Infantile Glaucoma

Chat Highlights

July 7, 2004

Norma Devine, Editor

On Wednesday, July 7, 2004, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Infantile Glaucoma."

Moderator:  Tonight we would like to discuss infantile glaucoma.  How does that differ from congenital glaucoma, the subject of last week's discussion? 

Dr. Rick Wilson:  Usually, congenital means present at birth or becomes evident within the first few days.  I use the term "infantile" from that time up until age three.

Moderator:  Are the structures of the eye fully developed in infantile glaucoma? 

Dr. Rick Wilson:  Usually they are not.  A Barkan's membrane is usually pulling the iris, where it meets the wall of the eye anterior, over the trabecular meshwork and the drainage angle.

Moderator:  What typically causes infantile glaucoma? 

Dr. Rick Wilson:  We don't know, but it may be a failure of the drainage angle to develop normally.  Sometimes that failure is offset by the slow development of the part of the eye that makes the fluid.  The onset of glaucoma is delayed until the eye starts to produce a more normal amount of fluid.  

Moderator:  Are infants sedated for examinations?   

Dr. Rick Wilson:  In young infants, a drop of topical anesthesia may allow an adequate evaluation while awake.  It is best to have the baby hungry, and then start feeding him or her just as the examination starts.  If there is any doubt, an evaluation under anesthesia is used.  We use an inhalation anesthetic -- that is, gas. 

P:  My daughter has primary infantile glaucoma.  Is there a gene my husband and I can be tested for to determine whether we will have another child with glaucoma?

Dr. Rick Wilson:  Yes, there are many genes that can be tested for.  Unfortunately, we don't know all the genes that are linked to infantile glaucoma.  Only a fairly sophisticated center could perform such tests.  

Moderator:  If you diagnose an infant with glaucoma , do you then wonder if the parent might also be affected and not know it?

Dr. Rick Wilson:  That is rarely the case with primary infantile glaucoma.  If the parent has a syndrome, then the chances are much higher.  The parent, however, would be aware of his or her eye problem.  For example, congenital cataracts are often associated with glaucoma after the cataract has been removed.

P:  Why, after congenital cataracts are removed, is a child more likely to develop glaucoma?

Dr. Rick Wilson:  One study suggests that the inflammation stirred up by the cataract surgery may injure the trabecular meshwork and limit the normal flow of fluid from the eye.  That may or may not take the form of the iris covering the drain.

Moderator:  If one child has infantile glaucoma, does that increase the risk of siblings having glaucoma?  

Dr. Rick Wilson:  Yes.  If one child has infantile glaucoma, the chance of his or her siblings having glaucoma increases.  The onset, however, is too variable to call.

P:  I discovered that a band of gypsies in Slovakia had the glaucoma gene.  My husband, who is part Slovakian, is from the same part of Slovakia as those gypsies. 

Dr. Rick Wilson:  That is interesting.  I remember reading an article about that.  

P:  My five-month-old baby has congenital glaucoma.  Her intraocular pressure (IOP) at birth was 40 mm Hg in both eyes.  She has had three operations:  Ahmed valves were implanted, and she had a pupil enlargement.  Her doctor started patching the "good" eye.  Just today, wearing the patch, she started tracking movement.  Does that mean she is getting her vision back in the "bad" eye? 

Dr. Rick Wilson:  That means the brain is starting to use the vision she still possesses in the eye.  When the brain neglects to use an eye, the eye becomes lazy and the vision declines because of the brain's neglect.  It is not, however, a physical loss of vision.  The brain is ignoring the sight impulses coming from the eye.

Moderator:  How is an infant's visual field tested?

Dr. Rick Wilson:  Early vision is hard to test.  It is only when the eyes really start fixating and following that the doctor can tell what the vision is.  A psychophysiologic test to determine the vision can be performed, but that is difficult with a baby.

Moderator:  What is the standard method of examining infants? 

Dr. Rick Wilson:  Because the wall of the eye is soft and stretches easily, elevated intraocular pressure causes the entire eye to expand. An enlarging cornea is a giveaway that the eye is not normal.  If the cornea is stretched too far, too fast, it will develop breaks in the endothelial lining of the cornea.  Those breaks cause tearing , a cloudy cornea, and light sensitivity -- the hallmarks of infantile glaucoma.  So we look very carefully at the cornea, at the angle of the eye where the trabecular meshwork is, to see if it is normal.  We also look carefully at the optic nerve and check the intraocular pressure. 

Moderator:  Do closed- and open-angle glaucoma occur in infants at the same rate as in the rest of the population?

Dr. Rick Wilson:  No, they do not.  Angle-closure in infants is entirely secondary to an abnormality of development, intraocular inflammation, or a membrane or mass pushing the lens and iris forward and closing the drainage angle.

Moderator:  What is the usual treatment for infants?  

Dr. Rick Wilson:  Most of the time, we use a goniotomy or trabeculotomy to treat elevated intraocular pressure in infants. Medicine is usually used only if surgery fails.

P:  What is the average prognosis for infantile glaucoma?  Is it about the same as for adults?

Dr. Rick Wilson:  The average prognosis for infantile glaucoma is much more guarded than it is for adults.  I have several patients now who had only one procedure in each eye as infants.  They are driving, married, and have children.  Others, however, may have suffered through several operations and still require medication to keep their pressure controlled.

P:  At what age are children started on eyedrops?  

Dr. Rick Wilson:  Usually,  we are more likely to start children in the over-three-years age group on medication.  The prognosis with surgery is not as good as it is before age three.  Therefore, we may turn to drops first, especially in children under 10 years of age or in their teens.  

P:  My daughter's eyes are so clear now.  Her pressures are 14 and 18 mm Hg, but I know she will have a problem with myopia.  Do infants respond well to corrective lenses, once they can wear them?  My daughters right eye is 40% cupped. What does that mean?  Will that cause vision loss?  

Dr. Rick Wilson:  Most of what infants are looking at is close to them, so myopia is less of a problem for them. Young children can wear glasses, especially if that helps them see clearer.  A 40% cup means that the depression in the middle if the cup makes up 40% of the whole optic nerve surface area.  If it is true that there is only 40% cupping, there will be little loss of her visual field. 

End of highlights for July 7, 2004.

On July 14, Dr. Wilson discussed "Primary Open-angle Glaucoma (POAG)" 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.