Glossary

Tapetum lucidum

A mirror-like layer behind a cat's retina that bounces light back through the eye, improving night vision and causing glowing eyes in photos.

Also called: eyeshine, cat eye reflection, reflective layer

The tapetum lucidum is a reflective layer of cells behind the retina at the back of the eye. Light that passes through the retina without being absorbed hits this layer and bounces back for a second pass, which gives the light-sensing cells another chance to catch it. This is one reason cats see well in dim light and need far less of it than people do.

The same layer causes eyeshine. When a torch beam or camera flash hits a cat's eyes in the dark, they seem to glow green, yellow or gold. Many Siamese-type cats and other blue-eyed cats have a weaker tapetum, so their eyeshine often looks red or pink instead.

Eyeshine is normal and needs no care. What deserves attention is a change in the eye itself: a cloudy pupil, a pupil that stays large in bright light, redness, squinting or discharge. Cats can go blind slowly without obvious signs, so mention any of these to your vet promptly and do not wait to see whether they pass.

Last reviewed November 7, 2026

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Related terms

Third eyelid A thin fold of tissue at the inner corner of a cat's eye that sweeps across the surface to protect and moisten it. Crepuscular Most active at dawn and dusk, the pattern cats follow because their natural prey is busiest at those times. Whiskers The long, stiff, touch-sensitive hairs on a cat's muzzle, brows, chin and forelegs that help it sense nearby objects and air movement. Brachycephalic Having a short, broad skull and flattened face, as in Persians and Exotic Shorthairs, which often brings breathing, eye and dental problems.

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