Author Affiliations: Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary (Drs Berson, Rosner, and Sandberg and Ms Weigel-DiFranco) and Department of Nutrition, Harvard School of Public Health (Dr Willett), Boston.
Seigel and Richoz write that our study1 combining observational data from 3 trials2- 5 reflects a “fragment of data.” As noted,1 only 17 of 374 patients randomized to the vitamin A groups were excluded owing to outlying Early Treatment Diabetic Retinopathy Study visual acuity values or because they participated in more than 1 trial. Therefore, our study should not be considered a subset analysis. Our data showed a significant (P = .001) inverse relationship between ω-3 intake and rate of visual acuity decline among patients with retinitis pigmentosa receiving vitamin A.1
Berson EL, Rosner B, Sandberg MA, Weigel-DiFranco C, Willett WC. ω-3 Intake in Patients With Retinitis Pigmentosa Receiving Vitamin A—Reply. JAMA Ophthalmol. 2013;131(2):267-268. doi:10.1001/jamaophthalmol.2013.1722