Overview

• Inflammation of the optic nerve
• Most common cause → Multiple Sclerosis (may be presenting manifestation of MS)
• F>M, typical age range 30-50 yrs old

Making Diagnosis

Clinical Features:

• Vision Loss → occurs quite quickly, over hours to days
• Decrease in visual acuity over days to a couple of weeks with scotoma → described as seeing through cloud or fog
• Peri-Orbital Pain → exacerbated by eye movements
• Colour desaturation → colour of objects not as bright as before
• RAPD (Relative Afferent Pupillary Defect) → sign observed during the swinging-flashlight test whereupon the patient's pupils (both) dilate when a bright light is swung from the unaffected eye to the affected eye (afferrent = optic nerve, efferent = occulomotor nerve, afferrent defect in this case).
  • RAPD Explanation
• Optic Disc Swelling → papillitis
• Symptoms of MS

Investigations:

• Gadolinium-Enhanced MRI of Orbit and Brain → may show enlarged optic nerve and help diagnose MS too.
• Swinging-flashlight test → for RAPD