Pupillary reactivity in children with recurrent abdominal pain.

Electronic pupillometry before and after phenylephrine instillation in the right eye was carried out in 18 children aged 10 to 16 years suffering from recurrent abdominal pain (RAP) and 15 age-matched controls. Before stimulation the pupillary diameter was almost equal in the two groups. After phenylephrine eye drops iris dilatation was greater in RAP patients than in controls, even though the difference was not statistically significant. These results seem to suggest children with RAP have a chronically disturbed receptor sensitivity in their iris neuromuscular junction caused by a sympathetic hypofunction, similar to that already reported in migrainous patients.