Research overview: photon catch and quantum efficiency in feline vision

The ultimate limit on night vision is how efficiently an eye captures and counts individual photons. This overview surveys research framing the cat eye in terms of quantum catch, including the contributions of a wide pupil that admits more light, dense rod packing, and the tapetum lucidum that gives photons a second pass through the photoreceptors. Together these features raise the probability that any given photon triggers a response. Studies of feline scotopic performance have been used to estimate how close the cat operates to the physical limits set by photon noise. The topic matters because it reframes night vision as a problem of optics and statistics rather than mystery: cats are not generating light, they are squeezing maximal information from the few photons available at dusk and dawn when their prey is active.