Pediatric Glaucoma
Chat Highlights
October 16, 2002

Norma Devine, Editor

On Wednesday, October 16, 2002, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Pediatric Glaucoma."

Moderator:  Dr. Rick, please begin by describing pediatric glaucoma.   

Dr. Rick Wilson:  The pediatric glaucomas consist of congenital glaucoma (present at birth); infantile glaucoma (presents during the first three years);  juvenile glaucoma (varies, but for me is age three through the teenage years, though some authors include three to thirty-five years); plus all the secondary glaucomas occurring in the pediatric age group.  

Moderator:  What are some of the causes of the secondary glaucomas?    

Dr. Rick Wilson:  Pediatric glaucoma can follow cataract surgery (aphakic glaucoma), be due to ocular inflammation (iritis), trauma, malformation of the eye (Axenfeld-Rieger, aniridia, Peters' anomaly), and diseases that affect the rest of the body (Sturge-Weber Syndrome, Lowe's Syndrome, congenital rubella).  

P:  Is congenital glaucoma always apparent at birth, or can it take some time before it and the damage are noticed?  

Dr. Rick Wilson:  Congenital glaucoma is present at birth or shortly thereafter.  If it occurs after birth, it is infantile glaucoma.  The usual signs of glaucoma in infants are elevated IOP that increases the corneal diameter (and results in a cloudy cornea), tearing, and optic nerve changes.

P:  How rare is familial, post-cataract removal (aphakic) glaucoma?  How successful is treatment?  What are the known long-term effects of prescription treatment?

Dr. Rick Wilson:  In children, aphakic glaucoma is fairly common.  I am not sure of the number off-hand.  Congenital cataracts are about 6 per 100,000.  Usually aphakic glaucoma requires a shunt and is moderately successful.  Often it requires a vitrectomy to remove the jelly in the eye that could block up the shunt.

P:  I'm 14-years old.  I was aphakic for awhile; then I got glaucoma.  Is there any cure for juvenile aphakic glaucoma?  Is there any cure for any type of glaucoma?

Dr. Rick Wilson:  I see a lot of children who have had congenital cataracts removed and later develop glaucoma.  We don't know enough yet about why the iris covers the angle and drain after congenital cataract surgery to be able to prevent it.  There's no cure, but it can be controlled with medications or surgery.  During your lifetime, I am confident it will be possible to reshape and repopulate the trabecular meshwork with effective cells. 

P:  Is congenital glaucoma hereditary?

Dr. Rick Wilson:  Yes, the tendency is hereditary.

P:  I was born with congenital glaucoma to parents with no family history of glaucoma.  My wife and I are expecting a child in a month and we are concerned about congenital glaucoma being hereditary.  Is this something we should be worried about and what precautions should we be taking?  My family has been recommending we have an ophthalmologist present at the birth.  Would you recommend that?  

Dr. Rick Wilson:  I don't think an ophthalmologist needs to be present at the birth.  If anything seems amiss, an ophthalmologist can be consulted directly.

Moderator:  What are the pros and cons of shunts in pediatric patients?

Dr. Rick Wilson:  Aqueous shunts in pediatric patients are much more problematic than in adults. Some of the problems common in children are:  inflammatory membranes that encase the internal tube and block the inner ostium or pull the iris over it; migration of the tube in the anterior chamber against the cornea or into the iris; and build-up of fibrous tissue around the plates, limiting aqueous filtration.  On the other hand, the shunts don't result in too low an IOP (intraocular pressure) and usually aren't subject to late leaks and infections, as trabeculectomies are.

P:  How long do the results of the surgeries last?

Dr. Rick Wilson:  Most surgeries gradually lose effectiveness over three to ten years, and often need to be augmented.

P:  I had tube shunt surgery not too long ago.  Would I need a tube shunt replacement in 10 years? 

Dr. Rick Wilson:  With shunts, it is possible to soak the scar tissue overlying the shunt reservoir with mitomycin and then remove it without doing anything to the shunt itself.  This usually returns most of the function to the shunt.

P:  What is the purpose of tube shunt surgery?

Dr. Rick Wilson:  The tube provides a bypass for eye fluid around the blocked drain of the eye so that eye pressure doesn't build up.

P:  My son, who was a year old last week, had a shunt implanted in his right eye in June.  He had two goniotomies before that. This evening I noticed that the pupil in his right eye is not round.  It looks egg shaped at the top.  Do you have any idea what might be going on?

Dr. Rick Wilson:  Yes.  The tube enters the eye just in front of the iris.  If it rubs on the iris, the iris contracts up and scars to the area around the tube, pulling the pupil up.

P:  Why did that happen all of a sudden?

