Study: Omega-3 Fatty Acids and Retinitis Pigmentosa (2004)
While a 4 year long study published in 2004 reported that 1,200 mg of supplemental DHA along with high dose vitamin A did not slow the course of RP overall, further subgroup analysis showed benefit for those starting vitamin A supplementation for the first time (5-6). In addition, those study participants taking vitamin A (but not DHA) who also had a higher dietary omega-3 intake experienced substantial benefit. The rate of visual field decline was retarded by 40-50% yearly in those whose omega-3 intakes were equivalent to 1-2 servings of fatty fish weekly.
Berson EL, et al. Further evaluation of docosahexaenoic acid in patients with retinitis pigmentosa. 12:1306-14, 2004.