Which three components are evaluated in Parks three-step test?

Which three components are evaluated in Parks three-step test?

• A. Gaze direction, saccade direction, and head tilt.
• B. Ductions, versions, and vergence.
• C. Pupillometry, accommodation, and vergence.
• D. Visual acuity, diplopia field, and head position.

Answer: (A)

Parks three-step test uses how a vertical misalignment behaves as you change where the patient looks and how their head is tilted, to pinpoint which muscle is involved. You start by noting which eye sits higher in the primary position. Next, you check in which gaze direction the hypertropia becomes largest. Finally, you tilt the head to either side to see which tilt makes the deviation worse. This trio of observations—which eye is hypertropic in primary position, how the deviation changes with gaze, and how it changes with head tilt—lets you infer the responsible cyclovertical muscle. The option that includes gaze direction and head tilt aligns with the key dynamic factors tested by Parks, since these two variables are central to revealing the pattern of the misalignment. The third element, identifying which eye is hypertropic in primary position, is the baseline observation that accompanies these maneuvers. The other choices don’t reflect these critical components of the test.

Parks three-step test uses how a vertical misalignment behaves as you change where the patient looks and how their head is tilted, to pinpoint which muscle is involved. You start by noting which eye sits higher in the primary position. Next, you check in which gaze direction the hypertropia becomes largest. Finally, you tilt the head to either side to see which tilt makes the deviation worse. This trio of observations—which eye is hypertropic in primary position, how the deviation changes with gaze, and how it changes with head tilt—lets you infer the responsible cyclovertical muscle.

The option that includes gaze direction and head tilt aligns with the key dynamic factors tested by Parks, since these two variables are central to revealing the pattern of the misalignment. The third element, identifying which eye is hypertropic in primary position, is the baseline observation that accompanies these maneuvers. The other choices don’t reflect these critical components of the test.