Title: Cornea I: Form, Swelling Pressure, Transport Processes, and Optics
Abstract: This chapter discusses the cornea and its form, swelling pressure, transport process and optics. The cornea and sclera together form the outer tunic of the eye and give the eye its shape. The cornea occupies about 7% of the total area of the globe in humans. The corneal portion is greater in lower animals—25% in the rabbit and 50% in the rat. The combination of cornea and crystalline lens provides most of the light focusing power of the eye. The cornea is the dominant partner in this collaboration, even though it is quite thin compared to the lens. The anterior surface of the cornea, covered by the tears, faces the air to give a refractive index change from the air to the cornea of 1.000 to 1.376. In an external examination of the human eye, the outer surface of the cornea appears elliptical because of the inferior and superior anterior extensions of the opaque sclera. The major axis is horizontal and is about 11 to 12 mm long in 95% of eyes. A comparison of the cornea with opaque connective tissues discloses more similarities than differences—for example, the cornea and sclera share similar collagen fibrils and are about the same in thickness. The cornea, however, acts as a transparent lens, whereas the sclera is sufficiently opaque to form a light-tight chamber for the eye.
Publication Year: 1992
Publication Date: 1992-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
Access and Citation
Cited By Count: 6
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