What is the difference between conjunctiva and sclera

Sclera and conjunctiva are two important parts of the eye. Both are protective layers of the eye. Conjunctiva is the thin transparent layer that lies on the sclera and interior lining of eyelids. Conjunctiva is a highly vascularized tissue while sclera has a limited blood supply.

The below infographic presents the difference between sclera and conjunctiva as a side by side comparison.

Sclera is also known as white of the eye is the dense connective tissue of the eyeball. It is an opaque protective layer that covers most of the eye areas. It extends up to the optic nerve as well.

Conjunctiva is the clear membrane covering the sclera and interior lining of eyelids. This is the difference between sclera and conjunctiva. Available here. Both these layers are important to maintain the structure and function of the eye. Let us understand how both of these work to maintain normal sight.

The term conjunctiva gets its name from the word Conjoin which means to join. This is a thin, translucent membranous structure that covers the eye ball. It extends backwards to cover the sclera and folds upon itself and comes forwards by lining the under surface of the eyelid.

At the margin of the eyelid it is continuous with the skin. The conjunctival fold allows unrestricted eyeball movement. The conjunctiva has its own nerve and blood supply. It is made up of non — keratinised stratified squamous epithelium and stratified columnar epithelium.

The main function of the conjunctiva is to keep the eye lubricated by producing mucus and some amount of tears. It also prevents foreign particles and microbes from gaining entry into the eye. The contact lenses are held in place due to the presence of conjunctiva. The conjunctiva is divided into palpebral, bulbar and fornix conjunctiva. The palpebral conjunctiva is located on the inside of the upper and lower eyelid.

The conjunctiva of the fornix is lining of the sac that is present at the junction between the posterior surface of the eyelid and the anterior part of the globe of the eye. The conjunctiva is relatively thicker and loose here which allows for free movement of the eyeball.

Large conjunctival hemangiomas can be surgically removed if they cause irritation. Conjunctival nevus. This is a common, benign growth in the bulbar conjunctiva. In fact, conjunctival nevi plural of nevus are the most common growth that occurs on the surface of the eye. A conjunctival nevus can range in color from yellow to dark brown and can darken or lighten with time.

In most cases, no treatment is needed for a conjunctival nevus, but if a nevus is growing in size, it can be surgically removed. Conjunctival melanoma. This is an elevated, dark or relatively clear cancerous growth in the bulbar conjunctiva. Conjunctival melanomas are uncommon but potentially lethal. The cancer cells from a conjunctival melanoma can infiltrate the eyeball and spread via the lymphatic system or bloodstream to the lungs, liver, brain and bones.

In some cases, a conjunctival melanoma can arise from a benign conjunctival nevus. To be safe, if you notice any type of growth or dark spot on your eye, or an unusual appearance to your conjunctiva, see your eye doctor immediately for an evaluation. Overview of conjunctival and scleral disorders. Merck Manual Consumer Version.

Accessed online May Diagnosis and treatment of conjunctival lymphoma. Edema of the tarsal conjunctiva typical of allergic conjunctivitis Allergic Conjunctivitis Allergic conjunctivitis is an acute, intermittent, or chronic conjunctival inflammation usually caused by airborne allergens.

Symptoms include itching, lacrimation, discharge, and conjunctival Hyperplasia of lymphoid follicles in the conjunctiva can occur in viral conjunctivitis Viral Conjunctivitis Viral conjunctivitis is a highly contagious acute conjunctival infection usually caused by an adenovirus.

Symptoms include irritation, photophobia, and watery discharge. Diagnosis is clinical Symptoms include chronic unilateral hyperemia and mucopurulent discharge.

Diagnosis is clinical. It appears as small bumps with pale centers, resembling cobblestones. It occurs most commonly in the inferior tarsal conjunctiva.

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