Chat Highlights
Glaucoma Suspect
November 1, 2000

Norma Devine, Editor

On Wednesday, November 1, 2000, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Glaucoma Suspect." 

Moderator:  The topic tonight is "Glaucoma Suspect."  

P:  Dr. Wilson, what categorizes someone as a suspect?

Dr. Wilson:  Either a borderline or high IOP, or a suspicious-looking optic nerve or visual field.

P:  What cup/disk ratio do you look for at that stage?  

Dr. Wilson:  More important than a specific cup to disk ratio is asymmetry (irregularity) of the two optic nerves, or changes in the substance of the nerve or changes in the shape of the cup that are suspicious for damage.

P:  Does a glaucoma suspect always progress to glaucoma?

Dr. Wilson:  No, a suspect does not always progress to glaucoma.

P:  Is it likely that IOP is not the cause of all glaucomas?

Dr. Wilson:   IOP is a risk factor in almost all glaucomas. Even patients with normal-tension glaucoma do much better when their IOP is lowered significantly.  However, more and more risk factors, like circulation and autoimmune disease, are being discovered.

P:  Typically, what percent of suspects progress to full-blown glaucoma?

Dr. Wilson:  That varies dramatically according to the expertise of who is labeling the suspects. 

P:  My IOPs are 20/21, my visual field is normal and so is my optic nerve.  First I was put on eye drops, then I was taken off eye drops.  Is that reasonable?

Dr. Wilson:  I don't know.  It depends upon how suspicious-looking your disc or fields were.

P:  Could elevated IOP be similar to fever with an infection?  That is, could IOP be a signal rather than a cause?

Dr. Wilson:  Probably not, but I cannot prove that thesis wrong.

P:  What is normal IOP?

Dr. Wilson:  "Normal" IOP is usually 12 to 22 mm Hg.  However, normal is normal for normal people.  People with glaucoma are no longer normal in the full sense of the word.  They may have risk factors we have not yet begun to suspect.

P:  If a suspect has normal fields and nerves, at what IOP would you put them on drops?

Dr. Wilson:  If the person were old , probably would not live more than four to five years, and the optic nerves appeared normal, the IOP would have to be over 30 before I would put that person on drops.  If the person were younger and would be subject to damaging IOP for years to come, the IOP at which I would treat might be 28 (without other risk factors), 23 or 24 with a family history of glaucoma, or a history of low blood pressure.

P:  Will you explain the purpose of reducing IOP in normal tension glaucoma?

Dr. Wilson:  The blood is pumped into the eye by the heart, against the pressure in the eye.  The higher the IOP, the harder it is for blood to get to the optic nerve.  Therefore, if circulation is a root cause of the glaucoma, lowering the IOP improves the blood flow and may counterbalance other causes for poor circulation.

P:  My maternal grandfather had glaucoma.  How much risk does that pose for me? 

Dr. Wilson:  That conveys risk, but not as high a risk as if the relative were your mother, father, brother, sister, son, or daughter.

P:  Can the cause of glaucoma be determined?

Dr. Wilson:  It can be in some cases.  

P:  In what cases and how? 

Dr. Wilson:  In pigmentary glaucoma the pigment granules on the back of the iris are knocked off and float in the aqueous until they are sieved out in the drain, thereafter blocking it.  The pigment is easy to see in the drain.  Pseudoexfoliative material acts the same way, although the source of the material is a mystery.

P:  Would you recommend checking IOP over a 24-hour period to confirm if "normal pressure" is normal over the entire day?

Dr. Wilson:  If you are a serious suspect, usually checking the IOP from 6:30 or 7:00 a.m. until 4:00 p.m. will catch most cases.

P:  Are a glaucoma patient's adult children and grandchildren at special risk?

Dr. Wilson:  Yes, their risk may be up to 15 times the normal risk.

P:  At the convention in Dallas, did you hear of any new anti-glaucoma medications?

Dr. Wilson:  An  improved Betoptic is in the wings.  It's supposed to have a better effect than the non-selective beta blockers, without nearly as many side effects.  Several more prostaglandins like Xalatan are coming out.  It remains to be seen whether they will be any better than Xalatan.

On November 8th, Dr. Rick Wilson discussed "Communicating with Your Ophthalmologist" in the Chat room. Click here for highlights of that meeting.

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