Seems this is a proper PVA or P-MVA panel, so unless it's broken it shouldn't be any worse than a modern screen, for trading purpose. I still have plugged in an old NEC1860nx IPS, which despite poor contrast is still the most comfortable to watch, due larger pixel-size/pitch. Of course it's very important that text and graphs must be 100% crisp. If it's tuned off I also get eye strain.
On Windows 7 you should not use smoothed font edges. It makes all text blurry. So:
Start > Adjust the appearance.... > uncheck "Smooth edges of screen fonts"
Distance to screen, if too far or too near, will stress the eyes. But that you should feel naturally.
One sure thing I have changed to reduce eye stress is to make all charts darker. Ideally no whites on the screen at all. My charts have black background, with boring dark gray and light gray bars. In my experience the amount of light your eyes take in is proportional to their stress. Other earth-tone colors may work well too. This also relates to light source behind your screens, a window is nice, but if too bright may be stressful.
Finally, if these things were already in order, I'd look to health, fitness and nutrition, for the source of your problem. And other life stress factors. Taking breaks, short and long, obviously is also helpful.
I just bought electric legs for my desk, so I can alternate standing and sitting. Long hours sitting is not really good for the lower back. And it's great exercise to stand compared to sitting. Who knows, it may even heal your eye strain. The body is one.