CASE REPORT

In March 1996, a 52 year old man presented with a 6 month history of slowly deteriorating vision in both eyes. By the time he sought medical help he had difficulty reading the newspaper and watching television. He was otherwise well except for a chronic productive cough.

He had worked for many years as a teacher in Botswana. He was heterosexual. His only risk factor for HIV transmission was a single encounter with an African woman in the mid 1980s. In 1988 he had dengue fever and malaria. The latter was treated in the UK with quinine and fansidar. In 1995 he was treated in Botswana for a pneumonic illness. He was known to be hypertensive and was taking nifedipine, bendrofluazide, and atenolol. There was nothing else of relevance in his history.

On examination he was clubbed and had bilateral coarse crepitations. General examination was otherwise normal. Higher mental function was normal. Visual acuities were 6/18 on the right and 6/9 on the left. He had marked colour desaturation being able to read 2/17 Ishihara plates with the right eye and 3/17 with the left. Both visual fields showed a marked concentric constriction (Fig 1A). Funduscopy revealed bilateral optic disc pallor (Fig 2). Intraocular pressures were normal. Eye movements were normal. His visual evoked response was virtually extinguished on the right and was delayed and of small amplitude on the left. No …