Assuming you have Anisometropia (difference in prescription strength between the two eyes), this is only half the deal. You'll additionally want so called /Ise

Assuming you have Anisometropia (difference in prescription strength between the two eyes), this is only half the deal. You'll additionally want so called /Iseikonic/ glasses, which equalize the magnification/minification between the two lenses, AND THUS also equalize the angles of prismatic diversion induced outside the center of vision by glasses. This SIGNIFICANTLY reduces eye strain.