Pupillary Response to Chromatic Stimuli

Czech version

Authors: K. Skorkovská ^1,2; F. Maeda ²; C. Kelbsch ²; T. Peters ^2,3; B. Wilhelm ^2,3; H. Wilhelm ²
Authors‘ workplace: Klinika nemocí očních a optometrie LF MU a FN u sv. Anny v Brně ¹; Pupil Research Group, Centre for Ophthalmology, Institute of Ophthalmic Research, University of Tübingen, Germany ²; STZ eyetrial at the Centre for Ophthalmology, University of Tübingen, Germany ³
Published in: Cesk Slov Neurol N 2014; 77/110(3): 334-338
Category: Short Communication

Studie byla podpořena Jungovou nadací pro vědu a výzkum (Jung Stiftung für Wissenschaft und Forschung).

Overview

Aim of study:
To compare chromatic pupillary responses in a group of healthy subjects and to determine if this method can be used for assessing outer and inner retinal function.

Material and methods:
The study group consisted of 17 healthy subjects. Subjects were tested with a chromatic pupillometer. The parameters of the stimulus were as follows: intensity 28 lx, duration 4 sec, and color blue (420 ± 20 nm) and red (605 ± 20 nm). The examined pupil parameters were baseline pupil diameter, maximal constriction time, relative amplitude at maximal constriction, at 3 sec after stimulus onset, at stimulus offset, at 3 sec after stimulus offset and at 7 sec after stimulus offset. Pupil response parameters to red and blue light were evaluated by paired t-test.

Results:
Except for the baseline pupil diameter (p = 0.148), there was a significant difference in all pupil response parameters to red and blue light (p = 0.001). With blue light, the relative amplitude was significantly greater and the time to maximal pupil constriction significantly longer compared to red light for all tested time points. Blue light evoked “sustained” pupil contraction, while red light rather induced “transient” contraction.

Conclusions:
Our examination protocol allowed us to unmask differences in pupil response to red and blue light in healthy subjects and to confirm involvement of the melanopsin retinal ganglion cells in the pupil light reflex, particularly with blue light. Chromatic pupillography appears to be a highly sensitive method for objective evaluation of the outer and inner retina function.

Key words:
pupillary reflex – melanopsin – photoreceptor cells

The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study.

The Editorial Board declares that the manuscript met the ICMJE “uniform requirements” for biomedical papers.

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