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54 active trials for Retinitis Pigmentosa

Rod and Cone Mediated Function in Retinal Disease

Background: Retinal diseases cause the loss of rod and cone photoreceptors. Symptoms include vision loss and night blindness. Researchers want to learn about rod and cone function in healthy people and people with retinal disease. They want to know if how well a person sees in the dark can test the severity of retinal disease. Objectives: To find out if how well a person sees in the dark can test the severity of retinal disease. To find out if this can help detect retinal disease and track its changes. Eligibility: People ages 5 and older with: Retinal disease OR 20/20 vision or better with or without correction in at least one eye Design: Participants will be screened with medical and eye history and eye exam. Those with retinal disease will also have: Eye imaging: Drops dilate the eye and pictures are taken of it. Visual field testing: Participants look into a bowl and press a button when they see light. Electroretinogram (ERG): An electrode is taped to the forehead. Participants sit in the dark with their eyes patched for 30 minutes. Then they get numbing drops and contact lenses. Participants watch lights while retina signals are recorded. Visit 1 will be 3-8 hours. Participants will have up to 6 more visits over 6-12 months. Visits include: Eye exam and imaging Time course of dark adaptation: Participants view a background light for 5 minutes then push a button when they see colored light. Dark adapted sensitivity: Participants sit in the dark for 45 minutes. They push a button when they see colored light. For participants with retinal disease, ERG and visual field testing

Start: March 2016
Retinitis Pigmentosa Clinical Measures and Repeatability Testing of Potential Outcome Measures

Background: Retinitis pigmentosa (RP) is a group of blinding eye diseases. It is caused mostly by mutations in photoreceptor-expressed genes. RP affects about 2 million people globally. There is no cure, butut treatment and diagnosis can be guided by certain tests. Researchers want to see how well these tests capture stages of RP. Objectives: To find out how well certain tests track changes in retinitis pigmentosa. Eligibility: People ages 12 and older with RP Design: Participants will be screened in another protocol. Participants will have 2 visits about 6 weeks apart. Both will include all the tests below. Each visit will last 5 6 hours, or a visit can be split into 2 days. Participants will give their medical and eye history. Participants will have an eye exam. Their pupils will be dilated with eye drops. Participants will give blood samples. Pictures of participants retinas will be taken. Their retinas will be measured. Participants will take several eye tests. They will: Sit in a dark room and press a button when they see lights. View a bright background then press a button when they see lights. Look into a bowl and press a button when they see lights. Sit in the dark with their eyes patched. Then they will take eye-numbing drops and wear contacts as lights flash. A small electrode taped to their forehead will record signals from their retinas. Minors will give written consent to stay in the study when they turn 18. After the study ends, they may also be asked to give consent for researchers to continue to use their study information. Sponsoring Institute: National Eye Institute

Start: September 2019
FIGHT-RP 1 Extension Study

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 and eventual blindness. 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. Cone cell death gradually spreads from the periphery of the retina toward its center, narrowing the visual field and eventually resulting in tunnel vision. 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. Since oral and/or topical administration of NAC is feasible for long-term treatment in humans, and NAC has a good safety profile, there is good rationale to test the effect of NAC in patients with RP. Oxidative damage has been implicated in several diseases including cystic fibrosis, chronic obstructive pulmonary disease (COPD), and Idiopathic Pulmonary Fibrosis. The effect of oral NAC has been tested in these indications in several clinical trials providing extensive safety data. In COPD, NAC 600mg bid improves airway function and reduces the frequency of acute exacerbations. Doses of up to 1800mg/day have been well-tolerated in the treatment of Idiopathic Pulmonary Fibrosis. Paracetamol (acetaminophen) toxicity is treated with a loading dose of 140 mg/kg NAC followed by 70 mg/kg every 4 hours for 17 doses. Normal volunteers tolerated a dose of 11.2 grams NAC/day for three months without any serious undesirable effects and in another study a dose of 500mg/kg/day was tolerated. The most frequent adverse events associated with the oral administration of NAC are gastrointestinal in nature and include vomiting, diarrhea, stomatitis, abdominal pain and nausea (incidence rate >1/1000 to <1/100). Hypersensitivity reactions including anaphylactic shock and anaphylactic/anaphylactoid reaction (incidence rate <1/10,000), dyspnea, bronchospasm (incidence rate >1/10,000 to <1/1000), angioedema, tachycardia, urticaria, rash and pruritus (incidence rate >1/1000 to <1/100) have been reported less frequently. Finally, reports of headache, tinnitus, pyrexia, blood pressure decreased (incidence rate >1/1000 to <1/100), face edema and hemorrhage have also been collected with oral NAC. In the FIGHT-RP 1 Study, the investigators used escalating doses of NAC effervescent tablets (from 600 mg in Cohort 1 to 1800 mg in Cohort 3). The maximum tolerated dose was 1800 mg twice a day which will be continued in this study.

