| 1. |
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| 2. |
- Behaegel, Josephine, et al.
(författare)
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Outcomes of Human Leukocyte Antigen-Matched Allogeneic Cultivated Limbal Epithelial Transplantation in Aniridia-Associated Keratopathy-A Single-Center Retrospective Analysis
- 2022
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Ingår i: Cornea. - : LIPPINCOTT WILLIAMS & WILKINS. - 0277-3740 .- 1536-4798. ; 41:1, s. 69-77
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To assess the efficacy and safety of human leukocyte antigen-matched allogeneic cultivated limbal epithelial stem cell grafts in the treatment of aniridia-associated keratopathy (AAK). Methods: Six eyes of 6 patients with severe AAK received an allogeneic stem cell graft between January 2010 and March 2017. Anatomical and functional results were assessed at 6 months, 1 year, 2 years, and the final follow-up visit available. Safety analysis was performed by considering all perioperative and postoperative adverse events and additional surgeries required during the follow-up period. Results: The mean follow-up was 53.6 months (range 24-104 months). In most patients (80%), there was an early improvement of the keratopathy postoperatively, which slowly regressed during longer follow-up. At the final follow-up, 4 of the eyes were graded as failure and 1 eye was graded as partial success. Grading the sixth eye was not possible because of an adverse event. None of the patients maintained a total anatomical success in the long-term. Only 1 patient maintained a modest improvement in best-corrected visual acuity from hand motion to counting fingers. Four serious adverse events were recorded in 2 patients. Conclusions: Severe AAK remains a challenging condition to manage. Transplantation of allogenic ex vivo cultivated limbal stem cells may provide a temporary improvement in ocular surface stability, but anatomical and functional results are poor in the long-term. The eyes are prone to adverse events, and any surgical treatment should take this into consideration.
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| 3. |
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| 4. |
- Bentley, E, et al.
(författare)
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Biosynthetic Corneal Substitute Implantation in Dogs
- 2010
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Ingår i: Cornea. - : LWW. - 0277-3740 .- 1536-4798. ; 29:8, s. 910-916
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To assess integration of a biosynthetic corneal implant in dogs. Methods: Three normal adult laboratory Beagles underwent ophthalmic examinations, including slit-lamp biomicroscopy, indirect ophthalmoscopy, applanation tonometry, and Cochet-Bonnet aesthesiometry. Biosynthetic corneas fabricated from glutaraldehyde crosslinked collagen and copolymers of collagen and poly (N-isopropylacrylamide-co-acrylic acid-co-acryloxysuccinimide, denoted as TERP) were implanted into dogs by a modified epikeratoplasty technique. Ophthalmic examinations and aesthesiometry were performed daily for 5 days and then weekly thereafter for 16 weeks. Corneal samples underwent histopathological and transmission electron microscopy examination at 16 weeks. Results: Implants were epithelialized by 7 days. Intraocular pressure was within normal range throughout the study. Aesthesiometry values dropped from an average of 3.67 cm preoperatively to less than 1 mm for all dogs for the first postoperative weeks. By week 16, the average Cochet-Bonnet value was 1.67 cm, demonstrating partial recovery of functional innervation of the implant. No inflammation or rejection of the implant occurred, and minimal haze formation was noted. Light microscopy revealed thickened but normal epithelium over the implant with fibroblast migration into the scaffold. On transmission electron microscopy, the basement membrane was irregular but present and adhesion complexes were noted. Conclusion: Biosynthetic corneal implantation is well tolerated in dogs, and the collagen-polymer hybrid construct holds promise for clinical application in animals and humans.
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| 5. |
- Bourghardt Peebo, Beatrice, et al.
