Pseudoexfolition Glaucoma
Chat Highlights
January 7, 2004

Norma Devine, Editor

On Wednesday, January 7, 2004, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Pseudoexfolition Glaucoma."

Moderator:  Dr. Rick, welcome back and happy new year.  Tonight we will discuss pseudoexfoliation (PSXF) glaucoma.  Will you explain what that is?

Dr. Rick Wilson:  Pseudoexfoliation is a material that is abnormally made on basement membranes throughout the body, but seems to cause trouble that we can see only in the eye.  It is most visible on the surface of the lens, but also is found on other parts of the eye.  The material flakes off the lens, floats in the fluid of the eye into the trabecular meshwork, blocking it and causing glaucoma.

P:  What causes the material to flake off?

Dr. Rick Wilson:  The rubbing of the iris over the surface of the lens.

Moderator:  If eye drops are unable to control intraocular pressure (IOP) in PSXF, what is the next treatment?  

Dr. Rick Wilson:  Laser trabeculoplasty.  Both argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT) work quite well. 

P:  Is there a preference?  

Dr. Rick Wilson:  Presently, we lean toward SLT, not because it is more effective, but because it seems to give a similar effect but is more benign to the eye.

P:  What type of medication would you use after laser surgery, once the pressure again rises to dangerous levels?   I understand the pressure often does rise, and rather quickly.

Dr. Rick Wilson:  Prostaglandins would be my first choice, followed by beta blockers, and then Azopt/Trusopt or Alphagan.

P:  Is PSXF treated the same as other types of glaucoma?

Dr. Rick Wilson:  Yes, except there is more concern with cataract extraction, since the flakes may undermine the ligaments holding the lens, both the natural and artificial lens, in place. 

P:  Is the intraocular pressure level in pseudoexfoliative glaucoma usually higher than it is in primary open-angle glaucoma, and more difficult to control?

Dr. Rick Wilson:  Yes, slightly, since it is really a secondary glaucoma.

P:  Might a general ophthalmologist miss seeing the symptoms of PSXF?

Dr. Rick Wilson:  There are no symptoms.  It is fairly easily seen in full-blown cases on the anterior surface of the lens.  Any asymmetric glaucoma is a tip-off to look for PSXF.  

P:  Can anything unblock the meshwork once it has been clogged?

Dr. Rick Wilson:  Yes, the Germans have used a specially designed needle to vacuum the flakes out of the trabecular meshwork at the time of cataract surgery.  It seems to work to some extent for up to a year after surgery.

P:  Is that needle used in the U.S. at all?  And would it also work for uveitic glaucoma?  

Dr. Rick Wilson:  I use it on PSXF glaucoma patients who are having cataract surgery, but don't need a trabeculectomy.  There are other reasons for the IOP rise in inflammatory glaucoma besides the white cells clogging up the trabecular meshwork, so it doesn't work as well.

P:  Why does the flaking occur in some people and not in others? 

Dr. Rick Wilson:  Superb question.  Nobody knows.  The prevalence increases with age, so it is quite common in older patients, especially in Scandinavians, Mongolians, and South African blacks.

P:  If patients with pseudoexfoliative glaucoma have wider fluctuations in pressure throughout the day than patients with POAG (primary open-angle glaucoma), wouldn't the highest IOPs in patients with pseudoexfoliative glaucoma occur outside of normal office hours?

Dr. Rick Wilson:  I've heard recently that in almost everyone the highest IOP occurs just before or right after awakening in the morning.  But the timing of the diurnal pressure swing has nothing to do with the pseudoexfoliation and everything to do with the hormonal influences that cause more aqueous production at some times of the day.

P:  I am using a Bausch & Lomb Proview tonometer to check my intraocular pressure at home.  I have measured the pressure with it day and night, early and late.  I do not find much fluctuation in my eye pressures, and I have exfoliation syndrome.  That has surprised me a lot.  I was first diagnosed in China and my diurnal pressure swings were measured by keeping me in the hospital for 48 hours.  They did swing from 18 to 30 mm Hg there.  Perhaps I am just not accurate enough to catch them?

Dr. Rick Wilson:  If you are on medications the medications limit the fluctuation quite a bit.  Lasers do better and surgery does the best.

Moderator:  Do you think people should monitor their own eye pressure on a regular basis?

Dr. Rick Wilson:  Unfortunately, most people are not real accurate with the Proview and presently there are no other machines to test the IOP with at home.  However, some are in the pipeline.

