Oculopharyngeal muscular dystrophy is an autosomal dominant condition usually evident in the fifth decade of life. It is characterised by ptosis with progressive involvement of extraocular muscles until total paralysis of eye movements results. The pupillary reactions are spared. Flaccid dysphagia, flaccid dysarthria, facial weakness and proximal limb weakness are late features. Investigations reveal an elevated creatine phosphokinase - up to five times - and characteristic muscle biopsy - "rimmed" vacuoles in a proportion of muscle fibres. Treatment is supportive. Dysphagia may require nasogastric feeding. Death usually results from infection. It must be distinguished from myasthenia gravis and mitochondrial myopathy in which ptosis is also a distinctive feature.