(författare)
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Transient Anterior Corneal Deposits in a Human Immunodeficiency Virus-Positive Patient
- 2010
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Ingår i: CORNEA. - : Lippincott Williams and Wilkins. - 0277-3740. ; 29:11, s. 1323-1327
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To report findings of pigmented anterior corneal deposits in a human immunodeficiency virus-positive patient. Methods: Case report. A 49-year-old human immunodeficiency virus-positive patient was examined after the appearance of pigmented corneal deposits. Slit-lamp biomicroscopy, fundus photography, and laser-scanning in vivo confocal microscopy were performed to visually document the ocular condition. Results: The patient had a history of Mycobacterium avium infection and was suspected to have recovery uveitis from a cytomegalovirus infection. Small, rounded, light brown-colored deposits were distributed across the anterior cornea from limbus to limbus, bilaterally. In vivo confocal microscopy revealed the deposits to be confined to the basal epithelium and Bowman layer, whereas the posterior stroma, Descemet membrane, and the endothelium appeared normal. Systemic steroid treatment was administered, and 2 weeks later, the deposits had vanished on slit-lamp examination, whereas remnants were observed at the microscopic level. Conclusions: The deposits were unusual for their anterior corneal location and pancorneal distribution. The response to systemic steroid treatment remains unexplained and illustrates the complexity of the underlying conditions, their treatment, and the associated pathways of ocular manifestation.
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| 6. |
- Claesson, Margareta, et al.
(författare)
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Validation of Catquest-9SF-A Visual Disability Instrument to Evaluate Patient Function after Corneal Transplantation
- 2017
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Ingår i: Cornea. - 0277-3740 .- 1536-4798. ; 36:9, s. 1083-1088
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Catquest-9SF is a 9-item visual disability questionnaire developed for evaluating patient-reported outcome measures after cataract surgery. The aim of this study was to use Rasch analysis to determine the responsiveness of Catquest-9SF for corneal transplant patients. Methods: Patients who underwent corneal transplantation primarily to improve vision were included. One group (n = 199) completed the Catquest-9SF questionnaire before corneal transplantation and a second independent group (n = 199) completed the questionnaire 2 years after surgery. All patients were recorded in the Swedish Cornea Registry, which provided clinical and demographic data for the study. Winsteps software v.3.91.0 (Winsteps.com, Beaverton, OR) was used to assess the fit of the Catquest-9SF data to the Rasch model. Results: Rasch analysis showed that Catquest-9SF applied to corneal transplant patients was unidimensional (infit range, 0.73-1.32; outfit range, 0.81-1.35), and therefore, measured a single underlying construct (visual disability). The Rasch model explained 68.5% of raw variance. The response categories of the 9-item questionnaire were ordered, and the category thresholds were well defined. Item difficulty matched the level of patients' ability (0.36 logit difference between the means). Precision in terms of person separation (3.09) and person reliability (0.91) was good. Differential item functioning was notable for only 1 item (satisfaction with vision), which had a differential item functioning contrast of 1.08 logit. Conclusions: Rasch analysis showed that Catquest-9SF is a valid instrument for measuring visual disability in patients who have undergone corneal transplantation primarily to improve vision.
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| 7. |
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| 8. |
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| 9. |
- Griffith, May, et al.
(författare)
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Artificial human corneas - Scaffolds for transplantation and host regeneration
- 2002
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Ingår i: Cornea. - : Lippincott, Williams andamp; Wilkins. - 0277-3740 .- 1536-4798. ; 21:7, s. S54-S61
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Tidskriftsartikel (refereegranskat)abstract
- Purpose. To review the development of artificial corneas (prostheses and tissue equivalents) for transplantation, and to provide recent updates on our tissue-engineered replacement corneas. Methods. Modified natural polymers and synthetic polymers were screened for their potential to replace damaged portions of the human cornea or the entire corneal thickness. These polymers, combined with cells derived from each of the three main corneal layers or stem cells, were used to develop artificial corneas. Functional testing was performed in vitro. Trials of biocompatibility and immune and inflammatory reactions were performed by implanting the most promising polymers into rabbit corneas. Results. Collagen-based biopolymers, combined with synthetic crosslinkers or copolymers, formed effective scaffolds for developing prototype artificial corneas that could be used as tissue replacements in the future. We have previously developed an artificial cornea that mimicked key morphologic and functional properties of the human cornea. The addition of synthetic polymers increased its toughness as it retained transparency and low light scattering, making the matrix scaffold more suitable for transplantation. These new composites were implanted into rabbits without causing any acute inflammation or immune response. We have also fabricated full-thickness composites that can be fully sutured. However, the long-term effects of these artificial corneas need to be evaluated. Conclusions. Novel tissue-engineered corneas that comprise composites of natural and synthetic biopolymers together with corneal cell lines or stem cells will, in the future, replace portions of the cornea that are damaged. Our results provide a basis for the development of both implantable temporary and permanent corneal replacements.
