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New Treatments for Neuro-ophthalmology

Sheehan’s syndrome can occur with bleeding into the pituitary, and it’s something we need to be aware of when patients complain of decreased vision after giving birth. Very important to try to get corticosteroids in. You may save sight. Rarely though will you have acute compression that’s relieved within a couple of days, causing permanent visual loss.

Optic nerve gliomas, also known as juvenile pilocytic astrocytomas now. The treatment here is incredibly controversial. You’ve got to be very careful with kids with gliomas. Remember, meningiomas are deadly in kids, gliomas are deadly in adults. So a kid with an optic nerve sheath meningioma, you’ve got to be very careful.

Now, visual fields. This is the diagram you’ve got to remember, for when you are evaluating visual fields. Just stare at this for a couple of seconds. Get this into your mind. The images come into the eye - you don’t have to remember this - but nasal images go to temporal retina, they travel in the temporal fibers. Temporal fibers tend to stay ipsilateral. Going back, it’s the nasal retinal fibers that cross. Nasal retinal fibers serve temporal visual field. That’s why you get at level B, a bitemporal hemianopia. This is the optic nerve. You get a central scotoma or a complete wipeout of vision. If the lesion is at C here, you can get a contralateral visual field.

All this stuff has not been difficult, conceptually. Diplopia is. There’s got to be a little bit of thinking with diplopia. However, there are some easy ways to evaluate which muscles and which nerves are involved. First thing you have to do is ask the patient which eye is involved. Is it one eye, both eyes, or each eye? If it’s one eye, you send them to the eye doctor. If it’s each eye separately you send them to the eye doctor. If it’s only with both eyes open together that it’s in your ballpark. That’s called binocular diplopia. It has to be in both eyes at the same time. Monocular diplopia is going to be most likely a refractive error.

Metamorphopsia can occur is there is fluid in the retina and the image in that eye will be wavy. Again, the brain will not be able to fuse it well. Now if you have binocular diplopia, the eyes are not misaligned and the images are similar but it is intermittent, not constant. Then you have to look for disease. Myasthenia gravis far and away the most likely thing that the neurologist will see. But you can also have decompensating phorias. A phoria is a tendency for an eye to drift, either up, down, in or out. If it drifts up it’s a hyper, down it’s a hypo, in it’s an esophoria, out it’s an exophoria.

Binocular diplopia that is commitant - commitant means the same in all fields of gaze - can be from a phoria that’s breaking down, childhood strabismus that may have been operated on, or not operated on. But if it’s acquired you can have a skewed deviation, and you’ve probably read about it. A skewed deviation classically is a hyper-deviation or a vertical deviation of the eyes that is not due to a superior oblique palsy. If you can’t put a fourth cranial nerve palsy tag on it, then we call it a skewed deviation. Generally due to a brainstem infarct. We’re going to talk about that a little bit more. If you have incomitant strabismus - that’s means it’s worse in one particular field of gaze, you do something called forced-duction testing.

Now they have binocular diplopia, it’s intermittent, and it’s incomitant. You do a Tensilon test. There are many ways to do a Tensilon test. You can either do 0.2 cc followed by successive injections of 0.2. You can do 0.2 and 0.8, 0.2, 0.4 and 0.4. Whatever you are more comfortable with. You can pre-treat with atropine or you can not pre-treat with atropine. But you have to have a parameter to follow. You can’t do a Tensilon test unless you have something to look at to see if it gets better. Either ptosis or an eye that’s turned, don’t do a Tensilon test unless you have a parameter to follow. If it’s positive, you’ve got myasthenia. If it’s negative you can have a cranial neuropathy. What does a sixth nerve palsy do? Sixth nerve palsy gives you an esotropia. The sixth nerve is called the abducens nerve. It pulls the eye to the side. If it doesn’t work well the eye will turn in and it will appear to turn in more the further towards that paretic muscle you look. So if you have a right sixth nerve palsy and you are looking to the right.

Internuclear ophthalmoplegia; remember that is pathognomonic in people under the age of 45 for MS. The sixth nerve and the third nerve have to communicate to move the eyes to the right or the left, because it’s the sixth nerve that moves the eye out and the third nerve that moves the eye in. The way they communicate is by virtue of something called the MLF, medial longitudinal fasciculus. An MLF lesion can either be anterior - more towards the third nerve - or posterior - more towards the sixth nerve. You’ll see here the PPRF; paramedian pontine reticular formation, or the horizontal gaze center. A lesion of the MLF will give you a patient who cannot adduct, cannot move that eye inward. That is an INO, internuclear ophthalmoplegia. Something that neurologists must be familiar with. It will also give you nystagmus in the abducting eye.

