Chat Highlights
Glaucoma Medications
September 20, 2000

Norma Devine, Editor

On Wednesday, September 20, 2000, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Glaucoma Medications." 

Moderator:  The topic tonight is "Glaucoma Medications."  I would like to start with the types of drops commonly used in glaucoma treatment.  Doctor, what is the difference between miotics and beta blockers?

Dr. Wilson:  Miotics make the pupil small, mechanically pulling open the drain (trabecular meshwork).  Beta blockers cut down on the amount of fluid the eye makes. 

P:   Dr. Wilson, can you recommend an eye drop/treatment for me?  I have NTG (Normal Tension Glaucoma) and an intraocular pressure up to 19.  Xalatan and Alphagan cause severe, blurred vision.  Ginkgo biloba oral pills, which I took while participating in a study, also caused severe, blurred vision.  

Dr. Wilson:   The other two types of  meds are beta blockers and topical carbonic anhydrase inhibitors. Beta blockers are stronger, so if you need a greater reduction of  IOP, I would try that first. If you have gray irises, 1/4% would be enough, maybe once a day.

Moderator:  Can you give us some examples of miotics and some possible side effects?  

Dr. Wilson:  Pilocarpine is the main miotic in use today. Because it makes the pupil smaller, it makes vision darker as well. There may also be an ache around the eye when you start, because the eye muscles are not used to working that hard  twenty-four hours a day, seven days a week, 365 days a year.  

P:  Why do so many people have bad reactions to the meds?  Is it the preservatives, or something else?

Dr. Wilson:  Most people have reactions to the medications themselves.  Some people are allergic to the preservative in the medication.

P:  Can I take beta blockers if my blood pressure is 90/60 or 110/70?

Dr. Wilson:  Betoptic S would not cause much problem with blood pressure.  (Be sure to read the disclaimer at the bottom of the first page of this web site.) 

P:  Are there any studies about the use of  anti-glaucoma medications on children?

Dr. Wilson:  There are few studies on kids.  There's not enough business to make it worth the costs of the studies for the companies.

P:  It sounds as if it's difficult to find preservative-free meds.  Do they have to be refrigerated?

Dr. Wilson:  No, many come in sealed containers, so they don't need preservatives. Alcon makes preservative-free Pilocarpine and Merck makes timolol.

P:  In the last five years the FDA has approved 20 meds for use in the human eye.  Only three are glaucoma meds, and of those, only one was approved last February.  Is there a reason progress is so slow? 

P:  I wonder if Dr. Wilson lost his connection.

Moderator:  Doctor, are you there?

Dr. Wilson:  It is incredibly expensive to look at literally thousands of compounds to find the best one, test it in animals, then in a pilot study in humans, then in a much larger study, then  take it to the FDA with  a moving van full of documentation. Only in America does the stock market send a company's stock soaring when the company fires 10% of its workforce.  Only in America, when a company brings out a new medicine does the company's stock value go down.  The market knows the chances of lawsuits are great.  Look at the silicone breast implant suits. Many studies have been done, and NONE showed a link to the implants causing autoimmune disease in women.  Yet, if I remember correctly, the company paid over a  billion dollars in lawsuits. 

Dr. Wilson:  Yes, I'm here on my soapbox. 

P:  Doctor, you look good up there.

Dr. Wilson:  Thanks.

P:  Is Cosopt a beta blocker?

Moderator:  Can you give  us examples of beta blockers and common side effects?

Dr. Wilson:  Cosopt contains the beta blocker, Timolol, and the carbonic anhydrase inhibitor, Trusopt.  The side effects of beta-blockers include exacerbating pulmonary disease, congestive heart failure and heart block, slowed heart rate, fainting , headache, loss of hair, etc.

P:  I hope I never need to move to a beta blocker. Side effects like those would scare me to death.

P:  Those are possible side effects.  I've used several beta blockers and never had any of those side effects.

Dr. Wilson:  My dad was on a beta blocker at age 94.  Side effects have to be unusual, rather than the rule, or the drug wouldn't make it to market.

