Fig. 6. Forced duction test. A. Inability of the patient to elevate the right eye on upward gaze. B. Using cocaine 10%, the insertion of the right inferior rectus muscle is anesthetized. C. The insertion of the inferior rectus is grasped with toothed forceps (Elschnig), and, with the patient looking upward, an attempt is made manually to rotate the right globe upward. D. For comparison, the left globe is manually rotated upward following instillation of cocaine.