Stearate supplementation had no effect on eye size, retinal degeneration, or Xbp1-EGFP signal in Rh1G69D control flies (13478 ± 1197 pixels on stearate and 12873 ± 1006 pixels on standard media; P = 0.502; 0.83 ± 0.15 on stearate relative to standard media, 1.00 ± 0.21; P = 0.171) (Fig 3B–3D), likely because of the high level of ER stress signaling already present. The gene discussed is XBP1; the disease is retinal degeneration.