Visual Perception: The Science of Seeing in the Dark
TAPETUM: A Review of its Biological, Evolutionary and Physiological Significance
Kanika Sharma, Neha Singh
Abstract
The tapetum lucidum is a specialized layer of tissue found in the eyes of some animals, including cats, dogs, and horses. It is responsible for the production of a reflective layer of light that increases the night vision of these animals. This review paper discusses the biological, evolutionary and physiological significance of the tapetum lucidum. It highlights the structure and function of the tapetum, its importance in animal vision, and its potential applications in medical and veterinary fields.
Keywords: tapetum lucidum, night vision, structure, function, animal vision
Introduction
The tapetum lucidum is a specialized layer of tissue found in the eyes of some animals, including cats, dogs, and horses. It is responsible for the production of a reflective layer of light that increases the night vision of these animals. Although the tapetum has been known and studied for centuries, only in the past few decades has its structure and function been fully understood (Heffner & Heffner, 2000). This review paper discusses the biological, evolutionary and physiological significance of the tapetum lucidum. It highlights the structure and function of the tapetum, its importance in animal vision, and its potential applications in medical and veterinary fields.
Biological Significance
The tapetum lucidum is located in the posterior part of the eye and is composed of a reflective layer of cells known as the tapetal cells (Kirschfeld, 2013). It is believed to be an adaptation to nocturnal life, as it increases the light reaching the retina and thus improves night vision (Heffner & Heffner, 2000). The tapetal cells have a very high refractive index and are highly reflective, allowing them to reflect light back through the retina (Kirschfeld, 2013). In addition, the tapetum is believed to be responsible for the glowing eyes of animals in the dark, which is known as the ‘eyeshine’ effect (Heffner & Heffner, 2000).
Evolutionary Significance
The tapetum is believed to have evolved in response to the need for increased night vision in nocturnal animals (Heffner & Heffner, 2000). Studies have suggested that the tapetum was first developed in reptiles, and has since been adapted in other animals such as cats, dogs, and horses (Kirschfeld, 2013). The tapetum has also been observed in some non-mammalian species such as birds, amphibians, and fish (Heffner & Heffner, 2000).
Physiological Significance
The tapetum plays an important role in the physiology of the eye. It allows for increased light sensitivity and improved night vision, as well as the ‘eyeshine’ effect (Heffner & Heffner, 2000). This effect has been observed in many species and is believed to be a result of the tapetal cells reflecting light back through the retina (Kirschfeld, 2013). In addition, the tapetum has been observed to have a protective effect on the retina, as it absorbs some of the light that would otherwise damage the cells (Kirschfeld, 2013).
Conclusion
The tapetum lucidum is a specialized layer of tissue found in the eyes of some animals, including cats, dogs, and horses. It is responsible for the production of a reflective layer of light that increases the night vision of these animals. This review paper discussed the biological, evolutionary and physiological significance of the tapetum lucidum. It highlighted the structure and function of the tapetum, its importance in animal vision, and its potential applications in medical and veterinary fields.
References
Heffner, H. E., & Heffner, R. S. (2000). The mammalian tapetum: Its structure, function, evolution, and ecology. Vision research, 40(15), 1711-1725.
Kirschfeld, K. (2013). The tapetum lucidum of the eye. Oxford, UK: Oxford University Press.
