Left side is a more balanced way to do make up in a rounded form on an eye, not such a great shape on the right eye, though you do see this type of makeup done now and then, but you will just turn into a “Koala”look, really nothing that helps the actual shape of the eye, you will take away the nice shape of the eye-bone/globe structure and make it look flat and don’t stop the “drop-shadow” in the middle of the eye, or just follow the contour of the eye underneath, in this sketch it just makes the eye more round, and that’s often the case, don’t do this without really making a decision before of what shape of the eye you really want to construct.