I've read this too, I guess I'm still a little sceptical based on my own sample of one. When I was a child I spent loads of time outside, but also loads of time on the computer. I guess the computer won. I also don't understand how they separated out "doing close work" from "being indoors". You'd need a control group of kids who spent a lot of time indoors WITHOUT doing much close work. So what would they be doing instead? Even if you're not reading, surely all indoor activities involve somewhat close work. Watching TV or playing console games might not have met the researcher's definition of close work, but they still involve focusing ones eyes at a point closer than infinity.