Randomized Clinical Trial for Retinitis Pigmentosa

The purpose of this trial is to determine whether a nutritional supplement in addition to vitamin A will slow the course of retinitis pigmentosa.

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.

The 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 the supplement under study. 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 for the 30-2 program of the Humphrey Field analyzer (HFA). In addition, computer-averaged 30-Hz cone ERG amplitudes and visual acuity are measured annually.

Eligible patients must:

1. Have typical retinitis pigmentosa
2. Be between the ages of 18 and 60
3. Be able to see the entire face of someone sitting across the table from them without scanning
4. Read newspaper-size print without special magnifying aids
5. Walk unaided in daylight
6. Hear on the telephone
7. Have a normal fasting serum vitamin A and normal liver function profile
8. Be a non-smoker
9. Eat a balanced diet
10. Be in good general health
11. Reside in the United States

Exclusion Criteria:

1. Women who are pregnant or planning to become pregnant (Vitamin A supplements can increase the risk of birth defects.)
2. Current participation in another clinical trial for RP

No longer recruiting. Comments: Total recruitment of 241 participants was reached on November 24, 2004.

Ongoing. Comments:

None at this time.