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.
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.