[tracey1]

I really don't think it's that hard to understand. Watching TV doesn't demand a lot of focus, reading does. Watching TV or being on my computer or phone hurts my eyes as well by the way but working on an essay on MS word for instance demands more focus, hence it is more challenging to your eyes which is why I would love to have an E-paper monitor. Also, there's a pretty huge difference between ambient light and looking directly at a lit object, the light that's used in phones etc. also usually differs from domestic room lamps. Lastly, light sensitivity isn't necessarily tied to ametropia/defective vision.