Refsum disease (heredopathia atactica polyneuritiformis) was first described in 1946 and is a rare recessively inherited metabolic disease affecting phytanic acid metabolism. It causes retinitis pigmentosa, cataracts, a chronic polyneuropathy, cerebellar ataxia and cardiac arrhythmias amongst other clinical signs. By limiting dietary intake, plasma phytanic acid levels fall with an improvement in the neurological signs. The onset of retinitis pigmentosa usually precedes biochemical diagnosis by several years by which time the retinal damage is severe. A series of 23 patients have been reviewed. There was an average delay of 11 years (range 1-28 years) between the patient presenting to the ophthalmologist and being diagnosed as having Refsum disease. Although serial examinations have failed to show a definite change in the course of visual deterioration with treatment, early diagnosis is important to prevent the development of neurological disease.