Optic neuritis

It's inflammation of the optic nerve. According to the anatomical site of inflammation two entities are recognised 1) retrobulbar Neuritis 2) papillitis.

Etiology :

The first cause which must be considered in both entities is demyelinating disease i.e multiple sclerosis. Other causes are infective diseases whether bacterial or viral. The optic nerve may be also involved in nearby inflammation from the brain, orbit or nasal sinuses. Uveitis and rhinitis may cause secondary papillitis.

Clinical picture:

1) retrobulbar Neuritis:

The condition is usually unilateral.

Symptoms:

The patient typically complains of defective vision of variable degree, defective Color vision and pain on moving the eye.

Signs:

Fundus examination is normal. Relative afferent pupillary defect can be detected.

Investigations:

1. Visual field commonly shows central scotoma.

2. Pattern visually evoked potential may detect increased latency.

3. Brain MRI may reveal demyelinating plaques.

2) papillitis :

Signs:

The optic disc is edematous and hyperemic it must be differentiated from papilledema the later is almost always bilateral without diminution of vision.