It is so sad that Hannah's lost her sight but I promise she will manage ok.
Animals seem to accept easier than humans as they don't live in the past just the now, and her other senses hearing, smell, touch, taste will take over the loss of her eyesight.
I can speak from experience as my Tess went slowly blind and we all coped fine for quite a few years and she didn't miss out on a thing......
Sadly she went deaf as well over time and it was only then that she lost her will to live (her being in a dark place and not hearing) only touch and smell, she went off her food and would only eat 'big soup' as it was smelly, hot and easy to eat, after a mild stroke she stopped eating and the kindest thing we could do, we did.......
Edited: to say she did live until 16 yrs old!
Live everyday like it's your last and don't put off until tomorrow what you can do today.....
Lots of treats and hugs and act as normal as you can, make sure there's no sharp corners on furniture and doors are left open all the time oh yes and have a centrifugal living room (everything against the walls), BTW the different air freshners in each room is a good idea.