I wasn't sure where to post this question. Professional traders: what color background do you have on your charts? Black, white, some other color? My eyes are getting very dry from staring at the monitors all day!
I doubt it is from the colors. Try Visine or something. FWIW, I have light color backgrounds on my charts, with different colors for 3 to 8 symbols I usually trade.
Light, dark or gray themes; try to lower the contrast between your background and the candles & indicators. Force yourself to take breaks to rest and refocus your eyes.
What size screen and resolution do you have? Maybe you need a bigger monitor with a higher resolution. Try increasing the font size of the numbers on the scale of the charts. In a browser do ctrl plus several times to make the font size larger (ctrl Minus to make it smaller).
When I was a sniper in the Marine Corps we were told to focus on something green for as long as possible before taking the shot to rest the eyes. Never missed!! So I have a black background with green bars.