Completed

Clinical Trial of Docosahexaenoic Acid (DHA) in Patients With Retinitis Pigmentosa Receiving Vitamin A Treatment

0 criteria met from your profileSee at a glance how your profile meets each eligibility criteria.
What is being tested

Vitamin A

+ Control fatty acid

+ Docosahexaenoic acid

Dietary Supplement
Who is being recruted

Eye Diseases+5

+ Congenital, Hereditary, and Neonatal Diseases and Abnormalities

+ Retinal Degeneration

From 18 to 55 Years
See all eligibility criteria
How is the trial designed

Treatment Study

Placebo-ControlledPhase 3
Interventional
Study Start: May 1996
See protocol details

Summary

Principal SponsorCarol Weigel DiFranco
Last updated: January 28, 2026
Sourced from a government-validated database.Claim as a partner

Study start date: May 1, 1996

Actual date on which the first participant was enrolled.

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.

Official TitleClinical Trial of Docosahexaenoic Acid (DHA) in Patients With Retinitis Pigmentosa Receiving Vitamin A Treatment
NCT00000116
Principal SponsorCarol Weigel DiFranco
Last updated: January 28, 2026
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details

221 patients to be enrolled

Total number of participants that the clinical trial aims to recruit.

Treatment Study

These studies test new ways to treat a disease, condition, or health issue. The goal is to see if a new drug, therapy, or approach works better or has fewer side effects than existing options.

Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Conditions
Criteria

Any sex

Biological sex of participants that are eligible to enroll.

From 18 to 55 Years

Range of ages for which participants are eligible to join.

Healthy volunteers allowed

If individuals who are healthy and do not have the condition being studied can participate.

Conditions

Pathology

Eye DiseasesCongenital, Hereditary, and Neonatal Diseases and AbnormalitiesRetinal DegenerationRetinal DiseasesRetinitis PigmentosaEye Diseases, HereditaryGenetic Diseases, InbornRetinal Dystrophies

Criteria

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

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Treatment Groups
Study Objectives

2 intervention groups are designated in this study

50% chance of being blinded to the placebo group

Treatment Groups

Group I

Placebo
Patients randomized to this arm received 500 mg/d of fatty acid with no docosahexaenoic acid and 15000 IU/ Vitamin A as retinyl palmitate

Group II

Experimental
Participants randomized to this arm received 1200 mg/d docosahexaenoic acid and 15000 IU/d Vitamin A as retinyl palmitate

Study Objectives

Primary Objectives

Secondary Objectives

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.

This study has 1 location

Suspended

Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary

Boston, United StatesOpen Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary in Google Maps
CompletedOne Study Center