Double Image on Binocular

[Bob Ballantyne]

I have started to have problems with a double image with my trinocular microscope (a Wolfe).

This is a problem when the 4X and 10X objectives are in place. Doesn't seem to be a probelm with the 40X objective in place.

I find no loose lenses in the objectives and the trinocular's ocular head is solidly in place.

I cannot get rid of this probelm by adjusting the intra-ocular distance. My eyes are around 20/30 but the left eye has a slightly different prescription than the right. I adjust for this using the variation in focus settings on the two eyepieces.

As far as I know this 'scope has never been bumped or dropped. It is about 5 years old, but I do not use it that often and mostly for observation of protozoans and other microinvertebrates.

Does anyone have any suggestions?

[g4lab]

It sounds like a prism has been bumped loose inside the trinoc head.

You are going to need to open it. Usually there is some lacquer flowed over the screws which hold down the prisms. These usually give away the broken one.

Before you open it try to see if you can ascertain which one got moved.
Open one eye then blink to the other. Make a tiny concentric circles and crosshairs centering target. Observe it with the trinoc removed and center it to the objective. Then reattach the trinoc. Probably one side will be centered.
And the one that isn't is probably the one that moved.

Note what direction the centered cross hair moves when you blink and correct for it.

If you are very lucky there will be some lacquer that will show you exactly how to put it back.

This job can be a pain because you may need to reassemble the whole thing again to see if what you did helped.

I have done it a couple of times and it is not a moon shot.

[Bob Ballantyne]

Many thanks for the info. I had thought a prism might be the problem. Just cannot imagine how one would have gotten bumped.

There is a microscope repair outfit not too far from me. I think I'll have them do it.

RLB

[Bob Ballantyne]

I have been working again on this problem.

Using a prepared (commerical) slide of Paramecia I put one specimen dead center in the field of view. I noticed a double image.

As I moved the slide so that the image appeared to move to the top of the field of view, the two images merged into one.

When I brought it back down to the center of the field of view it remained as one image. However, if I continued to observe it the image split into two and appeared to drift apart into two images.

I think this is a topic for me and my optometrist to discuss and probably has nothing to do with the 'scope.

RLB

[g4lab]

Your brain has the ability to fuse out of alignment images but this ability is not without limits.

While it is possible that you are seeing a physiological symptom that is taking place in you brain or your eyes I still would bet on the binocular head.

It sounds like the misalignment is less at a different point in the field.

If the prism was not properly pinned down and cemented into place it does not take much to bump them out of alignment.

There are numerous axes too. X, Y and Theta (rotational)

Are you having any other problems like problems with binoculars or watching TV? Have you ever had strabismus?

[Bob Ballantyne]

Thanks for your reply. Haven't had any double-vision problems or using binoculars.

I taught HS biology 30 yrs, but always had student grade monoculars in the classroom. Taught college a few years after retirement and used binocs there without any problems but that was a few years ago.

It dawned on me - why don't I just have a friend familiar with 'scopes look at some images and see what they notice.

I think that's where I'll go next, or take it into a local repair shop - one is close by - and just have a tech look through it and get an opinion.

I go back and forth with this issue, and I really think, as you do, it is the 'scope itself.

Thanks again.

Bob B

[Pau]

Bob,
I teach Biology, and in the lab we have binoculars that have resisted 10 years of rude work without prism misalignement, but it is a big problem with our stereomicroscopes, four of them need reparation and it's a complex one.

My vote is to your microscope, no to your eyes .

[g4lab]

With stereo microscopes this problem is usually a much bigger headache to repair. It usually requires a laser and fixturing jigs. Of course you can still take a look at them because if they are already out of alignment you won't usually make the repair any worse.

Stereos have two separate optical systems down to the objective whereas a binocular compound just splts the image at the binoc or trinoc.

[Bob Ballantyne]

Well, my optomitrist says it isn't my eyes. (He's a personal friend.) He is sure its the prisims.

The shock is, a local specialist in microscope repairs says it is not cost effective to have it repaired.

This is in agreement with the above.

I'll try one other place, but I'm not buying another one. This is a once in a awhile hobby, and I'll use it as best possible.

Bob B

[g4lab]

If it's not cost effective to repair then it means he is a hack lens cleaner or just a sales person.

If the prism isn't broken you don't need any parts.
Just dig into it yourself and fix it. You'll do fine.

Where I work we had a Nikon student scope that somehow the binoc got taken off and dropped. One side was broken.

Nikon wanted more than the cost of a new one to fix it. But they did sell the part for a reasonable price and it pretty much dropped right in. I think it took two trys to get it where it needed to be.

[Bob Ballantyne]

Weel, you know what. I don't really know why I didn't do this earlier.

My wife is also trained as a biology teacher. I set up a prepared slide and had her view. I had double imaging with this slide. She did not.

I think its just eye fatigue. So I'll give it a rest.

Sorry to have trouble folks.

Bob B

[g4lab]

She probably has more ability to fuse than you do.

Is she familiar enough with microscopes to recognize the ocular muscle tension (and subsequently usual eyestrain) that accompanies "forced fusion"

When you look into a binoc your eyes are supposed to be relaxed (or perhaps slightly converging and accomodating according to one school of thought) and focused at infinity.

Of course since there is (mostly) no stereo information in a compound view you can just close one eye and use your master eye as though it was a monocular scope.

Its no trouble.

[Choronzon]

It sounds to me, like one of the eyepieces is improperly assembled; one of the lenses is in upside down. Convex surfaces should face each other internally. Check this first, before any alignment.

[microcollector]

You might want to contact Absolute Clarity about this problem. They are a retail and repair service and are well like by people into micro mineral collecting.

Doug

[Bob Ballantyne]

Just to come back to this issue and post on behalf of anyone else with this problem.

I have been to a neuro-opthomologist and have a definate problem with diplopia beyond the microscope. It goes unrecognized right now in my everyday vision.

I have to go through some tests; however the opthomologist has been in practice for almost 30 years and has seen at least 50 cases where patients of his that are microscopists have first noticed the problem using binocular microscopes.

Apparently some people who depend on microscope work for a livelyhood have had eyepieces made with prisims in them to correct for the problem. They are quite expensive. Assuming the outcome of my tests are good - with age being the probable factor - I don't intend to go that route. Since I use the trinocular tube mostly for digital camera and videocamera - I can use the binoc feature and just close one eye and adjust the scope as a monocular for focusing.

In my search on the internet I actually found a posting by a young M.D. who experienced the problem. His was a 2008 posting on a medical site, so I don't know his outcome although I have posted there requestihg same.

Bob B