January 06, 2007

Eye Socket Disorders


The eye sockets (orbits) are bony cavities that contain and protect the eyes. Disorders affecting the orbits include fractures, infections, inflammation, and tumors. Thyroid disease can also affect the orbit.

Exophthalmos is an abnormal bulging of one or both eyes.
Many conditions can cause exophthalmos. In some types of thyroid disease, especially Graves' disease the tissues in the orbit swell and accumulate certain types of cells (such as lymphocytes), which push the eyeball forward. Exophthalmos can develop rapidly from bleeding behind the eye or from inflammation in the orbit. Tumors, either cancerous or noncancerous, can form in the orbit behind the eyeball and push it forward. An unusual noncancerous accumulation of inflammatory and fibrous tissue (pseudotumor) may produce exophthalmos with pain and swelling. Cavernous sinus thrombosis causes swelling because blood in the veins cannot exit the eye. Abnormal connections between the arteries and veins (arteriovenous malformations) behind the eye may produce a pulsating exophthalmos, in which the eye bulges forward and pulses along with the heartbeat.

The protruding eye is less protected by the eyelids, and the cornea may become too dry. As a result, corneal ulcers may form, which can become infected. Prolonged exophthalmos can impair vision because the optic nerve is stretched. The increased pressure within the orbit may also result in compression of the optic nerve, which can also impair vision.

Diagnosis and Treatment
All people with protruding eyes do not necessarily have exophthalmos. Some people simply have prominent eyes with more white showing than normal. The extent of the protrusion can be measured with an ordinary ruler or with an instrument called an exophthalmometer. Further diagnostic tests may include computed tomography (CT) and thyroid function tests.

The treatment depends on the cause. If the problem is an abnormal connection between arteries and veins, surgery may be needed to close off certain blood vessels. Thyroid disease that is severe enough to cause exophthalmos may need to be treated. But it is unclear if treating the thyroid condition actually improves bulging of the eyes. Treatment of exophthalmos includes eyeshades and eye drops if symptoms are mild, or corticosteroids, radiation therapy, or surgery if the condition is more severe. Treatment of bleeding or inflammation involves treating the underlying disorder Tumors (depending on type) are treated with chemotherapy, radiation therapy, or surgery. Corticosteroids may help the inflammation caused by a pseudotumor.

An injury to the face can fracture any of several bones that form each orbit.
Vision may be impaired when blood that accumulates after a fracture, typically from torn blood vessels, puts pressure on the eye or on the nerves and blood vessels going to and from it (retrobulbar hematoma). Pressure on the nerves may impair vision by interfering with nerve impulses going from the eye to the brain. The fracture (or a bone fragment) may also impair the function of the muscles that move the eye (possibly by damaging the muscles themselves or the nerves that move the muscles). Damage to these muscles may inhibit eye movement up, down, or to the right or left and thereby produce double vision. The eyeball may become sunken (enophthalmos) if the fracture is large. The eyeball itself also may be damaged in these injuries.

Diagnosis and Treatment
Diagnosis is suspected based on the symptoms. X-rays of the skull and computed tomography (CT) or magnetic resonance imaging (MRI) confirm the diagnosis. When a fracture traps muscles or soft tissues of the orbit and produces double vision or makes the eyeball sunken, surgical repair of the facial bones is usually necessary. After ensuring that the fracture has not damaged a vital structure, the surgeon restores the bones to their proper positions, sometimes using small metal plates and screws or wires to hold them in place. The surgeon may use a thin plastic sheet or a bone graft to connect the broken parts and assist healing.

An infection may spread from the sinuses, teeth, or bloodstream to the orbit. Infection of the orbit is called orbital cellulitis. Eye infections may develop after an injury. Symptoms include pain, a bulging eye, reduced eye movement, swollen eyelids, and fever. The eyeball has a swollen, indistinct appearance. Vision may be impaired.

Without adequate treatment, orbital cellulitis can lead to blindness. Infection can spread to the brain and spinal cord, or blood clots can form and spread from the veins around the eye to involve a large vein at the base of the brain (the cavernous sinus) and result in cavernous sinus thrombosis.

Diagnosis and Treatment
Doctors can usually recognize orbital cellulitis without using diagnostic tests. However, determining the cause may require further assessment, including examination of the teeth and mouth and x-rays or computed tomography (CT) of the sinuses. Often, doctors obtain samples from the lining of the eye and from the skin, throat, or sinuses as well as blood samples and send them to a laboratory for testing. The samples are cultured (to grow organisms) to determine where the infection that gave rise to the orbital cellulitis is located, which type of organism is causing the infection, and which treatment should be used.

Antibiotics are started before the results of the laboratory testing are known. Oral antibiotics are given for mild cases; intravenous antibiotics are given for severe cases. The antibiotic used at first may be changed if the culture results suggest that another drug would be more effective. Sometimes surgery is needed to drain a collection of pus (abscess) or an infected sinus.


Any or all of the structures within the orbit may become inflamed. The inflammation can be part of another disease process, such as Wegener's granulomatosis, in which inflammation affecting blood vessels (called vasculitis) occurs, or inflammation may occur for no apparent reason. Inflammation affecting the white coat (sclera) of the eye is called scleritis. Inflammation affecting the lacrimal gland, located at the upper outer edge of the orbit is called inflammatory dacryoadenitis. If inflammation affects one of the muscles that move the eye, it is called myositis. Inflammation affecting the entire orbit and its contents is called inflammatory orbital pseudotumor (which is not really a tumor and is not a cancer) or nonspecific orbital inflammation.

Symptoms vary depending on which structures are actually inflamed. In general, symptoms start rather suddenly, typically over a few days. Pain and redness of the eyeball or eyelid occur. Pain can be severe and incapacitating at times. A doctor may take a sample from the inflamed area for examination under a microscope (biopsy) to determine the cause.
Inflammation is usually treated with a corticosteroid drug, which can be given by mouth. Corticosteroids can be given intravenously if the inflammation is severe.

Rarely, tumors, either cancerous or noncancerous, can form in the tissues behind the eye. Tumors can form within the tissues behind the eye, or cancerous tumors from elsewhere in the body can spread (metastasize) to the tissues behind the eye.

These tumors can push the eye forward (exophthalmos). Usually a biopsy is needed to determine what type of tumor is present, and treatment depends on these results. Treatment may include surgical removal, radiation therapy, chemotherapy, or a combination of these treatments.

Adapted from Merck Online Medical Library