P:  Your comment that side effects are unusual just made all the difference in the world to me! But I get so upset when I hear about people suffering so much with their medications.

P:  It seems that few drug companies make preservative-free meds. I guess because most people tolerate the meds with preservatives in them.

Moderator:  Even preservative-free, artificial tears bother me.

P:  Is Betoptic S a beta blocker that is okay to use if one has low blood pressure (90/60; 110/70)?

Dr. Wilson:  Yes.  

P:  During the last chat you mentioned a new drug that you said would beat all the others. It was just going to start on its FDA maze.  Can you elaborate at all?

Dr. Wilson:  No, sorry.  After the American Academy meeting in October, I may have more information.

P:  How about cannabis?  Does it work?  Does one have to take a whole lot and be doped up, or can small amounts do the trick?

Dr. Wilson:  Cannabis may work by relaxing the muscles around the eye.  Clearly, to get the necessary pressure-lowering effect, one may well be too relaxed to go to work.  The other worry is that it also lowers blood pressure, which is a problem if you have glaucoma.  

P:  By getting in better shape, losing weight, working out and walking, won't all that end up lowering  blood pressure?  If so, would that have an adverse effect on glaucoma?

Dr. Wilson:  No, because all those things, I believe, lower the eye pressure and improve circulation.

Moderator:  Can you tell us about oral medications used for glaucoma?  When would they be indicated?  Is there any risk from using oral meds long term? 

Dr. Wilson:  The only oral medications used in glaucoma are Diamox and Neptazane.  They cause lethargy, depression, upset stomach, gas, hives  (if allergic) and can cause severe anemia.  In other words, they are now medicines of last resort.

P:  Don't forget the kidneys.

Dr. Wilson:  Right .  There's an increased incidence of calcium kidney stones with CAI's (carbonic anhydrase inhibitors). 

Moderator:  What about intravenous meds?  Can you tell us what they are and why they would used?

Dr. Wilson:  The two oral medications I told you about above are also used IV in emergency situations. Mannitol is the usual medicine used IV.  It is osmotically dense and pulls fluid out of the eye into the blood stream, lowering IOP.

P:  It seems as if  the combination of Xalatan and Alphagan is extremely popular, at least judging from the people in this room.  Why is that?

Dr. Wilson:  They are two of our newest and most powerful medications.

P:  My doctor changed  my prescription from 2% Pilocarpine three times a day to 4% gel at bedtime.  I also use Timoptic 5% two times a day.  What will the gel do that the drops didn't?

Dr. Wilson:  The change will give you greater effect and may be easier than trying to remember all the drop doses. They work by different mechanisms, as well.  

P:  Would using glaucoma eye drops over the years cause too much iron in the blood?

Dr. Wilson:  Not that I know of.  

P:  Is gel easier on the eye?

Dr. Wilson:  No, it is not.

P:  Doesn't Xalatan have fewer potential side effect, also?

Dr. Wilson:  For the body, not for the eye.

Moderator:  I have a question from a patient in Canada who could not be here. "What percentage of patients respond just as well or better to .25% timolol (Timoptic in the U.S., I believe) than to .5%?"

Dr. Wilson:  If you have light irises, you will get the same effect from 1/4% twice a day as you will get from 1/2% twice a day.  After six weeks of use and all the beta receptors are blocked, you may well be able to get almost the same effect from once a day use.  Dark irises need at least 1/2% once a day.

P:  I get a dull ache on the side of my left eye about two or three  times a week.  Could the meds be putting a strain on the muscles surrounding the eye?

Dr. Wilson:  If you are on Pilocarpine, maybe.  It could just as easily be another reason. 

P:  Are Xalatan and Alphagan pharmaceutically very similar?

Dr. Wilson:  Very, very dissimilar.  Xalatan causes a very slight inflammation in the eye that encourages fluid to escape the eye between the muscle fibers in the wall of the eye. Alphagan cuts down on the amount of fluid the eye makes.

P:  Which would be better, Xalatan or Alphagan? 

