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New Treatments in Neuro-ophthalmology

Parinaudís syndrome can occur with pineal tumors. There can be compression of the area of the superior calyculi and Parinaudís syndrome can develop. You will have what are called mid-brain pupils that are 5 mm, totally reactive to light. They do react to accommodation. On attempted up-gaze there will be something called convergence retraction nystagmus. The eyes will beak and try to come inward. It is not a true nystagmus.

Hornerís syndrome can either be first or second order, versus third order. The reason we divide it into first or second versus third is because of a drug we have called Paredrine. Itís hydroxyamphetamine 1%. When you are testing for Hornerís syndrome you put cocaine in the eye, either 4% or 10%, one drop in each eye. Cocaine will allow any norepinephrine thatís in the area to stick around longer and the pupil will dilate. If there is no norepinephrine around it will not be able to stick around so it will not dilate. So cocaine will not dilate the eye. Paredrine will cause release of norepinephrine from the terminal bouton and will also cause dilation.

Disorders of accommodation. We talked about most of them already. The ailment that I mentioned to you regarding the near reflex. If the entire near reflex is out, if you have spasm of the near reflex that can be a problem. (break in tape) Öand theyíll complain of double vision. That is usually supratentorial, rarely is it isolated as a cause of intracranial pathology. You can see it with other problems intracranially.

Physiologic anisocoria. It is normal to have pupils that are half a millimeter or so different in size. Once you get past that half millimeter you have to start thinking of pathology. Third nerve palsy can be pupil-involving or pupil-sparing. Pupil-involving third nerve palsies are often compressive. Pupil-sparing third nerve palsies are generally ischemic. A diabetic third nerve palsy will generally spare the pupil, but in about 5% of diabetic third cranial nerve palsies the pupil can be involved. Keep that in mind. The important part is the compressive lesion, the tumor or the aneurysm. If the pupil is even slightly involved youíve got to start thinking aneurysm.

Now, ocular disease that can cause pupillary asymmetry. Acute glaucoma; acute glaucoma. Acute glaucoma is also known as narrow-angle glaucoma. It can give you a steamy cornea, so you may not be able to see very well. The patient will be acutely blurred, in pain with a red eye. This is completely different than chronic open-angle glaucoma. The pupil in acute glaucoma can be in the mid-dilated region, about 4.5 to 5 mm. And there is something called pupillary block. Aqueous humor flows from just behind the iris through the pupil and into the anterior chamber.

Now you just had a lecture on cutaneous illnesses and oculocutaneous illnesses. You saw albinism and Waardenburgís syndrome. I was going to take out the slide on Waardenburgís but we can talk about it now. Things that cause heterochromia. Remember, the involved pupil could be either lighter or darker. Darker pupils can happen when the iris has iris nevi or melanoma making it darker. Neurofibromatosis has Lisch nodules associated with it; 93% of patients.

We are going to go on to talk about the chiasmal syndromes, and here we are going to talk about tumors and visual fields. Remember, there are signs and there are symptoms. The symptom that a patient may come in with is visual loss, generally to the sides, but it may be straight ahead. Double vision can occur and the patient will complain of either constant.

The anatomy here is important because you need to know that cranial nerves can be involved, or blood supply to the brain can be involved, because you have the anterior cerebral and anterior communicating arteries in that area. The circle of Willis is right there and you can have ischemia to the cortex being the presenting symptom sometimes, or sign, from a chiasmal lesion. Fibers decussate more readily inferiorally than superiorally and the inferior fibers control superior visual field. What you need to know when looking at visual fields on your test is that the right eye will always be on the right, the left eye will always be on the left and you name the visual field defect by how the patient sees.

A junctional scotoma occurs when the posterior optic nerve and the chiasm are involved, and you get a central scotoma - scotoma is an area you donít see in - central scotoma in one eye and in the contralateral eye you get a superior temporal visual field defect. The fibers that are crossing in the chiasm from the right islet, donít just go into the chiasm and head back in the optic tract. They bend forward slightly into the anterior optic nerve on the contralateral side. You can therefore get central visual field defect in one eye and a superior temporal visual field defect in the other eye. Itís known as a junctional scotoma and itís something you need to be aware of in your clinical practice. Because you are going to be testing people for their visual field.

Youíve got to think of pituitary tumors when youíve got a chiasmal syndrome, far and away the most common. Cranial pharyngeomas will give you a bitemporal hemianopia but are more likely than pituitary tumors to give you an optic tract syndrome.

Now visual fields to confrontation. I always tell residents that they can do cataract surgery a number of different ways, they can test visual acuity a number of different ways, but with visual fields thereís only one way Iíd like them to do it.

This is a bitemporal visual field defect. As you can see, right is on the right, left is on the left. This is a right visual field defect in the right eye obeying a vertical meridian. This is the normal natural blind spot. That is not abnormal. Left visual field defect obeying a vertical meridian in the left eye. These are non-homonymous visual fields. It is a bitemporal hemianopia.

Pituitary apoplexy. You can see any one of the visual field defects that I mentioned to you. But you can also see unilateral hemianopic defects. I didnít think this was possible. It is rarely discussed in the literature but if somebody has lost visual field in just one eye but it obeys a vertical meridian, it could be pituitary apoplexy.