You didn't include "none," which fits me since I can't see the rear screen without reading glasses.
Nor can I ... but I still have one.. and a
Matin LCD viewfinder which is excellent and travels with the camera. Without this, the camera would indeed be useless in some situations. Hangs round your neck and when you need it, apply it to the back and hold in place with your eye/face. You can tie it on if you want a permanent fit. It is a low magnification and adjustable so you don't need to wear glasses.
Seems the example I have is optically good and well made. This is on a Quattro so I don't know how well it would work on earlier cameras, if they are ~3in LCD screens it likely will. It is rubber coated all over- so is not going to scratch the back or the camera.. and much, much cheaper than an optical finder or the Sigma equivalent. No excuse not to add one or indeed many of these cameras to your collection :-D
go for it!
James