The last couple times I've gone riding (about 20-30 degrees) my fingers have been getting numb. The first time I wore regular Thor riding gloves which weren't well insulated at all. The next day I wore regular multipurpose winter gloves, my hands got pretty cold but not numb, when I took the gloves off I realized there was a hole in them.

 

There are so many things that can contribute to numbness so it is hard to say. You might be resting your arms on the edge of the desk and that could be causing you to cut off circulation... you might be over using your thumb etc. If you are right handed, chances are you play video games with it the most, and you use it to hit the space key too. Pay a little attention to hand position during the day and see if there are things you can do to help. I also recommend one of those split keyboards where the keys are split and are turned a little. It works wonders once you get used to it. The hand position is very important. I think doctors rush to diagnose Carpal tunnel, and order surgery when there are so many things that could be tried first. I'd recommend surgery as a last resort.