To the Editor The study by Christen et al,1 with associated commentary by Frank,2 has highlighted an interesting line of research that has produced mixed results. The objective of this study was to determine whether vitamin D3 (2000 IU per day) and marine ω-3 fatty acids (1 g per day) would prevent development or progression of age-related macular degeneration (AMD). The trial was secondary to the Vitamin D and Omega-3 Trial (VITAL). Christen et al1 concluded that there was no significant overall effect from either supplement on the incidence or progression of AMD. The authors noted previous studies have produced mixed results, often reporting inverse relationships between vitamin D and risk of AMD. These studies used cross-sectional, case-control, or prospective data, whereas this study used randomized trial data.