View clinical trials related to Retinitis Pigmentosa.Filter by:
Retinitis Pigmentosa (RP) is a devastating eye disease and at present there are no known treatment options that can alter the rate of vision loss. In a series of studies in animal models, the effects of exposing cones in the periphery of the retina to a large excess of oxygen results in progressive oxidative damage to cone photoreceptors and cone cell death. Compared to control patients, those with RP showed significant reduction in the reduced to oxidized glutathione ratio (GSH/GSSG) in aqueous humor and a significant increase in protein carbonyl content. This demonstration of oxidative stress and oxidative damage in the eyes of patients with RP, suggests that oxidative damage-induced cone cell death in animal models of RP may translate to humans with RP and support the hypotheses that (1) potent antioxidants will promote cone survival and function in patients with RP and (2) aqueous GSH/GSSG ratio and carbonyl content on proteins provide useful biomarkers of disease activity in this patient population. Orally administered N-Acetylcysteine (NAC) has been found to be a particularly effective antioxidant that promotes prolonged cone survival and maintenance of cone function in a mouse model of RP. There is good rationale to test the effect of NAC in patients with RP. The first step is to do test different dosing regimens to identify the lowest dose that is able restore aqueous GSH/GSSG ratio and reduce carbonyl adducts on aqueous proteins. In patients with Idiopathic Pulmonary Fibrosis, polymorphisms within the TOLLIP gene were found to influence outcomes of NAC-treated patients. The product of the TOLLIP gene, toll-interacting protein, is an inhibitory adaptor protein downstream of toll-like receptors, mediators of innate and adaptive immunity. The identification of the influence of TOLLIP polymorphisms on the effect of NAC in Idiopathic Pulmonary Fibrosis provides rationale for collecting DNA and genotyping the same single nucleotide polymorphisms (SNPs) in the current trial. In addition to this candidate gene genetic analysis, patient RNA will be collected and banked for future transcriptome analysis. The rationale for this is to identify gene expression changes that modify disease progression in RP. There is substantial variability in rate of progression among patients with RP. A patient who loses all vision early in life can have a sibling with the same mutation who maintains vision into advanced age. This suggests that modifier genes can have a major impact on cone survival. This study will test the hypothesis that the level of expression of gene products that contribute to the antioxidant defense system may influence cone cell death and hence the rate of loss of visual field. It is also possible that gene expression differences may contribute to differences in response to NAC. For these reasons collecting RNA samples from patients will allow next generation sequencing in the future to understand the transcriptome background on which the study intervention has been performed.
This study evaluates a novel collision warning device to help people with severe vision impairment or blindness avoid collisions with obstacles. The main hypothesis to be tested is that the device reduces the number of collisions with obstacles in everyday activities.
This study will evaluate the use of autologous bone marrow derived stem cells (BMSC) for the treatment of retinal and optic nerve damage or disease.
The purpose of this study is to gain an understanding of how adRP progresses over time in patients with misfolded rod opsin mutations.
This pilot study will evaluate the visual response to infrared (IR) in humans after dark adaptation. The investigators plan to determine which wavelength and intensity the human eye is most sensitive too, using a broad spectrum light source and wavelength-specific bandpass filters. The investigators will then evaluate the electrophysiologic response in healthy humans to IR, followed by studies in those with specific retinal diseases. The long-term goal of this research is to better understand the role that IR plays in visual function, and whether this can be manipulated to allow for vision in certain retinal pathologies that result from loss of photoreceptor cells. The investigators central objective is to test the electrophysiologic response to IR in the dark-adapted retinal and visual pathways. The investigators central hypothesis is that IR evokes a visual response in humans after dark adaptation, and the characteristics of this response suggest transient receptor potential (TRP) channel involvement. The investigators rationale is that a better understanding of how IR impacts vision may allow for an alternative mechanism for vision in a number of diseases that cause blindness from the degradation or loss of function of photoreceptor cells. The investigators will test the investigators hypothesis with the following Aims: Aim 1: To determine the optimal IR wavelength for visual perception in dark-adapted human participants. The investigators hypothesize that the healthy human eye will detect IR irradiation, with a maximum sensitivity at a specific wavelength. Using a broad-spectrum light source with wavelength-specific bandpass filters, the spectral range of visual perception to IR will be evaluated. The same will be done on colorblind participants. Aim 2: To test the electrophysiologic response to IR in healthy humans after dark adaptation. The investigators hypothesize that IR will elicit an amplitude change on electroretinography (ERG) and visual evoked potential (VEP) responses after dark adaptation in healthy human participants. Participants will be tested with both test modalities to evaluate their response to IR. Aim 3: To test the electrophysiologic response to IR after dark adaptation in humans with certain retinal diseases. Participants with retinitis pigmentosa, age related macular degeneration and congenital stationary night blindness, will be tested. Results will be compared to baselines and to those of healthy participants. The investigators hypothesize that there will be a response to IR on ERG and VEP, which will provide clues to the retinal cell layer location of the response to IR and the nature of potential TRP channel involvement.
