Childhood Glaucoma
Chat Highlights
May 29, 2002

Norma Devine, Editor

On Wednesday, May 29, 2002, Dr. Elliot Werner, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Childhood Glaucoma."

Dr. Elliot Werner:  Hello, everybody.

Moderator:  Welcome back, Dr. Werner.  Our topic tonight is "Childhood Glaucoma."  We'll discuss the topic until about 9:00 p.m., EDT, and then patients may ask general questions related to glaucoma.  

P:  What type of doctor usually treats a child with glaucoma?

Dr. Elliot Werner:  An ophthalmologist with training and experience in treating childhood glaucomas.  Depending on the training and interests of the doctor, that may be either a glaucoma specialist or a pediatric ophthalmologist.  Does anybody here have a childhood glaucoma?

P:  I have a seven-month-old child who was just diagnosed with glaucoma.

Dr. Elliot Werner:  I don't remember seeing you here before.  How did you learn about this chat? 

P:  I saw it on the parent support group for childhood glaucoma.

P:  I'm also a parent of a child with glaucoma.

P:  My two-year-old son has congenital glaucoma.

Moderator:  How is childhood glaucoma usually detected?  

Dr. Elliot Werner:  That depends on the child's age.  In infants it is usually discovered by the parents or pediatrician, who notice something abnormal about the eyes.  In older children, glaucoma is usually detected during a routine eye exam.

P:  Do children with glaucoma usually have a parent with glaucoma?  

Dr. Elliot Werner:  That varies.  A family history is often found, but many cases are spontaneous.  Many cases also are due to some other eye disease, such as injuries or uveitis.

P:  How is congenital glaucoma different from other forms, such as open- or closed-angle glaucoma?  

Dr. Elliot Werner:  Congenital or infantile glaucoma is an open-angle glaucoma, but results from a fairly well-defined developmental abnormality in the structures of the eye.  These abnormalities can be seen clinically and during a pathological examination.  Adult forms of open-angle glaucoma usually have normal appearing structures in the front of the eye until late in the course of the disease.

P:  What does 70% cupping signify?

Dr. Elliot Werner:  Seventy percent cupping means that the diameter of the cup is 7/10 of the diameter of the entire optic disc.  In general, the larger the cup, the more damage. 

P:  Is cupping of .8 the same thing as 80%? 

Dr. Elliot Werner:  Yes. 

P:  Does the cupping have to stay above a certain level to cause vision damage or is any vision loss not known until later, when the child is able to tell you? 

Dr. Elliot Werner:  Cupping in children is different than in adults and is often reversible.  There are some ways to evaluate vision in young children, but very fine and sophisticated testing requires some level of cooperation. 

P:  What does a doctor mean when he says "rim?"

Dr. Elliot Werner:  "Rim" refers to the remaining viable nerve tissue in the optic nerve.  Think of the optic disc (or nerve) as a donut.  The cup is the hole and the rim is the edible part.  As glaucoma progresses, the cup (the hole of the donut) gets bigger and the rim (the edible part) gets smaller.

P:  Does the depth of the cup have as much significance as the diameter?

Dr. Elliot Werner:  Probably not, although when deepening of the cup occurs in glaucoma, it is not as indicative of damage as increasing diameter.

P:  At what age does the eye stop growing? My son has really large eyes and I wonder about that.  

Dr. Elliot Werner:  The eye usually reaches adult size about age two,  unless the child has progressive myopia,in which case growth  may continue in teenage years.  Glaucoma in children causes a progressive and abnormal enlargement of the eye.  

P:  What does "progressive myopia" mean?  

Dr. Elliot Werner:  Progressive myopia is continuing, increasing nearsightedness throughout childhood. 

P:  About what percentage of congenital cataracts patients eventually get glaucoma?

Dr. Elliot Werner:  About 25 to 50% of patients who have congenital cataract surgery develop glaucoma later in life. 

P:  Why do 50% of children born with congenital cataracts get glaucoma?

Dr. Elliot Werner:  I don't know.  It probably has to do with a general abnormality of the embryologic development of the eye that results in both the cataract and the glaucoma.

P:  Do repeated surgeries on an eye with glaucoma lead to the development of cataracts?

