NEURO OPHTHALMOLOGY

NEURO OPHTHALMOLOGY

NEURO OPHTHALMOLOGY




OCULOPLASTY

The optic nerve carries the information of vision from the eye to the brain. Diseases involving the optic nerve are dealt with by a Neuro-ophthalmologist.

OPTIC NEURITIS

Optic neuritis is inflammation of the optic nerve. It may cause sudden, reduced vision in the affected eye.

Causes

The exact cause of optic neuritis is unknown. The optic nerve carries visual information from your eye to the brain. Sudden inflammation of this nerve can cause the optic nerve to swell. This can result in injury to the nerve fibers and some or permanent loss of vision. Conditions that have been linked with optic neuritis include:

* Autoimmune diseases, including lupus, sarcoidosis, and Behcet’s disease

* Cryptococcosis, a fungal infection

* Bacterial infections, including tuberculosis, syphilis, Lyme disease, and meningitis

* Viral infections, including viral encephalitis, measles, rubella, chickenpox, herpes zoster, mumps, and mononucleosis

* Respiratory infections, including Mycoplasma pneumonia and other common upper respiratory tract infections Multiple sclerosi

Symptoms

* Loss of vision in one eye over an hour or a few hours

* Changes in the way the pupil reacts to bright light

* Loss of color vision

* Pain when you move the eye

Exams and Tests

A complete medical examination can help rule out related diseases. Tests may include:

* Color vision testing

* MRI of the brain including special images of the optic nerve

* Visual acuity testing

* Visual field testing

* Examination of the optic disc using indirect ophthalmoscopy

Treatment

* Vision often returns to normal within 2 to 3 weeks with no treatment.

* Corticosteroids given through a vein (IV) or taken by mouth may speed up recovery. The final vision after recovery is no different with or without steroids. Oral steroids may actually increase the chance of recurrence.

* Further tests may be needed to determine the cause of the neuritis. The condition causing the problem can then be treated.

Prognosis

People who have optic neuritis without a disease such as multiple sclerosis have a good chance of recovery. Optic neuritis caused by multiple sclerosis or other autoimmune diseases has a poorer outlook. However, vision in the affected eye may still return to normal.

Possible Complications

Body-wide side effects from corticosteroids Vision loss About 1 in 5 patients with a first episode of optic neuritis will develop nerve problems elsewhere in the body, or will develop multiple sclerosis.

When to Contact an eye doctor

Call your health care provider immediately if you have a sudden loss of vision in one eye, especially if you have eye pain. If you have been diagnosed with optic neuritis, call your health care provider if: Your vision decreases The pain in the eye gets worse Your symptoms do not improve within 2 to 3 weeks

PAPILLOEDEMA

Papilledema is an optic disc swelling that is secondary to elevated intracranial pressure. In contrast to other causes of optic disc swelling, vision usually is well preserved with acute papilledema. Papilledema almost always presents as a bilateral phenomenon and may develop over hours to weeks.The term, as a matter of definition, is incorrect to be used to describe optic disc swelling with underlying optic nerve infectious, infiltrative, or inflammatory etiologies; but, it is correctly used if the underlying cause of elevated intracranial pressure is infectious, infiltrative, or inflammatory.

History

Most symptoms in a patient with papilledema are secondary to the underlying elevation in intracranial pressure. Headache: Increased intracranial pressure headaches are characteristically worse on awakening, and they are exacerbated by coughing or other type of Valsalva maneuver.

Nausea and vomiting: If the rise in intracranial pressure is severe, nausea and vomiting may occur. This eventually may be followed by a loss of consciousness, pupillary dilation, and death. Pulsatile tinnitus

Visual symptoms often are absent, but the following symptoms can occur:

Some patients experience transient visual obscurations (graying-out of their vision, usually both eyes, especially when rising from a lying or sitting position, or transient flickering as if rapidly toggling a light switch).Blurring of vision, constriction of the visual field, and decreased color perception may occur. Diplopia may be seen occasionally if a sixth nerve palsy is associated. Visual acuity may be well-preserved, except in very advanced disease. Papilledema is sometimes found at routine examination in an asymptomatic individual. Inquire about potential causative medications.

Causes

Any tumors or space-occupying lesions of the CNS

* Idiopathic intracranial hypertension (also known as pseudotumor cerebri).

* Decreased CSF resorption (eg, venous sinus thrombosis, inflammatory processes, meningitis, subarachnoid hemorrhage)

* Increased CSF production (tumors)

* Obstruction of the ventricular system

* Cerebral edema/encephalitis

* Craniosynostosis

* Medications, for example, tetracycline, minocycline, lithium, Accutane, nalidixic acid, and corticosteroids (both use and withdrawal)

Medical Treatment

Therapy, whether medical or surgical, is tailored to the underlying pathological process and the progression of the ocular findings.Specific therapy should be directed to the underlying mass lesion if present.

Diuretics: The carbonic anhydrase inhibitor, acetazolamide (Diamox), may be useful in selected cases, especially cases of idiopathic intracranial hypertension. (In the presence of venous sinus thrombosis, diuretics are contraindicated. In this scenario, evaluation by a hematologist is recommended.)

