Corneosclera

Corneosclera

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Diagram of the human eye showing the corneosclera
Latin	corneosclera
System	Visual system

The corneosclera is a composite structure of the human eye, consisting of the cornea and the sclera. These two components form the outermost layer of the eye, providing both protection and structural integrity. The corneosclera plays a crucial role in maintaining the shape of the eye and facilitating vision by allowing light to enter through the cornea.

Structure

The corneosclera is divided into two distinct parts:

Cornea

The cornea is the transparent, dome-shaped surface that covers the front of the eye. It is responsible for refracting light and contributing to the eye's focusing power. The cornea is composed of five layers:

• Epithelium: The outermost layer that provides a barrier against dust, debris, and bacteria.
• Bowman's layer: A tough layer that protects the corneal stroma.
• Stroma: The thickest layer, composed of collagen fibers, providing strength and elasticity.
• Descemet's membrane: A thin but strong film that supports the endothelium.
• Endothelium: The innermost layer that maintains corneal dehydration and transparency.

Sclera

The sclera is the opaque, fibrous, protective outer layer of the eye, commonly referred to as the "white of the eye." It extends from the cornea to the optic nerve at the back of the eye. The sclera is composed of dense connective tissue and provides attachment for the extraocular muscles.

Function

The corneosclera serves several important functions:

• Protection: It acts as a tough protective layer, shielding the inner components of the eye from injury and infection.
• Support: Provides structural support and maintains the shape of the eye.
• Light Refraction: The cornea refracts incoming light, contributing significantly to the eye's total optical power.
• Attachment for Muscles: The sclera provides a surface for the attachment of the extraocular muscles, which control eye movement.

Clinical Significance

Disorders of the corneosclera can lead to significant visual impairment. Common conditions include:

• Keratitis: Inflammation of the cornea, often due to infection.
• Scleritis: Inflammation of the sclera, which can be associated with systemic diseases.
• Corneal Ulcers: Open sores on the cornea, usually caused by infection.
• Keratoconus: A progressive thinning of the cornea, leading to a cone-shaped deformity.

Also see

• Cornea
• Sclera
• Eye anatomy
• Visual system
• Ophthalmology