JillyB: noting your issues with your vision and joints, are you able to be physically active on a frequent basis, even if in very short bursts and at a very easy pace?
By active I mean, for example: brief walks before each meal, or sedate lane swimming (with goggles), or water aerobics for seniors, or seated aerobics for seniors, or tai chi, or gardening, or a few stairs instead of elevator/ lift/ escalator.