# Optical Forums > Ophthalmic Optics >  Biocular v Binocular

## sarahr

Hello again you helpful people!

I'm at a loss with this question on my Low Vision Assignment this week.
Q: Explain the difference between Biocular and Binocular correction.

I have found out that Biocular correction supplies the same image to both eyes and the binocular correction provides separate images to each eye, but could anyone elaborate on this with regard to the practice of Low Vision.
Would a CCTV system be regarded as biocular?
All the info I can find is on Night vision goggles and Army stuff, not really relevant to this topic.
Any help would be appreciated, I have to post this paper tomorrow!!:drop:

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## care4vision

Hi!
As far as i know concerning visually impaired patients there are 4
cases.
1)A patient can use two eyes at once(binocular).
2)a patient suppresses one eye (monocular)
3)A patient can use each eye independently by alternative use of 1 eye while suppressing the other.This patient can be given a telescope for distance for 1 eye and a microscope for the other.
each eye acts independently when 1 is on the other one is of.
4)retinal rivalry
look at The art and practice of low vision 
by P.Freeman

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## care4vision

sorry
number 3 is called biocular concerning my previous e-mail

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## Tim Hunter

I would have called that monovision, correcting one eye for near and one for distance and relying on suppression of each image to prevent diplopia.

How would a CCTV be biocular?

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## Darryl Meister

> *Tim Hunter said:* 
> How would a CCTV be biocular?


While I've never heard of the term _biocular_, I could certainly see its intended meaning, even with CCTVs. When looking at a CCTV, as with any television or monitor, you are basically perceiving the same image with both eyes since the monitor picture is flat, two-dimensional (i.e., has no depth), and generally viewed from straight on. Consequently, while there will be some disparity between the monitor images on the retinas, the images won't be seen from noticeably different perspectives or seen with depth, which is what provides us with stereopsis and the benefits of binocular vision.

Best regards,
Darryl

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## sarahr

Thanks care4vision, Tim and Daryl. I have posted my assignment with the little info I have, asking for further help from my tutor. When I receive the sample answer in a few days I will post it here.

Sarah:cheers:

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## Tim Hunter

> *Darryl Meister said:* 
> While I've never heard of the term _biocular_, I could certainly see its intended meaning, even with CCTVs. When looking at a CCTV, as with any television or monitor, you are basically perceiving the same image with both eyes since the monitor picture is flat, two-dimensional (i.e., has no depth), and generally viewed from straight on. Consequently, while there will be some disparity between the monitor images on the retinas, the images won't be seen from noticeably different perspectives or seen with depth, which is what provides us with stereopsis and the benefits of binocular vision.


Darryl I'm not convinced that biocular is quite the same as binocular, at least I would assume not unless Sarah is being asked trick questions.  I look forward (biocularly??) to seeing the model answer!:D

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## Darryl Meister

> *Tim Hunter said:* 
> Darryl I'm not convinced that biocular is quite the same as binocular, at least I would assume not unless Sarah is being asked trick questions.


I don't think they are the same thing either. I was attempting to explain the potential differences, and why a CCTV could be considered "biocular" (at least by Sarah's definition) and not _binocular_.

Best regards,
Darryl

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## care4vision

> *Tim Hunter said:* 
> I would have called that monovision, correcting one eye for near and one for distance and relying on suppression of each image to prevent diplopia.
> 
> How would a CCTV be biocular?


Hi.I would like to  further clarify the point on biocular vision.Imagine a patient right eye -1 and left eye -4.While going through Worth-4-dots and having red filter on the right eye and green filter on the left eye the patient is asked how many objects he sees the answer is generally as following."2 red and wait a moment now its 3 green".The answer is never 5 objects meaning the patient never experiences diplopia.So the patient is using either his right or left eye.There is therefore no fusion between two eyes.Therefore when I correct one eye for near and the other for distance I dont rely on suppression of each image to prevent diplopia.The reason being that there is no fusion.Therefore I am not fully sure of the connection between CCTV and biocular vision.The patient who is binocular has a fusion when he uses CCTV.Someone who is biocular watches CCTV either with the right or left eye.Is there possibly another definition of biocular vision that someone could eleborate on?

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## chip anderson

Perhaps there is another word that should be in this discussion, and it probably means a lot more than binocular.  It's stereopsis (sorry about the spellling the only dictionary I have at the house doesn't have it in it) but when you are trying for ocular fusion this is what you want.


Chip:cheers: 

Biocular sounds like one of them British words, like boot for trunk.

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## 10 Pence Short

With regards to CCTV being biocular-

Do you mean the image the camera sees, or the on-screen picture it produces?

A CCD camera is in effect just one eye, so is not biocular or binocular. I do not know of a camera where the images from two CCDs using two lenses have been interpolated to create a true binocular image with a proper impression of depth. I wouldn't be surprised if there was, though. If engineers want to create 'androids' with truly useful sight, then this I imagine would be quite important.

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## sarahr

:hammer: I disagree with my initial comments now that I have read more.Biocularity is pertaining to the eyes rather than to the object viewed so CCTV cannot be biocular as it does not have eyes!I think that biocular correction is more like the monovision that was describd earlier but perhaps with some difference which escapes me at present.

Not long till the model answer! :Confused:

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## sarahr

Here is the Model answer to the original question:

A Biocular device is "an optical device in which both eyes view through a single optical system.Thus an example of a biocular aid is a magnifier that allows binocular viewing whilst utilising a single lens.This could be a low powered hand or stand magnifier.
A binocular correction is one that uses two separate lens systems to permit binocular viewing.These may take the form of prisms incorporated into positive lens systems as well as more complicated convergent optics."

Thanks everyone.

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## Darryl Meister

> *sarahr said:* 
> Here is the Model answer to the original question:
> 
> A Biocular device is "an optical device in which both eyes view through a single optical system.


Then I would still stick by my original post. As I interpret Sarah's "model answer," a CCTV would still be considered a _biocular_ system -- since a CCTV acts like a single optical system viewed with both eyes. By that, I mean that a single camera captures the image, which is then subsequently magnified and relayed to both eyes through the CCTV monitor.

Best regards,
Darryl

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