Editor,—Vitamin A deficiency remains a leading cause of blindness worldwide with xerophthalmia affecting 5–10 million children, resulting in 250 000–500 000 new cases of blindness each year. In the developed world, vitamin A deficiency is rare and usually occurs in the setting of malabsorptive states (such as cystic fibrosis and small bowel disease), liver disease, or malnutrition. Xerophthalmia is a medical emergency carrying a high risk of blindness, infection and death. Immediate administration of massive doses of vitamin A is required. Such rapid restoration of vitamin status is felt to be extremely safe at recommended doses. Appropriate dosing regimens in infants have been less clear than in older children and adults.1 Reports of side effects are limited, and therefore we report a case of acute sixth nerve palsy in an infant receiving intramuscular vitamin A for xerophthalmia secondary to cystic fibrosis.