Yes you can, but the third sentence is not using the idiom" my eyes are deceiving me" or a version of it. we usually say "my eyes are failing me" if we are using it to make a statement about our eyes being/getting old. However I have heard it used in the same way as "my eyes are deceiving me" (probably by non natives) Deceive = to trick. Fail= to stop working or not work as well. unless my eyes are deceiving me unless my eyes are not deceiving me if my eyes don't deceive me if my eyes are not deceiving me if my eyes aren't deceiving me ------- my eyes are beginning to fail me, I am getting old my eyes are starting to fail me, I must be getting old. you can swap interchange beginning/starting in any sentence