Comparison of three different technologies for pupil diameter measurement.
BACKGROUND
The pupil diameter plays an important role in the occurrence of photopic phenomena after refractive surgery. Standardized estimation can be performed using a lens system with a built-in millimeter scale (Colvard, Oasis Medical, California). A new computerized technique allows dynamic and binocular measurement of the pupil diameter by use of infrared light (P2000SA, Procyon Instruments, London, UK). An additional approach is a wavefront aberrometer based on the Hartmann-Shack principle (WASCA; Asclepion-Meditec-Zeiss, Jena, Germany). These strategies were compared.


METHODS
Non-randomized comparative trial.


METHODS
The pupil diameter of 56 eyes of 28 probands (18 female, mean age 23 years) was measured under scotopic conditions by three independent examiners with each measurement device. The measurement devices were compared intraindividually by pairwise sign tests. Description was based on the intraindividual differences' medians and quantiles.


RESULTS
Median pupil diameters were 6.67 mm for the scale pupillometer (interquartile range 6.07-6.94 mm), 6.60 mm for the dynamic pupillometer (6.0-7.02 mm), and 6.37 mm for the wavefront-based aberrometer (5.9-6.7 mm). Pairwise comparison revealed statistically significant ( P<0.05), although not clinically relevant median deviations. Although no clinically relevant median differences were observed (when based on intraobserver means), deviations for single pupil diameter assessments ranged up to 1 mm.


CONCLUSIONS
No clinically relevant median deviations were observed in the underlying repeated measurement scenario. The scale pupillometer showed greater interobserver variation than the objective tests.
Department of Ophthalmology, Johannes Gutenberg University, Langenbeckstrasse 1, 55101, Mainz, Germany. Schmitz@augen.klinik.uni-mainz.de
Sabine
S
Schmitz
Frank
F
Krummenauer
Sebastian
S
Henn
H Burkhard
HB
Dick
D000328:Adult; D003936:Diagnosis, Computer-Assisted; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D007259:Infrared Rays; D007498:Iris / Q000033:anatomy & histology*; D008297:Male; D015588:Observer Variation