The sclera is commonly known as the “white” of the eye. It surrounds your entire eyeball, except for the clear covering in the front of your eye, the cornea. The area where the sclera meets the cornea is called the limbus.
Several layers comprise the sclera, including (in order from outermost to innermost layer) the episclera, stroma, lamina fusca, and endothelium. The front part of your sclera is covered with a thin layer of tissue with blood vessels, called the bulbar conjunctiva.
The sclera is a tough, fibrous, opaque tissue that protects the inner structures of your eye from trauma and helps maintain the shape of your eyeball. Most of your eyeball is filled with a gel-like fluid called the vitreous humor. Your eye muscles, which control your eye movements, also attach firmly to the sclera.
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Several conditions can affect the sclera. It is important to note that while some problems may appear to affect the sclera, they actually affect the overlying bulbar conjunctiva. The appearance can be misleading because the bulbar conjunctiva is mostly transparent.
Sclera conditions include:
There are other conditions present at birth that may affect the sclera. Some of these are harmless, but others are more severe and may affect vision or eye health.
There are two acquired forms, primary and secondary acquired melanosis. The primary form is more common in light-skinned individuals and may grow in size. In rare cases, primary acquired melanosis may develop into malignant (cancerous) melanoma. The secondary form is associated with hormonal changes, radiation exposure, chemical exposure, or metabolic disorders. People with darker skin and hair are more likely to have secondary acquired melanosis, which rarely develops into melanomas.
Scleral expansion is a somewhat controversial procedure that is designed to treat presbyopia. Presbyopia is the loss of the ability to focus up close with age. The surgery involves inserting four plastic pieces into the sclera, between the eye muscles. This technology is still improving, and some researchers feel that this procedure can become the gold standard in presbyopia treatment.
A scleral buckle procedure is performed to repair a retinal detachment. During the surgery, the doctor uses cryopexy (freezing therapy) to seal your retina to the eye. Then, the surgeon places a silicone or plastic band around your eyeball (this is the scleral buckle), which helps the retina stay in place. The buckle remains in your eye permanently.
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