Cat
Feline nocturnal vision operates through a layered system of optical enhancements. The tapetum lucidum, a reflective layer behind the retina, provides the characteristic eyeshine whilst effectively doubling light exposure to photoreceptors. Vertical slit pupils can expand to occupy nearly the entire visible eye surface, admitting 135 times more light than contracted during daylight exposure.
Cats possess approximately 200 million rod cells per retina, six times the human density, enabling functional vision at light levels where human eyes perceive only darkness. However, this adaptation sacrifices colour discrimination and fine detail resolution, rendering the feline visual world a landscape of movement and contrast rather than chromatic nuance.
Owl
The owl's visual apparatus represents the most extreme nocturnal adaptation among vertebrates. Tubular eyes, physically incapable of rotation, contain rod-cell densities approaching 1,000,000 cells per square millimetre, enabling photon detection at the theoretical minimum for biological vision. Some species demonstrate functional sight at illumination levels of 0.00003 lux, approximately one-tenth of starlight on a moonless night.
This extraordinary sensitivity derives from multiple adaptations: enormous corneal aperture, tubular eye shape maximising retinal surface area, and neural processing optimised for extracting signal from minimal photonic input. The owl perceives its nocturnal environment with clarity humans cannot comprehend, seeing clearly where cats merely navigate and humans stumble blind.