View clinical trials related to Corneal Transplantation.
Filter by:The trial evaluates the effect of corneal crosslinking as pre-treatment before corneal transplantation. The goal is to improve graft survival by reducing pathological vessels through pre-treatment.
Optical Coherence Tomography (OCT) image data will be evaluated for image quality and used to test post-processing algorithms to improve detection sensitivity for ophthalmic diseases.
Because of the immunologically privileged nature of the cornea, the graft rejection rate is less than 10% for low-risk keratoplasty. But when the cornea performed 2 or more quadrants of corneal neovascularization after ocular trauma or infection, the graft rejection rate is more than 65%, it is called high-risk keratoplasty. This study will observe the graft survival of high-risk corneal transplantation using mixed component cornea from different donors.
Glaucoma is the most common threat to vision rehabilitation in patients with Boston keratoprosthesis type 1 (KPro) implantation. High intraocular pressure (IOP) is the most important risk factor for glaucoma and may lead to irreversible retinal and optic nerve damage. Glaucoma drainage device (GDD) surgery is used to divert aqueous humor (AH) from the anterior chamber to an external reservoir to regulate flow and decrease the IOP. The AH is in direct communication with any corneal damage or surgery undertaken in the anterior chamber and can serve as a source of potential biomarkers to detect early inflammatory or glaucomatous changes. Tears are also one of the most accessible and non-invasive source of biomarkers, especially in Kpro eyes where the central optic allows communication between aqueous humor and the tears at the surface of the eye. The investigators propose to test the hypothesis that distinct inflammatory mediators in the AH and tears can serve as biomarkers for glaucoma development and progression after CT, making them specifically amenable to targeted treatment strategies to minimize vision loss.
Common complications of the Boston keratoprosthesis type 1 (KPro) surgery include retroprosthetic membrane formation, glaucoma, and retinal detachment. Often pars plana vitrectomy (PPV) is performed at the same time as KPro surgery for different indications. It has been shown to reduce postoperative complications in comparison to when it is performed after the KPro surgery. Patients who receive a complete PPV with peeling of the anterior hyaloid membrane have a lower incidence of retroprosthetic membrane formation and less vision loss due to glaucoma when compared to patients with partial PPV or anterior vitrectomy. During a complete PPV, peeling of the anterior hyaloid membrane is a difficult step because visualisation is poor, but it can be improved using endoscopy. The investigators suggest that peeling of the anterior hyaloid membrane assisted by endoscopy during KPro surgery would decrease postoperative complications in comparison to a PPV done after KPro surgery and without endoscopy.
The development of optical coherence tomography (OCT) and its application for in vivo imaging has opened entirely new opportunities in ophthalmology. The technology allows for both noninvasive visualization of the morphology and measurement of functional parameters within ocular tissues to a depth of a few millimetres even in nontransparent media. Until now the resolution of commercially available OCT systems is, however, much lower than that provided by light microscopy. Recently, an ultrahigh-resolution OCT system was developed by our group providing resolutions of 1.7 and 17 µm in axial and lateral direction, respectively. This axial resolution is about four times better than that provided by standard OCT systems. It allows to perform in vivo imaging with a resolution close to biopsy of tissue and to visualize structures of the anterior eye segment with a remarkable richness of detail. The prototype was applied for in vivo imaging of the cornea including the precorneal tear film. The goal of the planned pilot study is to apply this innovative imaging modality for visualization of the ultrastructure of the different parts of the anterior eye segment structures in diseased subjects, as well as in patients who underwent minimally invasive glaucoma surgery (MIGS). The obtained in vivo cross sectional images and three-dimensional data sets are hoped for contributing to the knowledge about the anatomy and physiology of the corresponding tissues. This could allow for a better interpretation of clinical features and findings obtained in slit lamp examination.
Aim of this study is to reflect on the changing trends in absolute numbers, surgical techniques and indications of corneal transplantations being performed in Germany. In 2017, the Section Cornea of the German Ophthalmological Society provides an interim-assessment about the most up-to-date results of this long-term study over a period of sixteen years between 2001 and 2016.
