Optic neuritis in an urban black African community

To describe the clinical profile of idiopathic optic neuritis in South African blacks.

South African black patients with acute isolated idiopathic optic neuritis, treated and followed for at least 3 months at a large medical centre, were studied. Exclusion criteria were other causes of optic neuropathy (such as ischaemic optic neuropathy, toxins or Leber's hereditary optic neuropathy); all causes of optic neuritis (such as HIV, neurosyphilis, sarcoid or connective tissue disease); neurological disease outside of the optic nerves; and any race other than South African black. Patients underwent extensive ophthalmic, neurological, radiological, cerebrospinal fluid and blood assessment.

Eighteen eyes of 10 patients were studied. The mean age was 35.7 years and 9 patients were female. Only 2 patients had truly unilateral optic neuritis, the other 8 having either bilaterally simultaneous or consecutive disease. Presenting visual acuity (VA) was less than 6/60 in 17 of 18 eyes, with severe dyschromatopsia in all eyes. Fifteen eyes had optic disc swelling. All patients were treated with corticosteroids. After at least 3 months follow-up only 6 eyes recovered VA of 6/12 or better, with only 3 eyes recovering colour vision of 10/13 or better on Ishihara plate testing. No patient had multiple sclerosis (MS) on presentation, nor developed MS on follow-up.

Idiopathic optic neuritis in black South Africans differs from that in whites. The higher prevalence of bilateral cases and of optic disc swelling, the weaker association with MS and the extremely poor visual outcome distinguish optic neuritis in black South Africans.