A histological study of the eye in Hyla orientalis (Bedriaga, 1890) (Anura, Hylidae)

Abstract. Amphibian eyes have an important role in vision and in several physiological processes, such as feeding and locomotion. In the present study, the eye of Hyla orientalis was investigated in terms of histological structures. Light microscopic observations revealed that the eye of H. orientalis was formed by three layers from outside to inside: (a) outer layer- the sclera and the cornea; (b) middle layer- the choroid, ciliary body and the iris; and (c) inner layer- the retina. The cornea was composed of well-defined layers, including a squamous corneal epithelium, the stroma, and corneal endothelium. The lens of H. orientalis was spherical and enclosed by a lens capsule, and its anterior surface was covered by a monolayer of epithelial cells. The posterior sclera consisted of a cartilaginous cup, embedded within a collagenous matrix unlike terrestrial animals. The retina was avascular, and layers of the retina conformed in principle to the standard vertebrate arrangement. ©Biharean Biologist, Oradea, Romania, 2013.