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Randomized Trial of Vitamin A and Vitamin E Supplementation for Retinitis Pigmentosa

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00000114
Recruitment Status : Completed
First Posted : September 24, 1999
Last Update Posted : September 17, 2009
Information provided by:
National Eye Institute (NEI)

Brief Summary:
To determine whether supplements of vitamin A or vitamin E alone or in combination affect the course of retinitis pigmentosa.

Condition or disease Intervention/treatment Phase
Retinitis Pigmentosa Drug: Vitamin E Drug: Vitamin A Phase 3

Detailed Description:

Retinitis pigmentosa (RP) is a group of inherited retinal degenerations with a worldwide prevalence of about 1 in 4,000. Patients typically report night blindness in adolescence and lose vision in the midperipheral followed by far-peripheral visual field in adulthood due to progressive loss of both rod and cone function. Most patients have reductions in central vision by age 50 to 80 years. Modern-day electroretinograms (ERGs) make it possible to record retinal responses from most patients with remaining vision and thereby monitor objectively the course of their disease.

While the natural course of retinal degeneration in the common forms of RP was being studied, it was noted that a subgroup of patients aged 18 through 49 who were treating themselves with both vitamin A and vitamin E and other nutritional supplements exhibited less decline in ERG amplitude over a 2-year period. These preliminary findings, as well as the known roles of vitamins A and E in maintaining normal photoreceptor function and structure, prompted this randomized, controlled trial to determine whether these vitamins alone or in combination would halt or slow the progression of the common forms of RP.

This study was a randomized, controlled double-masked trial with 2 x 2 factorial design and duration of 4 to 6 years. Patients were assigned to one of four treatment groups:

15,000 IU/day vitamin A

15,000 IU/day vitamin A + 400 IU/day vitamin E

trace amounts of both vitamins A and E

400 IU/day of vitamin E

The main outcome measure was the 30-Hz cone ERG amplitude. In addition, visual field and visual acuity were measured annually.

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Study Type : Interventional  (Clinical Trial)
Allocation: Randomized
Intervention Model: Factorial Assignment
Masking: Double
Primary Purpose: Treatment
Study Start Date : May 1984
Actual Study Completion Date : June 1987

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 49 Years   (Adult)
Sexes Eligible for Study:   All
Men and nonpregnant women between ages 18 and 49 years with common forms of RP were included. All eligible patients had retinal arteriolar attenuation, elevated dark adaptation thresholds, and reduced ERGs. Patients had best corrected Snellen visual acuity of 20/100 or better, central visual field diameter on the Goldman perimeter with V4 e white test light of 8 degrees or greater, and ERG amplitude of 2.5 or greater in response to 0.5-Hz white light or of 0.12 ultraviolet light or greater in response to 30-Hz white flickering light in at least one eye. In addition, patients had normal fasting serum retinol and serum liver function profile and weight above the lower fifth percentile for age, sex, and height. All patients had a total estimated pre-trial intake of vitamins A and E from diet plus pills not greater than 11,500 IU/day and 40 IU/day, respectively.

Additional Information:
Layout table for additonal information Identifier: NCT00000114     History of Changes
Other Study ID Numbers: NEI-10
First Posted: September 24, 1999    Key Record Dates
Last Update Posted: September 17, 2009
Last Verified: September 2009
Keywords provided by National Eye Institute (NEI):
retinitis pigmentosa
vitamin supplements
Additional relevant MeSH terms:
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Retinitis Pigmentosa
Retinal Diseases
Eye Diseases
Eye Diseases, Hereditary
Retinal Dystrophies
Retinal Degeneration
Genetic Diseases, Inborn
Vitamin E
Vitamin A
Retinol palmitate
Growth Substances
Physiological Effects of Drugs
Molecular Mechanisms of Pharmacological Action
Protective Agents
Anticarcinogenic Agents
Antineoplastic Agents