View clinical trials related to Corneal Dystrophies, Hereditary.
Filter by:The pathophysiology of the most common corneal endothelial dystrophies (Fuchs' Corneal Endothelial Dystrophy (FECD)) is beginning to be dismembered. One of the most common genetic anomalies is a triplet repetition in one of the introns of the Transcription Factor 4 (TCF4) gene located on chromosome 18. However, the number of repetitions varies greatly from one patient to another.
Rationale: Intra-operative optical coherence tomography (iOCT) is a new technology that incorporates advanced imaging techniques in the ophthalmic operating theatre. This allows surgeons to visualize tissues in a way previously impossible We conceptualized an iOCT-guided surgical protocol for the treatment of endothelial cell dysfunction, that refrains from the current practice of over-pressurizing the eye at the end of surgery. Objective: The aim of this study is to assess the clinical value of intraoperative OCT (iOCT) for Descemet Membrane Endothelial Keratoplasty (DMEK) by comparing an iOCT-optimized surgical protocol with current practice, where the eye is over-pressurized for a set period of time, in terms of surgical efficiency, clinical outcomes, and adverse events. Study design: International multicentre non-inferiority randomized clinical trial Study population: Patients scheduled for posterior lamellar corneal surgery for endothelial cell dysfunction above the age of 18 years. Intervention: Both groups will undergo Descemet Membrane Endothelial Keratoplasty. Patients will be randomized for either the iOCT optimized surgical protocol or current standard surgical protocol using 8 minutes of overpressure to facilitate graft adherence. Both groups will be evaluated with iOCT at the end of surgery. Main study parameters/endpoints: The main study parameter is the rate of adverse events (particularly graft dislocations). Secondary parameters/endpoints are surgical time, the recovery of visual acuity and endothelial graft quality at 3 and 6 months follow-up, and a detailed evaluation of the extent/duration of surgical tissue manipulations. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The use of iOCT during surgery does not entail additional risk to the patient. Participants to this study will adhere to the standard of care after corneal transplant surgery. In addition, they will receive study specific measurements and questionnaires. The additional measurements and questionnaires will be combined with regular follow up moments.
The cornea forms our "window to the world". Hence, its transparency is of utmost importance for vision. Corneal endothelium plays a central role in the maintenance of a transparent corneal stroma. It limits stromal fluid uptake from the anterior chamber of the eye through the formation of tight junctions. Simultaneously, fluid is actively transported from corneal stroma into the anterior chamber. This maintains the corneal stroma in a state of relative dehydration, thereby ensuring a constant distance of stromal collagen lamellae to each other, which in turn forms the basis for transparency of this tissue. If however corneal endothelial function is impaired, stromal swelling leads to corneal clouding and loss of vision. Fuchs endothelial corneal dystrophy represents the most common form of corneal dystrophy. It occurs sporadically, however in some cases autosomal dominant inheritance has been described. This condition leads to progressive loss of corneal endothelium (typically around the age of 50-60 years), causing visual impairment due to swelling and opacification of corneal stroma. Cell culture experiments have been able to show that chemical inhibitors of Rho-Kinase promote corneal endothelial cell proliferation and reduce apoptosis, while topical application in an animal model promoted corneal endothelial wound healing. This has prompted the notion of using topical Rho-kinase-inhibitor treatment to support endothelial cell regeneration in Fuchs endothelial corneal dystrophy. Since September 2014, Rho-kinase-inhibitor eye drops (ripasudil) are clinically available in Japan for reduction of intraocular pressure in Glaucoma patients. Ripasudil eye drops therefore represent a strong candidate for safe and effective adjunctive treatment in patients with Fuchs corneal endothelial cell dystrophy.
This main goal of this study is to improve the detection, classification, monitoring, and treatment of irregular corneas due to keratoconus, warpage, dry eye, scar, stromal dystrophies, and other corneal conditions. The primary goal will be achieved by using optical coherence tomography (OCT) to: 1. Develop an OCT-based system to classify and evaluate corneal-shape irregularities. 2. Develop OCT metrics for more sensitive detection of keratoconus progression. 3. Develop OCT-and-topography guided phototherapeutic keratectomy (PTK) for irregular corneas.