Dr. Elliot Werner:  Yes, there is a significant rate of cataract formation in patients who have had glaucoma surgery.

P:  Are children with glaucoma more likely to have offspring with glaucoma?  

Dr. Elliot Werner:  Yes, because most childhood glaucomas are genetic, unless it is a secondary glaucoma from some other condition.

P:  My child is the only person in our entire family to have glaucoma.  Does that mean he is likely to pass it on to his children?

Dr. Elliot Werner:  That's difficult to say.  It may be a spontaneous mutation or a recessive gene. In that case, there is a greater likelihood of passing it on.  If it is not genetic, but due to some acquired condition, there may be no increased risk.  It's best to see a medical geneticist and get genetic counseling.

P:  What causes a child to be born with glaucoma?  Is it something the mother did or did not do, eat or not eat, etc?

Dr. Elliot Werner:  Most cases are probably genetic.  Occasionally, it can result from an intra-uterine infection, such as German measles or herpes.  Generally, there is not any contributory factor by the mother.  

P:  How common is childhood glaucoma?

Dr. Elliot Werner:  It's fairly rare.  I don't know the exact numbers, but the average ophthalmologist doesn't see it very often.  Even glaucoma specialists, unless they have a heavy pediatric practice, don't encounter it all that often. 

P:  I have aniridia and have bad optic nerve damage from glaucoma.  What are the chances that my 16-year-old son will have this?  

Dr. Elliot Werner:  Does he also have aniridia?

P:  Yes.  

Dr. Elliot Werner:  Your case is probable;  therefore, a dominant gene.  Most affected family members tend to behave similarly.

P:  My son has his eye pressure checked only once a year.  Is that often enough for him, since I have aniridia and severe glaucoma?  

Dr. Elliot Werner:  That depends on his clinical situation.  But if your glaucoma problems developed early in life, I, personally, might be inclined to check him more often.  But if he is basically okay and not showing any problem, once a year might be adequate.  I really would need to know more about your clinical situation and family history to answer your question.

P:  Would a geneticist be able to know where to look for the glaucoma genes?

Dr. Elliot Werner:  I am not a geneticist, but well-trained medical geneticists know their stuff and can usually figure these things out.

P:  One form of juvenile glaucoma is reported to have been traced to a couple that lived in the French village of Wierr-Effroy, near Calais, in the 15th century.  Purportedly, thirty thousand descendants have been traced and the diagnosis of the disease was a clue to where their ancestors originated.  Was this primary open-angle glaucoma?  It doesn't seem very likely that accurate medical records existed dating back that far.  Isn't there a likelihood that other forms of eye disease and trauma were mixed in the population statistic?

Dr. Elliot Werner:  I am not intimately familiar with that case, but if a gene has been identified and DNA analysis has been done, you can trace the path of the gene in the population without medical records.

P:  How long do trabeculectomies last in young children?  

Dr. Elliot Werner:  Trabs have a very low success rate in young children, and a high risk of complications.  Most glaucoma surgeons avoid them in very young children.

P:  It seems that the first two years after my daughter was diagnosed were extremely difficult, but once her pressures were controlled through surgeries and drops, she's been stable for some time.  Is that common?

Dr. Elliot Werner:  Yes.  It is a difficult condition to get under control, but treatment is usually successful, although several procedures may be needed.

P:  What is meant by "trabs?"  I read that a goniotomy is an inside "trab" or something.  

Dr. Elliot Werner:  "Trab" usually refers to a trabeculectomy.  There is another operation called a trabeculotomy, which is similar to a goniotomy and is often used in congenital glaucoma.

P:  What is the best we can hope for someone so young with this disease?  Is it possible to hold off the progression long enough for them to live an entire life with vision?

Dr. Elliot Werner:  Yes.  Modern treatments for childhood glaucomas have a fairly high success rate, but they are difficult and nothing is 100%.

P:  Should a trabeculotomy (not a "trab") always be considered as a first surgery in very young children with open-angle glaucoma?  Are there many surgeons that do them or are they few and far between?

Dr. Elliot Werner:  That depends on the training and comfort level of the surgeon.  Studies have shown that goniotomy and trabeculotomy have the same results in infantile glaucoma.

P:  How many trabeculectomies can be performed on a child's eye?  

