Final answer:
The Parks 3 Step Test helps diagnose which extraocular muscle is dysfunctional, causing vertical diplopia. The patient's symptoms point to a possible issue with one of the right eye's cyclotorsion muscles. Extraocular muscles, innervated by cranial nerves, are essential for coordinated eye movement, and issues with them can lead to diplopia.
Step-by-step explanation:
The Parks 3 Step Test is a clinical tool used to identify the muscle involved in a case of acquired vertical diplopia, by determining the dysfunction of extraocular muscles, particularly the vertical movers: the superior and inferior obliques and the superior and inferior recti. In the scenaro described, where a patient's right eye is higher in the primary position and the hyperdeviation worsens in gaze to the right and with head tilt to the right, the muscle with the highest probability of dysfunction (3 circles in the Parks 3 Step Test) would typically be one of the right eye's cyclotorsion muscles, either the superior oblique or the inferior oblique. However, the answer to which specific muscle is implicated would require further clinical investigation and testing.
The extraocular muscles are responsible for eye movements and are innervated by cranial nerves III (oculomotor), IV (trochlear), and VI (abducens). They are interconnected by the medial longitudinal fasciculus (MLF) to coordinate conjugate gaze. Diplopia, or double vision, is a common symptom when any of these muscles fail to function properly, leading to non-conjugate eye movements. Testing for convergence and accommodation uses the accommodation-convergence reflex, involving both skeletal muscles for convergence and the smooth muscles of the ciliary body for accommodation.