Chat Highlights
Systemic Factors Contributing to Glaucoma
August 1, 2001

Norma Devine, Editor

On Wednesday, August 1, 2001, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Systemic Factors Contributing to Glaucoma." 

Moderator:  Welcome, Dr. Wilson.  Our topic tonight is "Systemic Factors Contributing to Glaucoma."  Can you start by telling us what systemic means?

Dr. Rick Wilson:  Systemic means the body systems, like the cardiovascular, urinary, digestive, etc., systems.  Some that come easily to mind are cardiovascular, such as low blood pressure, high blood pressure, obesity, irregular heart beat, and thyroid disease.

P:  Glaucoma is always treated as a disease unto itself,  but do doctors considered the possibility of it being a secondary result of systemic factors?

Dr. Rick Wilson:  The more

we learn about glaucoma, the more we understand that eye pressure is a major risk factor for glaucoma, but only one of several risk factors.

P:  What part does obesity play in glaucoma?

Dr. Rick Wilson:  Obesity is linked to high blood pressure and at least through high blood pressure, if not more intrinsic ways, to high eye pressure.

P:  Then if a person's blood pressure is 120/75 and he is 40 pounds overweight is the blood pressure contributing to his glaucoma?  

Dr. Rick Wilson:  We don't know for sure.  

P:  About what percentage of glaucoma specialists actually require or perform a systemic workup of patients?  

Dr. Rick Wilson:  All glaucoma specialists should take a medical history of the patient and review all the systems in the body, looking for possible links to glaucoma.  

P:  What type of autoimmune diseases affect glaucoma?

Dr. Rick Wilson:  We are not sure.  There is a higher prevalence of autoimmune diseases in patients with normal-tension glaucoma.  These include lupus, rheumatoid arthritis, mixed connective tissue disease, and many more.  Marty Wax in St. Louis isolated autoantibodies to one of the components of the retina in patients with normal-tension glaucoma.  

P:  Would carbachol be an appropriate replacement for phospholine iodide (which has been discontinued) for a patient who has myasthenia gravis and takes a systemic cholinergic? 

Dr. Rick Wilson:  Carbachol is our second strongest miotic, so it should be a good choice if a miotic (medicine that makes the pupil small) is needed.

P:  I have sarcoidosis.  My dad had glaucoma.  Is there a link between sarcoidosis and glaucoma?   I'm 57 years old, my visual fields and optic nerve are normal, but my intraocular pressures of  24 to 28 mm Hg. are creeping up.  Should I try laser (trabeculoplasty) or try Timoptic again? 

Dr. Rick Wilson:  Patients with sarcoidosis may have intraocular inflammation that can cause the eye pressure to go up.  Much as I would like to help, I can't judge whether you are an excellent candidate for a laser without knowing how your optic nerves and visual fields look, what medications you have taken in the past and what the drain (trabecular meshwork) looks like. 

P:  How are the characteristics of the drain determined?

Dr. Rick Wilson:  By looking with a microscope and a slit lamp beam into a mirror set on the cornea.

P:  Something called "vision dimming" happens with orthostatic hypotension (blacking out or feeling dizzy when standing up).  Is that cased by the blood flow not making it to the eye? 

Dr. Rick Wilson:  It's just as likely the part of the brain t

hat interprets what the eye sees.  

P:  What is the best way to control intraocular inflammation?

Dr. Rick Wilson:  Steroids or non-steroidal eye drops. 

P:  What diseases can causes eye inflammation?

Dr. Rick Wilson:  Syphilis, sarcoidosis, juvenile rheumatoid arthritis, toxoplasmosis, retinal viral infections and many more can cause intraocular inflammation.  At least 50 % of the causes of intraocular inflammation are never found.

P:  I have had several blood tests that indicate I may have an autoimmune disease.  My rheumatoid count is higher than normal; I have spirochetes in my blood.  I'm symptom free, except for glaucoma.  My blood has even been sent to CDC (the Center for Disease Control) in Atlanta.  I can't seem to find a local doctor who will take on the challenge to find out what autoimmune disease I have.   

P:  Aren't  spirochetes associated with Lyme disease?  

Dr. Rick Wilson:  Spirochetes can refer to syphilis or Lyme disease.

P:  I don't have syphilis.

P:  Why is it important to block the tear duct when using certain glaucoma eye drops?  

Dr. Rick Wilson:  It's important to block your tear ducts when using  beta blockers and Alphagan because, in my opinion,  these medications are much more likely to cause systemic side effects than the other commonly used medications.  

