Chat Highlights
The Interface of Neurology and Glaucoma
May 31, 2000

Norma Devine, Editor

On Wednesday, May 31, 2000, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "The Interface of Neurology and Glaucoma."  

Dr.  Wilson:   Hello Gang.

Moderator:   Hello, Doctor.  As you know, the topic tonight is "The Interface of Neurology and Glaucoma."

P:   Doctor, will you describe "optic neuropathy?"

Dr.  Wilson:   Glaucoma is just one kind of optic neuropathy, or process, that damages the optic nerve.  Glaucoma seems to be pressure related, though more so in some patients than in others. Other common causes of optic neuropathy are blood flow disorders, multiple sclerosis, and brain tumors pressing on the optic nerve.

P:   Do some of those disorders cause glaucomatous damage? Or is it a different type of damage?

Dr.  Wilson:   Autoimmune disorders in which the body attacks its own tissues, like Giant Cell Arteritis or inflammations of the blood vessel walls, can also cause problems with circulation.

P:   What are the symptoms of Giant Cell Arteritis?

Dr.  Wilson:   They are headache, tender scalp, aching in the jaw muscle when chewing, and fatigue.

P:   What about Myotonic Dystrophy?  Is there a relationship?

Dr.  Wilson:   Patients with Myotonic Dystrophy usually have IOPs under 10, because the muscles squeezing on the eyeball are slack.

P:   So the muscle can affect the pressure of the eye? If it is tight or in a spasm, can the pressure be high?

P:   Can the musculature surrounding the eyeball squeeze hard enough enough to raise IOP?

Dr.  Wilson:   Yes, as is seen in some forms of thyroid eye disease.  The mechanism by which marijuana seems to work is to relax the person to the point that the extraocular (outside the eye) muscles relax and don't put their usual pressure on the eye.

P:   Can you have pain from the muscle being in spasm around the eye?

Dr.  Wilson:   My feeling is that the very sharp, quick  pains that seem to emanate from the center of the eye are spasms of the muscle inside the front of the eye.

P:   How is it diagnosed?

Dr.  Wilson:   In diseases like thyroid disease, the muscles thicken and can be seen by MRI. Otherwise, it is difficult to tell.

P:   Are those sharp pains common in people with glaucoma?

Dr.  Wilson:   No more than in the general population, unless the pain is related to the medications being taken.

P:   As a child I had a 'lazy' eye.  Is that caused by muscles not being tight enough? Actually, I still have it.

Dr.  Wilson:   No, the usual cause is one eye not seeing as clearly as the other so that the brain tends to disregard it.  The brain's ability to interpret the signals the eye is sending back to the brain is not developed as much as it should be.  If the eye is made healthy so the vision potential is 20/20 later, the brain would still not be able to interpret the clear vision signals.

P:   I recently had GDx nerve fiber analysis.  My optic cups were not symmetric.  The doctor thought it was congenital, since the nerve fibers were normal.  I return next month for IOP measurement.  My doctor said that if my IOP is over 26, he will start treatment.   The doctor is not a glaucoma specialist.  Any comment?

Dr.  Wilson:   I wouldn't put much reliance on the GDx.  It may be decent in terms of telling if there is any change from an earlier exam, but it cannot diagnose glaucoma.

P:   What are the recommended tests to definitively determine damage to the optic nerve?

Dr.  Wilson:   Unfortunately, the state-of-the-art is a dilated exam by a glaucoma specialist looking at the nerve for signs of damage, followed by a short-wavelength Humphrey visual field.

P:   What types of meds would cause those pinprick pains?

Dr.  Wilson:   Pilocarpine causes more of an ache.  Those complaints of hat-pin pains are not common.

P:   How can you tell if the glaucoma is secondary to a neurological condition?

Dr.  Wilson:   The visual field is often helpful.

P:   What about some kind of pictures they take of the nerve?

Dr.  Wilson:    There are stereo color pictures and computerized scans of the topography (surface contour) of the optic nerve.

P:   Does Azopt cause hair loss?

Dr.  Wilson:   It can, but not as commonly as beta-blockers.

P:    Have migraine headaches been linked in any way to glaucoma?

Moderator:  Good question.  Many of us suffer from migraines.

P:   Aren't migraines more common with Normal Tension Glaucoma?

P:   I get migraines, too.  They got worse as my glaucoma progressed.

P:   I suffer from Normal Tension Glaucoma and have numerous migraines every month.

Dr.  Wilson:   Migraines are present in 25% of the normal population and 47% of patients with Normal Tension Glaucoma.

P:   Is there a relationship between blood flow to the brain, migraines, and glaucoma?

Dr.  Wilson:   Yes.  That is why there is a higher incidence of migraines in those with Normal Tension Glaucoma.  Migraines are a spasm of the blood vessel, which cuts down the blood flow to the area in question--brain, eye, etc.   

P:  Do those photos help track progression of glaucoma or are visual field tests adequate?

Dr.  Wilson:   Both are helpful.  I get a stereo photo whenever I see a change in the optic nerve, and a visual field at least every year.

P:   How can one be losing visual field without the optic nerve showing change?

Dr.  Wilson:   In early glaucoma, it is easier to tell change by the optic nerve.  In later glaucoma, it is easier to tell change by the visual field.

P:   Is there ever any relationship between changing acuity, ability to focus, and glaucoma? Some of the things one reads say if your glasses need changing frequently that can be a symptom of glaucoma.  My doctor says there's no relationship between acuity or refraction and glaucoma.  What's your view?

Dr.  Wilson:   If one is young, so that the eye tissue is more elastic, a higher than normal pressure in the eye will cause it to grow and become more near-sighted (myopic).  This is seen most commonly in 3 to 14 year olds. 

P :   My doctor told me to stop doing step aerobics due to possible pressure spikes.  What is your feeling?  

P:   I have read that exercise helps lower the IOP, especially for open angle glaucoma.  True?

Dr.  Wilson:  True, if one exercises 20 minutes per day,  four times a week.   

P:   I  have been told it is different with pigmentary glaucoma.  So is there no truth to it being different with pigmentary glaucoma and exercise?

Dr.  Wilson:   In pigmentary glaucoma, exercise that jars the eye knocks more pigment off the iris to block the drain.

P:   You might want to see if you can get a pressure check right after exercise

Dr.  Wilson:   A patient with pigmentary glaucoma can ride an exercise bicycle, especially the kind that one reclines on to ride.  That causes no jarring motion.   

Dr.  Wilson:   Got to go.  Have a great week.

P:   I tried to access the American Glaucoma Society on the Web without success.  Does anybody know the address? I want to find a glaucoma specialist in my area.

Moderator:   I do not think the American Glaucoma Society has the site up and running yet.  Group, what Web site did we suggest to locate a glaucoma specialist?

P:   The AAO web site.

Moderator:   Thanks, the address is http://www.eyenet.org/

P:   Thanks all.

End of Highlights for May 31st chat.

On June 7th, Dr. Wilson discussed Angle Closure Glaucoma in the Chat room. Click here for highlights of that meeting.

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