inversion tables??

my lower back is really in pain on some days it's unbearable! Has anyone used inversion tables before and what were the results? I sometimes hang on my chin up bar to loosen up my lower back but it's not the same as hanging upside down.
I heard that anyone with high blood pressure or cluacoma should'nt use them because it increases blood pressure as well as increasing circulation to the heart/brain and other organs.
my back hurts and I need relief!
help!