y'all please dont follow this tutorial anymore -- its very old, i did it when i was 13 and thought my art was the best thing ever. its outdated, inaccurate and I'm actually pretty ashamed of it haha, i'm only keeping it up because so many people used it.
for better eye tutorials please visit deviantart or study real eyes !! the latter is the best option, imo.
Thank you to all who tried it, even if I cannot advise to use this method now!