Narrow-Angle

[TomOD]

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Andrew and others,

I have a 55 year old patient with grade 1+ angles nasal and temp. in each eye. Last year I graded her c/d ratio at 0.30/0.30 and this year, I estimated them at 0.40/0.40 (could be my variance in grading). Gonioscopy showed a faint line of anterior trabecular meshwork in all angles. Pressures have remained around 14 mmHg in each eye.

There is no history of glaucoma or closure attacks and her 80 y.o. mother (came with her) has grade 2+ angles (with hx of cataract surgery).

I understand the prophylactic use of an iridotomy is somewhat controversial. I was wondering what the current thinking in Ophthalmology was in regards to performing the LPI as a safeguard.

Thanks,

Tom

 

[Andrew_Doan]

Originally posted by TomOD
Andrew and others,

I have a 55 year old patient with grade 1+ angles nasal and temp. in each eye. Last year I graded her c/d ratio at 0.30/0.30 and this year, I estimated them at 0.40/0.40 (could be my variance in grading). Gonioscopy showed a faint line of anterior trabecular meshwork in all angles. Pressures have remained around 14 mmHg in each eye.

There is no history of glaucoma or closure attacks and her 80 y.o. mother (came with her) has grade 2+ angles (with hx of cataract surgery).

I understand the prophylactic use of an iridotomy is somewhat controversial. I was wondering what the current thinking in Ophthalmology was in regards to performing the LPI as a safeguard.

Thanks,

Tom

I've been taught that if you think the angles could occlude, then do a LPI. An LPI will prevent an acute angle closure. Additionally, a well placed LPI is harmless.

 

[JDENTHOPEFULL]

bump

 

[GlaucomaMD]

The guideline for when to do LPI is unfortunately unclear with no clear consensus.

If you can really see TM in all 4 quadrants, the angle is unlikely to be "occludable."

More importantly, does the patient report any h/o closure attacks, i.e. halos, pain, etc. (you indicated NO) and also if gonioscopy indicates finding consistent with angle closure, such as peripheral anterior synechiae.

This can be subtle, but you may also find that the pigmentation of the trabecular meshwork is darker superiorly in angles that has had closure attacks (normally inferior angle is darker).

Other indications for LPI include need for frequent dilated eye exam (diabetc, etc.) as well as someone who will be traveling abroard, etc. and will be far away from medical attention should acute angle closure attach occur.

Hope this helps.

 

[TomOD]

Thank you Dr. Chang,

I truely appreciate your information.

 

[TomOD]

GlaucomaMD,

A serious question:

I spent the afternoon observing our local glaucoma specialist. I have been referring to him for a few years- cases that progressed out of my scope.

What struck me as strange is that this guy never picked up a 78/90D lens the whole time. He chose to view every nerve with an old direct scope. I asked him about this and he did say he had a 90D lens "somewhere" (really his exact words).

I have seen older OD's use a direct o-scope exclusively and thought they were way behind the times and behind the curve.

Do you think it is "reasonable" or I guess a better word is justifiable to evaluate the optic nerve monocularly with a direct scope? I don't know. I just may be spoiled with my 78D/90D and HRT.

Is this guy just "doing his own thing" or is he so good that he can use the direct with great confidence.

This just seemed odd for an Ophthalmolgist and certainly for a glaucoma specialist?? I have to think that he is the exception?

Thanks

 

[GlaucomaMD]

I am shocked to say the least, but read all the way...

First, I will refer you to the Preferred Practice Pattern published by the American Academy of Ophthalmology, in regard to Primary Open Angle Glaucoma as well as POAG-Suspect.

Following is quotation from the PPP.

"The preferred technique for optic nerve head evaluation involves magnified stereoscopic visualization (as with the slit-lamp biomicroscope) through a dilated pupil whenever feasible."

Note STEREOSCOPIC!!!

Now, there could be several explanation for the lack of 78/90D examination.

1) Examination with Hruby lens also provides excellent magnified stereoscopic visualization of the optic nerve head; some would say superior to any other method. Unfortunately, Hruby lens examination has become largely ignored by the new generation of ophthalmic specialists, probably due to more difficult learning curve and greater dependence on patient cooperation

2) If the glaucoma specialist is using a gonioprism such as Zeiss or Posner (or even Goldmann), s/he may be using the center lens to visualize the optic nerve head. This also provides very magnified stereoscopic visualization of the optic nerve head.

Both Hruby lens and the center lens of the gonioprism provides magnified stereoscopic visualization.

Pros:
-direct view (NOT inverted upside down image!)
-very magnified view (a la direct ophthalmoscope)

Cons:
-very magnified view (a la direct ophthalmoscope) - you may not be able to see the whole nerve in a single shot; you may have to move around to see the whole nerve
-more dependence on patients to cooperate by looking where you want them to (this is the one that kills it for me most of the times); for me, I have found that monocular patients have the hardest time doing this; as much as patients hate the bright light from the slit lamp, they have tendency to start searching for it when the light is shining on their optic nerve which is the anatomical blind spot and thus be most comfortable!

I have been forced to use direct ophthalmoscope alone in patients who just would not dilate more than 1-1.5 mm regardless of how many sets of drops were put in the clinic.

In conclusion, my opinion is that proper examination of the optic nerve head cannot be done without stereoscopic viewing. Monocular viewing through direct may be misleading as color and cupping do not always go together.

Hope this helps...