Im on the computer all the time with my 21" CRT, he should have turned the HZ up to 85... no flicker at all.
He did... but his eyes are the same age as mine... about 57 years old. There is still a flicker, especially if there is any ambient lighting at 60Hz... you get beat frequencies that can really strain your eyes. He worked in an office with a lot of fluorescent lighting. Incandescent lighting is better because the filament stays white hot despite the alternation of the current.
After the upgrade, the fluorescents were still present, but the headache and eyestrain were gone. I have made similar recommendations to my clients... including several optometrists with similar results. People really don't realize that they are frogs swimming in hot water until you take the hot water away and plunk them down in a cool pond.