Look, if you haven't felt weird sickness, eye fatigue and headache while using iOS 7 then you're not susceptible to whatever subtleties in the design are causing a growing number of people to feel it.
It's not a spontaneous mass conspiricy to mess with Apple. I have used and loved Apple products for over 23 years. I have to say; It's not helpful to come on here and brow beat and dismiss others who are having a very real reaction to iOS 7.
If you're not experiencing headache and nausea using iOS 7 then consider yourself very lucky. I envy you because not only is it physically near debilitating but there is also an emotional edge to it as well, I found myself sinking into depression everytime I was overcome by iOS 7 nausea.
Furthermore, if physical and emotional effects can be triggered so easily by using these kinds of devices, there is probably a larger conspiracy to be addressing.