Pseudoexfoliative Glaucoma
Chat Highlights
March 29, 2006

On Wednesday, March 29, 2006, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Pseudoexfoliative Glaucoma."

Moderator:  Welcome back from China, Dr. Wilson.

Dr. Wilson:  Thank you. I'm still suffering from jet lag.

Moderator:   Tonight the topic is pseudoexfoliation (PSXF) glaucoma. How does PSXF differ from PSXF syndrome?

Dr. Wilson:   When PSXF is discovered in the eye, it is called PSXF syndrome; when it causes glaucoma, it is termed PSXF glaucoma.  PSXF syndrome occurs when a flaky, white, amyloid-like material peels off the outer layer of the lens within the eye.  The material is deposited on different parts of the eye and, indeed, throughout the body.

P:     What causes the material to peel off the lens?

Dr. Wilson:   The PSXF material deposited on the front surface of the lens in the eye is partially rubbed off by the movement of the pupil over the lens.  The material then floats in the aqueous fluid of the eye until it is sieved out by the trabecular meshwork.  The material gradually blocks the trabecular meshwork, causing glaucoma.

P:   Has anyone ever tried to remove this material from the eye by chemical or mechanical means before it can clog the trabecular meshwork?

Dr. Wilson:   The chemicals that could dissolve the amyloid-like material are usually toxic to the inside of the eye.

P:   Does that amyloid-like material cause problems in other parts of the body?

Dr. Wilson:   Not that we know of.  It is unusual in that it is a systemic condition in which the main side effects are in the eye. It seems to be genetic.  The amount of pseudoexfoliation increases with age, as does the chance of getting glaucoma.

P:   Does PSXF syndrome always lead to PSXF glaucoma?

Dr. Wilson:   No. Many people die before they have had PSXF long enough for it to cause glaucoma.

P:   In an earlier chat you said: ". . . the chances of developing PSXF increase rapidly with age and it is quite common in the over-75 age group."  Can you be more specific?

Dr. Wilson:   The incidence of PSXF increases markedly in the elderly: 0.67% in the 52 to 64-year age group; 2.6% in the 65 to 74-year age group; 5.0% in the 75 to 85-year age group.

P:   Once PSXF starts, does it ever go away?

Dr. Wilson:   No, it keeps coming.

Moderator:   Are the lenses abnormal?

Dr. Wilson:   The lenses are usually normal in shape and size.  It is the PSXF that makes them abnormal.

P:   PSXF was described to me as similar to "shedding" our skin, which happens all over our bodies.  Is that an accurate description?

Dr. Wilson:   Not exactly, because our skin is meant to chronically replenish itself from the inside out.  Pseudoexfoliation forms on the surface in question, and usually stays there unless it is rubbed off.

P:   What does "amyloid-like" mean? Isn't the stuff that causes Alzheimer's an amyloid?

Dr. Wilson:   There is, as I remember, amyloid deposition in Alzheimer's, but also pruning of the neuronal fibris and tangles, which form in the fibrils that communicate among the neurons.

P:   Why is it called "pseudo" exfoliative?  Is the material mimicking something?

Dr. Wilson:   It is called pseudo, because it was originally thought that the material was not derived from the basement membrane of the lens, and therefore was not really exfoliating.  Now we know it to be a basement membrane disorder, and therefore a real exfoliation.  However, we already have an exfoliation syndrome that is a splitting of the capsule of the lens in response to heat, irradiation, trauma, etc.  It is not associated with glaucoma. I have seen it in glass-blowers from New Jersey.

P:   What is a basement membrane?  Is there any way to control basement membrane disorders?

Dr. Wilson:   A basement membrane is a basal layer of tissue.  There is no way I know of to control basement membranes, especially in hard to access areas like the inside of the eye.

P:   When is ALT (argon laser trabeculoplasty) used to treat PSXF?

Dr. Wilson:   Treatment varies by physician.  Most doctors try eyedrops before trying ALT or SLT (selective laser trabeculoplasty).  Some now are offering SLT earlier in the course of the disease, since SLT is more benign than ALT and may be repeatable.

P:   I was diagnosed with PSXF in one eye only.  Before that, I had had several "attacks" with profound halos around lights.  ALT didn't help. SLT lowered my intraocular pressure from approximately 36 to 23 mm Hg.  How long will the SLT remain effective?

Dr. Wilson:   That is quite variable, it is impossible to predict.  Usually, the SLT remains effective for no more than a year or two.

P:   Can SLT be performed every year or so?

Dr. Wilson:   We don't know yet how often the SLT can be repeated.

P:   Is PSXF ever controlled long-term, whether by medications or surgery?

Dr. Wilson:   PSXF glaucoma is somewhat more difficult to control than primary open-angle glaucoma, but most people are controlled with drops, laser or both.

P:   Does PSXF syndrome eventually affect both eyes, or can it remain a monocular problem?

Dr. Wilson:   Since it is a systemic disease, it will affect both eyes if given enough time.

P:   Is PSXF so subtle that it can be overlooked in an eye exam?

Dr. Wilson:   In the early stages, yes. It should not be overlooked, especially if the doctor dilates the eye.

P:   What is a zonule, and can PSXF material damage it?

Dr. Wilson:   A zonule is a very thin ligament that holds the lens in place, centered behind the pupil. Pseudoexfoliation can form under its attachment to the ciliary body or the lens and loosen the support for the lens (the zonule).

P:   How does PSXF affect the cataract patient getting an implanted intraocular lens?

Dr. Wilson:   The cataract is not held in place nearly as securely in PSXF patients.  When the cataract is removed, the lens capsule and zonules are left; only the cloudy insides of the cataract are removed.  If the zonules are not strong enough due to PSXF, the intraocular lens cannot be put inside the capsule for support and either needs to be put in the front of the eye or sewn in.

P:   Is there anything, such as lifestyle changes, that help to reduce the risk of PSXF?

Dr. Wilson:   No, I don't think so.

P:   Are there any special symptoms of PSXF that the patient can sense?

Dr. Wilson:   Only if the IOP is so high it causes halos or discomfort, both of which are quite unusual.

Moderator:   Thank you, Dr. Wilson.  See you next week.

On April 5, Dr. Wilson discussed "Common Mistakes Using Eyedrops" in the Chat room. Click here for highlights of that meeting.

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