P:  How long should you apply pressure at the corner of the eye near the nose?  

Dr. Rick Wilson:  Three minutes is best. 

Moderator:  What kind of tests can be done on a patient with normal-tension glaucoma to see whether the patient's low blood pressure is causing damage, and who should conduct these tests? 

Dr. Rick Wilson:  Many internists have access to a 24-hour blood pressure monitoring instrument.  We have one at Wills to determine whether blood pressure drops too low during the night.  In many patients, the blood pressure may even be too low during the day.

P:  My blood pressure is 90/40 mm Hg.  

Dr. Rick Wilson:  A diastolic pressure of 40 mm Hg. is worrisome.

P:  You're the first doctor to ever tell me that.  

Dr. Rick Wilson:  Sorry to be the first.  I recall that your optic nerves don't show any sign that low blood pressure is a worry for you.  Low eye pressure can be protective.

P:  How low is too low?  What can be done for low blood pressure?

Dr. Rick Wilson:  I dislike diastolic blood pressures below 60 mm Hg. in patients with glaucoma.  Salt tablets may help some patients, but low blood pressure is much more difficult to affect medically than high blood pressure.

P:  Have there been any studies done on hemachromatosis and glaucoma? 

Dr. Rick Wilson:  Not that I know of.

Moderator:  What effect would Imitrex injections for migraines have on tiny blood vessels in very small eyes?   

Dr. Rick Wilson:  Hopefully, Imitrex keeps them dilated and the blood free-flowing.  

P:  I have thyroid antibodies in my system.  Does that mean I have an autoimmune disease?

Dr. Rick Wilson:  Probably a kind of autoimmune disease. 

P:  Is the current thinking not to treat someone with intraocular pressures of 23 to 25 mm Hg., but no visual changes, if there is family member with glaucoma? 

Dr. Rick Wilson:  That varies according to all the risk factors the patient may have.  

P:  I have optic pits in both eyes, and normal-tension glaucoma.   I have no upper vision remaining in my left eye, and have lost 30% of the  upper vision in my right eye.  My IOPs are usually 12  to 14 mm Hg.  I am using Alphagan, Betoptic S, and Xalatan.  I have not had any surgery yet.  My doctor wants to do a trabeculectomy.   Will a trabeculectomy affect my optic pits?  

Dr. Rick Wilson:  Are your optic pits the result of glaucoma damage or were you born with them?

P:  I was born with optic pits, but they were not discovered until I was 30 years old.  I am 40 now.  

Dr. Rick Wilson:  Perhaps your doctors feel the pits predispose you to damage at a lower IOP than usual.

P:  Will optic pits make a macula detachment more likely if I have a trab?

Dr. Rick Wilson:  Yes.

P:  If systemic factors can contribute to or even cause glaucoma, why isn't it routine for glaucoma specialists to take take blood pressure, etc?  The doctors seem to concentrate on just the eye.  I have a great glaucoma specialist, but I have to push for answers about whether I have low blood pressure and should I get it checked out.  He was not too concerned.  

Dr. Rick Wilson:  Unless you have normal-tension glaucoma, low or high blood pressure is not as important.

P:  I do have NTG. 

P:  Is the benefit from glaucoma eyedrops derived from absorption through the cornea or does the surrounding tissue also absorb the drops and contribute to the effectiveness?  

Dr. Rick Wilson:  Absorption is through the cornea, except for beta blockers.  If  those drops are placed in only one eye, the IOP in the fellow eye will drop  approximately 2 mm Hg.  

P:  Will using Cosopt in one eye cause the hypotony in my other eye to become worse?  

Dr. Rick Wilson:  Yes, but the use of Cosopt in your case may be necessary.   

P:  Can a woman's menstrual cycle affect IOPs? 

Dr. Rick Wilson:  Yes.

P:  Can hormone replacement therapy (estrogen) affect IOP?

Dr. Rick Wilson:  According to what we know now, it should lower it.  

P:  The more fluid is retained, the higher the IOP?  

P:  You mean a woman's menstrual cycle can affect her IOP?  In what way?

Dr. Rick Wilson:  Yes.  Hormones may affect the amount of fluid the eye makes, and there may be fluid retention.  

End of highlights for August 1, 2001.

On August 8, Dr. Wilson discussed "What's New in Laser Surgery" in the Chat room. Click here for highlights of that meeting.

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