Opaque films adhering electrostatically to lenses of eyewear, are used to train baseball fielders and golfers. For baseball, the films, placed on the lower parts of the lenses establish opaque areas which encourage the player to follow a ball visually throughout its entire path of travel toward the player's glove. The opaque areas may have a convex upper edge or a concave upper edge. In the latter case, the training aid can be used, without modification to train the player in batting. For golf an opaque film covers one lens, and an opaque film having a lenticular transparent opening in its upper part is placed on the other lens. The films encourage the golfer to keep his or her head down and behind the ball during the downswing.