Pupillary dysfunction as a concomitant of cystic fibrosis.

This study extends previous observations on pupillary reactivity in patients with cystic fibrosis by carrying out measurements of pupillary dilatation and constriction under conditions of rest, stress, and after termination of a painful stimulus (homeostatic recovery) on 9 well children and 11 children with cystic fibrosis. At rest a significantly diminished rate and absolute level of dilatation was confirmed in the cystic fibrosis group with no difference in the two groups in pupillary constriction. During stress, the cystic fibrosis group showed a significantly smaller increase in pupillary dilatation and decrease in pupillary constriction than the normal group. During homeostatic recovery, the cystic fibrosis group showed a much slower response of the stress, darkadapted pupil diameter requiring 12 minutes before returning to the rest level while the normal group fell below the rest level within 1 minute. With respect to pupillary constriction, the normal children showed significantly smaller pupil diameters through the period of homeostatic recovery. The results of these studies suggest that the generalized derangement of exocrine glands in cystic fibrosis may be concomitant with a dysfunction of the autonomic nervous system.