Stop that annoying Blue light in the daytime or night time.
Do you really need a screen calibrated to 6500k?
Try looking at a screen with the settings wound down to a nice 3600k florescent or 2700 tungsten colour. Much more relaxing on the eyes. Crappy colour = more relaxed eyes. Go figure. The Human eye is least sensitive to red and most sensitive to green. Do you remember the old CRT screen TV set? The tube had a green cast when it was old… the red gun in the colour emission wore out faster because it had to work harder, leaving the green and blue colour guns to dominate the colour on the screen. Here is a quick question for you… Why is the human eye most sensitive to green? Ans: Because we are hunters and gatherers and our ancestors lived in the green jungle. (if you believe in evolution)
Search this free software on the web, available for Mac or Windows. The photos of the screen below: left is at 2700k, right is at 6500k. The Nikon D5100 has tried to reproduce the colours exactly, there is a big colour shift between the two.
I can work for hours at night with 3200k but if I do with 5000k… I will have sore eyes and a bad sleep. Read the research at f.lux website.