Start: June 2019
Effects of Treatment With N- Acetylcysteine on Visual Outcomes in Patients With Retinitis Pigmentosa

Retinitis pigmentosa (RP) is an inherited retinal disease with great heterogeneity. RP comprises a large group of genetic disorders causing progressive loss of vision. Despite many suggested treatments, there is actually no effective therapy for most types of RP at present. Mutations that cause RP initially lead to rod cell death. After rod photoreceptors' death, cone photoreceptors also gradually die. There are several hypotheses as to why mutation-induced rod photoreceptor cell death invariably leads to gradual dysfunction and death of cone photoreceptors resulting in severe visual acuity loss and blindness. Rods constitute 95 percent of cells in the outer retina. As they degenerate, oxygen consumption is reduced and the level of tissue oxygen markedly increases. After rods degeneration, several markers of oxidative damage appear in cones. This oxidative stress over time may lead to cone dysfunction and death. Antioxidants reduce markers of oxidative damage and promote cone function and survival. In RP, cone death occurs as a result of the death of rods, rather than as the result of the pathogenic mutations and therefore treatment with antioxidants may have the potential to be applied to all patients with RP irrespective of the disease-causing mutation. N-acetylcysteine is a derivative of L cysteine that plays a role in the biosynthesis of glutathione and neutralizes reactive oxygen species. It also has a direct antioxidant activity via its reactive sulfhydryl agent. Its systemic use shows an acceptable safety profile. It has been shown that the use of systemic N-acetylcysteine provides significant intraocular concentration and antioxidant activity that may lead to the promotion of cone function and survival. In a recent phase 1 randomized clinical trial (RCT), it was revealed that oral N-acetylcysteine (NAC) was safe and well-tolerated in patients with moderately advanced RP and might improve sub-optimally functioning macular cones. The authors concluded that a randomized, placebo-controlled trial is needed to determine if oral NAC can provide long-term stabilization and/or improvement in visual function in patients with RP. In this phase 2 RCT, eligible patients with the diagnosis of moderately advanced RP are randomly divided into two groups; treatment group (N-acetylcysteine tablets) and controls (placebo). Each group will be treated for 6 months. In this study, we will investigate if the use of oral N- acetylcysteine as a potent antioxidant agent can slow down or reverse the disease process in RP patients with prior moderate loss of vision. It may potentially demonstrate a treatment modality regardless of the genetic type of RP. The primary outcome measure will be the stability or improvement of the best-corrected visual acuity (BCVA). The secondary outcome measures will be changes in color vision, electroretinogram, visual field, structural OCT indices after 6 months. The same parameters will be re-evaluated 3 months after discontinuation of treatment at month 9.

Start: April 2021
Characterizing Rate of Progression in USHer Syndrome (CRUSH) Study

Mutations in USH2A give rise to two phenotypes: Usher syndrome type 2a (USH2A) and nonsyndromic RP (USH2A associated nsRP). Usher syndrome is the most common form of congenital deafblindness. Patients with Usher syndrome are hearing impaired or profoundly deaf from birth and this can be rehabilitated with hearing aids or a cochlear implant. Furthermore, these patients develop retinitis pigmentosa (RP), a slowly progressive type of retinal degeneration that usually starts in the first or second decade of life. In both USH2A and nsRP patients the disease leads to severe visual impairment and eventually blindness around the 50th-70th year of life. There are no treatment options for the retinal degeneration. We do not know if they also suffer from balance complaints. Currently, genetic therapy for Usher syndrome type 2 and USH2A associated nsRP is in development. But to measure the effect of a (genetic) therapy, it is crucial to know the detailed natural course of the visual and hearing deterioration over time. Several genetic therapy studies for other disorders are currently delayed, because the natural history of the disease has not been studied in detail previously. The main objective is to map the natural course of the visual and hearing deterioration in Usher Syndrome 2 and USH2A associated nsRP for upcoming genetic therapy studies. Secondary objectives are: 1) To determine the necessary type of (combined) examinations, the sample size and length of studies (in years) essential to evaluate future genetic therapy in Usher syndrome. 2) To improve counselling of patients with Usher syndrome type 2 and USH2A associated nsRP with detailed information on the prognosis. 3) To identify additional etiological factors that explain variability in hearing impairment by adding questionnaires and psychophysical audiometric tests; and to assess the vestibular phenotype in Usher syndrome type 2 and USH2A associated nsRP patients. This is a longitudinal, prospective natural history study. The study population consists of healthy human volunteers, 16 - 55 yr old with a confirmed genetic diagnosis of Usher Syndrome type 2 or and USH2A associated nsRP. The main study endpoint is the natural course of the visual and hearing deterioration in Usher Syndrome type 2 and USH2A associated nsRP, over a time span of 4 years. There are no risks associated with participation.

Start: February 2019