A randomized trial of vitamin A and vitamin E supplementation for retinitis pigmentosa

Arch Ophthalmol. 1993 Jun;111(6):761-72. doi: 10.1001/archopht.1993.01090060049022.

Abstract

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

Design: 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.

Setting: Clinical research facility.

Patients: 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.

Intervention: 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.

Main outcome measure: 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.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Double-Blind Method
  • Drug Therapy, Combination
  • Electroretinography / drug effects*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Regression Analysis
  • Retina / drug effects
  • Retinitis Pigmentosa / drug therapy*
  • Retinitis Pigmentosa / pathology
  • Survival Analysis
  • Visual Acuity
  • Visual Fields
  • Vitamin A / adverse effects
  • Vitamin A / therapeutic use*
  • Vitamin E / adverse effects
  • Vitamin E / therapeutic use*

Substances

  • Vitamin A
  • Vitamin E