Dr. Elliot Werner:  Most most people would limit it to two.  My personal preference is to do a shunt if the first trabeculectomy fails.

P:  After a trabeculotomy, what's left of that section of the (trabecular) meshwork?  If it's gone, does it grow back?

Dr. Elliot Werner:  What's left is a hole in the wall of the eye.  Trabecular meshwork does not regenerate or grow back.  

P:  My son had his first goniotomy on Monday.  His pressures were back up by Friday.  Is that normally the case?

Dr. Elliot Werner:  That's hard to say.  It's not unusual for infants to require more than one procedure to get the IOP (intraocular pressure) under control, but often one procedure is enough.

P:  How long is a mitomycin-C trabeculectomy supposed to last?  

Dr. Elliot Werner:  There is no such thing as "supposed to" in glaucoma treatment.   What there is, is success rates.  Mitomycin trabeculectomies have a success rate of between 50 and 80% in children and a significant complication risk.

P:  My son's pediatric ophthalmologist said the effect of the mitomycin-C should last a lifetime.  My son's intraocular pressures of 8 and 11 mm Hg have been stable almost two years.  He requires no drops.  Can I anticipate this to remain the same, or with the infantile glaucoma, should I not expect things to stay as stable as they have been?  I know there are no guarantees, but I would appreciate your opinion.

Dr. Elliot Werner:  Every treatment SHOULD last a lifetime, but in glaucoma they often don't.  The longer an operation lasts, the more likely it will last in the future, but mitomycin trabeculectomies have a cumulative failure rate over the years.  In adults, about 60% of initially successful operations are still successful after 10 years.

P:  This is a very broad question. Our son has suffered a very traumatic time with all the exams and operations.  He is involved with early intervention to help with developmental delays. All have improved, except speech and eating.  Do you have any suggestions on how to deal with these problems or how to lessen the effects of the examinations?  

Dr. Elliot Werner:  I really feel for you.  I have three children myself, and I am fortunate that none has had any serious health problems.  I suggest that you talk to your pediatrician and possibly ask about a referral to a good child psychologist or therapist to help deal with the very real and profound and inevitable difficulties a child faces in coping with a physical illness.

P:  Here's the home page of the American Association for Pediatric Ophthalmology and Strabismus: http://med-aapos.bu.edu/  It has some good pediatric ophthalmology support and information.  

Dr. Elliot Werner:  Thanks for your help.

P:  Since instilling eye drops in very small children is difficult, would you suggest using two drops instead of one to make up for the drops that spill out? 

Dr. Elliot Werner:  No, because over-dosage and side effects may occur.  Generally, if any of the drop hits the eye, it will work -- even if it looks like most leaks out.

P:  Is it also dangerous for the eye to have too low a pressure?

Dr. Elliot Werner:  Yes.  Too low an IOP can cause permanent damage and is much harder to fix than high IOP.

P:  Do shunts have to be replaced at some point or are they good forever?

Dr. Elliot Werner:  Glaucoma is a very unpredictable disease.  Shunts have a certain success rate, like all other glaucoma treatments.  Sometimes they last and are effective for many, many years.  Sometimes other patients do not get good results.  It is very difficult to predict in any individual case.

P:  My son's doctor said my son may have some decreased appetite as a result of the oral medication (acetazolamide).  He only weighs 17 pounds, and has lost over a pound a week.  That's a lot for his small body.  What are the alternatives?  He is also on Timolol eye drops, three times a day, plus steroids and antibiotics, and one other after the surgery.  

Dr. Elliot Werner:  Oral medications are tough on children.  If he is losing weight that rapidly, it might be a good idea to try a different medication or a lower dose.  It is tough sometimes to get things under control.  He might need more surgery. 

P:  As a last resort, my son tried 2% pilocarpine before his second trabeculotomy.  I saw his pupil get smaller, so I know there was at least some effect from the medication.  Is it possible for a miotic to make the pupil so small that the IOP could rise, due to the fluid not being able to enter the anterior chamber?  I should say that my son is aphakic and his angles are wide open, but his IOP may have increased on pilocarpine, which is unusual for aphakes.

Dr. Elliot Werner:  Only in patients with very narrow angles .  Did your son's IOP, in fact, increase on pilocarpine?  