Weight reduction is recommended in cases of idiopathic intracranial hypertension and can be curative. Bariatric surgery may be considered in cases refractory to conventional methods of weight loss.

Corticosteroids may be effective in cases associated with inflammatory disorders (eg. Sarcoidosis)

OPTIC NERVE ATROPHY

Optic nerve atrophy is damage to the optic nerve. The optic nerve carries images of what the eye sees to the brain.

Causes

There are many causes of optic atrophy. The most common is poor blood flow. This is called ischemic optic neuropathy. The problem most often affects older adults. The optic nerve can also be damaged by shock, toxins, radiation, and trauma.Eye diseases, such as glaucoma, can also cause a form of optic nerve atrophy. The condition can also be caused by diseases of the brain and central nervous system. These may include:

* Brain tumor

* Cranial arteritis (sometimes called temporal arteritis)

* Multiple sclerosis

* Stroke

There are also rare forms of hereditary optic nerve atrophy that affect children and young adults

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Symptoms

Optic nerve atrophy causes vision to dim and reduces the field of vision. The ability to see fine detail will also be lost. Colors will seem faded. Over time, the pupil will be less able to react to light, and eventually, its ability to react to light may be lost.

Exams and Tests

The health care provider will do a complete eye exam to look for the condition. The exam will include tests of:

* Color vision

* Pupil light reflex

* Tonometry

* Visual acuity

You may also need a complete physical exam and other tests.

Treatment

Damage from optic nerve atrophy cannot be reversed. The underlying disease must be found and treated. Otherwise, vision loss will continue.Rarely, conditions that lead to optic atrophy may be treatable.

Prognosis

Vision lost to optic nerve atrophy cannot be recovered. It is very important to protect the other eye.

When to Contact a Medical Professional People with this condition need to be checked regularly by an eye doctor with experience in nerve-related conditions. Tell your doctor right away about any change in vision.

Prevention

Many causes of optic nerve atrophy cannot be prevented.

Prevention steps include:

Older adults should have their health care provider carefully manage their blood pressure.Use standard safety precautions to prevent injuries to the face. Most facial injuries are the result of car accidents. Wearing seat belts may help prevent these injuries.Schedule a routine annual eye exam to check for glaucoma.

OPTIC GLIOMA

Gliomas are tumors that grow in various parts of the brain. Optic gliomas can affect: One or both of the optic nerves that carry visual information to the brain from each eye. The optic chiasm, the area where the optic nerves cross each other in front of the hypothalamus of the brain An optic glioma may also grow along with a hypothalamic glioma.

Causes

Optic gliomas are rare. The cause of optic gliomas is unknown. Most optic gliomas are slow-growing and noncancerous (benign) and occur in children, almost always before age 20.

There is a strong association between optic glioma and neurofibromatosis Type 1 (NF1).

Symptoms

The symptoms are due to the tumor growing and pressing on the optic nerve and nearby structures. Symptoms may include:

* Involuntary eyeball movement

* Outward bulging of one or both eyes

* Squinting

* Vision loss in one or both eyes that starts with the loss of peripheral vision and eventually leads to blindness

* The child may show symptoms of diencephalic syndrome, which includes:

* Daytime sleeping

* Decreased memory and brain function

* Delayed growth

* Loss of appetite and body fat

Exams and Tests

A brain and nervous system (neurologic) examination reveals a loss of vision in one or both eyes. There may be changes in the optic nerve, including swelling or scarring of the nerve, or paleness and damage to the optic disc.The tumor may extend into deeper parts of the brain. There may be signs of increased pressure in the brain (intracranial pressure). There may be signs of neurofibromatosis type 1 (NF1). The following tests may be performed:

* Cerebral angiography

* Examination of tissue removed from the tumor during surgery or CT scan-guided biopsy to confirm the tumor type

* Head CT scan or MRI of the head

* Visual field tests

Treatment

Treatment varies with the size of the tumor and the general health of the person. The goal may be to cure the disorder, relieve symptoms, or improve vision and comfort. Surgery to remove the tumor may cure some optic gliomas. Partial removal to reduce the size of the tumor can be done in many cases. This will keep the tumor from damaging normal brain tissue around it.Radiation therapy may be recommended in some cases where the tumor is larger and surgery is not possible. In some cases, radiation therapy may be delayed because the tumor is slow growing. Corticosteroids may be prescribed to reduce swelling and inflammation during radiation therapy, or if symptoms return.Chemotherapy may be used in some children. Chemotherapy may be especially useful when the tumor extends into the hypothalamus.

Prognosis

The outlook is very different for each patient. Early treatment improves the chance of a good outcome. Many tumors are curable with surgery, while others return.Normally, the growth of the tumor is very slow, and the condition remains stable for long periods of time. However, in adults and some children, when the optic chiasm is involved, the tumor is more aggressive.

Possible Complications

Decreased vision

Blindness

When to Contact an eye doctor

Call your health care provider for any vision loss, painless bulging of the eye, or other symptoms of this condition.

Prevention

Genetic counseling may be advised for people with neurofibromatosis-1. Regular eye exams may allow early diagnosis of these tumors before they cause symptoms

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Alternative Names

Glioma – optic; Optic nerve glioma; Juvenile pilocytic astrocytoma

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