Trouble fusing with Zeiss Slit Lamp

[4ophtho]

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I am noticing that I am having trouble maintaining fusion with a Zeiss slit lamp
I do not have this problem with the Haag Streit slit lamps

I have noticed that it is particularly problematic when performing a dilated fundus exam.

Anyone else notice this difference between slit lamps and anyone have any suggestions?

 

[DrZeke]

This happened to me too. Same thing.

 

[DrZeke]

http://forums.studentdoctor.net/thr...ulty-with-stereopsis-on-the-slit-lamp.671492/

 

[WilburSK]

Going to start ophtho residency soon...I noticed that I have a strong eye dominance. I don't see an image simultaneously while looking through a microscope. I can easily compensate by switching eyes, and I haven't had any difficulties yet. I had an amblyopia as a kid, but I just sort of grew out of it. Never saw anyone to get it fixed, so this is likely a residual problem from that.

are there any solutions to this problem? I've heard that there are exercises that can help

 

[DrZeke]

Going to start ophtho residency soon...I noticed that I have a strong eye dominance. I don't see an image simultaneously while looking through a microscope. I can easily compensate by switching eyes, and I haven't had any difficulties yet. I had an amblyopia as a kid, but I just sort of grew out of it. Never saw anyone to get it fixed, so this is likely a residual problem from that.

are there any solutions to this problem? I've heard that there are exercises that can help

Did you check your stereopsis and worth 4 dot test??

 

[WilburSK]

No, I haven't had these checked. If I do poorly, what could I do?

 

[DrZeke]

No, I haven't had these checked. If I do poorly, what could I do?

I understand the way these tests work, but I don't really know what's to tell you...

Can any senior members comment?

 

[WilburSK]

What is the relationship between eye dominance and stereopsis?

I for sure know that I have a pretty strong eye dominance, but I don't know if it affects my depth perception. I have never had any issues with it, but I am worried due to reading some previous posts.

I know with eye dominance, you can use the push-pull technique to improve your bilaterality of eye dominance. Is there anything that can be done to improve depth perception?

 

[DrZeke]

What is the relationship between eye dominance and stereopsis?

I for sure know that I have a pretty strong eye dominance, but I don't know if it affects my depth perception. I have never had any issues with it, but I am worried due to reading some previous posts.

I know with eye dominance, you can use the push-pull technique to improve your bilaterality of eye dominance. Is there anything that can be done to improve depth perception?

Have you ever been able to use both eyes simultaneously while looking through a telescope/microscope/slit lamp?

 

[WilburSK]

No, I usually use one eye. But I switch between eye dominance, and I have no issues with acuity.

 

[RestoreSight]

What is the relationship between eye dominance and stereopsis?

I for sure know that I have a pretty strong eye dominance, but I don't know if it affects my depth perception. I have never had any issues with it, but I am worried due to reading some previous posts.

I know with eye dominance, you can use the push-pull technique to improve your bilaterality of eye dominance. Is there anything that can be done to improve depth perception?.

Stereopsis tests your ability to fuse two similar objects in space. There are a number of tests for this. The fly/circles/animals test is probably most common. Worth 4 dot testing identifies suppression due to a central scotoma or diplopia. Testing fixation preference is a means of determining if amblyopia is present particularly in preverbal children and is not the same as ocular dominance. If a child does not alternate and hold fixation on cover/uncover testing we say he has a strong fixation preference with the assumption the non-fixating eye has amblyopia. People that are right or left eye dominant do not have any problems with depth perception or fusing unless they have some disruption of binocular fusion as a child.

As far as I know, there are no exercises or techniques to improve fusion, although patients often feel otherwise. Fusion/depth perception is a cortical phenomenon. Disruption of those pathways due to strabismus or amblyopia are not correctable beyond a critical period in early development. A better question is what degree of stereopsis is necessary to view depth at the slit lamp and using the indirect? My guess is gross stereopsis would be enough (i.e. fly), but this would not be optimal for discerning fine detail

 

[DrZeke]

Stereopsis tests your ability to fuse two similar objects in space. There are a number of tests for this. The fly/circles/animals test is probably most common. Worth 4 dot testing identifies suppression due to a central scotoma or diplopia. Testing fixation preference is a means of determining if amblyopia is present particularly in preverbal children and is not the same as ocular dominance. If a child does not alternate and hold fixation on cover/uncover testing we say he has a strong fixation preference with the assumption the non-fixating eye has amblyopia. People that are right or left eye dominant do not have any problems with depth perception or fusing unless they have some disruption of binocular fusion as a child.

As far as I know, there are no exercises or techniques to improve fusion, although patients often feel otherwise. Fusion/depth perception is a cortical phenomenon. Disruption of those pathways due to strabismus or amblyopia are not correctable beyond a critical period in early development. A better question is what degree of stereopsis is necessary to view depth at the slit lamp and using the indirect? My guess is gross stereopsis would be enough (i.e. fly), but this would not be optimal for discerning fine detail

But what degree of stereopsis does someone need to operate? I thought without binocular viewing it becomes very difficult.

I definitely notice and appreciate the difference in depth and detail between a binocular view in a dilated pupil compared to the monocular view I get with a tiny pupil. You can probably manage with a monocular view though at the slit lamp.

 

[WilburSK]

I did the Wirt circle test today and I only got to the second set...I may be screwed. This is devastating cause I am just about done with the terrible intern year. I guess I never really recognize it as a problem as it doesn't cause me any troubles in normal life.

 

[DrZeke]

Read this
http://www.forums.studentdoctor.net/index.php?threads/No-streo.-Am-I-out?.465678/

 

[WilburSK]

Yesh, doesn't look good for me! What about these prisms, perhaps they help me. It would be devastating to have to give up now.

If anyone has experience with overcoming this challenge, please PM me!

 

[PBEA]

Yesh, doesn't look good for me! What about these prisms, perhaps they help me. It would be devastating to have to give up now.

If anyone has experience with overcoming this challenge, please PM me!

To me it sounds like you have no real idea what problem you are having with your eyes. You should think about seeing either a pediatric OMD or an OD (or both) and describe exactly the problem you are having, specifically your lack of binocular vision. At least you will know what your options are.

 

[OphthoApp]

Most ophthalmologists prefer not to be called OMD. Just a heads up. Technically it's just MD or DO depending on their medical degree.

 

[PBEA]

it's a shortcut to spelling out ophthalmologist, not meant to be offensive. In my post had I written "pediatric MD" I would be left dissatisfied.

 

[DrZeke]

Most ophthalmologists prefer not to be called OMD. Just a heads up. Technically it's just MD or DO depending on their medical degree.

.

 

[KHE]

I am noticing that I am having trouble maintaining fusion with a Zeiss slit lamp
I do not have this problem with the Haag Streit slit lamps

I have noticed that it is particularly problematic when performing a dilated fundus exam.

Anyone else notice this difference between slit lamps and anyone have any suggestions?

As I mentioned in the other thread, see an optometrist who does some VT and get some basic VT exercises....Brock String, vectograms, some basic accommodative rock therapy. This problem is generally easily fixable.