acid and TGF- ß seem to have a crucial role in the neural crest cell migration in the stroma. Several technologies can be used to produce artificial stroma. Taking advantage of the liquid-crystal properties of acid-soluble collagen, it is possible to produce transparent stroma-like matrices with native-like collagen I fibrils and plywood-like organization, where epithelial cells can adhere and proliferate. Other approaches include the use of recombinant collagen, cross-linkers, vitrification, plastically compressed collagen or magnetically aligned collagen, providing interesting optical and mechanical properties. These technologies can be classified according to collagen type and origin, presence of telopeptides and native-like fibrils, structure, and transparency. Collagen matrices feature transparency >80% for the appropriate 500-µm thickness. Non-collagenous matrices made of biopolymers including gelatin, silk, or fish scale have been developed which feature interesting properties but are less biomimetic. These bioengineered matrices still need to be colonized by stromal cells to fully reproduce the native stroma.


Asunto(s)
Bioingeniería/métodos , Colágeno/farmacología , Sustancia Propia/citología , Células Madre Mesenquimatosas/citología , Animales , Sustancia Propia/crecimiento & desarrollo , Sustancia Propia/metabolismo , Implantes de Medicamentos , Humanos , Proteínas Recombinantes
16.
Artículo en Inglés | MEDLINE | ID: mdl-32671048

RESUMEN

PURPOSE: Human cornea substitutes generated by tissue engineering currently require limbal stem cells for the generation of orthotypical epithelial cell cultures. We recently reported that bioengineered corneas can be fabricated in vitro from a heterotypical source obtained from Wharton's jelly in the human umbilical cord (HWJSC). METHODS: Here, we generated a partial thickness cornea model based on plastic compression nanostructured fibrin-agarose biomaterials with cornea epithelial cells on top, as an orthotypical model (HOC), or with HWJSC, as a heterotypical model (HHC), and determined their potential in vivo usefulness by implantation in an animal model. RESULTS: No major side effects were seen 3 and 12 months after implantation of either bioengineered partial cornea model in rabbit corneas. Clinical results determined by slit lamp and optical coherence tomography were positive after 12 months. Histological and immunohistochemical findings demonstrated that in vitro HOC and HHC had moderate levels of stromal and epithelial cell marker expression, whereas in vivo grafted corneas were more similar to control corneas. CONCLUSION: These results suggest that both models are potentially useful to treat diseases requiring anterior cornea replacement, and that HHC may be an efficient alternative to the use of HOC which circumvents the need to generate cornea epithelial cell cultures.

17.
Methods Mol Biol ; 2145: 197-214, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32542609

RESUMEN

The femtosecond laser has achieved widespread use in ophthalmology owing to its ability to deliver focused high energy that is rapidly dissipated and thereby does not damage surrounding tissue outside the precise focal region. Extremely accurate and smooth cuts can be made by the laser, enabling a range of applications in anterior segment surgery. Minimally invasive corneal surgical procedures can be performed using the femtosecond laser, and here we describe the application of such procedures to improve implantation of bioengineered materials into the cornea. Bioengineered corneal tissue, including the collagenous corneal stroma, promises to provide a virtually unlimited supply of biocompatible tissue for treating multiple causes of corneal blindness globally, thereby circumventing problems of donor tissue shortages and access to tissue banking infrastructure. Optimal implantation of bioengineered materials, however, is required, in order to facilitate postoperative wound healing for the maintenance of corneal transparency and avoidance of postoperative complications such as scarring, inflammation, and neovascularization. Moreover, the avoidance of a detrimental physiological physiological wound healing response is critical for facilitating the corneal stromal regeneration enabled by the bioengineered stroma. Without proper implantation, the tissue response will favor inflammation and pathologic processes instead of quiescent keratocyte migration and new collagen production. Here we describe several procedures for optimized biomaterial implantation into the corneal stroma, that facilitate rapid wound healing and regenerative restoration of corneal transparency without the use of human donor tissue. A step-by-step methodology is provided for the use of the femtosecond laser and associated techniques, to enable seamless integration of bioengineered materials into the corneal stroma.


Asunto(s)
Bioingeniería/métodos , Córnea/crecimiento & desarrollo , Sustancia Propia/trasplante , Regeneración/genética , Córnea/patología , Sustancia Propia/crecimiento & desarrollo , Sustancia Propia/patología , Humanos , Terapia por Láser
18.
Exp Eye Res ; 195: 108037, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32343943

RESUMEN

Artificial cornea is an effective treatment option for cases of severe corneal loss. In this study, we prepared a core-skirt designed artificial cornea with orthogonal microfiber grid scaffold. We fabricated PCL orthogonal microfiber grid scaffolds by a direct writing technique, and then combined them with compressed collagen (CC) to obtain a sandwich-like CC/P (where P is used to represent the PCL microfiber grid scaffold). PHEMA hydrogel and the CC/P served as the core and the skirt, respectively, with the P also serving as an intermediate between the two. The physical properties of the artificial cornea, including the morphology, the mechanical properties and the light transmittance, were evaluated. SEM images showed an effective connection and a lack of phase separation at the interface between the core and the skirt, and the skirt formed a highly porous scaffold that promoted tissue biointegration. In addition, we used the skirt structure to construct a corneal tissue model containing two cells types: corneal stromal stem cells (CSSCs) and mouse hippocampal neurons. The results showed that the cells could grow and differentiate well, and the orthogonal microfiber grid scaffold fibers were good guides for the structural growth of CSSCs and neuronal axons.


Asunto(s)
Materiales Biocompatibles , Córnea/citología , Ensayo de Materiales/métodos , Prótesis e Implantes , Andamios del Tejido , Animales , Animales Recién Nacidos , Células Cultivadas , Córnea/cirugía , Femenino , Ratones , Modelos Animales , Porosidad , Diseño de Prótesis , Ratas , Ratas Sprague-Dawley
19.
Middle East Afr J Ophthalmol ; 27(3): 150-155, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33488010

RESUMEN

PURPOSE: To report the medium to long-term safety and performance outcomes of the KeraKlear nonpenetrating artificial cornea (KeraKlear) as the primary procedure in patients with corneal blindness due to noninflammatory anterior cornea disease. METHODS: Fifteen patients with corneal blindness (preoperative visual acuity [VA] of ≥20/200) due to a non-inflammatory anterior corneal condition were included in this prospective, single-center study. Preoperative diagnoses included corneal scars, keratoconus, and corneal dystrophies. Diseased corneas were implanted with the KeraKlear (KeraMed Inc., Irvine, California, USA) by a single surgeon (JMV) using a femtosecond laser to create all incisions. Participants were followed up with for as long as 64 months. Uncorrected Snellen VA and postoperative complications were recorded. RESULTS: The average age at the time of surgery was 49.6 years old and 67% of patients were female. The patients experienced an average improvement in uncorrected Snellen VA of 7.6 lines (-1.17 logMAR). Average uncorrected vision at the last visit was 20/100 (0.73 logMAR), and median uncorrected vision at the last visit was 20/70 (0.54 logMAR). One patient experienced extrusion of the KeraKlear due to infection. There were no cases of glaucoma, retroprosthetic membrane, or endophthalmitis, the three most common complications of penetrating keratoprostheses (KPro). CONCLUSIONS: Medium and long-term outcomes of the KeraKlear indicate that this device is a viable alternative to corneal transplantation as a primary procedure in patients with non-inflammatory causes of corneal blindness, especially when corneal tissue is not available. The KeraKlear does not penetrate into the anterior chamber, and therefore, is less susceptible to the most common complications of penetrating KPro including endophthalmitis, glaucoma, and retroprosthetic membrane. The KeraKlear also has a comparable or improved adverse event rate compared to penetrating keratoplasty.


Asunto(s)
Órganos Artificiales , Ceguera/cirugía , Córnea , Enfermedades de la Córnea/cirugía , Adulto , Anciano , Ceguera/fisiopatología , Enfermedades de la Córnea/fisiopatología , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias , Estudios Prospectivos , Implantación de Prótesis , Agudeza Visual/fisiología
20.
Transl Vis Sci Technol ; 9(13): 41, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33442495

RESUMEN

Purpose: To evaluate titanium (Ti) sputtering of the poly(methyl methacrylate) (PMMA) stem of the Boston Keratoprosthesis (BK) as a method to enhance interfacial adhesion between the PMMA and the recipient corneal tissue. Methods: PMMA specimens were plasma treated with Ar/O2 and coated with Ti using a DC magnetron sputtering instrument. The topography and hydrophilicity of the surfaces were characterized using atomic force microscopy and a water contact angle instrument, respectively. Scratch hardness and adhesion of the Ti film were measured using a mechanical tester. Biocompatibility assessments were performed using cultured human corneal fibroblasts and whole blood ex vivo. The optical quality of the Ti sputtered BK was evaluated using a custom-made optical bench. Results: By contact angle studies, the Ti coating improved PMMA hydrophilicity to match that of medical-grade Ti (Ti-6Al-4V-ELI). Ti sputtering of contact surfaces resulted in a plate-like morphology with increased surface roughness, without impacting the transparency of the BK optical component. Scratch testing indicated that the mechanical behavior of the Ti coating was similar to that of casted Ti, and the coating was stable in pull-off adhesion testing. Sputtered Ti film was highly biocompatible based on tests of cell viability, adhesion, proliferation, differentiation, collagen deposition, and keratocan expression, the properties of which exceeded those of uncoated PMMA and did not induce increased complement activation. Conclusions: Titanium coating of the BK stem generated a mechanically and biologically favorable interface, which may help to enhance corneal stromal adhesion and biocompatibility. Translational Relevance: Improving the biocompatibility of the BK PMMA stem may improve long-term outcomes of implantation.


Asunto(s)
Polimetil Metacrilato , Titanio , Córnea , Humanos , Prótesis e Implantes , Propiedades de Superficie
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