Those of us who are near- or far-sighted have a rigid focusing system so that the muscles that control our ability to focus are more stiff and inflexible than they need to be to focus clearly. Hold your hand up near your face and focus on it, and...
Those of us who are near- or far-sighted have a rigid focusing system so that the muscles that control our ability to focus are more stiff and inflexible than they need to be to focus clearly. Hold your hand up near your face and focus on it, and...