Silmavalged

Silmavalged are the sclerae, the opaque white outer coat of the eyeball. They surround most of the eyeball, except for the transparent cornea at the front, and are continuous with the cornea at the limbus. In Estonian anatomy, silmavalged (singular: silmavalge) refer to the white of the eye collectively or to each individual sclera.

Anatomy and structure: The sclera is a dense connective tissue composed mainly of collagen arranged in lamellae, which gives the eye its strength and shape. It is relatively avascular, with nutrition and waste exchange primarily through the underlying choroid and the superficial episclera. The sclera forms the posterior roughly five-sixths of the globe and becomes thickest toward the back, thinning slightly near the attachments of the extraocular muscles. The inner surface is lined by the lamina fusca, and the sclera is continuous with the cornea at the limbus.

Function: The sclera provides structural support and protection for intraocular structures, maintains the globe’s shape under intraocular pressure, and serves as an anchor for the extraocular muscles. Its opacity helps protect internal tissues from light exposure.

Clinical significance: Changes in the sclera can indicate disease. Inflammation can present as episcleritis (usually mild) or scleritis (often painful and linked to systemic autoimmune conditions). Scleral thinning or blue sclera can occur in conditions such as osteogenesis imperfecta or high myopia. Surgical procedures may involve the sclera, including scleral buckling for retinal detachment or grafting techniques.

Etymology: The term derives from Estonian words for eye (silm) and white (valge).