Vitamin A and fish oils for retinitis pigmentosa.

CONCLUSIONS: Based on the results of three RCTs, there is no clear evidence for benefit of treatment with vitamin A and/or DHA for people with RP, in terms of the mean change in visual field and ERG amplitudes at one year and the mean change in visual acuity at five years follow-up. In future RCTs, since some of the studies in this review included unplanned subgroup analysis that suggested differential effects based on previous vitamin A exposure, investigators should consider examining this issue. Future trials should take into account the changes observed in ERG amplitudes and other outcome measures from trials included in this review, in addition to previous cohort studies, when calculating sample sizes to assure adequate power to detect clinically and statistically meaningful differenc…