Chat Highlights
Recalcitrant Glaucomas
April 25, 2001

Norma Devine, Editor

On Wednesday, April 25, 2001, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed "Recalcitrant Glaucomas." 

Moderator:  Dr. Rick, what does "recalcitrant" glaucoma mean?

Dr. Wilson:  Recalcitrant means hard to do much with.  A few examples are aphakic, neovascular, malignant, and inflammatory.  Recalcitrant glaucomas are the main reason we have glaucoma specialists.  No one else wants to take care of these difficult problems.

P:  Are recalcitrant glaucomas rare? 

Dr. Wilson:   No.  Inflammatory and neovascular glaucomas are not all that infrequent. 

Moderator:  What does it mean to have an attack of malignant glaucoma?  

Dr. Wilson:  An attack of malignant glaucoma (aqueous misdirection syndrome) occurs when fluid that is made in the eye just behind the iris becomes directed back into the vitreous, or  jelly, in the eye, pushing everything forward and causing fluid to back up behind the vitreous. 

P:  Does "misdirection" also imply that the angle is closed?

Dr. Wilson:  The pressure from behind the lens and iris pushes the iris forward, closing the angle.

P:  Is there no way to re-open an angle in aqueous misdirection? 

Dr. Wilson:  The surgeon has to either make a path for aqueous trapped in the back of the eye to come forward, or to take out part of the vitreous, allowing the lens and iris to fall back and the  aqueous to more forward normally.

P:  Does the aqueous misdirection syndrome only happen suddenly or can it happen gradually?  

Dr. Wilson:   Usually an event disturbs the equilibrium of a predisposed eye and the aqueous misdirection comes on within a matter of hours.

P:  I have malignant glaucoma in both eyes after trabeculectomies.  The trab in my left eye is starting to fail, I have a cataract starting, and my angle is closed.  My IOP is controlled by eye drops, but what happens if the drops do not keep the IOP under control?  Will I need another trab?  Am I at greater risk?  

Dr. Wilson:  Another trab would be the probable answer, if there is enough conjunctiva above that is not scarred -- or a shunt, if there isn't.  

P:  Are shunts available for nanophthalmic eyes?

Dr. Wilson:   Yes, we use baby shunts.  We even have shunts for monkey eyes, which are very small.

P:  Monkeys get glaucoma, too?

Dr. Wilson:  Usually researchers give the monkey glaucoma, so they can try new medications and surgery to relieve the glaucoma.

P:  Can hypotony caused by a trab also cause aqueous misdirection?  

Dr. Wilson:  No, hypotony is usually a long- term problem, whereas aqueous misdirection is an acute problem.

P:   I guess I am glad that I did not know of these possibilities before I had my trab. How common are such occurrences?

Dr. Wilson:  The incidence of hypotony requiring repeat surgery is probably about 1 in 50.  Aqueous misdirection is only seen in those with small anterior chambers, and is even more rare. 

P:  Are you saying that 1 out of 50 patients with hypotony needs a second trab?  

Dr. Wilson:   No.  The need to drain fluid from between the layers in hypotonous eyes happens about once in 50 times.   

P:  What is a neovascular glaucoma?

Dr. Wilson:  Neovascular glaucoma usually follows a disease like diabetes that slowly cuts off the blood supply to the retina, or like an occlusion in a vein that takes blood out of the eye.  The blood cannot circulate and, again, the retina is deprived of blood and its oxygen and nutrients. The retina sends messages to the body saying it needs blood,  and the body tries to build vessels to the retina in response to these messages.  Unfortunately, the vessels the body builds are in the wrong area and they leak and bleed.  They often grow in the drain of the eye, blocking off outflow and causing intraocular pressures in the 70's and 80's.

P:  If you decrease the inflammation in inflammatory glaucoma, does the IOP follow? 

Dr. Wilson:  The IOP may follow the inflammation, but it often lags for a while.

P:  Does the size of the eye play a big part in these types of glaucomas?

Dr. Wilson:  Small eyes are the ones prone to malignant glaucomas. 

P:  Is the inflammation visible in the eye or does that happen behind the eye?  

Dr. Wilson:  No, the eye may become red and externally inflamed, as well.

P:  Isn't there a membrane (the hyaloid) that keeps the aqueous out of the vitreous?

Dr. Wilson:  The hyaloid is often stuck to the back of the lens in the eye. If something causes the lens to shift forward, like too much fluid coming out of a trabeculectomy, the vitreous is brought forward and aqueous may be pushed backwards, squeezing the vitreous forward without breaking its surface.

