silmänvalkuaisten

Silmänvalkuaisten refers to the sclera, the tough, opaque, white outer layer of the eyeball. It is a fibrous connective tissue that covers about five-sixths of the eyeball's surface, extending from the cornea at the front to the optic nerve at the back. The sclera's primary function is to maintain the eye's shape and protect its internal structures. It also serves as an attachment point for the extraocular muscles, which are responsible for eye movement.

The sclera is composed of dense collagen fibers, which give it its strength and white appearance. It is relatively avascular, meaning it has few blood vessels, which contributes to its white color. However, the conjunctiva, a thin, transparent membrane that covers the sclera, is rich in blood vessels and can become red and inflamed in conditions like conjunctivitis.

Several medical conditions can affect the sclera. Scleritis is an inflammation of the sclera, which can cause severe pain, redness, and blurred vision. Blue sclera can be a sign of certain connective tissue disorders, such as osteogenesis imperfecta. Thinning or rupture of the sclera can occur due to trauma or certain diseases, potentially leading to vision loss. In some cases, surgical repair or medical treatment is necessary to address scleral abnormalities.