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| 10. |
- Khodaparast, Mehdi, et al.
(författare)
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Sutureless Femtosecond Laser-Assisted Anterior Lamellar Keratoplasty Using a Bioengineered Cornea as a Viable Alternative to Human Donor Transplantation for Superficial Corneal Opacities
- 2020
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Ingår i: Cornea. - : LIPPINCOTT WILLIAMS & WILKINS. - 0277-3740 .- 1536-4798. ; 39:9, s. 1184-1189
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate the safety and efficacy of a bioengineered corneal implant using femtosecond laser-assisted anterior lamellar keratoplasty for superficial corneal opacities. Methods: Six eyes of 6 consecutive patients with superficial corneal stromal opacities involving <220 mu m owing to various pathologies were included in the study. Preoperatively, all patients underwent anterior segment optical coherence tomography (Visante; Carl Zeiss Meditec AG) to evaluate the depth of the corneal opacity. All patients underwent sutureless femtosecond laser-assisted anterior lamellar keratoplasty using a bioengineered collagen corneal implant (linkcor). Visual indices, refraction, and keratometry were evaluated preoperatively and 12 months postoperatively. Results: Corrected distance visual acuity improved significantly in all patients (P= 0.02). A significant decrease was seen in refractive astigmatism postoperatively (P= 0.04). Flat keratometry reduced significantly 12 months after the intervention (P= 0.04). No intraoperative or early postoperative complications were noticed. All implants were fully covered by healthy epithelium within a month after the surgery and remained clear at follow-up visits. The results of this procedure remained stable throughout the follow-up period. In 1 patient, mild inferior collagen melting and epithelial defect formation occurred at 1-year follow-up. Despite frequent topical corticosteroid therapy the melting progressed, the collagen tissue was removed and the patient was treated accordingly with good visual outcomes. Conclusions: Femtosecond laser-assisted anterior lamellar keratoplasty with bioengineered corneal (linkcor) implantation is an effective treatment for improving vision quality in anterior stromal opacities. This procedure reduces the need for human donor tissue and avoids human donor-related and suturing complications.
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| 11. |
- Kronschlager, Martin, et al.
(författare)
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Apoptosis in Rat Cornea After In Vivo Exposure to Ultraviolet Radiation at 300 nm
- 2015
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Ingår i: Cornea. - 0277-3740 .- 1536-4798. ; 34:8, s. 945-949
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Tidskriftsartikel (refereegranskat)abstract
- Purpose:Peak toxicity for in vivo ultraviolet radiation (UVR) exposure to the lens is in the 300-nm wavelength region. However, little is known about corneal cell damage at 300 nm. The purpose of the study was to determine the time evolution of apoptosis in the cornea after in vivo exposure to 300-nm UVR.Methods:Altogether, 16 Sprague Dawley rats were divided into 4 groups and unilaterally exposed to 5 kJ/m(2) UVR ((max): 300 nm; (0.5): 10 nm) for 15 minutes. After a predetermined latency period of 1, 5, 24, and 120 hours, depending on the group, the animals were killed and eyes were enucleated. Eye globes were further cryosectioned in 10-m thick midsagittal sections. For the detection of apoptosis, the TUNEL method was applied.Results:TUNEL-positive signals were observed in the superficial epithelial cells in the exposed and control eyes at all latency periods. At 5 hours, TUNEL staining was detected in the exposed corneas in epithelial cells, keratocytes, and endothelial cells with a maximum signal at 24 hours. At 120 hours, no TUNEL staining was found in endothelial cells and only occasionally in keratocytes in exposed corneas. Signs of ulceration and stromal thinning were observed at 120 hours.Conclusions:UVR in the 300-nm wavelength region induces TUNEL staining in all 3 corneal layers. TUNEL staining of all 3 corneal layers is an early postexposure event observed after a 5-hour latency period. Corneal sterile keratolysis occurs in the time window of 24 to 120 hours probably induced by neutrophils.
