Using Red and Green: In Black and White – Part Five
Fifty Shades of Green…and Red
When Part 4 concluded last week, we had covered many aspects of how and why to use red and green filters. After a brief bout with writer’s interruptus (yes, I made it up), it’s time to complete the journey.
One common perception, or dare I say misconception, is that all red/green activities are essentially accomplishing the same goal, making them interchangeable. While there a few groups of activities that go together, some of the common ground in the activities ends there. Here are some general ideas of where the many red/green activities we all do may fit.
Maintain The Lock
When working with a patient with Strabismus, MFBF activities (Monocular Fixation in a Binocular Field) usually is done with red/green filters. Using the appropriate filter/filter or filter/target combination, the Vision Therapist can arrange conditions so that the ‘weaker’ eye is the only eye capable of viewing the target, although both eyes are open and seeking input. This works because with both eyes open, the patient is able to maintain a ‘lock’ of peripheral fusion, which would be impossible were they wearing a patch. This process becomes invaluable in treating strabismus whereby suppression is deeply embedded. MFBF is also an important step in eliminating Amblyopia and/or eccentric fixation (if present) by way of keeping both eyes in the same field and “paying attention”. This is, of course, a general guideline for MFBF setup and as always, the setup will be patient specific and should be discussed with the doctor prior to implementation.
One of my more favorite activities to have a patient attempt goes by the name of Lustre. The crux of the activity is to have the patient view a flashlight while wearing red/green filters and ask them to report their findings. Among other areas, the activity builds simultaneous perception. The reason there is so much value for me is that there are many variables to manipulate that challenge the patient in various ways. For example, distance from the flashlight, back-lighting in the room (this activity is far different in the dark vs a lit room), moving to different fields of gaze, and making the target static or dynamic are all areas that can be probed. This is also interesting to me because much like SILO, Lustre occurs in the brain and of yet, is not a phenomenon that can be recreated in a photograph; making it a great tool for self discovery.
Anaglyphs, which can be one of the strongest and most successful activities we will use, are an example of how we work in the therapy room to improve binocularity. Without much in the way of relative accommodative demand, this target allows for work more specifically on the convergence and divergence ranges on a gross peripheral basis, allows the patient to experience feeling tone with the different postures, allows for an initial localization attempt, and provides an opportunity for parallax. The Therapist can choose a target which does not offer much in the way of a central, or focal, target which will help build strong peripheral fusion. This is important because we can have the patient gaze in ‘towards’ the target while learning how to rely on their periphery to appreciate the changes in size and depth, or SILO. You may have noted that many of the benefits of Anaglyphs are similar that of Vectograms and again, your particular setup will be patient specific and should be discussed with the doctor prior to implementation.
Take A Look For Yourself
Following one of my earlier posts in this series, there was a conversation in email in regard to how a red/green setup might be referred to as MFBF and/or bi-ocular. In researching this idea – meaning I asked someone else who knows more than me – I found these concepts to be very nuanced. Or more simply stated, some offices use red/green early and often, some hardly ever, and many at different times for different reasons. None of these choices seem better or worse; rather, it seems to be personal preference. The best way to understand if your particular red/green activity is for anti-suppression, MFBF, bi-ocular or strengthening binocularity is to refer to your Developmental Optometrist and really seek a detailed explanation. Or as I often tell Vision Therapists I mentor, “work to understand the why”.
The real value in all of this, both in my writing and hopefully in your reading it, is to identify and remind us all of how red/green can be a powerful tool and how building your knowledge base around its uses can be extremely useful. And so, my friends, I leave you with a small and important challenge. During your next staff meeting, pull out an activity that involves red and green filters and review some basic concepts with your doctor and VT staff. Try starting with:
- What is this activity addressing?
- Where does it fit in our VT hierarchy?
- What is the desired outcome?
- Where do we go from here?