Emergency Medicine

Further Reading

Ophthalmic Emergencies 425

Optic neuritis

DIAGNOSIS

1 This may be idiopathic, post-viral or associated with demyelination from
multiple sclerosis. It is more commonly unilateral but may occasionally be
bilateral.

2 There is progressive loss of central, particularly colour vision over hours to
days, wit h pain on mov ing t he eye.

3 Visua l acuit y is reduced, and a R APD (Marcus Gunn pupil) is seen.

4 Look at the fundus for papillitis if the optic disc is involved. This must be
distinguished from papilloedema:
(i) Papilloedema tends to be bilateral and pain-free with normal
pupil responses.
(ii) There is little or no visual loss, but an enlarged blind spot is
found on field testing.

5 Examine the patient for other signs of demyelination.
(i) Never inform him or her of your suspicions at this early stage.

MANAGEMENT

1 Refer the patient to the ophthalmology clinic.

2 A lumbar puncture or MRI followed by parenteral steroid treatment such as
methylprednisolone 250 mg i.v. q.d.s. for 3 days may be indicated for
demyelination.

FURTHER READING

Cochrane Collaboration. http://www.cochrane.org/reviews/en/topics/63.html/
(Cochrane review topics: Eyes and vision).

NSW Department of Health (2009) Eye Emergency Manual. An Illustrated Guide,
2nd edn. http://www.health.nsw.gov.au/resources/