Ollivier F J, Samuelson D A, Brooks D E, Lewis P A, Kallberg M E, Komáromy A M
Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida 32601-0126, USA.
Vet Ophthalmol. 2004 Jan-Feb;7(1):11-22. doi: 10.1111/j.1463-5224.2004.00318.x.
The phenomenon of 'eye-shine' is seen in a variety of animal species, and is generally thought to be related to the presence of an intraocular reflecting structure, the tapetum lucidum. The tapetum lucidum is a biologic reflector system that is a common feature in the eyes of vertebrates. It normally functions to provide the light-sensitive retinal cells with a second opportunity for photon-photoreceptor stimulation, thereby enhancing visual sensitivity at low light levels. The tapetum lucidum is presented here according to a classification based on the location, as well as the composition, of this reflective layer. Finally, the physical and chemical properties, as well as the origins of the different tapeta lucida, are discussed and compared.
The anatomic and biochemical aspects of the tapetum lucidum in various vertebrates are examined. Morphologic observations were made from paraffin and plastic embedded specimens. Specimens were treated with traditional stains and observed by light and transmission electron microscopy.
Some species (primates, squirrels, birds, red kangaroo and pig) do not have this structure and they usually are diurnal animals. In vertebrates, the tapetum lucidum exhibits diverse structure, organization and composition. Therefore, the retinal tapetum (teleosts, crocodilians, marsupials, fruit bat), the choroidal guanine tapetum (elasmobranchs), the choroidal tapetum cellulosum (carnivores, rodents, cetacea), and the choroidal tapetum fibrosum (cow, sheep, goat, horse) are described.
The tapetum lucidum represents a remarkable example of neural cell and tissue specialization as an adaptation to a dim light environment and, despite these differences, all tapetal variants act to increase retinal sensitivity by reflecting light back through the photoreceptor layer. These variations regarding both its location and structure, as well as the choice of reflective material, may represent selective visual adaptations associated with their feeding behavior, in response to the use of specific wavelengths and amount of reflectance required.
“眼耀”现象在多种动物物种中都能见到，一般认为这与眼内反射结构——反光层有关。反光层是一种生物反射系统，是脊椎动物眼睛的一个常见特征。它的正常功能是为光敏感的视网膜细胞提供第二次光子 - 光感受器刺激的机会，从而在低光照水平下增强视觉敏感度。本文根据该反射层的位置以及组成对反光层进行分类介绍。最后，对不同反光层的物理和化学性质以及起源进行了讨论和比较。
研究了各种脊椎动物中反光层的解剖学和生物化学方面。从石蜡和塑料包埋标本进行形态学观察。标本用传统染色剂处理，通过光学显微镜和透射电子显微镜观察。
一些物种（灵长类动物、松鼠、鸟类、红袋鼠和猪）没有这种结构，它们通常是昼行性动物。在脊椎动物中，反光层呈现出多样的结构、组织和组成。因此，描述了视网膜反光层（硬骨鱼、鳄鱼、有袋动物、果蝠）、脉络膜鸟嘌呤反光层（板鳃亚纲鱼类）、脉络膜纤维素反光层（食肉动物、啮齿动物、鲸目动物）和脉络膜纤维反光层（牛、羊、山羊、马）。
反光层是神经细胞和组织特化以适应弱光环境的一个显著例子，尽管存在这些差异，但所有反光层变体都通过将光反射回光感受器层来提高视网膜敏感度。其位置和结构以及反射材料的选择方面的这些差异，可能代表了与其摄食行为相关的选择性视觉适应，以响应特定波长和所需反射率的使用。
