Pseudotumor Cerebri & Optic Nerve Disease
We offer a comprehensive approach to the diagnosis and management of optic nerve problems. Our goal is first to keep you from getting worse, second to decrease the threat of visual loss in your other eye and third to help you regain functional vision in the eye with the problem. Many doctors cannot offer the full range of diagnostic and therapeutic modalities needed to help you, but we can. We have a lot of arrows in our quiver, and it may require more than one shot. We will not give up the fight unless you want us to.
After reviewing your records and performing a history and eye examination, you will undergo visual field testing and we will look at your retina and optic nerve. This is called the posterior segment examination. It involves dilating your pupils and is an essential part of every neuro-ophthalmic examination. We dilate your pupils at every visit. If Dr. McHenry can’t see enough through an undilated pupil doing it a hundred times a day, no one can. The appearance of “the back of your eye” along with your visual field test will help us localize your problem. The optic nerve may appear swollen, pale, or normal. We will follow its appearance at each visit to decide which step to take along the pathway to improvement.
If your nerve is swollen, it is important to consider the appearance of your other eye. If that optic nerve is also swollen, then we become concerned that the pressure of the fluid surrounding your brain is too high. In the vast majority of patients this is due to being overweight, but we get an MRI to make sure nothing bad is going on. Then if you have visual loss, we must check the intracranial pressure. This is done by experts in anesthesia and neuroradiology who perform lumbar punctures for a living.
If the pressure is high, we try medicines first. If that does not work, then we consider removing some fluid behind the eye around the optic nerve. This is called an optic nerve sheath decompression. In many ways it is like a lumbar puncture behind the eye, except we do it for you while you are asleep. This is a specialized procedure that only a few neuro-ophthalmologists perform. Dr. McHenry has been doing this procedure several times a week for the last 20 years. It takes about 20 minutes. You get to go home afterwards. You will have a patch over your eye overnight. We take it off the next day and start you on an antibiotic-steroid ointment. There are microscopic sutures that dissolve and don’t need to be removed. We only do one eye at a time.
Patients that do not respond may need to be evaluated for a neurosurgical shunt. The shunt is a better operation for headaches than an optic nerve sheath decompression. Shunts, however, tend to fail over time, requiring reoperation. They are also subject to infection. The operation involves placing a tube from an area where the cerebrospinal fluid collects – such as the lumbar cistern in the lower back or the ventricles in the brain – and passing the tube to the abdomen.
We follow you with repeat visual fields throughout the process. We intervene with medicines or surgery if your visual fields are tending to worsen. While it is a long process, we gradually decrease your visits from weekly to every 6 months. Diet and weight loss are difficult but extremely important. We will look for causes of the raised intracranial pressure. This will involve MRVs which look at the outflow system of the brain. Sometimes there are constrictions which may require angiography and stents. In rare cases there is a clot which will require anti-coagulation.
Some patients have a pale optic nerve when we perform the posterior segment examination. These patients also have visual field defects. There are a variety of conditions that can cause this, the worst which is a brain tumor. We rule this out with an MRI. Then we perform a battery of laboratory tests to help us find the cause.
In order to help your vision return, we will reduce your intraocular pressure with eye drops. If you show signs of poor blood flow to the optic nerve, or ischemia, we may start you on aspirin therapy. Patients with ischemia may either have segmental pallor of the optic disc or there may be hemorrhages on the disc.
If we find signs of inflammation, or an inflammatory optic neuropathy, we may start you on corticosteroids. Patients with an inflammatory optic neuropathy, can have leakage on fluorescein angiography. This is an intravenous dye test we can perform in the office.
Some older patients can have a pale swollen nerve with an elevated erythrocyte sedimentation rate. These patients must undergo a temporal artery biopsy. This is a relatively simple procedure that can be performed under local anesthesia in the office. These patients are started on high dose corticosteroids to controls the inflammation.
No matter the cause of your optic neuropathy, there are things we can do to stabilize and hopefully improve your vision. Click here to schedule an appointment.