Parks Three Step

  • Superior Rectus (RSR)
  • Superior Oblique (RSO)
  • Inferior Oblique (RIO)
  • Inferior Rectus (RIR)
  • Superior Rectus (LSR)
  • Superior Oblique (LSO)
  • Inferior Oblique (LIO)
  • Inferior Rectus (LIR)

Left Hyper Right Hyper Which eye is hyper deviated in primary gaze?

Left Gaze Right Gaze Right Gaze Left Gaze Is the vertical deviation greater in right gaze or left gaze?

Left Tilt Right Tilt Is the vertical deviation greater with right head tilt or left head tilt?

The Parks Three Step test (also know as Parks-Bielschowsky Three Step Test as well as the Parks-Helveston 3 step test) is used to isolate a paretic extraocular muscle in acquired vertical diplopia or double vision. It is not effective for use in assessing horizontal diplopia and it is not reliable in patients with prior strabismus surgery. The test is more reliable with recent onset diplopia. Because of the spread of concomitance, eventually the muscle actions that the test relies on become more difficult to isolate. By calculating the vertical deviation in primary gaze, left and right gaze, and right and left head tilt, the Park's Three Step Test is able to eliminate each muscle's primary field of action. Eventually the affected muscle will be the only one remaining.