Don’t let the picture scare you away from reading this. It’s easy to follow. Really. Easy, in fact, because its source is a wonderful paper entitled Effectively Reducing Sensory Eye Dominance with a Push-Pull Perceptual Learning Protocol based on principles that we know and love.
PERCEPTUAL LEARNING – Ooi et al – Current Biology 10
Published in a well-regarded journal, Current Biology, the paper is co-authored by Jingping Xu and Zijiang He from the Department of Psychological and Brain Science at the University of Louisville in Kentucky, and Teng Leng Ooi from the Pennsylvania College of Optometry at Salus University in Philadelphia. The concept of perceptual learning and neuroplasticity as applied to optometric vision therapy should sound familiar because our colleague, Dr. Fortenbacher and I have blogged about it.
So what’s the concept we already know that is virtually identical to the push-pull training that Xu, He and Ooi diagram above? It’s good ol’ MFBF – Monocular Fixation in a Binocular Field. (Okay, so it would be nice if researchers acknowledged that they’ve re-invented a clinical wheel. But let’s not get hung up in attribution of the concept – let’s embrace the support this research gives to the powerful mechanisms of MFBF.)
“Push-only training” is excitatory stimuli delivered through the weak or amblyopic eye, while the stronger or dominant eye receives no excitation. This is the approach taken when the only treatment for amblyopia is patching the better eye. “Push-pull training” is done with the weaker eye engaged in excitation while the stronger eye is simultaneously being inhibited. This is precisely what occurs in MFBF therapy, in which the weaker eye takes the lead, and the stronger eye comes along for the ride. This is commonly done in atropine penalization therapy, a passive pharmacologic version of MFBF, or more actively under anaglyphic or polarized conditions in vision therapy.
I reviewed the concept of MFBF as related to amblyopia therapy in a PowerPoint presentation included in an earlier blog entry during a seminar with SUNY Residents. Push-pull training principles go back to Schapero’s book on Amblyopia therapy 40 years ago, were popularized in an article by Dr. Allen Cohen, and detailed in a chapter on Amblyopia therapy in a textbook I’ve written – which is why all this is so near and dear to my heart.
The most exciting part of this paper is that the authors documented that push-pull training resulted in a learning effect on stereopsis, presumably through reduction on interocular suppression, even though the training stimuli carried no binocular disparity. We congratulate the researchers for re-discovering and applying the design principles of MFBF and bringing it to a wider audience of vision scientists in Current Biology. It lends further support to the power of optometric vision therapy.
– Leonard J. Press, O.D., FCOVD, FAAO
The VisionHelp Blog 
Interesting blog. I thought I was an avid reader, but you are a reading geek.
The topic rang a bell. I looked in: Kavner R, Suchoff IB. Pleoptics Manual, New York, New York; Optometric Center of New York, 1969 and found the bell. While the text is mainly on using the Visuscope and Euthyscope there is a section in therapy that goes beyond flashing the macular and direct occlusion. It is entitled “The Use of Colored Filters.”
“We can do this in a simple coloring situation. The practitioner draws a picture on a sheet of white paper with a red pencil. He places red-green goggles on the patient, with the red goggle in front of the better eye. The picture is now invisible to the better eye, and appears as a black outline to the amblyopic eye. The patient is then given the red pencil and told to color in the picture.”
I’m sure we didn’t invent the technique and as you point out, Allen really elucidated the concept beautifully and made it a defineable entity. So, keep up the good work in informing all of us of timely topics. I’ll bring the only copy of the manual that I have to Memphis in Feb. and you’ll probably read the 60 pages in 10 minutes.
Thanks for the perspective on that, Irwin.
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Len,
Nice blog. The technique is even more powerful when presented, not as stimulus-response, but as an opportunity for gaining voluntary control. The patient wears red-green glasses to that the green eye sees the target. Adjusting target size and distance, the patient is placed near threshold and instructed to look more out of the red eye (tapping the temple on the red side helps)until the target disappears. Then the instructions are reversed, the green eye now stimulated so the target can be seen. The procedure works much faster as the patient learns to voluntarily make the target disappear. Making the target reappear is a simple as doing the opposite. Thanks again for the blog.
You’re welcome, David. Thanks for the comments.
I would like to implement this push pull eye training method with my son. How can I find someone who employs these techniques or acquire the materials to do so myself?
First try a practitioner who is board certified in optometric vision therapy. See wwww.covd.org for a doctor locator.
Thanks Leonard. We have been seeing a vision therapist for 1 1/2 years now and seen mild improvement. They do not do the “push pull” and were unaware of it when I asked. They are the only option in my area. I was hoping to try and find so some who does that technique close by or do it at home myself.