Pupillography provides information on the vegetative nervous system. It is an important tool for critical care patients on ICUs. The NPi200 provides normal data only for a compound result (NPI). Therefore, we performed pupillography on healthy control persons derived from our department to establish further normative data.

To establish normal values for healthy adults for the hand held device NPi200, a tool widely used in neurological clinics, and to examine if an all-age control group was sufficient or if the normative data should rather be grouped by gender and age.

108 healthy adults (51w/ 57m, 20-83yrs.) took part. Those with previous operations on their pupillary complex or medications known to influence pupillary functions (e.g. beta blockers cholinergic agents) were excluded. Both eyes were examined with an NPi200 under standardized illumination conditions controlled with luxmeter. The pupillary diameters, the percentual change due to light, and contraction velocities. were recorded. Data were analyzed with R. Descriptive and comparative statistics were given as median / quartiles and mean / standard deviations for the decades 20-29, 30-39, 40-49, 50-59, and older than 60 years.

The age groups differed significantly from each other concerning the pupillary speed, maximum/minimum sizes (both p < 0.001), and percentual size after light exposure (p = 0.01). Gender differences were not present for the minimal but for the maximal diameter (p = 0.12 and p = 0.03, respectively). The constriction velocities (p = 0.12) did not show gender differences but the percentual pupillary change (p = 0.009). Age was negatively correlated with all the parameters above.

Our study demonstrates the importance of taking age and gender into account before using normative pupillographic data on individual patients. Using all-age control groups (often consisting of younger healthy persons) might lead to false-positive pathological results in older individuals.