title: Digital Pupillometry in Normal Subjects.
abstract: The aim of this study was to evaluate the pupil size of normal subjects at different illumination levels with a novel pupillometer. The pupil size of healthy study participants was measured with an infrared-video PupilX pupillometer (MEye Tech GmbH, Alsdorf, Germany) at five different illumination levels (0, 0.5, 4, 32, and 250 lux). Measurements were performed by the same investigator. Ninety images were executed during a measurement period of 3 seconds. The absolute linear camera resolution was approximately 20 pixels per mm. This cross-sectional study analysed 490 eyes of 245 subjects (mean age: 51.9 ± 18.3 years, range: 6-87 years). On average, pupil diameter decreased with increasing light intensities for both eyes, with a mean pupil diameter of 5.39 ± 1.04 mm at 0 lux, 5.20 ± 1.00 mm at 0.5 lux, 4.70 ± 0.97 mm at 4 lux, 3.74 ± 0.78 mm at 32 lux, and 2.84 ± 0.50 mm at 250 lux illumination. Furthermore, it was found that anisocoria increased by 0.03 mm per life decade for all illumination levels (R2= 0.43). Anisocoria was higher under scotopic and mesopic conditions. This study provides additional information to the current knowledge concerning age- and light-related pupil size and anisocoria as a baseline for future patient studies.
authors.affiliation: Knappschaft Eye Clinic Sulzbach, Knappschaft Hospital Saar , Sulzbach/Saar, Germany.
authors.forename: Annekatrin
authors.initials: A
authors.lastname: Rickmann
authors.affiliation: Knappschaft Eye Clinic Sulzbach, Knappschaft Hospital Saar , Sulzbach/Saar, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Waizel
authors.affiliation: Knappschaft Eye Clinic Sulzbach, Knappschaft Hospital Saar , Sulzbach/Saar, Germany.
authors.forename: Sara
authors.initials: S
authors.lastname: Kazerounian
authors.affiliation: Knappschaft Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach/Saar, Germany; University Eye Clinic Tübingen, Centre for Ophthalmology, Tübingen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Szurman
authors.affiliation: University Eye Clinic Tübingen, Centre for Ophthalmology , Tübingen, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Wilhelm
authors.affiliation: Knappschaft Eye Clinic Sulzbach, Knappschaft Hospital Saar , Sulzbach/Saar, Germany.
authors.forename: Karl T
authors.initials: KT
authors.lastname: Boden
keywords: Pupil size; anisocoria; pupillometer