Estimates of the cost of invasive species to the United States alone are in the tens of billions of dollars yearly. Annual federal expenditures on prevention and management of invasive species are estimated to exceed $1.3 billion.
Depending on what specific conditions are. Some of the color we see when we close our eyes is light that gets thru the eye lid. It usually has a red componenet to it because of the blood veins. Sone, especially right after closing our eyes is the various elements in our visual system settling down (rods, cones, ...).
Your pupils will narrow as you change your focus to something in front of your face. You can start by closing one eye and placing your finger in front of the open one. With practice, you can learn to focus your eyes close even when there's nothing there.