View clinical trials related to Retinitis Pigmentosa.
Filter by:Retinitis pigmentosa (RP) is a collective term for a group of inherited retinal dystrophies that are a major cause of irreversible blindness. RP of some type occurs in approximately 1 out of 3500 persons in the United States(1). Gene mutations are responsible for the majority of RP. To date, mutations have been identified in 30 different genes linked to RP(2). The visual prognosis of RP is poor, since the gradual but relentless visual field loss leads eventually to some degree of blindness(3). Although no effective treatment for RP has been identified, participants supplemented with a daily oral dose of 15,000 IU vitamin A palmitate have shown, on average, a slower rate of deterioration of retinal function when the intervention is continued over several years(4). The purpose of this research is to determine whether administration of high oral doses of vitamin A can acutely improve cone photoreceptor function in RP participants as measured by electroretinography (ERG). In this interventional, non-randomized, prospective, pilot study, 5 participants will receive a daily oral dose of 50,000 IU of vitamin A palmitate for 4 weeks, followed by a maintenance dose of 15,000 IU daily for the subsequent 2 weeks. The primary efficacy outcome is a relative percentage change in ERG response amplitude subsequent to vitamin A supplementation. A secondary efficacy outcome is a relative percentage change in implicit time from pre- to post- vitamin A supplementation, with improvement specified as a shorter response implicit time. Other secondary outcomes will be improvements in visual field (Humphery, 10-2; sum of thresholds). Safety outcomes include visual fields, ETDRS visual acuity, intraocular pressure, serum vitamin A level and liver function tests.
This study will evaluate the safety of a ciliary neurotrophic factor (CNTF) implant placed in the eye to allow the release of CNTF directly on the retina. The results of this study may lead to a larger investigation of CNTF implants to treat retinitis pigmentosa (RP), a progressive degenerative eye disease that begins with loss of peripheral vision and night blindness and often leads to blindness in later life. Currently, there are no effective treatments for RP. Researchers have found, however, that certain proteins, called ciliary neurotrophic factor (CNTF), can partially protect cells in the eye if given directly inside the eye. A major challenge in treating RP is to deliver medicine directly into the eye. One way to ensure that CNTF gets into the eye is to surgically place an implant inside the eye to release the protein. Patients 18 years of age and older with retinitis pigmentosa whose visual acuity is 20/100 or worse may be eligible for this study. Candidates will be screened with a medical history, physical examination, eye examinations, and eye photographs. The eye examination includes measurement of visual acuity and eye pressure, examination of the pupils and eye movements, and examination of the lens and back of the eye. In addition, patients will have the following tests: - Visual field test: Patients look at a central spot on a white screen and tell the examiner whenever they see a small light appear at other places on the screen. - Electroretinogram (ERG): Electrodes are taped to the patient's forehead. Special contact lenses are placed on the eyes, similar to normal contact lenses, after the eye has been numbed with drops. The contact lenses sense small electrical signals generated by the retina. The ERG measures the electrical activity of the retina when it is stimulated by light. For the ERG recording, the patient looks inside a large, hollow, dark sphere, and sees flashes of light, first in the dark, and then with a light turned on in the sphere. - Optical coherence tomography: This test, done with the machine used to examine the eye, measures retinal thickness by producing cross-sectional pictures of the retina. Participants undergo surgery at the NIH Clinical Center in a 30-minute operation to place the implant in one eye. The surgery is done under local anesthetic. Before the procedure, patients are given a steroid injection along side the eye to minimize inflammation after surgery. Following the procedure, patients return for follow-up visits once a month for 6 months. At these visits, several of the exams described above are repeated to evaluate treatment effects and check for adverse side effects. After 6 months, the implant is surgically removed. Post-surgical care for both implant and explant surgeries include examinations the day and week after surgery to examine the wound, a high dose of steroid immediately after surgery, oral antibiotics for 7 days, and eye drops for 1 week to prevent infection and inflammation.
Phase I/II double-masked, randomized, placebo-controlled, cross-over trial to determine effects of lutein on vision in retinitis pigmentosa, including safety and effective dosage assessment
Hearing loss and loss of vision can be very harmful to the well-being and life of people who suffer from them. Usher syndrome is the name of a disease where people have both hearing loss and visual loss. In fact more than half of people who are deaf and blind have Usher syndrome. In this study we are trying to find the causes of all types of Usher syndrome and to learn more about how the eyes and ears work. Usher syndrome is caused by changes in our genes that lead to mistakes in the functioning of our eyes and ears. We may conduct hearing tests called audiograms to test hearing and a vision test called an electroretinogram (ERG) to test how well the retina (the part of your eye that senses light) is working on participants in the study. From these tests we can tell what kind of Usher syndrome a participant may have. We will then get DNA from participants by drawing blood. The DNA will be studied, along with DNA from members of the participant's family and other families, to try to find the gene that is causing Usher syndrome in the participant. Once the gene is found we will be able to study it to learn more about how the eyes and ears work. If a subject has already been diagnosed we may just need copies of their medical records and blood can be drawn locally. In order to increase the power of the study and the likelihood of detecting relevant genes participants will be taken from the Ashkenazi Jewish population group only. This will make it much easier to find the genes.
OBJECTIVES: I. Evaluate the potential of nutritional docosahexaenoic acid (DHA) supplementation to normalize the level of DHA in red blood cells, and to retard the progression of visual function loss in patients with early stage X-linked retinitis pigmentosa.
The purpose of this investigation is to gain additional knowledge about what causes type 1 and type 2 Usher syndrome-inherited diseases that can cause balance problems and impaired hearing and vision-and to develop better diagnostic tests. Patients with type 1 Usher syndrome usually are deaf from birth and have speech and balance problems. Patients with type 2 disease generally are hearing impaired but have no balance problems. All patients develop eye problems that cause difficulty seeing in the dark. The development of newer and more sophisticated diagnostic tests may detect subtle differences in signs and symptoms that allow more accurate distinction between the two types of Usher syndrome. This study will use these tests to classify these syndromes and eventually identify the genes responsible for them. Study participants will have a medical and family history taken and a family tree constructed. They will undergo a thorough eye examination, including special tests of color vision, field of vision, and ability to see in the dark. An electroretinogram will be done to measure the function of cells in the retina, and a procedure called fluorescein angiography will be done to look at and photograph the blood vessels in the retina. Special hearing and balance tests will also done. Hearing tests include physical examination of the ears and wearing earphones while listening to tones. Balance and coordination tests require tasks such as walking in a straight line and standing in the dark with eyes closed. A caloric stimulation test will also be done, in which a small amount of water is irrigated into the ear canal. For gene studies, blood samples will be collected from patients and all available family members.
The purpose of this trial is to determine whether a nutritional supplement in addition to vitamin A will slow the course of retinitis pigmentosa.
To determine whether supplements of vitamin A or vitamin E alone or in combination affect the course of retinitis pigmentosa.