Ahistological study of the corneosclera layer (Fibrous tunic) of ostrich (Struthio camelus)

The Ostrich is an interesting subject concerning animal evolution and morphology studies. It has been speculated that ostrich eyes would have distinct tissue structures and this has not been previously studied in detail. The aim of the present study was to investigate the histology of the outer layer of the ostrich. Ten mature ostriches were chosen from an ostrich breeding center in Jupar, Kerman, Iran. All of them were in a good shape and healthy condition. After slaughter, their heads were kept in 10 % formalin solution for 7 days and then the eyes were removed. Routine histological techniques were done and 6-μmthick sections were cut. Sections were stained with standard hematoxylin and eosin (H&E) and Masson's trichrome and PAS. The sections were studied under a light microscope. Thecornea of ostrich had both dermal and sclera components and the two distinct parts were separated by a distinct zone; in addition, the sclera was divided into an episclera zone and a sclera proper zone. The outer layer of the episclera composed of connective fibers loosely attached to the sclera proper. The inner layer of the sclera consisted of dense connective tissues with two cartilaginous parts continuing over the oraserrata that composed dense connective fibers and ossicles.