The phenomenon of tortuosity of the central retinal arteries (CRA) and the changes within a few hours are documented by photographs centered on the disc of different newborns. Tortuosity is more marked in the temporal than in the nasal branches: it may be sinusoidal, but is more often irregular inasmuch as bends alternate with straight parts. In the latter, there is no rule for the distance of the bend from the disc, for the length of its chord, or for the steepness of the ascending and descending parts. With regard to pathophysiology, tortuosity is seen in, and a few hours after, fetal or neonatal circulatory distress, but the anatomy causing a vessel to become tortuous is not understood. In an appendix we propose rules on how to obtain a quantitative value of tortuosity for a single artery if it is irregular, and how to calculate a value we term mean temporonasal tortuosity for interindividual comparison.