Optometry

Disorders of Sclera, Cornea, Iris and Ciliary Body

Sclera: The white, opaque, fibrous, outer covering of the eyeball, capping its entire part except the piece covered ahead by the cornea. It is essentially avascular but contains opening for vessels, lymphatics, and nerves. It receives the tissue of positioning of the extraocular muscles and at the corneoscleral  junction contains the channel of Schlemm.

Cornea: The crystalline anterior part of the fibrous coat of the eye consisting of five layers. It serves as the first deflecting channel of the eye. It is continuous with the SCLERA, avascular, and it receives its nutrition by interpenetration through gaps between the lamellae, and is stimulated by the ophthalmic division of the TRIGEMINAL NERVE and those of the surrounding conjunctiva and they together form plexuses.

•  Stratified squamous CORNEAL EPITHELIUM

•  BOWMAN MEMBRANE

•  CORNEAL STROMA

•  DESCEMET MEMBRANE

•  Mesenchymal CORNEAL ENDOTHELIUM

Iris: The most anterior portion of the ocular layer, disconnecting the front chamber from the posterior. It consists of two films - the stroma and the pigmented epithelium. Color of the iris hangs on the amount of melanin in the stroma on reflection from the pigmented epithelium.

Ciliary Body: A ring of material expanding from the scleral spur to the ora serrata of the retina. It consists of the ocular portion and the epithelial part. The ciliary muscle is in the ocular portion and the ciliary processes are in the epithelial part.