The most common cause of sixth nerve or third nerve palsies, it depends on who you are talking to. Pediatric ophthalmologists will say one thing, neuro-ophthalmologists will say another, neurosurgeons will say another. You can’t go wrong saying trauma. You can’t go wrong saying ischemia, if the patient is in the vasculopathic age group.

Double vision is scary to ophthalmologists and neurologists. It doesn’t have to be if you just try to think it out. Remember, the first thing is, is it monocular? If it is monocular, don’t worry about it. If it is binocular - meaning if it goes away when you cover either eye.

Now this is where we all join forces; neurologists and ophthalmologists all have to know about the elevated optic nerve head. It goes by lots of different names. And you can have a swollen or elevated nerve from inflammation, ischemia, elevated intracranial pressure, disease in the orbit, or disease in the eye. We are going to go through each of these categories so that you are familiar with them because it will help in diagnosis and treatment if you know the differences between all these groups. This is a normal disc. The big red things are veins. The little red things are arteries. This is the optic disc, optic nerve head, papilla, whatever you want to call it. The margins should be distinct and there should be no hemorrhages on it. Optic neuritis; inflammation of the optic nerve can either be at the level of the optic nerve head, the papilla.

Optic neuritis. Usually unilateral but can be bilateral in 7% of adults. These statistics come from the Optic Neuritis Treatment Trial, which you may have heard of. It's now called the Longitudinal Optic Neuritis Study. It was based here at the University of South Florida. My former partner Roy Beck was the head of the study. We eventually got $6.2 million from the Federal Government to look at optic neuritis, regarding its treatment and its natural history. It began in 1989 here and at 15 other centers around the country. The information garnered has led to changes in which optic neuritis is worked up and treated.

To review. I’m going to be saying this four or five times in this half hour. Optic neuritis; decreased vision, decreased color vision, decreased visual field, relative afferent pupillary defect and a disc that is elevated in papillitis or not elevated in retrobulbar optic neuritis. You get an MRI. You are looking for UVO’s because of the results of the Optic Neuritis Treatment Trial. In this study we treated with intravenous methylprednisolone for three days followed by an oral taper. We now don’t use the oral taper. Those people treated in the study were divided into three groups: placebo, oral steroid, or intravenous steroid.

Ischemic optic neuropathy is divided into two categories, arteritic and non-arteritic. Arteritic is giant cell arteritis. Non-arteritic occurs generally in people over the age of 50, arteritic over the age of 60 or 65. Neither visual loss is necessarily associated with pain in the eye or pain in eye movements. Giant cell arteritis, as you know, can be associated with temporal tenderness, headaches, jaw claudication, fever, malaise. Usually occurs over the age of 65, when it’s arteritic. The disc is elevated but pale and elevated. There is a relative afferent pupillary defect, visual field loss, and there is loss of central vision. So it’s just like optic neuritis except there is no pain and it’s in older people, and the disc is pale and elevated, not erythematous and elevated. The visual field defect is often altitudinal. Either the entire top or the entire bottom of the patient’s visual field is gone. You gotta get a sed rate right away, if you suspect giant cell arteritis.

Non-arteritic generally occurs in patients who are diabetic or hypertensive and whose optic nerve head does not have a good central cup. Meaning, it’s not about 0.3 or 0.4 but that central cup is about 0.1 or non-existent. It’s a crowded disc, susceptible to lack of blood flow. This is a crucial finding. It was first noted in the late 70’s or early 80’s. We’ve tried steroids, surgery, for this. Nothing has worked. There is no treatment. What we do is offer them an aspirin per day to try to thin the blood out to hopefully prevent this from happening in the other eye.

Papilledema: this is where the differentiation occurs and you really need to know how different an acute papilledema is than optic neuritis and ischemic optic neuropathies. Elevated intracranial pressure causing swelling of the nerves is called papilledema. If that’s the case, it’s bilateral and symmetric usually. Only in the chronic stages is it asymmetric.

Now we all think of pseudotumor cerebri but we must also think of tumor cerebri, even if the patient is young and overweight and a woman. So you’ve got to scan them, then you do your tap, and then you treat. Pseudotumor cerebri is usually in young, overweight women. Very rare in men. Some people say in 10%. It is nowhere near 10% in my patient population. It can be caused by numerous agents.