Dr. Wilson:  That depends on several things, including the individual patient.  Alphagan usually causes more allergic reactions and more systemic side effects than Xalatan,  so it usually my second choice of those two.

P:  Can these medications make your eyesight sharper, better?  It seems that I can see in the distance now with my computer glasses as well as with my distance glasses.

Dr. Wilson:  Are you on Pilocarpine? It can easily do that by increasing your depth of field with the small pupil.

P:  No,  just Alphagan and Xalatan. 

Dr. Wilson:  I doubt that those two would make much difference in your vision. 

P:  I read that glaucoma specialists are shifting from maximum medical therapy (adding more drops) to minimum-required therapy. 

Dr. Wilson:  That's true.  

P:  I have two questions related to taking medication just prior to a trabeculectomy.  I'm going to be having a trab on my only good eye in six weeks.  You mentioned that Xalatan works by causing slight ocular inflammation. Because inflammation can sometimes reduce the chances of success in a trab, should Xalatan be stopped earlier than other meds? (I'll ask my doctor, of course, but two points of view can't hurt!)

Dr. Wilson:  I usually ask patients in whom a short pressure rise would not hurt to go off Xalatan for a week before surgery.  If they have to stay on it, then I don't have much choice.

P:  Second question.  I am currently taking Propine, which causes the eye to be red most of the time.  My doctor let me stay on it despite the redness, and another specialist didn't seem to think it was a problem.  Would there be a benefit to stopping that drug early?  Would it reduce the chance of complications?

Dr. Wilson:  The British did a study that showed (at that time) that adrenergic drugs like Propine are the greatest risk factor for failure of  trabeculectomy.  Therefore, I would try to have you off  Propine, as well, for a while, and maybe treat you with mild steroids for a week before the surgery. (That's my approach.  All glaucoma doctors are different.)

Moderator:  It seems to be common for doctors to start their patients on .5% timolol first, rather than trying the lower dosage. What percentage do you usually start out with or do you go right to the .5%, and why?

Dr. Wilson:  I use 1/4% in light colored irides to lessen systemic side effects and 1/2% in patients with brown irises.

P:  Why is there a difference in the action of  timolol, depending on the iris color?

Dr. Wilson:  The pigment granules absorb timolol,  leaving less in the eye to work.  The more pigment, the less timolol.

P:  Does Xalatan lose its punch as the years go on?  It works fine for me now.  Is it probable that it will continue to work for me as the years pass on?

Dr. Wilson:  From what we know now, it will remain useful. Your disease may get worse, however, so that you may need more medication in the future.

P:  I tolerated timolol for many years;  tolerated the bad effects unwittingly.  I've thought a lot about it.  I believe that after six months of using timolol, patients should be routinely taken off of it for two weeks or a month.  Only then can the effects show themselves.  What about that?

Dr. Wilson:  It would only take a week on average for the majority of the systemic effects to leave.  Not a bad idea.  

P:  I had some bad effects from Timoptic.  I think it would be a good idea to stop the drug for at least a week to see if the patient feels any better.

P:  Is there really a need to prescribe beta blockers these days?

Dr. Wilson:  Yes.  We have more experience with this medication than any others in common use now. It is still a good medicine and often one of the first I pick.

P:  Are NTG (Normal Tension Glaucoma) patients harder to treat?  Do they need more medications?

Dr. Wilson:  Yes, because the IOPs must be lower.

P:  Why don't most eye doctors care when we say our eyes with glaucoma hurt? Do they think it is our imagination? 

Dr. Wilson:  No.  It is likely that they can't do much about it and therefore don't acknowledge your complaints.

Dr. Wilson:  Good night.

Moderator:  Good night and thank you Dr. Wilson.

End of highlights for September 20th chat.

On September 27th, Dr. Rick Wilson discussed "Pediactric Glaucoma" in the Chat room. Click here for highlights of that meeting.

Click here for the most recent glaucoma chat highlights and links to the chat archives.

Click here for upcoming glaucoma chat events.