P:  I can't be sure about the effect of pilocarpine, because the exam was one month after my son started on pilocarpine, and there were other medications before that, so we didn't have a recent baseline IOP.  Thanks, though!

P:  Our little boy is almost three-years old.  What is the average success rate with the use of mitomycin?

Dr. Elliot Werner:  That's hard to say, because there aren't enough young children who have had "mito" filters to get a good number.  It's probably better than 50%, and may be as high as 80%.  

P:  Do shunts have to be replaced at some time, or do they last a lifetime?  

Dr. Elliot Werner:  Glaucoma is a very unpredictable disease.  Shunts have a certain success rate, like all other glaucoma treatments.  Sometimes shunts last and are effective for many, many years.  Other patients do not get good results.  It is very difficult to predict in any individual case.

P:  I've heard of several different types of valves.  Are there any big differences between them?  My daughter has a Baerveldt.  Why do some doctors prefer one rather than another? 

Dr. Elliot Werner:  A lot depends on personal experience.  My preference is the Baerveldt, because I have had uniformly the best results with this device compared to the others.

P:  Is it unrealistic to hope that an implant (like our Baerveldt) would last 10 years?  After four years -- so far, so good.  

Dr. Elliot Werner:  No, it is not unrealistic.  Many shunts last a very long time.

P:  Are there some circumstances when more than one implant would be put in an eye?

Dr. Elliot Werner:  Yes.  If the first shunt blocks up or is not controlling the IOP adequately, we sometimes put in a second shunt. 

P:  Is there much difference between a Molteno and a Baerveldt shunt?

Dr. Elliot Werner:  Not much.  The Baerveldt seems to give marginally better results, but they tend to behave similarly, especially the twin plate Molteno.

P:  Aren't shunts a last alternative?

Dr. Elliot Werner:  Not really.  In the right kind of patient, a shunt is a pretty good operation.  The last alternative is what is called a ciliodestructive procedure, such as laser cyclophotocoagulation.

P:  If the effect of mitomycin should fail, what would be the next step? 

Dr. Elliot Werner:  Probably a shunt.

P:  My son's last surgery was May 20th.  His next one is scheduled for June 29th.  Does that seem like a reasonable time frame between surgeries?

Dr. Elliot Werner:  Yes, that is a reasonable interval.

P:  Why can't shunt surgery be performed on both eyes at the same time?  

Dr. Elliot Werner:  Because of the risk of complications.  If there were an infection, the patient could lose both eyes. 

P:  Are the complications greater with shunts than with goniotomy?  

Dr. Elliot Werner:  Complications are considerably greater with shunts.  Goniotomy is actually a pretty safe, low-risk procedure.

P:  Our doctor talked about going straight to the shunt if pressures were high at the next scheduled goniotomy.  Does that sound okay?  

Dr. Elliot Werner:  That's not unreasonable, because in very young children and infants, results with shunts are better.  

P:  Why would you suggest a limit of two trabs on an eye? 

Dr. Elliot Werner:  Because the success rate is lower and lower for each successive operation, and the risk of complications is higher and higher.

P:  My 11-year-old son and I both have glaucoma (Axenfeld's syndrome, no Riegers*).  My son had two trabeculectomies a year ago, and I had one this past winter.  Now that summer is arriving, what concerns should I have about about swimming, in either chlorinated pools , fresh water lakes, or the ocean?  

[*Axenfeld anomaly:  Congenital defect.  Eye formation consisting of a white ring along the innermost surface of the cornea.  Associated with high IOP.  Rieger's anomaly:  Genetic defect occurring during the 5th or 6th week of fetal development.  Eye findings include glaucoma,  underdeveloped iris, deformed pupil, corneal defects and astigmatism.]

Dr. Elliot Werner:  Generally, swimming is safe, but I recommend a good pair of swimmers' goggles to keep the water out.

P:  Do you recommend herbs for children with glaucoma?

Dr. Elliot Werner:  It doesn't hurt, but many herbs have active pharmacologic substances and you should check with a pediatrician before using them.  I will sign off now.  See you next month.

Moderator:  Thank you,  Dr. Werner.

End of highlights for May 29, 2002.

On June 5, Dr. Wilson discussed "Glaucoma and the Workplace" in the Chat room. Click here for highlights of that meeting.

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