The Misnomer of MFBF


MFBF.  Monocular Fixation in a Binocular Field.  There is even a Pinterest page dedicated to ideas for MFBF, demonstrating that the habitually amblyopic or suppressed eye is doing alot more than “fixation” in the binocular field.  These procedures need not be reserved for amblyopia.  There are times when one eye is really struggling with accommodative, ocular motor and other abilities relative to the other eye without meeting criteria for amblyopia based on acuity deficits.  Pursuits and saccades and alot of active cortical processing are involved, which goes to the heart of why this is such a powerful state in which to engage the patient.  Were I to re-name it, we should really refer to these procedures as MTBF – Monocular Therapy in a Binocular Field.  But that’s not as catchy as MFBF, so we’ll persist with the misnomer – kind of like persisting with ARC vs. AC in correspondence, or jump ductions vs. jump vergence in vergence therapy.

One of my staff, and I wish I could remember who gets credit for suggesting this, came up with the idea of adapting our NVR projector as an MFBF procedure.  The NVR is a very useful tool in vision therapy, as reviewed by Dr. Iwrin Suchoff in his JBO article on the product.  Dr. Dan Fortenbacher has a nice video with a sample NVR procedure on his WOW Vision Therapy Facebook page.  The modification that we made was to hang a red filter in front of the NVR projector that is suspended from the ceiling.

MFBF - NVR Projector

Done in this manner, the projection onto the wall immerses the patient in an MFBF environment, where the input through the eye viewing with the red filter captures a larger portion of the central field than usually occurs in such activities.  Take for example the Dynamic Ocular Motor Processing Field which looks like this:


As projected through the red filter it appears on the wall like this:



There’s another reason I like the idea of using projection MFBF, and it taps into the idea of the different regions of neuropsychological visual space that I blogged about here.  Much as MFBF is a bridge between monocular and binocular vision, NVR projection utilizing the hand or head controller is a bridge between peri-personal and extra- personal space.  Visual pathway preferences associated with right eye vs. left eye channel inputs can be different in different regions of space and this helps smooth out the continuum.

8 thoughts on “The Misnomer of MFBF

  1. We used to have an old-fashioned tachististoscope – the type with a shutter, and you could regulate the speed of the flash with a dial. We put a red filter over the projection stage and flashed the images through the filter – a sort of homemade way to practice speed of recognition.

  2. Another excellent example, Linda. Thanks for contributing ideas. There are many variations of projection MFBF. The old Brock StereoMotivator Technique used overhead projection with various acetates, some of which were monocular, some MFBF, some bi-ocuar, and then the three grades of fusion. From that we got the idea of taking any of the print targets we had, such as MacDonald Form Field, Lora’s Chart, VO Star, Hart Chart, etc. – and making acetates out of them for overhead projection. Placing a red acetate over this made for a great MFBF projection. The beauty of the NVR is that the feedback is directly integrated with eye-hand, eye-head, or eye-whole body interaction with the target through the hand controller, velcro head controller, or the platform.

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