Dr. Rick Wilson:  Usually the iris pulls up and then stops changing.  I think you just noticed it. I think it took several weeks to happen.

P:  So, his pupil will stay like that?  Sorry, to ask so many questions.

Dr. Rick Wilson:  Yes.

P:  Do I need to call my son's doctor about the change in his pupil or just wait until the next appointment in four weeks?

Dr. Rick Wilson:  It would probably be best to call his doctor, but it is unlikely that he or she would want to reposition the tube.

Moderator:  Doctor, what is a goniotomy?  

Dr. Rick Wilson:  It's an incision into the abnormal membrane covering the trabecular meshwork to all the aqueous (the watery fluid in the eye) to gain access to the drain.

P:  How well does laser surgery work with infants and children?

Dr. Rick Wilson:  The kind of laser surgery (trabeculoplasty) used for adults does not work at all in infants and children.  Actually, it works poorly on patients younger than 50-years-old, unless they have pigmentary glaucoma or pseudoexfoliation.  Laser to kill part of the eye that makes fluid in the eye is an end-stage procedure and works at any age.

P:  Would an infant, child, or teenager with enlarged optic nerve disc cups, but no other abnormal findings, be considered a suspect for normal-tension glaucoma?  

Dr. Rick Wilson:  I've never known a child to get normal-tension glaucoma.  An enlarged cup is suspicious at any age.

P:  I was diagnosed with pigmentary glaucoma in my teens, and am now 23-years-old.  Would laser surgery be a good option? 

Dr. Rick Wilson:  That's hard to say without seeing you.  A laser iridectomy might be helpful if your iris is pushed back onto the ligaments that hold your lens in place.

P:  Do younger eyes heal faster after surgery?  

Dr. Rick Wilson:  Yes.

P:  Does healing too fast hurt a younger glaucoma patient?

Dr. Rick Wilson:  Yes.  After glaucoma surgery, we do not want the patient to heal much, as the build-up of scar tissue inhibits the flow of aqueous.

P:  Many babies have blocked tear ducts.  What are the signs that something more serious is going on?

Dr. Rick Wilson:  An increase in corneal diameter, light sensitivity, and a cloudy cornea.

P:  My son had a blocked tear duct at two months of age.  His pediatrician  just gave him drops and said it was nothing.  Could this have been a signal that something was going on?  My son wasn't diagnosed with glaucoma until he was seven months old, and his pressures were in the 40's. 

Dr. Rick Wilson:  If the corneal changes weren't present, chances are it was a blocked tear duct, and he had two things wrong at different times.

P:  Is there any connection between congenital physiological abnormalities of the eye and later development of glaucoma?  Several members of my family were born with eye abnormalities.  There's also glaucoma spread about.  One family member was missing a pupil in one eye.  She developed glaucoma as a teenager.  Another appears to have pigment from the iris dispersed in the pupil, again since birth.

Dr. Rick Wilson:  Yes, if one part of the eye is not formed correctly, there is a greater chance that another part of the eye will be abnormal.

P:  Have you found that Goldmann/Perkins tonometer readings do not correlate well with TonoPen readings in children, or are they usually about the same?

Dr. Rick Wilson:  A proviso is the 1998 study by Eisenberg and others that looked at 72 patients comparing AC manometry with the IOP values obtained by applanation tonometry, pneumatonometry, and the TonoPen.  Their conclusions were that applanation tonometry markedly underestimated IOP in children.  The pneumatonometer was the best clinically. The TonoPen performed the best of the three in enucleated eyes, but was not adequately accurate for clinical use.  

Since our last pneumatonometer gave out several years ago, I use the Perkins tonometer in the operating room, corrected for central corneal thickness.  However, I place even more importance on the appearance of the optic nerve in young patients, whose tissue is so pliable that the disc changes rapidly in response to IOP.

P:  After having my congenital cataracts removed in 1958, and several needlings done in the next few years, I had surgery eight years later to remove a membrane from my right eye.  My records are sketchy.  Would you know what membrane might have been removed?

Dr. Rick Wilson:  Usually cataracts weren't removed in their entirety in 1958.  The instruments weren't available then.  The remnants of the cataract often grew over the pupil, blocking the visual axis. The resultant membrane could be removed with later technology.

P:  What can someone expect who visits you for a second opinion?

Dr. Rick Wilson:  A thorough exam and a thoughtful opinion with enough time to explain it.  They should expect to be in the office about two hours, sometimes more.

Moderator:  Thank you, Dr. Rick, for all your help.

Dr. Rick Wilson:  You're welcome.  The American Academy of Ophthalmology is meeting next week, so if there is anything new, Elliot Werner will have it next Wednesday.  Have a great week.

End of highlights for October 16, 2002.

On October 23, Dr. Werner discussed "Visual Fields" 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.