The performance of keratoplasty is hampered by the limited availability of donor cornea in many countries, especially in Asia. For this reason, attempts have been made to fabricate artificial substitutes for natural human cornea. So far, all polymeric biomaterials, such as collagen configurations and plastic compression, could mimic the functional optically transparent but failed to replicate the complicate three-dimension microstructure of natural cornea. Therefore, despite some favorable results yielded by polymeric biomaterials, they cannot be suited for long-term use. To overcome these disadvantages, in recent years, porcine cornea appeared specifically attractive for xenotransplantation, because of its accessibility and similarities to natural human cornea. However, xenotransplantation using fresh porcine cornea can occurs hyperacute immune rejection, resulting in graft failure. Such transplant rejection can be substantially lessened by using acellular porcine cornea (APC), which preserves the constructure of natural cornea, whilst having well biocompatibility and low antigenicity. These properties feature APC particularly suitable for high-risk keratoplasty, such as corneal grafting in infectious keratitis. Use of APC in LK has been shown promise in many preclinical animal studies and initially in human clinic trail. However, to optimize APC biological and biomechanical properties, the strategies for its preparation has evolved extensively over recent years, like various decellularization approaches (e.g. detergents, enzymes, human sera, hypertonic solutions and et al) and additional procedures (e.g. collagen re-crosslinking and repeated frozen-dry). Therefore, in the current study, the investigators analyzed the early surgical outcomes of deep anterior lamellar keratoplasty (DALK) using the APC that was very recently approved by the National Institutes for Food and Drug Control (NIFDC) of China for clinic practice, for management of infective keratitis, including fungal, viral and acanthamoeba keratitis. Here major concern of this study was to clarify the behavior of APC after implantation in participants.
Boston keratoprosthesis (KPro) is a piece of specialized plastic that replace sick cornea (transparent structure at the front of the eye) in patients who have failed or those who are expected to have poor results with traditional corneal transplantation. While the Kpro can offer dramatic improvement in vision, it is also associated with several complications. Glaucoma (optic nerve damage due to high pressure inside the eye) is one of the most common complications after KPro surgery and can potentially cause irreversible vision loss. The implantation of a glaucoma drainage device (GDD), a tiny tube that drains the liquid inside the eye by bypassing the natural drainage system, is an effective option to lower the eye pressure in patients with KPro. Given the frequency and potentially devastating effects of glaucoma among KPro patients, some surgeons recommend to put in a GDD as a preventative measure. However, there is no consensus on when is the best timing to perform such surgery in relation to the Boston Kpro surgery. Hypothesis: For patients undergoing the Boston KPro surgery, implanting a GDD simultaneously, at the time of surgery, is more efficacious than at 6 months later, in the prevention of the progression of glaucoma and in maintaining better visual functions. Methods: The investigators aim to recruit 40 patients over 4 years. Recruited patients will be randomly assigned to 2 groups: 1) simultaneous GDD implantation at the Boston KPro surgery, and 2) GDD implantation 6 months after the Boston KPro surgery. Once recruited, patients will be followed before the KPro surgery, postoperative day 1, week 1, month 1, 3, 6 and 12. Standard ophthalmological exam will be performed at each visit. Additional non-invasive glaucoma tests and evaluation (visual fields and optic nerve photo) will be performed on day 1, month 1, 3, 6 and 12. For patients assigned to group 2, a GDD will be implanted 6 months after the KPro surgery. They will have additional follow-ups on post-GDD surgery day 1, week 1 and month 1. Results of visual acuity, visual fields, optic nerve evaluation and complications will be compared between the two groups to determine the better timing of GDD implantation.
At present, all commercially available corneal organ culture media contain foetal calf serum (FCS) and sometimes other compounds extracted from animals. These compounds are necessary for corneal cell survival but are problematic because they theoretically have risk of anthropozoonosis transmission, especially for new variant of CJD and the variability between FCS batches influence graft quality. Our laboratory research allowed in vitro and ex vivo validation of a new medium free compound animal. We proved its superiority over conventional medium containing 2% FCS for endothelial cell survival during the storage time. The goal of this clinical trial is now to assess its superiority in patients.