I EDC a Streamlight and honestly, I noticed it was getting harder to see things.
Then I lost it for a few weeks, and I realized that my vision was getting weak because I used that light constantly. Once I lost it, my near vision got markedly better, and I only really need a light on rare occasions. I think having a bright-*** light isn't the best for my eyes, it seems to make 'em lazy. So I try to only use it when I need it. Since I quit using it all the time, I don't need to use it all the time.
After seeing how easy it is for a lithium-ion battery to go full-on smoke and fire mode, I have also sworn off having these batteries in the house except in my cell phone (where it's almost constantly monitored) and my work-related laptop which only comes home on rare occasions before trips. I have an MP3 player that uses Li-ion batteries as well, and when it's charging, I make sure it's on a non-flammable surface and I'm still nearby (stove top or in the kitchen sink, while I'm watching a movie in the next room with an open door.) When it dies, I'll move all that crap to my phone.
I think soon enough we'll be seeing lawsuits from cops claiming that the regular exposure to bright-*** LED's in the light bars have damaged their vision, and I think the spotlights that they like to BLIND you with when you're pulled over ought to be illegal. That's just too damned bright.