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| 12. |
- Lagali, Neil, et al.
(författare)
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Delayed Mustard Gas Keratitis : Clinical Course and In Vivo Confocal Microscopy Findings
- 2009
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Ingår i: CORNEA. - : LWW. - 0277-3740. ; 28:4, s. 458-462
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To report the detailed clinical and in vivo confocal microscopic findings in a patient with delayed-onset mustard gas keratitis observed 20 years after initial exposure. Methods: A 38-year-old man who was exposed to mustard gas in Iraq at the age of 19 years was examined after presenting with ocular symptoms 17 years after initial recovery from the exposure. Slit-lamp biomicroscopy, corneal topography, and in vivo confocal microscopy were performed on both corneas. Results: The clinical symptoms were consistent with a delayed form of mustard gas keratitis, although the patient had clear central corneas and good visual acuity. Confocal microscopic findings included evidence of epithelial abnormalities, necrotic changes in the anterior stroma, subbasal and anterior stromal nerve proliferation, and deep stromal keratocyte activation. Conclusions: In vivo confocal microscopy revealed persistent morphologic abnormalities in the anterior stroma of both corneas 20 years after initial exposure to mustard gas. The detection of a population of dendritic cell bodies in the central epithelium and evidence of keratocyte activation and migration in the deep stroma indicated the presence of ongoing subclinical processes.
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| 13. |
- Makdoumi, Karim, et al.
(författare)
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Infectious keratitis treated with corneal crosslinking
- 2010
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Ingår i: Cornea. - 0277-3740 .- 1536-4798. ; 29:12, s. 1353-1358
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To describe 7 eyes with severe infectious keratitis treated using collagen crosslinking (CXL) with riboflavin. Materials and Methods: Seven eyes of 6 patients with severe infectious keratitis were treated with corneal crosslinking. Three patients were contact lens users. Symptom duration before CXL ranged between 0 and 7 days. Corneal melting was present in all cases. Photodocumentation of the keratitis was carried out and repeated at follow-up. All but 1 patient received topical antibiotic treatment in addition to the CXL treatment. CXL was conducted according to the standardized protocol for keratoconus. Results: In all but 1 eye, patients experienced improvement in symptoms within 24 hours. Two patients reported no symptoms whatsoever at this time. Corneal melting was arrested and complete epithelialization was achieved in all cases. In the 2 eyes with hypopyon, this regressed completely within 2 days after the CXL. Follow-up ranged between 1 and 6 months. Discussion: Our experience based on the above and other cases suggest that CXL could be an effective tool in battling difficult cases of infectious keratitis. This treatment could present many advantages but will need further investigation.
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| 14. |
- McLaughlin, Christopher, et al.
(författare)
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Regeneration of Corneal Cells and Nerves in an Implanted Collagen Corneal Substitute
- 2008
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Ingår i: Cornea. - 0277-3740 .- 1536-4798. ; 27:5, s. 580-589
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Our objective was to evaluate promotion of tissue regeneration by extracellular matrix (ECM) mimics, by using corneal implantation as a model system.METHODS: Carbodiimide cross-linked porcine type I collagen was molded into appropriate corneal dimensions to serve as substitutes for natural corneal ECM. These were implanted into corneas of mini-pigs after removal of the host tissue, and tracked over 12 months, by clinical examination, slit-lamp biomicroscopy, in vivo confocal microscopy, topography, and esthesiometry. Histopathology and tensile strength testing were performed at the end of 12 months. Other samples were biotin labeled and implanted into mice to evaluate matrix remodeling.RESULTS: The implants promoted regeneration of corneal cells, nerves, and the tear film while retaining optical clarity. Mechanical testing data were consistent with stable, seamless host-graft integration in regenerated corneas, which were as robust as the untreated fellow corneas. Biotin conjugation is an effective method for tracking the implant within the host tissue.CONCLUSIONS: We show that a simple ECM mimetic can promote regeneration of corneal cells and nerves. Gradual turnover of matrix material as part of the natural remodeling process allowed for stable integration with host tissue and restoration of mechanical properties of the organ. The simplicity in fabrication and shown functionality shows potential for ECM
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| 15. |
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| 16. |
- Podskochy, A, et al.
