I would suggest keeping an open mind about the PCS. Just because vision issues and therapy have provided the most improvement does not mean that your daughters' brains were not injured. My most problematic symptom is visual. Second to that is auditory. When I close my eyes, my auditory functions improve markedly. Too bad I can't drive with my eyes closed.

The way I understand it is this. Each sense requires a minimum number of processing cells to process that sensory input. Lets just use tactile, visual and auditory. Say you need 100x cells per sense. You have 300x shared between tactile, visual, and auditory. If 20 visual cells are damaged, the tactile and auditory cells can 'donate' 10x cells to visual processing.

The more realistic example would be a blind person who now has 150x cells for tactile and 150x cells for auditory. Now, both tactile and auditory sense have 50% more processing power. The ability to process Braille and the taps of a cane on the sidewalk has now improved greatly.

The receptors in the eyes that process color (cones) specialize in a specific wavelength (color spectrum) L (long wavelength) is for yellow, M (medium wavelength) is green and S (short wavelength) is violet. With the tinted lenses, a specific wavelength is blocked. It is likely that this wavelength had been overpowering the brain as compared to the other wavelengths. This resulted in processing chaos.

The prism lenses work similarly. The brain dedicates a great amount of processing power when it merges the image from each eye. If the image is too divergent, this process requires an overload of processing power. Or, some of the brain cells that do this merging may be damaged limiting how divergent the images can be that are merged. The prism moves the images closer so the brain has less work to do to merge the two images.

My father needed prisms decades ago as he started developing chronic encephalopathy ( brain atrophy) from oxygen starvation to his brain from chronic sleep apnea. The prisms lightened his visual load immensely.

I think the gist of this issue is that your daughters' brain may need to have a lessened sensory work load to function and top capacity. There are plenty of skills and work-arounds to help with this situation. Hopefully, the vision therapists, etc. can direct you to some of these skills.

Just remember, their brains have already shown how they react to trauma. Please help your daughters understand their need to avoid future injuries. Life is too long with too much to enjoy to lose out to Multiple Concussion Syndrome. Their injuries of today will become much more evident as they approach mid-life (40 to 50 years old.) They will have plenty of risk of head impacts from just ordinary daily activities. Walking on to an athletic field is a serious choice to ponder.

The NCAA, NFL and NHL are all giving concussions a serious look as they try to reduce the life long disability concussions can cause.

My best to you.