Article Text

Novel diagnostic procedure
An unusual presentation of optic neuritis and the Pulfrich phenomenon
  1. Maeve O’Doherty1,
  2. Ian Flitcroft2
  1. 1
    Mater Misecordial Hospital, Eccles St, Dublin, Ireland
  2. 2
    Mater Hospital, Ophthalmology Department, Eccles St, Dublin, Nil, Ireland
  1. maeveodoherty{at}


The Pulfrich effect (named after Carl Pulfrich) is a well described visual stereoillusion observed when a swinging pendulum bob is viewed through a neutral density filter in front of one eye. The Pulfrich effect can be demonstrated spontaneously (ie, without a neutral density filter) in patients with multiple sclerosis because of the delayed optic nerve conduction seen after unilateral optic neuritis in multiple sclerosis. Here, a Pulfrich effect is described in a man with subclinical multiple sclerosis who only became symptomatic when playing squash.

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  • Competing interests: none.