(författare)
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Apoptosis in UV-exposed rabbit corneas
- 2000
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Ingår i: Cornea. - : Ovid Technologies (Wolters Kluwer Health). - 0277-3740. ; 19:1, s. 99-103
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Tidskriftsartikel (refereegranskat)
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| 17. |
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| 18. |
- Podskochy, A., et al.
(författare)
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The expression of fas ligand protein in ultraviolet-exposed rabbit corneas
- 2002
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Ingår i: Cornea. - : Ovid Technologies (Wolters Kluwer Health). - 0277-3740 .- 1536-4798. ; 21:1, s. 91-94
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Tidskriftsartikel (refereegranskat)abstract
- Purpose. Keratocytes undergo apoptosis during various pathologic conditions and after exposure to ultraviolet radiation (UVR). It was reported that the Fas/Fas ligand system is involved in modulating keratocyte apoptosis. The expression of Fas ligand (FasL) protein was studied in rabbit corneas after photokeratitis induced by different UV wavelengths. Methods. Six New Zealand albino rabbit corneas were exposed to 280- and 310-nm UVR in 10-nm full wavebands at doses producing biomicroscopically significant keratitis (0.12 J/cm2 for 280 nm and 0.47 J/cm2 for 310 nm). Animals were killed 24 hours after exposure. Immunohistochemistry was performed to localize FasL protein in paraffin sections of rabbit corneas. Primary antibody was polyclonal goat anti-FasL IgG. Results. FasL protein was uniformly detected in epithelial and endothelial layers of all UVR-exposed and control, nonexposed corneas. The positive staining of keratocytes was confined to the anterior stroma of corneas that were exposed to 280-nm UVR. Corneas exposed to 310-nm UVR showed positively stained keratocytes throughout the entire thickness of the stroma. Conclusions. These data strongly suggest that the Fas/FasL system may play an important role in apoptosis of corneal cells after UVR. The FasL expression in the corneal stroma was more extensive after exposures at 310-nm UVR than at 280-nm UVR.
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| 19. |
- Potapenko, Ivan O., et al.
(författare)
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Donor Endothelial Cell Count Does Not Correlate With Descemet Stripping Automated Endothelial Keratoplasty Transplant Survival After 2 Years of Follow-up
- 2017
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Ingår i: Cornea. - : Lippincott Williams & Wilkins. - 0277-3740 .- 1536-4798. ; 36:6, s. 649-654
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To analyze the influence of low endothelial cell density (ECD) of donor cornea tissue, donor age, and sex on the transplant survival rate after Descemet stripping automated endothelial keratoplasty (DSAEK). Methods: Graft ECD, age, and sex of donors used for DSAEK (n = 1789) during 7 years (2007-2014) in 4 Scandinavian hospitals were assessed for potential association with transplant survival at 2 years of follow-up using a Cox regression model correcting for confounding factors. The data were obtained from The Swedish Cornea Transplant Registry. Results: Transplant failure occurred in 196 patients, with 69 early failures during the first 3 postoperative months, and 127 late secondary failures. Twenty-five of the late secondary failures were due to rejection. Reversible rejections occurred in 67 patients. There was no significant impact of donor age [hazard ratio (HR) 1.0, 95% confidence interval (CI), 0.99-1.02, P = 0.32] or endothelial cell count (HR 1.00, 95% CI, 0.99-1.01, P = 0.3) on the survival rate of DSAEK transplants at 2 years of follow-up. The use of donor grafts with low ECD (, 2300 cells/mm(2)) did not influence the survival rate (HR 1.3, 95% CI, 0.76-2.35, P = 0.31). Male donor sex was associated with lower 2-year graft survival (HR 1.5, 95% CI, 1.042.28, P = 0.03), but not with rejection events (P = 0.26). Conclusions: Based on data from The Swedish Cornea Transplant Registry, low donor ECD was not detrimental to graft survival, whereas donor sex seemed to influence the outcome at the end of the 2-year follow-up.
