Upper eyelid

Upper Eyelid

The upper eyelid is a flexible and movable part of the human eye that serves to protect the cornea and the eye from foreign bodies and excessive light. It also helps to maintain the tear film on the surface of the cornea, which is essential for clear vision.

Anatomy

The upper eyelid is composed of several layers, including the skin, subcutaneous tissue, orbicularis oculi muscle, levator palpebrae superioris muscle, and the tarsal plate. The inner surface of the eyelid is lined by the conjunctiva, a thin, transparent membrane that also covers the white part of the eye.

The upper eyelid is larger and more mobile than the lower eyelid. It is responsible for two-thirds of the eye's blinking action, which helps to spread tears across the surface of the eye and remove debris.

Function

The primary function of the upper eyelid is to protect the eye from injury and to help maintain the health of the cornea. It does this by blinking, which spreads the tear film across the surface of the eye. This tear film is essential for keeping the cornea moist and nourished.

The upper eyelid also helps to regulate the amount of light that enters the eye. It can close completely to block out light, or it can partially close to reduce the amount of light entering the eye.

Disorders

There are several disorders that can affect the upper eyelid, including ptosis, which is a drooping of the upper eyelid, and blepharitis, which is an inflammation of the eyelid. Other conditions include chalazion, a lump in the eyelid caused by a blocked oil gland, and entropion, where the eyelid turns inward.

Treatment for these conditions can range from simple home remedies to surgical procedures, depending on the severity of the condition.

See also

• Eye
• Lower eyelid
• Blinking
• Tear film

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