Research overview: the tapetum lucidum and feline eyeshine

The tapetum lucidum is a reflective layer behind the cat retina that bounces light back through the photoreceptors, giving the eye a second chance to capture each photon and producing the familiar glowing eyeshine. This overview surveys its anatomy, optics, and function, framing it as a central component of feline night vision. By reflecting unabsorbed light, the tapetum increases sensitivity in dim conditions at the cost of slightly blurring the image through scatter. The survey reviews how the tapetum complements the rod-rich retina, wide pupil, and large cornea to optimize the cat for twilight hunting. It also discusses why eyeshine appears in flash photographs and at night when light strikes the reflective layer. The tapetum is one of the clearest examples of an anatomical adaptation that directly enhances an animal's ability to function in low light.