Big problem, Easy solution?

Due to poor eyesight, my elderly mother struggles to be able to ascertain whether or not the microphone & speaker are engaged or disengaged when someone rings the bell. The only indicator, is a small faint vertical line. That's difficult to see if the user does not have good eyesight. A very simple solution might be to make the icons green coloured when engaged. And red coloured when disengaged? I imagine a fair portion of the market caters to elderly members of the public, and we all know that elderly people rarely have good eyesight, therefore I am really surprised that this issue exists. I'm positive that I cannot be the only person that has experienced this problem. Do you have plans to address this issue? If not, I think it needs serious consideration. Thanks, Jason M.