Multiple Sclerosis

In the course of multiple sclerosis (MS) progression or as an indicator of early disease, ocular motor disorders may arise, when certain brain areas are affected by inflammation or demyelination. Eye-movement disorders are observed in 40-75% of patients and demyelinating optic neuritis occurs in 25-35% of these affected patients.

Signs and Symptoms

Ocular motor symptoms are frequently observed in association with MS and include internuclear ophthalmoplegia (INO), saccadic smooth pursuit, gaze-evoked nystagmus and downbeat, upbeat or acquired fixation pendular nystagmus.

The severity of ocular motor symptoms can range from barely noticeable by the patient to severe debilitation and can point to early disease (in particular the INO in so far undiscovered disease) or exacerbation/progression of MS. 

Diagnosis

The diagnosis of MS involves several different tests that also serve to rule out other conditions that may produce similar symptoms. MRI scans of the brain and spine, analysis of spinal fluid and a bedside examination including the ocular motor system are frequently used methods to diagnose MS.

An algorithm provided by the National Multiple Sclerosis Association (USA) aims to support physicians in the diagnosis of the complex disease.

Observable ocular motor disorders

  • INO
  • Gaze-evoked nystagmus
  • Isolated horizontal gaze-evoked nystagmus
  • Upbeat nystagmus
  • Acquired pendular nystagmus
  • Saccadic smooth pursuit, often asymmetrical
  • Downbeat-, upbeat, or acquired pendular nystagmus
  • Hypermetric saccades 
  • Hypometric saccades

Reference

Graves J & Balcer LJ Eye disorders in patients with multiple sclerosis: natural history and management. Clin Ophthalmol., 2010, 4:1409-1422.PubMed