Research overview: how the tapetum trades acuity for sensitivity

Reflecting light back through the retina improves sensitivity but also scatters photons, slightly degrading the sharpness of the image. This overview surveys discussion of that tradeoff in cats, where the tapetum's sensitivity benefit comes at a modest cost in acuity. Because each reflected photon may be absorbed a short distance from where it first passed, fine spatial detail is blurred even as overall light capture rises. The survey relates this to the cat's already low acuity, arguing the tradeoff is acceptable for an animal that values detecting any prey in darkness over resolving fine texture. It contrasts the tapetal eye with the human eye, which sacrifices low-light sensitivity for sharper daytime vision and absorbs stray light to keep the image crisp. The tapetum thus embodies, at the level of a single structure, the broader sensitivity-versus-resolution compromise that defines feline vision.