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| 20. |
- Ruutila, Minna, et al.
(författare)
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Diagnostic Criteria for Terrien Marginal Degeneration : Nordic Terrien Degeneration Study
- 2021
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Ingår i: Cornea. - : LIPPINCOTT WILLIAMS & WILKINS. - 0277-3740 .- 1536-4798. ; 40:2, s. 133-141
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To refine the diagnostic criteria for Terrien marginal degeneration (TMD) based on experience in 3 Nordic countries. Methods: This is a retrospective, multicenter, hospital-based cross-sectional study of 49 eyes of 29 white patients in tertiary referral centers in Finland, Sweden, and Denmark from 1998 to January 2018. The median follow-up was 3 years. Symptoms, best corrected visual acuity, astigmatism, corneal thickness, curvature and cavities, stage, and progression were analyzed. Results: TMD was diagnosed equally likely between 15 and 86 years of age (median, 47 years). Twenty patients (69%) had bilateral disease, and 62% were men. Seventeen patients (59%) had symptoms including blurred vision and ocular surface disease symptoms without inflammatory signs. Eight patients (28%) had slightly reduced corneal sensitivity. Median best corrected visual acuity was 20/25 (range, 20/16-20/200) and astigmatism was 2.6 diopters (D) (range, 0-10) with a mean progression of 0.41 D per year (range, 0-5.4). Age and astigmatism were not correlated. All eyes had peripheral vascularization, lipid deposits, and hyperreflectivity throughout thinned peripheral stroma and its anterior edge. The thinning progressed in 15 patients (52%). Of 26 patients, 8 (31%) had single or confluent paralimbal intrastromal cavities, most commonly superiorly. By Suveges classification, the stage was 2 (92%) or 3 (8%). Minimum corneal thickness and corneal curvature were loosely associated, leading to different stages in Wang classification in 34 eyes (69%). Conclusions: TMD is defined by peripheral corneal thinning, superficial neovascularization, lipid deposition at the leading edge, absence of ulceration and inflammation, and frequently cavitation. The most sensitive way to follow its progression is anterior segment optical coherence tomography.
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| 21. |
- Samarawickrama, Chameen, et al.
(författare)
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Collagen-Based Fillers as Alternatives to Cyanoacrylate Glue for the Sealing of Large Corneal Perforations
- 2018
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Ingår i: Cornea. - : LIPPINCOTT WILLIAMS & WILKINS. - 0277-3740 .- 1536-4798. ; 37:5, s. 609-616
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To describe the use of collagen-based alternatives to cyanoacrylate glue for the sealing of acute corneal perforations. Methods: A collagen analog comprising a collagen-like peptide conjugated to polyethylene glycol (CLP-PEG) and its chemical crosslinker were tested for biocompatibility. These CLP-PEG hydrogels, which are designed to act as a framework for corneal tissue regeneration, were then tested as potential fillers in ex vivo human corneas with surgically created full-thickness perforations. Bursting pressures were measured in each of 3 methods (n = 10 for each condition) of applying a seal: 1) cyanoacrylate glue with a polyethylene patch applied ab externo (gold standard); 2) a 100-mu m thick collagen hydrogel patch applied ab interno, and 3) the same collagen hydrogel patch applied ab interno supplemented with CLP-PEG hydrogel molded in situ to fill the remaining corneal stromal defect. Results: Cyanoacrylate gluing achieved a mean bursting pressure of 325.9 mm Hg, significantly higher than the ab interno patch alone (46.3 mm Hg) and the ab interno patch with the CLP-PEG filler (86.6 mm Hg). All experimental perforations were sealed effectively using 100 mu m hydrogel sheets as an ab interno patch, whereas conventional ab externo patching with cyanoacrylate glue failed to provide a seal in 30% (3/10) cases. Conclusions: An ab interno patch system using CLP-PEG hydrogels designed to promote corneal tissue regeneration may be a viable alternative to conventional cyanoacrylate glue patching for the treatment of corneal perforation. Further experimentation and material refinement is required in advance of clinical trials.
