Research overview: eyeshine colour variation and the structure of the tapetum

The colour of cat eyeshine varies, and this overview reviews how tapetal structure and composition produce different reflected hues across individuals and species. The layered, crystalline tapetum acts partly like a structural reflector, and variations in its spacing, thickness, and the pigments overlying it shift the wavelengths reflected, giving greens, yellows, and other tints. Age and eye colour can also influence the effect. Researchers study eyeshine through reflectance spectroscopy and tapetal microanatomy. Why it matters: eyeshine colour is a visible readout of the tapetum optical design, useful for identifying animals in the field and for understanding how the reflective layer balances sensitivity against image quality. It also connects the dramatic everyday phenomenon of glowing cat eyes to the fine structural optics that make night vision possible.