Retinitis Pigmentosa
Conditions
Brief summary
The purpose of this trial is to determine whether a nutritional supplement in addition to vitamin A will slow the course of retinitis pigmentosa.
Detailed description
Retinitis pigmentosa (RP) is a group of inherited retinal degenerations with a worldwide prevalence of approximately 1 in 4,000. Patients typically report night blindness and difficulty with midperipheral visual field in adolescence. As the condition progresses, they lose far peripheral visual field. Most patients have reductions in central vision by age 50 to 80 years. Based on electroretinograms (ERGs), the course of the disease can be slowed on average among adults on 15,000 IU/day of vitamin A palmitate. While conducting the trial on the effects of vitamin A on RP, it became apparent that another substance in the diet could be affecting the course of the disease. This prompted the present randomized, controlled trial. This study is a randomized, controlled, double-masked trial with a planned duration of 5 years. Patients with the common forms of RP are assigned to either a test or a control group. All receive 15,000 IU/day of vitamin A palmitate in addition to either 1200 mg/d of docosahexaenoic acid or control capsules. Participants will not know the contents of the supplement or the group to which they have been assigned until the end of the trial. The main outcome measurement is the total point score on the Humphrey Field Analyzer (HFA). In addition, computer-averaged 30-Hz cone ERG amplitudes and visual acuity are measured annually.
Interventions
DIETARY_SUPPLEMENTVitamin A
15000 IU/d as retinyl palmitate
DIETARY_SUPPLEMENTDocosahexaenoic acid
1200 mg/d
DIETARY_SUPPLEMENTControl fatty acid
Sponsors
Carol Weigel DiFranco
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Masking description
In this trial neither the participants, nor the clinicians, nor the investigators were aware of treatment group assignment.
Eligibility
Sex/Gender
ALL
Age
18 Years to 55 Years
Healthy volunteers
Yes
Inclusion criteria
Ocular Criteria: Retinitis Pigmentosa, typical (non-syndromic) forms Best corrected visual acuity Greater than or equal to (GE )20/100 HFA 30-2 total point score GE 250 dB (decibels) 30 (Hertz) Hz ERG cone amplitude GE 0.68 microvolts Dietary Criteria: Dark fish intake Less than or equal to (LE) five servings per week Dietary omega-3 fatty acid intake LE 0.41 g/d Preformed Vitamin A intake in diet and supplements LE 10,000 IU/d Supplement intake LE 5000 IU/d of Vitamin A and LE 30 IU/d Vitamin E Consumption LE 3 alcoholic beverages per day Medical and other criteria: Body Mass Index Less than (LT )40 and weight GE 5th percentile for age, sex, and height Serum retinol level LE 100 mg/dl and serum retinyl ester levels LE 380 nm/L Serum cholesterol level LT 300 mg/dL and serum triglyceride levels LT 400 mg/dL Agree not to know study capsule content
Exclusion criteria
Ocular criteria: No confounding ocular disease Dietary criteria: No intake of cod liver oil or omega-3 capsules Medical and other criteria: Not pregnant or planning to become pregnant No clinically significant abnormal result on Complete Blood Count or serum liver function profile No other disease which might affect absorption or metabolism of DHA or Vitamin A
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Humphrey Field Analyzer (HFA) total point score 30-2 program | Annual percent change per year at each of 4 years of followup | Sum of points in Decibels of total points seen in 30-2 program. Higher scores = better vision/larger visual field |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Humphrey Field Analyzer (HFA) total point score 30 -2 plus 30/60-2 programs combined | Annual percent change per year at each of four years of followup | Sum of points in decibels of total points seen in 30-2 and 30/60-2 programs combined- Higher scores = better vision/ larger visual field |
| Change in 30Hz Electroretinogram ( ERG) amplitude | Annual percent change per year at each of four years of followup | Value in microvolts of response to 30hz ERG. Higher values = greater visual function |
| Change in Early Treatment of Diabetic Retinopathy(EDTRS) Visual Acuity | Change in number of letters read per year at each of four years of followup. | Number of letters read per year. More letters read = better visual acuity |
Countries
United States
Outcome results
None listed