Acid sphingomyelinase deficiency (Niemann-Pick disease types A and B)
Aug. 11, 2022
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Single Maddox rod test: measuring vertical ocular misalignment in patient with right fourth and sixth cranial nerve palsies. (A) Maddox rod is placed in front of right eye with cylinders stacked horizontally as patient views a bright light (not shown in this frame). (B) Patient sees a horizontal red line (with right eye) that is displaced below the light, indicating a right hyperdeviation. (C) Vertical prism bar is placed base-down in front of Maddox rod and positioned such that the patient reports that the horizontal red line has moved upward so that it now appears to the patient to pass through the fixation light. (D) The amount of prism-diopters (read off the prism bar) necessary to bring the light into this position is the measure of the degree of right hyperdeviation. (Contributed by Dr. Kara Warden.)