Corneal dystrophies are usually classified histopathologically according to the layer of the cornea that is affected. The International Committee for the Classification of Corneal Dystrophies (IC3D) takes this anatomical classification as referral with summarizing clinical, genetic, and pathological data. Most of this classification relies on slit lamp findings or histologic specimen, since in-vivo imaging of corneal microstructures has only become available in the recent years. With confocal microscopy it is possible to image corneal microstructures at a high resolution, but this technique is limited by its reduced repeatability and the fact that only a small area can be imaged. By the use of optical coherence tomography (OCT) systems it is possible to overcome these limitations. Commercially available systems, however, only have an axial resolution of about 18 µm which is not sufficient for imaging of all corneal layers. Recently, a high-resolution optical coherence tomography (OCT) system was developed at the Center for Medical Physics and Biomedical Engineering that enables a resolution of about 1 µm. With this resolution, all corneal structures and several pathologies can be visualized. In the present study the investigators want to use this OCT system to image corneal dystrophies in patients scheduled for corneal transplantation.
Transplantation of cellularized human cornea impregnated and populated by mesenchymal stem cells derived from the patient's adipose tissue. The purpose of the study is to assess the safety, tolerability, and preliminary efficacy of transplantation of a single dose of autologous mesenchymal adipose tissue derived adult stem cells (ADAS) cellularized into laminas for subjects with corneal defects. 3 groups will be included in the study: (1) transplantation of ADAS alone without scaffold, (2) transplantation of scaffold (human corneal decellularized lamina) without ADAS, and (3) transplantation of ADAS cellularized on scaffold (the human corneal decellularized lamina)
Immune rejection episodes after penetrating keratoplasty occur in 30% of patients and constitute one of the main factors reducing graft survival. They mainly occur during the first 18 months. Prevention usually relies on a topical treatment with dexamethasone or prednisolone for standard risk patients. Eye drops are instilled three times a day during at least 3 months then tapered. OZURDEX is an absorbable small implant that releases a total of 700 micrograms dexamethasone during several months. It is indicated for intravitreal injection to treat macular edema. The investigators hypothesized that this implant could be used after subconjunctival injection during corneal graft, to prevent immune rejection and avoid repeated eyedrop instillations.
Penetrating keratoplasty (PKP) is an open-sky surgery that fundamentally has not changed for more than 100 years. Because conventional PKP is associated with the potential for the development of devastating complications such as expulsive suprachoroidal hemorrhage and endophthalmitis, we modified the technique to one that is a closed surgery under topical anesthesia with the anterior chamber maintained to achieve favorable results. Topical anesthesia is an attractive alternative to traditional injection local anesthesia since the potentially serious complications associated with retrobulbar and peribulbar anesthesia can be avoided. The closed PKP procedure with the stable anterior chamber essentially changes the open nature of conventional PKP. The advantages, i.e., decreased surgical risks, postoperative complications, and surgical difficulties, make PKP viable in most complicated cases.
To determine the prevalence of 5 specific corneal dystrophies in a subgroup of patients seeking refractive surgery, and to use that information to inform them and their refractive surgeons of the presence of the corneal dystrophies so that they may make safer choices when considering refractive surgery.
The investigators will evaluate 30 patients with surgical indication for corneal transplantation. Participants will be divided according to the following diseases diseases: keratoconus, bullous keratopathy, corneal dystrophies. Participants will be informed about the risks and benefits of the study and sign an informed consent form. In the preoperative evaluation will be submitted to a complete ophthalmologic examination with complementary tests, such as optical coherence tomography. One group of participants will undergo corneal surgery using the OCT Lumera microscope RESCAN - ZEISS and another group with a conventional microscope. Everyone will have their filmed and documented surgery. The team of surgeons will answer the questionnaire on the surgical difficulty about the ease of assessing corneal transplantation. After surgery, participants will be assessed on days 1, 7,15, 30, 60, 90 and 180 after surgery. Surgeries and study procedures will be performed by the same team of surgeons and performed by IPEPO - Paulista Institute of Studies and Research in Ophthalmology / Vision Institute.