Assuming your monitor is inside the range your eyes can focus on, if it's straining your eyes, you can try turning the brightness down, as well as using f.lux o

Assuming your monitor is inside the range your eyes can focus on, if it's straining your eyes, you can try turning the brightness down, as well as using f.lux or redshift to reduce the color temperature from ~7500K to ~3500K. You might appreciate the low color temperature even during the day, as it's less blue light for your eyes to deal with.