Neuro-ophthalmology is an ophthalmic subspecialty that addresses the relationship between the eye and the brain, specifically disorders of the optic nerve, orbit, and brain, associated with visual symptoms. Neuro-ophthalmologists provide comprehensive clinical care to a broad spectrum of patients with visual disturbance from optic nerve diseases, central nervous system disorders, ocular motility dysfunction, and pupillary abnormalities. Over 50 percent of all intracranial lesions involve the visual or oculomotor pathways. Shroff Eye Centre offers you a dedicated Neuro-Ophthalmology Service for the diagnosis and treatment of these neuro-ophthalmic disorders.

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This is the most common cause of sudden decreased vision in patients older than 40 years. We do not see with our eyes. We see with part of our brain that is capable of interpreting visual signals sent back from the eyes. This is located at the back of our head (the occipital lobes). Information is transmitted from the eyes to the brain via the optic nerves. These nerves are composed of the long tube extensions (axons) of cells (ganglion cells) located within the inner lining of the eye (the retina) that exit the back of the eye at the optic disc. Each of the optic nerves receives blood supply from branches of the ophthalmic artery within each eye socket. The optic disc has a unique blood supply (the posterior ciliary arteries).

Loss of blood supply within the posterior ciliary arteries deprives the optic nerve tissue of oxygen and results in damage to part or all of the optic nerve. This is a small "stroke" in the optic nerve. It is painless. Patients may become aware of decreased vision or difficulty seeing above or below the center of gaze. Loss of the blood supply results in swelling of the optic disc, often associated with hemorrhages. The hemorrhages and swelling will go away leading to the development of a pale disc (optic atrophy). As the swelling resolves, some of the axons will be permanently lost. We do know that this happens more often in patients who are born with small optic discs. These episodes may occur when there is a sudden drop in blood pressure (following an operation or associated with blood loss after an accident). Patients who smoke, or who have diabetes or high blood pressure, may be at higher risk for AION.

Symptoms that are more common in neuro-ophthalmic disease include visual loss, visual disturbance, diplopia, unequal pupils and eyelid and facial spasms.

This is the most common cause of sudden decreased vision in patients older than 40 years. We do not see with our eyes. We see with part of our brain that is capable of interpreting visual signals sent back from the eyes. This is located at the back of our head (the occipital lobes). Information is transmitted from the eyes to the brain via the optic nerves. These nerves are composed of the long tube extensions (axons) of cells (ganglion cells) located within the inner lining of the eye (the retina) that exit the back of the eye at the optic disc. Each of the optic nerves receives blood supply from branches of the ophthalmic artery within each eye socket. The optic disc has a unique blood supply (the posterior ciliary arteries).

Loss of blood supply within the posterior ciliary arteries deprives the optic nerve tissue of oxygen and results in damage to part or all of the optic nerve. This is a small "stroke" in the optic nerve. It is painless. Patients may become aware of decreased vision or difficulty seeing above or below the center of gaze. Loss of the blood supply results in swelling of the optic disc, often associated with hemorrhages. The hemorrhages and swelling will go away leading to the development of a pale disc (optic atrophy). As the swelling resolves, some of the axons will be permanently lost. We do know that this happens more often in patients who are born with small optic discs. These episodes may occur when there is a sudden drop in blood pressure (following an operation or associated with blood loss after an accident). Patients who smoke, or who have diabetes or high blood pressure, may be at higher risk for AION.

This is one of the most common causes of acute double vision in the older population. It occurs more often in patients with diabetes and high blood pressure. These will get better and essentially always resolve without leaving any double vision. However, compressive masses, infections, inflammation and injury can also cause cranial nerve palsy. The eyes are moved by 6 extra-ocular muscles. Four of these are rectus muscles (superior, inferior, medial, and lateral) that attach to the front part of the eye (just behind the iris, the colored portion of the eye). Two muscles (the superior and inferior oblique) attach to the back of the eye. These 6 muscles receive their signals from 3 cranial nerves (the IIIrd [oculomotor], IVth [trochlear], and VIth [abducens]). These nerves originate in the brain stem (at the base of the brain) and enter the eye socket through a fissure in the bone of the skull behind the eye.