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| 22. |
- Shimmura, Shigeto, et al.
(författare)
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Collagen-poly(N-isopropylacrylamide)-based membranes for corneal stroma scaffolds
- 2003
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Ingår i: Cornea. - : Lippincott, Williams andamp; Wilkins. - 0277-3740 .- 1536-4798. ; 22:7, s. S81-S88
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To investigate the feasibility of using the biocompatibility of collagen-based blended biomaterials as cell-delivery systems in ocular surface reconstruction in vivo. Methods: Collagen-based composites that were blended with synthetic acrylamide-based polymers [poly(N-isopropylacrylamide), pNIPAAm] were transplanted into corneal pockets of white rabbits, with a 3-mm epithelial window. Epithelial cells were allowed to migrate onto the polymer. Transplanted eyes were examined daily for up to 30 days, after which animals; were killed for histologic examination. lm- munohistochemistry was performed for vimentin, a-smooth muscle actin (alpha-SMA), CD4, and CD8. Gold-chloride staining was performed to observe neuronal regrowth. Human amniotic membranes (AMs) and sham-operated corneas served as controls. All animals received topical antibiotics (levofloxacin) without the use of steroids or other immunosuppressive agents. Results: The pNIPAAm polymer allowed smooth epitheliatization of the cornea, which was similar to the epithelialization observed in sham controls and AM-transplanted eyes. Histology revealed that epithelium overlying the polymer was bundled into several layers, without the orientation observed with AM and sham controls. The polymer gradually thinned and was gradually replaced by host tissue. Vimentin- and alpha-SMA-positive cells were found in stromal pockets up to 1 month following polymer transplantation. These cells were responsible for slight subepithelial haze near the wound edge. CD4- and CD8-positive lymphocytes were also observed in the vicinity of the polymer. Gold-chloride staining showed nerve regrowth in the wound edge after 1 month and subepithelial branches after 3 months. Conclusion: Collagen-pNIPAAm blended polymers may he effective as biomaterials to be used in the early stages of lamellar stromal replacement.
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| 23. |
- Viberg, Andreas, et al.
(författare)
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Frequency and outcome of emergency penetrating keratoplasty in infectious keratitis in Sweden during the 21st century
- 2024
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Ingår i: Cornea. - : Lippincott Williams & Wilkins. - 0277-3740 .- 1536-4798.
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To study the frequency over time and outcome of penetrating keratoplasty (PK), "keratoplasty à chaud," in patients with infectious keratitis with 2-year follow-up data.Methods: This register-based study included keratitis cases that had undergone PK in Sweden between 2001 and 2020 and reported to the Swedish Corneal Transplant Register.Results: During the study period, 69 eyes were subjected to acute PK due to progressive infectious keratitis. The number increased from 2 annual procedures in the first half of the study period to 5 in the second half (P = 0.01). Preoperative corneal perforation was present in 43.5% (n = 30) of the eyes. Two years after surgery, follow-up data were completed in the register for 53 eyes; of these, 62.3% (n = 33) were considered to have functioning grafts, and 20.8% (n = 11) had experienced a rejection episode. The visual acuity improved from hand motion to counting fingers (P = 0.002), and the proportion of eyes with a visual acuity of ≤1.0 logMAR increased from 5.7% (n = 3) before the surgery to 45.3% (n = 24) at the 2-year follow-up (P < 0.001).Conclusions: The number of active infectious keratitis cases undergoing keratoplasty à chaud increased in Sweden during the 21st century. Most of the cases were successful regarding the structural integrity of the bulb, that is, "had a saved eye" and even a functioning graft 2 years after corneal transplantation. The visual gain was distinct, albeit modest. In cases with severe infectious keratitis, and even a concomitant perforation in the cornea due to the infection, corneal transplantation should continue to be an option.