P:  Can neovascular glaucoma be treated surgically? 

Dr. Wilson:  Usually laser to the retina kills the retina that does not have enough blood supply and is sending out the message for the body to grow new vessels.  Sometimes a trabeculectomy will work if the eye is not inflamed.  Otherwise, an aqueous shunt is used.  Occasionally, in advanced cases, a laser or freezing probe is used to kill part of the ciliary body of the eye, the part that makes the watery fluid that fills the eye.  If little fluid can escape the eye, and if the amount of fluid made in the eye is cut way down,  then maybe an equilibrium at a controlled level can be achieved. 

P:  Can one develop these types of glaucoma after having open-angle glaucoma or normal-tension glaucoma for some time?  

Dr. Wilson:  Vein occlusions are more common in patients with glaucoma and may result in neovascular glaucoma.

P:  My mother, after cataract laser,  had the fluid leak out of her eye and she lost central vision.   Would that be aqueous misdirection?

Dr. Wilson:  Unless your mother was seeing Dr. Dodick in N.Y. and had an experimental laser removal of her cataract, her cataract was not removed  by laser. Some months after the original extraction, a hazy membrane could have formed behind the intraocular lens (secondary cataract,) which could have been removed by laser.  In all probability, your mother developed cystoid macular edema (swelling in the central part of the retina), in response to inflammation that persisted and left her with central loss of vision.

P:  How long does the eye remain inflamed after cataract surgery? 

Dr. Wilson:  The inflammation should quiet down within a week or two, unless  there was inflammation before surgery, the eye was on medications like Xalatan that cause inflammation, or there was trouble during the surgery. 

P:  Does the chronic inflammation do permanent damage? I have been on Xalatan for months.

Dr. Wilson:  Xalatan only rarely causes intraocular inflammation.  It is more common in patients with traumatized eyes.

P:  I am in my late teens and just had a trabeculectomy with mitomycin C.  Is there a good chance it will work?

Dr. Wilson:  I think there is a good chance the surgery will work.  

P:  What's a trabeculotomy? 

Dr. Wilson:  A trabeculotomy is an opening from Schlemm's canal,  the drainage canal of the eye, into the anterior chamber of the eye, breaking open the meshwork between the two.  Aqueous can then filter directly into the drainage canal.  

P:  Why wouldn't a trabeculotomy, instead of a trabeculectomy, be performed on a teenager?  

Dr. Wilson:  A trabeculotomy usually works less well in those over one-and-and-a-half years old. 

P:  I am going to have a cornea transplant and cataract surgery in early June.  I  am worried about the effect that will have on my fairly new trab, which is working nicely.  

Dr. Wilson:  That is a worry, but there is little you can do except take lots of topical steroids after the second surgery to protect your trab.  The chances are still in you favor, especially if drops can be used postoperatively for glaucoma.

P:  I am facing a trab, possibly very soon . I have cataracts that are not ready for surgery, so I can't have both procedures done at once. Will the cataract surgery later compromise the effectiveness of the trab? 

Dr. Wilson:  That's a possibility.  

P:  How many patients taking chronic steroids develop IOPs that are too  high?  How long does it take for the IOP to increase?

Dr. Wilson:   Approximately five percent of  patients taking chronic steroids will develop IOPs that were too high.  Usually it takes two to six weeks for the IOP to rise.

P:  I have heard so many different things about massaging the eyeball. Would you explain the pros and cons? 

Dr. Wilson:  There is an agreement to disagree at the Glaucoma Service. I have used massage in over 3000 patients after trabeculectomy and swear by it. George Spaeth doesn't believe in it and never uses it.  

P:  How do you tell patients to massage their eyes?  

Dr. Wilson:  When I tell patients to massage their eyes, they end up treating it like bread dough --  kneading instead of applying a steady pressure to force aqueous up through the trabeculectomy.  I have a patient look straight ahead with both eyes and close the eye to be "flushed."  The patient then places the soft pad of the index finger over the cornea at the foremost part and pushes firmly but slowly back toward the back of  the head. Once sufficient  pressure is achieved, a steady pressure is maintained for the length of time that was found in the office to be enough to lower the IOP to below the target.  

P:  Would the pressure from massage help to clear away some of the debris that collects in the trabecular meshwork?

Dr. Wilson:  No, massage is mainly used to prevent the trab flap from sealing down and causing the trab to fail.

On May 2nd, Dr. Wilson discussed "Childhood Glaucoma" in the Chat room. Click here for highlights of that meeting.

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