Hi, I have been strabismic since very early childhood and during that time have had 3 seperate surgeries to 'correct' my problem. Obviously none of these had the effect I had wished for of rendering me 'normal'. Now in my late thirties I have discovered the book of Sue Barry and for the first time realized that after all this time there was another way. A way that didn't involve butchery, a way that instead of treating the cosmetic aspect actually dealt with the visual problem itself. All of these years wasted if only someone had bothered to mention behavioural optometry instead of pushing me down the cheaper (for the NHS), quick fix route of opthalmology. This makes me so angry to know that I could have been helped years ago. Why is this topic such a closely guarded secret? Why does the surgical route hold the monopoly in this field?
Anyway, I digress. The question I wished to raise was what is the difference between Binocular vision and stereo vision. I have been in touch with a practitioner here in the UK and he said he may be able to help me (when I can afford the treatment), although he warned that attaining the miracle of stereo vision might be an impossible dream. He did say however that he should be able to improve my binocular vision at the very least. Surely seeing in binocularity without stereo 'fusing' is just confusing double vision. Could someone please explain how these two things can be sperated from one another? Surely overcoming the suppression to achieve binocular vision would just lead to impossible confusion within the visual field unless the images could be fused by the brain?
Thanks and sorry for rambling on.
I'm not sure what your eye care practitioner meant between the difference between binocular vision and stereovision. I think of stereovision as a part of binocular vision. Binocular vision to me means using the information from the two eyes simultaneously. This does not imply necessarily that they are used to an equal extent. Even if you are amblyopic, for example, you may have some binocular vision. Your weak eye may contribute to your view particularly in the peripheral part of the visual field where only that eye can see.
So, from the definition that I described above, double vision is a form, albeit not a good consequence, of binocular vision. Stereovision requires that the two eyes are both turned on AND that the information from the two eyes is combined into one view. For this to occur, the eyes have to be aimed at the same place in space. I think this is the key. You don't want to turn on the input from both eyes unless they are aimed at the same spatial location. For me this happened gradually. As I learned in vision therapy how to aim my eyes at the same place, suppression naturally lifted because it was no longer necessary, and I began to see more and more in stereo depth.
Hi Sue, Thank you so much for your reply. It is great to hear from you as you have become such an inspiration to me (and millions of others). You have attained an almost folk hero status. The pioneer and figure head for all of us desperate to follow in your footsteps.
Your reply was of great interest to me. Although , obviously, without having begun vision therapy myself I can't even begin to imagine how it would be possible to 'aim' the two eyes to a fixed point without first overcoming the suppression.
I have been carrying out one or two experiments myself to try and guage what my potential might be. I can achieve limited dual images with an appearance of some sense of depth when focusing on an object between 2 and 6 inches from my nose. This, whilst proving little has inspired me yet further.
I have always had roughly identical vision in both eyes and can switch at will which eye is the 'main' seeing eye. My natural default would always tend to be my left eye however, up until my latest surgery 5 years ago when it seemed to become my right eye. As I say, though, I can alternate at will with no real difference to my vision and the other eye providing full peripheral function.
I hope to begin therapy at some point in the near future as and when funds allow.
Thank you once again for your reply.