A randomized trial of vitamin A and vitamin E supplementation for retinitis pigmentosa.
OBJECTIVE
To determine whether supplements of vitamin A or vitamin E alone or in combination affect the course of retinitis pigmentosa.


METHODS
Randomized, controlled, double-masked trial with 2 x 2 factorial design and duration of 4 to 6 years. Electroretinograms, visual field area, and visual acuity were measured annually.


METHODS
Clinical research facility.


METHODS
601 patients aged 18 through 49 years with retinitis pigmentosa meeting preset eligibility criteria. Ninety-five percent of the patients completed the study. There were no adverse reactions.


METHODS
Patients were assigned to one of four treatment groups receiving 15,000 IU/d of vitamin A, 15,000 IU/d of vitamin A plus 400 IU/d of vitamin E, trace amounts of both vitamins, or 400 IU/d of vitamin E.


METHODS
Cone electroretinogram amplitude.


RESULTS
The two groups receiving 15,000 IU/d of vitamin A had on average a slower rate of decline of retinal function than the two groups not receiving this dosage (P = .01). Among 354 patients with higher initial amplitudes, the two groups receiving 15,000 IU/d of vitamin A were 32% less likely to have a decline in amplitude of 50% or more from baseline in a given year than those not receiving this dosage (P = .01), while the two groups receiving 400 IU/d of vitamin E were 42% more likely to have a decline in amplitude of 50% or more from baseline than those not receiving this dosage (P = .03). While not statistically significant, similar trends were observed for rates of decline of visual field area. Visual acuity declined about 1 letter per year in all groups.


CONCLUSIONS
These results support a beneficial effect of 15,000 IU/d of vitamin A and suggest an adverse effect of 400 IU/d of vitamin E on the course of retinitis pigmentosa.
Berson
E L
EL
Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston 02114.
Rosner
B
B
Sandberg
M A
MA
Hayes
K C
KC
Nicholson
B W
BW
Weigel-DiFranco
C
C
Willett
W
W
D000293:Adolescent; D000328:Adult; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D004596:Electroretinography / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012160:Retina / Q000187:drug effects; D012174:Retinitis Pigmentosa / Q000188:drug therapy* / Q000473:pathology; D016019:Survival Analysis; D014792:Visual Acuity; D014794:Visual Fields; D014801:Vitamin A / Q000009:adverse effects / Q000627:therapeutic use*; D014810:Vitamin E / Q000009:adverse effects / Q000627:therapeutic use*
D014801:Vitamin A; D014810:Vitamin E