Iris (Definition) The iris is a structure within the eye that helps reduce the amount of light that reaches the retina. The iris is known as the colored part of the eye, and can be blue, brown, or any color or combination of colors in between. The iris is the portion of the eye that responds to light stimulation. ...Read more.
Scientists also speculate that caffeine may provide a mood-boosting effect that helps ease pain. Regardless of the mechanism by which it works, the data does indicate that caffeine does indeed make pain medications more effective and help ease pain.
Caffeine can affect the body and brain in a number of ways. While it is most commonly used for alertness and mental focus, caffeine consumption does have other possible side effects that should not be overlooked. Blood vessel constriction, also known as vasoconstriction, is one of these potential side effects.