Vertical Strabismus

Vertical misalignment of the eyes: hypertropia (one eye higher), hypotropia, torsional deviation, or combination.

• Causes:
  • Cyclovertical muscle palsy: superior oblique palsy (most common), inferior rectus or superior rectus palsy in third nerve disease, and double elevator palsy.
  • Skew deviation from brainstem or vestibular lesions.
  • Dissociated vertical deviation (DVD) in early onset strabismus, with alternating elevation of the non-fixing eye.
  • Inferior oblique overaction (primary or secondary), superior oblique overaction with V pattern, Brown syndrome (superior oblique tendon sheath restriction), thyroid eye disease, orbital floor fracture, post-surgical (retinal detachment buckle, cataract block anaesthesia), and congenital fibrosis.
• Primary inferior oblique overaction and DVD are commonly associated with infantile esotropia.

• Vertical diplopia and torsional symptoms in adults; abnormal head posture (tilt, turn, chin down or up) in children.
• Superior oblique palsy: hypertropia worse on adduction and head tilt to the affected side.
• DVD: slow upward drift of the covered or dissociated eye with excyclotorsion, down drift on reversal, no corresponding hypotropia in the fellow eye (does not obey Hering law); worsens with fatigue or inattention.
• Inferior oblique overaction: upshoot in adduction; V pattern.
• Brown syndrome: limited elevation in adduction, a downshoot in adduction, clicking, and normal elevation in abduction, positive forced duction test.
• Thyroid or restrictive: limited elevation, raised IOP on upgaze.

• Three step test for cyclovertical palsy (identify hypertropic eye, whether worse in right or left gaze, and worse on head tilt right or left).
• Double Maddox rod test for torsion; fundus torsion on indirect ophthalmoscopy (fovea below the lower pole of the disc in excyclotorsion).
• Upright supine test: hypertropia that decreases by 50 percent or more when lying supine indicates skew deviation.
• Forced duction (traction) test for restriction; Hess chart or Lees chart.
• MRI brain and orbits for skew, associated neurological features, or no history of trauma in bilateral palsy; orbital CT for fracture or thyroid disease.
• Blood pressure, glucose, ESR in vasculopathic palsy; acetylcholine receptor antibodies if variable.

• Treat cause (thyroid disease, myasthenia, neurological causes).
• Prisms for small deviations (up to 10 prism dioptres); temporary Fresnel prism or occlusion for diplopia.
• Surgery (after 6 months stability for acquired causes) tailored to the pattern:
  • Superior oblique palsy: inferior oblique weakening (recession 10 to 14 mm to the nasal and posterior location or anteriorisation), superior oblique tuck (lax tendon), contralateral inferior rectus recession (3 to 5 mm) in downgaze deviations, or ipsilateral superior rectus recession; Harada-Ito procedure for excyclotorsion.
  • Inferior oblique overaction: inferior oblique recession, myectomy, or denervation and extirpation.
  • DVD: superior rectus recession 8 to 10 mm (or 6 to 10 mm, with or without posterior fixation suture), or inferior oblique anterior transposition.
  • Brown syndrome: observe in congenital, superior oblique tenotomy or spacer in severe cases; steroid injection near trochlea (triamcinolone 20 mg) for acquired inflammatory causes.
  • Double elevator palsy: transposition of horizontal rectus (Knapp procedure) and inferior rectus recession.
  • Skew: manage cause; prisms and botulinum toxin.
• Strabismus surgery complications include overcorrection, induced torsion, and Brown syndrome after superior oblique tuck.