Chat Highlights
Laser Therapy for Glaucoma
February 9th, 2000

On Wednesday, February 9, 2000, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Laser Therapy for Glaucoma."

Rick Wilson: OK. Any questions about glaucoma and laser therapy?

P: How old before you can have laser?

Rick Wilson: If a patient has pigmentary glaucoma, then I treat them under age 50. If they have open-angle glaucoma or pseudoexfoliation glaucoma with good pigment to absorb the laser energy, then 50 years and up. The laser works best to lower IOP in patients over 60; the older the better.

P: Why is it better in older patients? I don't get it.

Rick Wilson: It's not that the younger heal too fast with a laser, but it seems that the mechanism that gives people glaucoma is different in the young than the old and not as responsive to argon laser trabeculoplasty (ALT).

P: Rick, why can you only have lasers twice?

Rick Wilson: A laser trabeculoplasty destroys tiny spots of the trabecular meshwork, after two treatments over the entire meshwork, enough of the trabecular meshwork has been lost to make further treatments hazardous.

P: Can laser be done after trabulectomy (cutting) has been done?

Rick Wilson: An ALT can be done after a trabeculectomy (cutting) in older patients with good pigment and the right diagnoses, but it will not be as successful as if the patient had not had filtering surgery first.

P: What about SLT instead of ALT?

Rick Wilson: An SLT is a kind of laser that just hits the pigmented cells in the trabecular meshwork (TM) so is less harmful to the TM but still effective. It may be able to be repeated more often than an ALT.

P: Rick what is it that the ALT is hitting compared to the SLT? I don't understand the difference.

Rick Wilson: An argon laser hits all the tissue, burning it superficially. The laser used in the SLT, a frequency doubled YAG, is absorbed only by pigmented cells, leaving the other tissue relatively uninjured.

P: What is a PI?

Dr. Wilson: During a PI (peripheral iridectomy), a hole is made in the iris to equalize the pressure behind and in front of the iris. Since the fluid in the eye is made behind the iris, the pressure is higher there, bowing the iris forward. If the iris is too close to the trabecular meshwork, it could get stuck in the drain. An iridectomy will usually allow it to fall back away from the trabecular meshwork.

P: Do these laser treatments hurt?

P: Mine did.

P: I felt a small pinching sensation for each pulse, but I can't say that it hurt.

P: They sting a little!

P: No.

P: They do not hurt too bad, just a little tap tap, but after having many I am a bit gun shy.

P: My eyes were very tired.

P: The argon was used on me to remove some sutures and it hurt real bad.

P: Dr. Wilson, if laser is not the best treatment for the young, what is?

Dr. Wilson: We push medication in this country. The British try a drop or two, then move right to surgery.

P: Who's right, the British or us?

Dr. Wilson: All the studies that have been done show that surgery first gives better results than laser and meds. This is because it causes a bigger, more effective drop in IOP to begin with than laser and meds do together.

P: Rick, is there a reason that the US does not do surgery sooner?

Dr. Wilson: The Brits can treat people with surgery first because under their health system they don't have to worry as much about cost (mainly accessibility). As a matter of fact, I was depressed on reading a study about eight years ago comparing surgery in Britain to meds. The surgery was done by glorified residents and their results were as good as my own. I then realized the reason for this was the changes that occur in the conjunctiva of patients taking long-term drop therapy. This causes a low-grade inflammation that reduces the success of trabeculectomy.

P: Doctor, what is the success rate of surgery? What is the decision point for surgery?

Dr. Wilson: The success rate for surgery varies with the type of glaucoma, the race of the patient and age, whether there is any inflammation, etc. You can download what I wrote on Trabeculectomy for the web site. In general terms, the success rate without any added medication is probably in the 70 plus percent range when done by a glaucoma specialist. With the addition of medication, the success rate is in the low 90 percent range.

P: Doc, then those who have been on strong glaucoma eye drops for many years are more likely to have complications from a trabeculectomy, or less success, or both?

Dr. Wilson: Less success, not more complications.

P: When you say success, do you mean lowering pressure or stopping damage?

Dr. Wilson: Stopping damage.

P: Dr., are you saying that if you had your druthers, and insurance and cost were not an issue, you would go for surgery before medical treatment?

Dr. Wilson: I would be more tempted to do that in white patients with bad disease. If the glaucoma was early, I would stick with drops.

P: Why white patients?

Dr. Wilson: Black patients may do better with laser and drops first before surgery, according to a recent study.

P: Rick, What are some of the bad things that can happen when having a laser PI done?

Dr. Wilson: The laser can nick the cornea or the lens. It's real unusual though.

P: Is there a way to tell whether eye pain is coming from a raise in pressure or swelling of the cornea?

P: Or is it the same?

Dr. Wilson: Swelling of the cornea also often has a feeling of something in the eye. Both may cause light sensitivity.

P: Does the cornea swell because of glaucoma?

Dr. Wilson: It can, if the pressure goes high enough.

P: One of my eyes appears to be smaller after surgery. Any comments...

Dr. Wilson: That is usually because the eyelid is lower on that side.

P: What's ptosis?

P: It's a fancy term for a droopy eyelid

P: What can be done?

P: Why does the eyelid droop?

Dr. Wilson: The eyelid droops often because the levator tendon has stretched. It can be shortened surgically in a small procedure, often done in a minor surgery setting.

P: Since my eye has already ruptured once when I was six years old, can the high pressure from glaucoma make it rupture again?

Dr. Wilson: Not unless there is a very weak spot in the eye wall.

P: Has anyone ever heard of Iridocorneal Endothelial Syndrome with a subset of Chandlers Syndrome and Secondary Glaucoma????

Dr. Wilson: I have.

P: You have heard of it Rick?

P: Can you tell me what to expect?

P: Does the eye always hurt? Just ache?

Dr. Wilson: There is a wide spectrum of severity with the ICE syndrome. Many women have multiple surgeries to keep the IOP controlled. Sometimes the cornea gives out and a graft is needed.

P: Rick, will I get the glaucoma in my good eye?

Dr. Wilson: No, ICE Syndromes are 99% in one eye only. An unsolved mystery.

End of highlights for February 9th chat.

Click here to read more about Laser Therapy for Glaucoma.

On February 16th, Dr. Wilson discussed Cutting Surgery for Glaucoma in the Chat room. Click here for highlights of that meeting.

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