Chat Highlights
Open Angle Glaucoma
March 8, 2000

Norma Devine, Editor

On Wednesday, March 8, 2000, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Open Angle Glaucoma." Dr. Wilson also discussed the American Glaucoma Society Meeting he recently attended.

P: Doctor, can you tell us anything about the convention?

Dr. Wilson: Busy. I gave talks to the American Glaucoma Society Friday and Saturday and a four-hour lecture yesterday.

P: Any news?

Dr. Wilson: Many of you may have heard of viscocanalostomy for glaucoma. I was speaking on the panel with Dr. Stegman from South Africa. He says that his average preoperative IOP is 49.9 mm Hg. Now that's glaucoma!

P: That sure is.

Dr. Wilson: That also explains why viscocanalostomy works for him, but is rarely applicable for me. My average goal IOP after surgery is 12.03 mmHg.

P: What's his success rate?

Dr. Wilson: He says his success rate is high, but there are no visual fields to follow his patients with. Lowering IOP from 50 to 20 may be fine for him, but 20 would not work for the vast majority of my patients.

P: His patients are all referrals?

Dr. Wilson: Yes.

Dr. Wilson: Most of those (optic) nerves are shot. In Nigeria, 10% of the population has glaucoma. Of those, 34% are blind in both eyes, and 90% are blind in one eye.

P: And is that rate in Nigeria higher than for African-Americans?

Dr. Wilson: Yes, but African-Americans have four times the risk of glaucoma of whites, six times the risk of blindness, but only half the chance of being treated.

P: Doesn't IOP change throughout the day?

Dr. Wilson: Yes. The average swing for IOP in normals is about 4 mm. In those with glaucoma without medical treatment, the average swing is 11 mm. Some folks can have their IOP drop 18 mm during the first half-hour they are up in the morning.

P: Why does IOP go up during sleep?

Dr. Wilson: Aqueous production goes down 45% during sleep, and IOP is lowest from 2 to 4 A.M. in those on a normal schedule. However, some patients have a hormonal surge in the early A.M. that gets their aqueous production up and they may have their highest IOP at the time of awakening.

P: So is it good to take naps?

Dr. Wilson: Napping may lower IOP.

P: If it does lower the pressure, then why is pressure supposed to be at its highest in the morning?

Dr. Wilson: In the morning hours, not particularly on awakening.

P: Is that the case in males only?

Dr. Wilson: Is what the case in males?

P: The hormone rise, etc.

Dr. Wilson: I was thinking of the hormone serum cortisol, not sex hormones.

P: Is open angle the least serious of all glaucomas as far as causing blindness?

Dr. Wilson: More people go blind from open angle than any other kind because it has no symptoms and there are many more of this variety than any other. Still, I would rather have a steroid responsive glaucoma, traumatic glaucoma or a kind that could be cured if I had to have one kind.

P: Would you name some other types of glaucoma that can be cured?

P: So there some forms of glaucoma that can be cured?

Dr. Wilson: Angle Closure glaucoma if caught early. Inflammatory glaucoma sometimes.

P: Angle closure can be cured?

Dr. Wilson: If caught early before much damage to the drain is done.

P: I haven't been on drops for a long time. Are there any new ones?

Dr. Wilson: Not yet. Rescula, which is Xalatan lite, is about to be released. It has fewer side effects than Xalatan, but is less effective.

P: I don't think I had any side effects from Xalatan. But some (iris) color change, blue gray.

P: I had joint pain. But it (Xalatan) didn't lower the pressure anyway.

P: Is there a beta blocker for open angle that is a lite form of Ocupress?

Dr. Wilson: Betoptic S is the beta-blocker lite.

P: I have open angle. When should I have my children, six and eight years old, checked

Dr. Wilson: Before school age, and then every 3 years until about age 18, then every other year till age 28 to 30, then yearly.

P: Why do drops come in tiny little bottles, shrink wrapped?

Dr. Wilson: Probably to prevent tampering in this crazy world--product of Tylenol scare.

P: But I cannot see the tab.

Dr. Wilson: I agree. The bottles are often adult-proof.

P: I seem to be having increased sensitivity to daylight in my right eye with the Timolol. Is this a usual side effect and should I mention it to my doc?

Dr. Wilson: You should mention it to your doctor. In a few patients, Timolol can have an effect on the cornea that makes the patient light-sensitive.

P: Can open angle become closed angle?

Dr. Wilson: Yes, someone with open-angle glaucoma can get angle closure on top of the first kind.

P: A double sentence: open and closed glaucoma.

P: Can high tension glaucoma become normal tension, and when would this happen?

Dr. Wilson: As the optic nerve gets progressively damaged, it can tolerate less and less pressure. Therefore, advanced damage sustained at an abnormally high IOP can result in a patient who can get worse at IOPs of 12 to 16.

P: Can sensitivity to light cause pain? I say it does.

Dr. Wilson: Yes, definitely.

P: I get an ache if I watch TV, even for short periods, but I do work with computers all day long. Is this possible?

Dr. Wilson: Possible, but I am not sure of the reason.

P: If the eye is small, is it hard to evaluate the optic nerve?

Dr. Wilson: Yes, because the same 800,000 to 1,200,000 nerve fibers are bunched into a small canal, making recognizing early damage very difficult.

P: So how is a small eye evaluated?

Dr. Wilson: Just look carefully, with plenty of experience.

P: My IOP is at the 19-20 level, with Ocupress td. Is it advisable that it should be even lower?

Dr. Wilson: It depends upon the extent of your optic nerve damage. Did you say you were on Ocupress 3 x day?

P: No, twice daily. C/D ratio between 0.3 and 0.4, both eyes. Is that considered extensive damage?

Dr. Wilson: No.

P: Are there stages of open angle?

Dr. Wilson: The five stages are suspect, early, moderate, advanced, absolute.

P: Is absolute blind?

Dr. Wilson: Yes.

P: Will the changes in IOP throughout the day differ with Open Angle Glaucoma and other types?

Dr. Wilson: Yes. It's complicated, but some kinds, like pigmentary glaucoma, may vary quite a bit more than others.

P: How can open-angle glaucoma become closed angle?

Dr. Wilson: With age, the angle narrows and may close, especially if the patient is put on Pilocarpine chronically.

P: I assumed Pilo was the oldest and safest to use.

Dr. Wilson: Systemically that's true. Only people with narrow angles are worrisome.

P: What is pilocarpine?

Dr. Wilson: A medicine that makes your pupil small and pulls open the drain in the eye mechanically.

P: How does Pilocarpine cause open-angle glaucoma to become closed angle?

Dr. Wilson: Pilocarpine shallows the front of the eye, pulling the iris closer to the drain.

P: So Pilocarpine affects the cornea?

Dr. Wilson: No, the iris is pulled closer to the cornea.

Dr. Wilson: The lens becomes more round on Pilocarpine, and is therefore thicker.

P: So Pilocarpine affects the lens, too, besides the iris?  Interesting.

Dr. Wilson: Yes, mostly the shape of the lens, while you are on Pilocarpine.  It reverses off pilo.  The changes are only there when on the Pilocarpine.

End of highlights for March 8th chat.

On March 15th, Dr. Wilson discussed Congenital Glaucoma in the Chat room. Click here for highlights of that meeting.

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