Pressure on or Interruption of the blood supply to one of the cranial nerves causes it not to work. If there is interruption of signal to the VIth nerve (which innervates the lateral rectus muscle) the affected eye will not be able to move to the outside. The patient will be aware of side-to-side double vision that will be worse (further separation) when the patient looks towards the affected sideWhen the IIIrd nerve (which goes to multiple muscles) is involved the eye may be limited in up, down, and gaze toward the nose. The patient is usually aware of combined vertical and side to side double vision although there may be no double vision at all since the lid droops and may block the second image. The nerves are not permanently injured and over a period of 6 to 12 weeks the function should recover.

Pituitary tumors are benign (non-cancerous) overgrowth of cells that make up the pituitary gland (the master gland that regulates other glands in the body). Tumors that grow large enough to produce symptoms are less common but still are one of the most common tumors occurring within the head. These tumors may often be present for years without diagnosis or even symptoms.

The optic nerves coming from each eye meet just above the pituitary gland in the optic chiasm. An abnormal growth of cells within the pituitary gland may produce an excess of signal to the other endocrine glands leading to overproduction of thyroid, cortisone, or sex hormones. If the pituitary tumor extends out of the sella it may produce symptoms due to compression of surrounding structures including the optic nerves, chiasm, and cranial nerves in the cavernous sinus (controlling eye movement and facial sensation).

With muscle enlargement the globe (eyeball) is pushed forward leading to the characteristic "stare." In addition, the muscles become stiff and the upper lid tends to retract, pulling away from the colored portion of the eye. The eyes may become red due to difficulty closing as well as increased prominence of the blood vessels. This often results in double vision with one image seen on top of the other. If the muscles get large enough, they may press on the optic nerve causing damage to the nerve.

This dysfunction within the optic nerve, which transmits information from the eye to the brain, results in decreased vision. This, fortunately, occurs only in about 5% of the patients with thyroid orbitopathy and may be reversible if the pressure on the optic nerve is relieved.

In patients with mild involvement, irritation and foreign body sensation may improve with artificial tears and the use of lubricating ointment at night. If the lids are not closing completely, they may be taped closed at night. With more severe corneal problems, lid surgery to help partially close the lids or to raise the lower lids may be necessary. In severe retraction of the upper or lower lid, surgery to reduce the effects of the lid retractors, either without or with spacer placement (such as a piece of tissue removed from the roof of the mouth) can help the lids to close. Smoking may worsen symptoms and should be discontinued.

There is no medicine that improves the ability of muscles to move (and thus relieves double vision). Covering one eye immediately relieves double vision. It may be possible to optically realign eyes with the use of prisms either applied to glasses or ground into the lens although this may not be effective until things stabilize. When double vision cannot be corrected with prisms, eye muscle surgery may be necessary. Often multiple muscle operations are necessary. It is sometimes not possible to completely remove double vision, but the goal is to remove double vision looking straight ahead and in reading position, as these are the most important directions of sight.

Fortunately, optic nerve problems resulting in decreased vision are uncommon. When it occurs, treatment is aimed at shrinking the muscles, usually by the use of high dose steroids (prednisone). For those patients who will not tolerate steroids radiation therapy may be of benefit. If the muscles cannot be made small enough to relieve the compression of the optic nerve (resulting in decreased visual acuity) then the orbit can be made larger. This is usually done surgically by removing one or more of the bony walls of the orbit. Since the optic nerve is usually compressed at the very back of the orbit, removing the posterior medial wall of the orbit is most critical. This may be done directly (through the soft tissues or skin around the eye), through the sinus under the eye, or through the nose. To further reduce the eye bulge the floor, lateral wall, or even the roof of the orbit may be removed. One of the problems with surgical decompression is that this often affects eye movements, thus changing the pattern of double vision (if it already exists) or potentially producing double vision in those patients who don't have it before surgery.