My Mum doesn't use the phone either, they just hold the iPad up towards her ear so she can hear my voice and I can see her. There is nothing wrong with her vision but her poor brain doesn't process visuals anymore. I once had an eye specialist explain it to me that with dementia it is like an oldtime photo developing centre, her eyes are the camera which take the pictures just fine, but when her eyes send the images to the brain for developing it is unable to process the images , so the final product is not recognizable to her.
I also thought not seeing her was sparing myself heartache, but in truth, seeing her today on Skype was no harder than going without seeing her for the last 2 weeks
It's hard not to despair but we carers have learned to just soldier on.
Stay Strong