Case 4 · Trainee

Double vision with impaired adduction

A 31-year-old reports horizontal double vision. On lateral gaze, one eye fails to adduct fully while the abducting eye shows nystagmus. Convergence is preserved.

Findings

  • Impaired adduction of one eye on horizontal gaze
  • Abducting-eye nystagmus on the opposite side
  • Preserved convergence
  • Normal head impulse test and hearing

Where does this lesion localise?