Optic neuritis

Causes of optic neuritis: main cause is demyelination(MS), less common viral, vasculitis.

Clinical features:

1. rapid loss of vision - central scotoma with RAPD.
2. Pain on eye movements - stretching of the inflammed nerve fibre
3. Fundoscopy - optic disc can be normal or swollen. Optic atrophy develops months later.
4. vision usually improves in weeks.

Investigation:

1. MRI - to rule out MS.(plaques) Look for retrobulbar involvement or other brain plagues.