The retinitis pigmentosa (RP) are genetic conditions that cause retinal degeneration leading to severe low vision and is the leading cause of consultation in reference centers dedicated to the ophthalmic genetics. These rare diseases are characterized by a triple heterogeneity (clinical, genetic and molecular), which made them unreachable by traditional molecular diagnostic sequencing technology by the large number of genes to be tested (> 190). The advent of high-throughput sequencing (NGS) and targeted capture has opened unexpected possibilities of investigation and ultimately to improve the care of patients. This project aims to study the genetic and molecular epidemiology of an interregional french (grand EST) cohort of patients. Patients receive a detailed retinal phenotype (visual acuity, visual field, photographs of the fundus and ERG). Their DNA will be analyzed by NGS targets the 190 known genes (https://sph.uth.edu/retnet/). This research will provide a molecular epidemiological cohort study compared to prior publications on the frequency of genes involved. The benefit for patients is important to: establish a mode of transmission of the disease and optimize genetic counseling (currently very empirical); establish phenotype-genotype correlations in the French population (very few studies to date) and from the data of international literature; identify patients likely to be included in future therapeutic protocols of research; identify patients with significant potential for future projects to identify new genes. The primary purpose of the protocol is to use high throughput sequencing to identify pathogenic variants in genes involved in RP. The secondary purposes will be the following: - Determining the diagnostic yield - Study the genotype-phenotype correlation. The secondary purposes will be the following: - Determining the diagnostic yield - Study the genotype-phenotype correlation
The purpose of this study is to evaluate the effect of L-Dopa on the progression of retinitis pigmentosa.
Purpose: Cystoid macular edema (CME) in retinitis pigmentosa (RP) has been managed in several ways with little success. The aim of our study was to report the use of intravitreal dexamethasone implant in a large series of patients with RP and CME. Setting: Retrospective case series. Methods: Cases were diagnosed as RP based on the classic fundus triad of bone-spicule pigment deposits (intraretinal pigmentary migration), retinal vessel attenuation, waxy pallor of the optic disc along with night blindness and attenuated ERG amplitudes (delays in rod or cone b-wave implicit times). Family history of RP and family screening for RP were important in establishing the diagnosis in eyes with some diagnostic challenge. CME was diagnosed by intravitreous fluorescein angiography IVFA and spectral domain optical coherence tomography (SD-OCT). BCVA was monitored using Snellen visual acuity chart and CME was monitored by SD-OCT on follow-up visits.
Mutations in the PDE6A gene - encoding the -subunit of the rod cGMP-phosphodiesterase - account for 1% of autosomal recessive retinitis pigmentosa (arRP) through impaired regulation of cGMP levels in the rod outer segment. This study aims for a detailed clinical characterization of patients with PDE6A mutations in preparation of a clinical gene replacement study (phase I/II safety trial).
The aim of this single-centre study is to assess the safety and efficacy of the Retina Implant Alpha AMS (Retina Implant AG, Reutlingen, Germany) in participants with severe visual impairment secondary to outer retinal degeneration caused by retinitis pigmentosa (RP). The study is sponsored by the University of Oxford and funded by the National Institute for Health Research (UK).