The Maddox rod should then be restored to its original position, with the plus and minus on the 90 degree line of the scale (Fig. 37), and rotated upward at the temporal end until it again takes the form of the letter “X”. (Fig. 40.) The position of the indicator will now denote the amount of right minus cycloduction, or duction range of the right superior oblique muscles. Having determined the duction range of the oblique muscles of the patient’s right eye, both Maddox rods should be placed in original position with rods horizontal and plus and minus sign on 90° of scale, as shown in Fig. 37. The Maddox rod before the left eye is then employed exactly in the same manner as before when the test for the right eye was made. A plus cycloduction of the left eye would be indicated, as shown in Fig. 40, while a minus cycloduction of the left eye would appear to the patient, as shown in Fig. 39. By recording a comparison of each eye, as explained, it will be found that the range of duction usually averages five to twenty degrees on either side of the 90 degree line, as indicated on the scale surrounding the Maddox rods. It will be recalled that cyclophoria was only to be looked for in oblique astigmatic cases. It is frequently possible to correct the patient’s trouble, by changing the axis of the cylinder, before one or both eyes, a minus cycloduction signifying a change of axis towards 180° while a plus toward 90°, according to the amount lacking in full duction power. It is also well to exercise the oblique muscles through a rotation of the Maddox rod before the affected eye, whether it be one or both that is lacking in full duction power, until the required amount is reached to equal its fellow member. For a more exhaustive treatise the author suggests a reading of Dr. Savage’s work on the subject. TREATMENT FOR CYCLOPHORIA As previously stated, it often proves of great benefit to employ a muscular exercise where a patient has an existing cyclophoria of either one or both eyes, results derivable through the exercise of the recti muscles having been previously detailed. To exercise the oblique muscles of the right eye, _both_ Maddox rods should be placed in the original position employed for making cycloduction test, as previously explained (Fig. 37). This causes the patient to see but _one_ band or vertical streak (Fig. 38). The Maddox rod, placed before the right eye, should be slowly rotated inward from ninety degrees to a point on the scale where the single streak of light breaks, when it should again be returned to ninety degrees. This causes a contraction and relaxation of the muscles in the form of an exercise and should be repeated ten times—about five minutes each day. By employing the Maddox rod before the left eye in precisely the same manner, its oblique muscles will be exercised.