The glow of the night: The tapetum lucidum as a co‐adaptation for the inverted retina

Abstract

The vertebrate retina is said to be inverted because the photoreceptors are oriented in the posterior direction and are thus unable to maximize photodetection under conditions of low illumination. The tapetum lucidum is a photoreflective structure located posterior to the photoreceptors in the eyes of some fish and terrestrial animals. The tapetum reflects light forward, giving incident photons a "second chance" to collide with a photoreceptor, substantially enhancing retinal photosensitivity in dim light.Across vertebrates (and arthropods), there are a wide variety of tapeta that vary in structure, chemical composition, and even tissue architecture, indicating repeated convergent evolution. To date, the tapetum has not been observed in any cephalopod, however, which also possess a camera-like eye, but with the retinal photoreceptors oriented in the anterior direction. We therefore hypothesize that the tapetum lucidum is a compensatory adaptation for the suboptimal design of the inverted retina of vertebrates.

Evolution of natural eyes and biomimetic imaging devices for effective image acquisition

“…For the biological light reflector, tapetum lucidum is the representative structure that some nocturnal and deep-sea animals have behind their retina. [102][103][104][105] It reflects visible light back through the retina, increasing the light amount available for the photoreceptors to absorb. 106 Especially for the cat, the tapetum lucidum increases vision sensitivity by 44%, allowing the cat to see the imperceptible light to human eyes.…”

Spiders possess tapeta lucida to enhance photodetection in their inverse secondary retinas but not in their everse primary retinas

“…In volume 44, issue 10 of this journal, Vee et al proposed that the tapetum lucidum-the reflective structure found in the retina of some nocturnal vertebrates-evolved as a compensatory co-adaptation for the inverted nature of the vertebrate retina. [1] The tapetum enhances the sensitivity of visual perception through the reflection of photons that initially pass through the photoreceptor layer unabsorbed back toward the anterior direction. This gives these photons a second chance to collide with a photoreceptor, boosting photosensitivity under low illumination, and producing the phenomenon known as "eye shine" when viewed under high light conditions (e.g., the headlights of a car).…”

The Synergistic Effect on the Mimetic Optical Structure of Feline Eyes toward Household Health Monitoring of Acute and Chronic Diseases

“…4−9 The reflective layers in the eyes of felines help improve their vision at night. 10,11 Certain optical structures in some plants help improve the efficiency with which sunlight is used and thus increase the photosynthesis rate. 12,13 The diverse optical structures found in nature provide insight into how functional optical materials can be designed and exploited.…”