Anecdotal. Try again.It states it guy's post who took the 2 cell phones up.
https://discussions.apple.com/message/7877266#7877266
But you can demonstrate for yourself. Put your finger on your monitor and lightly press it and watch the distortions take place under your finger pressure. This happens because the lcd is pressure sensitive. The same thing happens at altitude but in the opposite direction. Instead of the vessel being pushed in it gets expanded outwards. The voids created start looking black.




