Pupillary light reflexes in premature infants prior to 30 weeks postmenstrual age.

Data regarding the pupillary responses in very premature neonates is scarce; what data exist, moreover, is not recent. The purpose of this pilot study is to collect data on direct and consensual pupillary light responses before 30 weeks postmenstrual age. Six neonates were studied. Mean pupillary size at rest was 3.6 +/- 0.4 mm. No direct or consensual responses to light were present in any of 12 eyes. Accurate information about pupillary reflexes in very premature neonates provides relevant information about the development of the visual and neurologic systems. Available information about the development of the Edinger-Westphal nucleus, sphincter pupillary muscle, optic nerve myelinization, and autonomic nervous system is briefly reviewed.