From One-Eyed Worm to Human Vision: The Incredible Evolutionary Journey of Our Eyes

• Our modern vertebrate eyes evolved from a one-eyed worm-like ancestor that roamed oceans 600 million years ago.
• Initially, this ancestor lost its paired 'steering' eyes due to a stationary, filter-feeding lifestyle, retaining only a midline light-sensing organ.
• A return to a swimming lifestyle necessitated new paired eyes for steering and motion, leading to the midline eye developing into two eye cups that separated and became our modern eyes.
• The original midline light-sensing cells evolved into the pineal organ in the brain, which produces melatonin, while the new paired eyes took over primary light detection.
• The complexity of our retina, with over 100 types of neurons, likely predates the retina itself, suggesting a sophisticated 'cyclops' ancestor eye.