P:  I understand there are remissions of some sort with PSXF.  Can you explain that?  

Dr. Rick Wilson:  There can be a lessening of the glaucoma with pigmentary glaucoma (PG) if the cause of the pigment elaboration is stopped, but I don't know of remissions in PSXF glaucoma.

P:  Are patients with PSXF more likely to have a pressure rise when their pupils are dilated?  If so, why would that be?  

Dr. Rick Wilson:  Patients with PSXF glaucoma are slightly more likely to have a rise of IOP post dilation due to extra pigment that is rubbed off the back of the pupil and iris as it is dragged across the rough surface of the lens.  Some PSXF material may also be knocked off.

P:  Does the iris rubbing on the lens cause the material to flake off because of lack of space between the iris and lens?

Dr. Rick Wilson:  The back side of the pupil rests on the front of the lens and acts as a flutter valve for the fluid coming from the ciliary body, where it is made, through the pupil into the front of the eye.  The flutter valve causes higher pressure in the posterior chamber, compared to in front of the iris.  The mid-part of the iris is bowed forward toward the trabecular meshwork.  A peripheral iridectomy for narrow angles equalizes the pressure in the back of the iris and the front of the iris, allowing the iris to fall back away from the trabecular meshwork.

P:  How successfully can vision be maintained with PSXF?  Is it harder to keep pressures low than in other types of glaucoma?  

Dr. Rick Wilson:  It is more difficult with medications, but laser trabeculoplasty works better in PSXF glaucoma. 

P:  I have read that pseudoexfoliation syndrome and glaucoma tend to occur in individuals around 60 years of age and older.  Is this true, and is there some later-life change in the size or shape of the lens that causes this condition?  

Dr. Rick Wilson:  As I mentioned above, the chances of developing PSXF increase rapidly with age and it is quite common in the over-75 age group.  I don't think it is age related, but I don't think the shape of the lens has anything to do with it. 

P:  Are there any other measures that can be taken when pressure rises, if it does, after surgery?

Dr. Rick Wilson:  Just back to medicines, a needling of the bleb, or repeat surgery.

P:  I understand there are fairly recent studies that show an association between high blood levels of homocysteine and exfoliation syndrome and, to a lesser extent, with normal-tension glaucoma.  Does that look like a promising line of investigation to you?

Dr. Rick Wilson:  I think so.  There are so many things we don't understand about how damage happens and how best to inhibit it and make the nerve more resistant to noxious influences.

P:  If you have already used prostaglandins, beta blockers and Alphagan, is there some chance they would again be effective if they had begun to lose effectiveness before laser surgery?

Dr. Rick Wilson:  The question is, did the medicines lose their effectiveness or were they working but inadequate to control your IOP?  If the latter, they can easily be tried again.

P:  When meds no longer worked for my angle closure (iridio-corneal syndrome), I had a trab (trabeculectomy). Would pseudoexfoliative glaucoma patients also be candidates for a trab?

Dr. Rick Wilson:  Yes, the usual course is meds, laser, trab.

P:  Could pseudoexfoliation be mistaken by an ophthalmologist for pigmentary glaucoma?

Dr. Rick Wilson:  It should not be, but on gonioscopy (looking at the angle), it might be possible to do that. 

P:  Does it make a difference in treatment?

Dr. Rick Wilson:  Stopping the pigment dispersion medically or with laser treatment seems to help those with pigmentary glaucoma but not PSXF.

P:  Is it frequently hard to keep pressures in the teens?  Would you feel comfortable with pressures in the low 20's, since there seems to be no change in the nerve and visual fields?

Dr. Rick Wilson:  If you have had your corneas checked and their thickness is normal so we can count on your IOP readings truly reflecting the IOP in your eye, then I would be uncomfortable with IOPs in the low 20's if you have any sign of damage at all.

P:  Can pseudoexfoliative glaucoma be controlled without vision loss for an extended period of time?

Dr. Rick Wilson:  Yes.

P:  Wouldn't early lens replacement, before ligaments holding the natural lens in place were greatly weakened, be a preventive measure in PSXF?

Dr. Rick Wilson:  Not really, because PSXF material is forming all over the ciliary body and is a large source of material blocking the trabecular meshwork.

P:  Thanks so much for a fantastic chat, Dr. Wilson.  I asked for this topic, and I am pleased to have learned a lot tonight.

End of highlights for January 7, 2004.

On January 14, Dr. Wilson discussed "The Use of Anesthetics in Glaucoma Care" in the Chat room. Click here for highlights of that meeting.

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