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| 24. |
- Wand, Kerstin, et al.
(författare)
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Riboflavin-UV-A Crosslinking for Fixation of Biosynthetic Corneal Collagen Implants
- 2015
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Ingår i: Cornea. - : LIPPINCOTT WILLIAMS and WILKINS. - 0277-3740 .- 1536-4798. ; 34:5, s. 544-549
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate riboflavin-UV-A crosslinking as an alternative suture-free fixation method for biosynthetic corneal collagen implants. Methods: A range of cell-free corneal implants consisting of recombinant human collagen type III were examined. In vitro, the implants were crosslinked with different riboflavin solutions and irradiations. Ex vivo, the biosynthetic corneal implants were placed on the anterior cornea of porcine and rabbit eyes after performing deep anterior lamellar keratoplasty with a trephine, femtosecond laser, or excimer laser. UV-A crosslinking was performed with isotonic or hypotonic riboflavin at either standard or rapid procedure. The corneas were excised, fixed in PFA 4%, and embedded in paraffin. Crosslinking effects on the implants and the adhesion between implant and corneal bed were evaluated by slit-lamp biomicroscopy, optical coherence tomography (OCT) images, and histologically. Results: After the crosslinking procedure, the implants showed different degrees of thinning. The accuracy of cutting the corneal bed was highest with the excimer laser. Good adhesion of the implant in the corneal bed could be demonstrated in OCT images. This was more accurate in porcine eyes than in rabbit eyes. Histologically, crosslinks between implant and corneal stroma were demonstrated. There was no difference between standard and rapid crosslinking procedures. Conclusions: Riboflavin-UV-A crosslinking as a fixation method for biosynthetic corneal collagen implants was demonstrated to be promising. It can reduce suture-related complications such as haze formation and surface irregularity. Stability of the implants, especially shrinkage after riboflavin-UV-A crosslinking, needs to be further evaluated. Biostability, integration, and long-term outcome are further evaluated in in vivo animal experiments.
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| 25. |
- Weber, Beat A, et al.
(författare)
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Short-term impact of corticosteroids on hyaluronan and epithelial hyperplasia in the rabbit cornea after photorefractive keratectomy
- 2001
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Ingår i: Cornea. - : Ovid Technologies (Wolters Kluwer Health). - 0277-3740 .- 1536-4798. ; 20:3, s. 321-324
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Tidskriftsartikel (refereegranskat)abstract
- Purpose. To investigate the impact of corticosteroids on subepithelial hyaluronan deposition and corneal epithelium thickness in the first 10 days after photorefractive keratectomy (PRK) and to analyze a possible contralateral effect of corticosteroids. Methods. Thirty-two New Zealand white rabbits were assigned into two groups and had a transepithelial 5.0-mm diameter, 8.00-diopter myopic PRK performed on one eye. The corticosteroid treatment group (16 animals) received 0.1 mL of methylprednisolone 4% subconjunctivally on the operation table, followed by 0.1% dexamethasone eye drops six times a day during the postoperative period. The sodium chloride (NaCl) treatment group received topical isotonic NaCl eye drops six times a day. In each treatment group, eight animals were killed after 3 and 9 days, respectively. The harvested specimens were stained for hyaluronan and the epithelial thickness was measured. Results. In contrast to the epithelial thickness, the subepithelial hyaluronan did not show a significant increase during the observation period. The corticosteroid treated group showed at both time-points significantly less subepithelial hyaluronan formation as well as a significantly thinner epithelium, when compared with the NaCl-treated group. At 9 days, the corticosteroid-treated group showed a mild epithelial hyperplasia in only one of eight eyes, whereas this was a common finding in the NaCl-treated group. We detected no hyaluronan deposits in any contralateral-untreated eye, and the epithelial thickness did not differ significantly between any of the four contralateral-untreated eye groups. Conclusions. Corticosteroid medication during the first 10 days after operation reduces the amount of subepithelial hyaluronan production and inhibits the epithelial proliferation, and epithelial hyperplasia is prevented. Neither a contralateral hyaluronan deposition nor a contralateral corticosteroid effect could be detected.
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