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.
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 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.
Corneal transplant is a surgical procedure where a damaged or diseased cornea is replaced by donated corneal tissue (the graft) in its entirety (penetrating keratoplasty) or in part (lamellar keratoplasty). One type of lamellar keratoplasty is DSAEK (Descemet's Stripping Automated Endothelial Keratoplasty), where only the damaged posterior section of the cornea is replaced. The purpose of this study is to investigate how immediate postoperative positioning of the patient affects the dislocation rate of the corneal graft. Since this is a new surgical method, little scientific documentation has been published in this area.
The purpose of this study is to evaluate the stability of artificial cornea manufactured by Aurolab and to assess its visual outcomes.