I have used a balans-type (kneeling) chair for over 15 years. Mine is has rollers and is heigh adjustable. I can sit in it for hours at the computer, and my particular flavor of back problem does not like sitting in a regular chair for too long. This is not for everyone - can be awkward to get in and out of until you are used to it, but it works well for me. If you have a relax the back type store, I'd recommend checking one out to see if it suits you. Kneeling Chair With Memory Foam | Relax The Back
They come in many options - I'd recommend the memory foam version.