Most people have a dominant eye - which means the eye you prefer to use (more than the other one). To figure out what your dominant eye, place one thumb over the other (so the tip of one thumb is at the other one's base and vice versa) and then angle your hands so that you have a triangle sized opening (surrounded by hands and thumbs). Hold your hands up in this position and pick something across the room (or out the window) to look at. Close one eye, open it, close the other eye. You will see that the selected object is in the center of the triangle with one eye, and way off center with the other eye. The eye that had the object in the center of the triangle is your dominant eye. About 2/3 of people are right eye dominant, 1/3 are left eye dominant. Once you know what eye you prefer, you can adjust things to make this easier for your body - if you want to often refer to papers while typing, put them on the side of your dominant eye.
I have not thought about how a dominant eye preference would affect piecing. It would make sense to make sure that your dominant eye has a really good angle on the needle and the fabric alignment line/guide. Moving your chair more to one side or the other can help with this. (Unfortunately, some old-time sewing cabinets (like my mother's 1960s one) do not make it easy to move the chair sideways.)