The Enigmatic Crystal Eyes of Ancient Trilobites

Trilobites, extinct marine arthropods, had complex eyes made of calcite, a hard crystal. These compound eyes consisted of clusters of photoreception units called ommatidia. The calcite lenses allowed light to penetrate and be focused, making trilobites sensitive to motion. There were three types of trilobite eyes, with the schizochroal eye being the most specialized. However, the exact functioning of the schizochroal eye remains a mystery. Recent studies have revealed that trilobite eyes may be more complex than previously thought, and there is ongoing debate about the true nature of trilobite vision.