Chat Highlights
What's New in Laser Surgery
August 8, 2001

Norma Devine, Editor

On Wednesday, August 8, 2001, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "What's New in Laser Surgery." 

Dr. Rick Wilson:  Hello, everyone.  

Moderator:  Hello, Dr. Wilson.  Our topic tonight is "What's New in Laser Surgery?"  What kind of new lasers are there? 

Dr. Rick Wilson:  The main new one for glaucoma is the selective laser.  It has a wavelength that targets just the pigment in the trabecular meshwork.  It provides the effect of the argon laser with less injury to the inside of the eye.

P:  I've read a little about the selective laser, but there are only a few here in the states.  Have you used one? 

Dr. Rick Wilson:  Yes, we have one at Wills, and it seems to work as advertised over the short term.

P:  Under what patient conditions do you recommend laser treatment?

Dr. Rick Wilson:  The three main determinants of who will do well are (1) patients with significant pigment in their trabecular meshwork (the drain of the eye); (2) the older, the better (I rarely use the laser on those under 60 unless they have a lot of pigment); (3) the right diagnosis: primary open-angle glaucoma, pseudoexfoliative, or pigmentary glaucoma.  The angle cannot be narrow or there will not be enough room to get the laser into the angle.

P:  Is there a limit to the number of times you can use the selective laser? 

Dr. Rick Wilson:  We don't know yet, since it hasn't been around that long.

Moderator:  How long has it been around?

Dr. Rick Wilson:  Mark Latina has been experimenting with it for a number of years.  I would guess it's been around five to seven years. 

Moderator:  How long has Wills had the selective laser?  

Dr. Rick Wilson:  We've only had it for several months.  

P:  Do you think the selective laser will become popular enough to get to the west coast?  There aren't any around here.

Dr. Rick Wilson:  Yes, I do.

P:  Other than targeting pigment, what's the exact mechanism of action of laser trabeculoplasty?

Dr. Rick Wilson:  We don't know for sure.  But the laser seems to stimulate the cells in the trabecular meshwork that have not been cleaning out the debris and dividing into new cells.  New cells are much more vigorous about cleaning out the drain.

P:  How effective is laser treatment in open-angle glaucoma in patients over 60 years of age?

Dr. Rick Wilson:  In patients with the characteristics I mentioned above, the laser routinely lowers IOP about 30 to 35% and keeps it down for several years.  Fifty percent or so of patients will still have a laser effect five years later.

P:  Why have laser treatments I've had in the past only lasted about a year?

Dr. Rick Wilson:  You might have not satisfied one of the criteria above, such as not enough pigment in the trabecular meshwork.  

P:  Can you briefly describe each type of laser surgery?  Are there just two types or are there more?  

Dr. Rick Wilson:  The argon laser, blue, blue-green and green are used for laser trabeculoplasty and to pull the iris away from the trabecular meshwork.  That's called a gonioplasty.  The Nd:YAG laser is used to make a hole in the iris in narrow-angle patients.  It's also used to cut the capsule behind the intraocular lens in those who have had a cataract extraction and the capsule has become cloudy with time.

P:  I've read that laser surgery is useful in older people and I've also read the opposite.  Which do you think is right, and what age do you consider old?

Dr. Rick Wilson:  The older the better.  Bring on those 90+ year-olds.  They get a terrific response from the laser if they have decent pigment in the trabecular meshwork.  

P:  What happens with young patients that have pigment?

Dr. Rick Wilson:  Young ones that have pigment may get a decent response, but it tends to last for a shorter period than in older folks.

P:  How would I know if I have pigment?

Dr. Rick Wilson:  Your doctor would have to look with a gonioscope, and then tell you.

P:  Do patients with lighter irises have less pigment?  Are those of us with blue-green-hazel eyes poorer candidates for laser treatment, other things being equal?

Dr. Rick Wilson:  No.  There is some tendency for eyes with darker irises to have more pigment, but not that much.  Lighter- colored irises are much better if you want to do a peripheral iridectomy with the laser.

P:  What causes spikes in intraocular pressure after ALT (argon laser trabeculoplasty)? And how long do they last?

Dr. Rick Wilson:  Inflammation from the laser burns causes a thicker fluid in the eye, and swelling in the burned tissue of the drain closes down some of the trabecular meshwork, resulting in an IOP spike until those effects wane.  The spikes are usually short-lived, i.e., less than 24 hours when treated with steroids and glaucoma medications.  We use Iopidine to cut down on the pressure spikes, and steroids for about five days to limit inflammation. 

P:  How long does it take for the eye to return to normal after laser surgery?

Dr. Rick Wilson:  Several days if there's inflammation, though with a laser trabeculoplasty the final effect is not seen for 6 weeks. 

P:  Is the Holmium laser still used?

Dr. Rick Wilson:  We don't use it. 

P:  I am 41.  On a glaucoma scale of one to four -- four being most advanced -- my left eye is a four.  My right eye is two to three.  My intraocular pressures are 10 and 9 mm Hg.  I have been using Xalatan, Betoptic-S and Alphagan for a year.  One doctor thinks I should have laser surgery (trabeculoplasty) and the other thinks I should have a trabeculectomy.  I also have optic pits.  How should a person choose a treatment when the doctors don't agree?  Is there any hope for me?  

Dr. Rick Wilson:  Certainly there's hope for you.  Are you getting worse at pressures of 10 and 9 mm Hg.?  Have they checked your pressures throughout the day?  Unless you have pigmentary glaucoma, I would not have a laser if I were I in your shoes.

P:  A patient here has the impression that you think laser surgery should only be used for pigmentary glaucoma.

Dr. Rick Wilson:  What I meant was I mainly use the laser trabeculoplasty for pigmentary glaucoma in those under 50 years of age. 

P:  And when do you use a trabeculoplasty to lower IOP in primary open-angle glaucoma? 

Dr. Rick Wilson:  Only in older patients with moderate or more pigment in the trabecular meshwork.

P:  How many laser surgeries can an eye tolerate in a lifetime?

Dr. Rick Wilson:  Two laser trabeculoplasties.  That is why the selective laser is seductive.

P:  Seductive?

Dr. Rick Wilson:  Seductive to us glaucoma specialists.  The idea of being able to repeat a laser whenever the effect is lost is appealing to us. 

P:  My doctor wants to do the 180-degree laser.  Could he do that four times on my eye?

Dr. Rick Wilson:  No.  Most of the effect is from the first 180 degrees.  I doubt if it would help much doing the second half anytime soon after the first.  

Dr. Rick Wilson:  Have a good week all.  To heap insult on injury, I have to have a hernia repair next Wednesday, so Jon Meyers promises on a stack of old testaments he will be here to cover for me.  My luck will change soon.

End of highlights for August 8, 2001.

On August 15, Dr. Wilson discussed "Understanding Glaucoma Medications" in the Chat room. Click here for highlights of that meeting.

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