It includes the inflammatory and demyelinating disorders of the optic nerve.
Hereditary : Leber's disease
Demyelinating disorders: multiple sclerosis, neuromyelitis optica
Mumps, measles, chicken pox, whooping cough and glandular fever
Acute ethmoiditis, syphilis,
Anatomical types :
Papillitis- involvement of optic disc
Neuroretinitis - combined involvement of optic disc and surrounding retina in the macular area
Retrobulbar neuritis - involvement of optic nerve behind the eye ball
Visual loss - sudden , progressive and profound visual loss
Dark adaptation - lowered
Impairment of colour vision
Impairment of depth perception (Pulfrich's phenomenon)
Pain - mild dull eyeache
Episodic transient obscuration of vision (Uhthoff's symptom)
Reduced visual acuity
Impaired colour vision
Marcus Gunn pupil - RAPD
Visually evoked response reduced
Ophthalmoscopic features : disc become oedematous and physiological cup is obliterated
Visual field changes : central or centrocaecal scotoma
Corticosteroid therapy may shorten the period of visual loss.
Oral prednisolone therapy alone is contraindicated in the treatment of acute optic neuritis.
Brain MRI scan - If the brain shows lesions supportive of multiple sclerosis, immediate intravenous methyl prednisolone (1 gm daily) for 3 days followed by oral prednisolone (1mg/kg/day) for 11 days.
Indications of intravenous methyl prednisolone in patient with normal MRI :
Visual loss in both eyes
When Only good eye is affected.
When slow progressive visual loss continue to occur.