In a patient with a lesion in the right paramedian pontine reticular formation (PPRF), the expected eye movement finding is:

• A Both eyes deviate to the right (ipsilesional conjugate gaze deviation)
• B Both eyes deviate to the left (contralesional conjugate gaze deviation) ✓
• C Right eye abducts but left eye cannot adduct (right INO)
• D Convergence-retraction nystagmus on attempted upgaze

Explanation

The PPRF is the horizontal gaze centre for ipsilateral conjugate horizontal gaze. A destructive lesion of the right PPRF impairs the ability to move both eyes to the right, resulting in both eyes deviating to the left (opposite to the lesion side, toward the hemiplegia side when associated with hemispheric stroke). This contrasts with a cortical frontal eye field lesion where both eyes deviate toward the lesion. INO is a medial longitudinal fasciculus lesion, not a PPRF lesion.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.