Bird Retina Uses Oxygen-Free Energy via Pecten Oculi Glucose Plumbing

A new study shows that birds’ inner retina operates without oxygen because retinal blood vessels are absent; instead, the pecten oculi delivers large amounts of glucose and helps remove lactic acid, enabling anaerobic glycolysis to power retinal cells. This anoxia tolerance supports high‑acuity vision and potential migration benefits, and could inform research into protecting brain tissue during strokes.