Eye care in the community: Part 10 – Optic neuritis

Optic neuritis describes inflammation of the optic nerve. This may be behind the globe, retrobulbar, involve the optic nerve head, papillitis, or sometimes affect the retinal nerve fibres, neuroretinitis. It may be idiopathic in those tending towards the condition, or triggered by an exogenous cause. Consider the following two cases.

Case 1
The mother of 16-year-old MR rang the practice explaining how her son had returned from holiday complaining of floaters in his left eye together with blurry vision. There was no reported pain and the teenager was keen to point out that he had not participated in any alcohol or drug misuse while on holiday. No other triggers for the event were identified, such as temperature changes from a hot bath or vigorous exercise.

Ocular examination
• No medical history; ‘fit and healthy’
• No family history of demyelination, though the mother had been diagnosed with Raynaud’s syndrome
• Visual acuity:
• R 6/6 N5
• L 6/6-2 N5.
• No colour vision defect detected in either eye
• Slight reduction reported in the brightness of light with the left eye compared to the right
• No ocular muscle abnormality and no pain or restriction on eye movement
• Left relative afferent pupillary defect
• Left vitreous showed vitreous floaters or inflammatory cells
• Fundoscopy revealed a swollen left optic disc with few haemorrhages and venous tortuosity (figure 1: Right optic disc appears normal with a visible capillary network on OCT-angiography. The left optic disc appears swollen, with haemorrhages and no cupping seen on the 3D image. OCT-angiography shows tortuous veins and poor visibility of the capillary network)
• OCT; swollen optic disc with superior and inferior disc thickness of 194 microns.
• OCT showed cells present in the vitreous body (figure 2) and swelling of his Henle nerve fibre layer