Hmm, it may be an actual function of my weak vision. When I get further from the screen, it gets hard for me to see any of the dots. So next I tried to get very close to the screen (normally I keep my monitor pretty far away) and I was able to see about 8 of them at once. I'm guessing having a smaller monitor might help too, based on the article, since I suppose they would be less in our peripheral vision then.