It is associated with hepatitis and other liver diseases. This condition - also called icteric sclera - is a yellowing of the white of the eye. Here are a few conditions that can affect the sclera: The sclera also provides a sturdy attachment for the extraocular muscles that control the movement of the eyes. The tough, fibrous nature of the sclera protects the eye from serious damage - such as laceration or rupture - from external trauma. The sclera and the intraocular pressure (IOP) of the eye maintain the shape of the eyeball. Other nourishment of the sclera comes from the underlying choroid, which is the vascular layer of the eyeball that is sandwiched between the sclera and the retina. Larger episcleral blood vessels are visible through the conjunctiva. Some of the nourishment of the sclera comes from the blood vessels in the episclera, which is a thin and loose connective tissue layer that lies on top of the sclera and under the transparent conjunctiva that covers the sclera and episclera. Some blood vessels pass through the sclera to other tissues, but the sclera itself is considered avascular (lacking blood vessels). The sclera is relatively inactive metabolically and has only a limited blood supply. The random arrangement and interweaving of these connective tissue fibers are what account for the strength and flexibility of the eyeball. It is composed of fibrils (small fibers) of collagen that are arranged in irregular and interlacing bundles. The sclera ranges in thickness from about 0.3 millimeter to 1.0 millimeter. The junction between the white sclera and the clear cornea is called the limbus. It is continuous with the stroma layer of the cornea. The sclera is the dense connective tissue of the eyeball that forms the "white" of the eye. Only a small portion of the anterior sclera is visible. In fact, the sclera forms more than 80% of the surface area of the eyeball, extending from the cornea all the way to the optic nerve, which exits the back of the eye. The sclera is the white part of the eye that surrounds the cornea.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |