Pupillary light reflex (PLR), i.e. pupil constriction in response to light stimulus, offers a sensitive index of parasympathetic nervous regulation. Yet, the studies on PLR in acute mental stress are rare. We aimed to study potential changes of PLR to acute mental stress in healthy young people with respect to sex. Thirty-eight participants (24 women, age: 22.95+/-0.19 yrs) were examined in a cross-sectional study under standard conditions. PLR parameters were measured separately for both eyes using PLR-2000 (NeurOptics, USA) before arithmetic test (baseline), immediately after arithmetic test, and after recovery period. Evaluated PLR parasympathetically-mediated parameters: pupil diameter (mm) before (initial value, INIT) and after illumination (peak of constriction, END), maximum constriction velocity (MCV), relative constriction amplitude (RCA). INIT and END diameters were significantly reduced immediately after mental stress and after recovery compared to baseline (left eye: INIT: p=0.044, p=0.035, respectively; END: p=0.004, p<0.001, respectively; right eye: INIT: p<0.001, p=0.002, respectively; END: p<0.001 for both comparisons). No significant differences were found in MCV and RCA. Moreover, the study established no significant changes in the assessed PLR parameters between sex throughout the stress protocol. Our study revealed that acute mental stress is associated with greater PLR-parasympathetic response resulting in prolonged pupil constriction. This finding could represent the first step for understanding the effect of cognitive processing on PLR under physiological conditions, before its clinical application. Key words Pupillary light reflex " Acute mental stress " Cognitive processing " Parasympathetic nervous system " Psychophysiology.

Department of Physiology and Biomedical Centre Martin Jessenius Faculty of Medicine in Martin Comenius University in Bratislava Martin Slovak Republic

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Steinhauer SR, Hakerem G. The pupillary response in cognitive psychophysiology and schizophrenia. Ann N Y Acad Sci. 1992;658:182–204. doi: 10.1111/j.1749-6632.1992.tb22845.x. PubMed DOI

Laeng B, Sirois S, Gredebäck G. Pupillometry: A Window to the Preconscious? Perspect Psychol Sci. 2012;7:18–27. doi: 10.1177/1745691611427305. PubMed DOI

Mestanikova A, Ondrejka I, Mestanik M, Cesnekova D, Visnovcova Z, Bujnakova I, Oppa M, et al. Pupillary light reflex is altered in adolescent depression. Physiol Res. 2017;66(Suppl 2):S277–S284. doi: 10.33549/physiolres.933683. PubMed DOI

Porges SW. Orienting in a defensive world: Mammalian modifications of our evolutionary heritage. A Polyvagal Theory. Psychophysiology. 1995;32:301–318. doi: 10.1111/j.1469-8986.1995.tb01213.x. PubMed DOI

Tonhajzerova I, Javorka K, Petraskova M. Changes in the variability of the heart rate during mental stress. Physiol Res. 1999;48:24P.

Visnovcova Z, Mestanik M, Javorka M, Mokra D, Gala M, Jurko A, Calkovska A, Tonhajzerova I. Complexity and time asymmetry of heart rate variability are altered in acute mental stress. Physiol Meas. 2014;35:1319–1334. doi: 10.1088/0967-3334/35/7/1319. PubMed DOI

Mestanik M, Mestanikova A, Visnovcova Z, Calkovska A, Tonhajzerova I. Cardiovascular sympathetic arousal in response to different mental stressors. Physiol Res. 2015;64(Suppl 5):S585–S594. doi: 10.33549/physiolres.933217. PubMed DOI

Tonhajzerova I, Farsky I, Mestanik M, Visnovcova Z, Mestanikova A, Hrtanek I, Ondrejka I. Symbolic dynamics of heart rate variability - a promising tool to investigate cardiac sympathovagal control in attention deficit/hyperactivity disorder (ADHD)? Can J Physiol Pharmacol. 2016;94:579–587. doi: 10.1139/cjpp-2015-0375. PubMed DOI

Tonhajzerova I, Mestanik M, Mestanikova A, Jurko A. Respiratory sinus arrhythmia as a non-invasive index of ‘brain-heart’ interaction in stress. Indian J Med Res. 2016;144:815–822. doi: 10.4103/ijmr.IJMR_1447_14. PubMed DOI PMC

Steinhauer SR, Condray R, Kasparek A. Cognitive modulation of midbrain function: Task-induced reduction of the pupillary light reflex. Int J Psychophysiol. 2000;39:21–30. doi: 10.1016/S0167-8760(00)00119-7. PubMed DOI

Hall CA, Chilcott RP. Eyeing up the Future of the Pupillary Light Reflex in Neurodiagnostics. Diagnostics (Basel) 2018;8:19. doi: 10.3390/diagnostics8010019. PubMed DOI PMC

Bitsios P, Szabadi E, Bradshaw CM. The inhibition of the pupillary light reflex by the threat of an electric shock: a potential laboratory model of human anxiety. J Psychopharmacol. 1996;10:279–287. doi: 10.1177/026988119601000404. PubMed DOI

Davis BC, Daluwatte C, Colona NC, Yao DG. Effects of cold-pressor and mental arithmetic on pupillary light reflex. Physiol Meas. 2013;34:873–882. doi: 10.1088/0967-3334/34/8/873. PubMed DOI PMC

Salvaggio S, Andres M, Zénon A, Masson N. Pupil size variations reveal covert shifts of attention induced by numbers. Psychon Bull Rev. 2022;29:1844–1853. doi: 10.3758/s13423-022-02094-0. PubMed DOI

Filipe JAC, Falcão-Reis F, Castro-Correia J, Barros H. Assessment of autonomic function in high level athletes by pupillometry. Auton Neurosci. 2003;104:66–72. doi: 10.1016/S1566-0702(02)00268-0. PubMed DOI

Fan X, Hearne L, Lei B, Miles JH, Takahashi N, Yao G. Weak gender effects on transient pupillary light reflex. Auton Neurosci. 2009;147:9–13. doi: 10.1016/j.autneu.2008.12.010. PubMed DOI

Jehu DA, Bolgla LA, Armas S, Dutton F. Assessing the Inter-Rater and Inter-Trial Reliability of the NeurOptics Pupillary Light Response-3000 Pupillometer. Int J Sports Phys Ther. 2025;20:157–167. doi: 10.26603/001c.128047. PubMed DOI PMC

Bradley JC, Cohn CD, Wu PW, Brown SM. Comparison of a monocular pupillometer and the pupillometry function of a binocular free-viewing autorefractor. J Cataract Refract Surg. 2011;37:1257–1262. doi: 10.1016/j.jcrs.2011.01.026. PubMed DOI

Schneider GM, Jacobs DW, Gevirtz RN, O’Connor DT. Cardiovascular haemodynamic response to repeated mental stress in normotensive subjects at genetic risk of hypertension: evidence of enhanced reactivity, blunted adaptation, and delayed recovery. J Hum Hypertens. 2003;17:829–840. doi: 10.1038/sj.jhh.1001624. PubMed DOI

Wang Y, Zekveld AA, Naylor G, Ohlenforst B, Jansma EP, Lorens A, Lunner T, Kramer SE. Parasympathetic Nervous System Dysfunction, as Identified by Pupil Light Reflex, and Its Possible Connection to Hearing Impairment. PLoS One. 2016;11:e0153566. doi: 10.1371/journal.pone.0153566. PubMed DOI PMC

Güler AD, Ecker JL, Lall GS, Haq S, Altimus CM, Liao H-W, Barnard AR, et al. Melanopsin cells are the principal conduits for rod-cone input to non-image-forming vision. Nature. 2008;453:102–105. doi: 10.1038/nature06829. PubMed DOI PMC

Köles M. A Review of Pupillometry for Human-computer Interaction Studies. Period Polytech Electr Eng Comput Sci. 2017;61:320. doi: 10.3311/PPee.10736. DOI

Posner MI, Fan J. Attention as an organ system. In: POMERANTZ JR, editor. Topics in Integrative Neuroscience: From Cells to Cognition. Cambridge University Press; 2008. pp. 31–61. DOI

Wilhelm B, Wilhelm H, Lűdtke H. Pupillography: Principles and applications in basic and clinical research. In: KUHLMANN J, BOTTCHER M, editors. Pupillography: Principles, Methods and Applications. Zuckschwerdt Verlag; Műnchen: 1999. pp. 1–11.

Porges SW. The polyvagal perspective. Biol Psychol. 2007;74:116–143. doi: 10.1016/j.biopsycho.2006.06.009. PubMed DOI PMC

Chougule PS, Najjar RP, Finkelstein MT, Kandiah N, Milea D. Light-induced pupillary responses in Alzheimer’s disease. Front Neurol. 2019;10:1–12. doi: 10.3389/fneur.2019.00360. PubMed DOI PMC

Fotiou F, Fountoulakis KN, Tsolaki M, Goulas A, Palikaras A. Changes in pupil reaction to light in Alzheimer’s disease patients: A preliminary report. Int J Psychophysiol. 2000;37:111–120. doi: 10.1016/S0167-8760(00)00099-4. PubMed DOI

Giza E, Fotiou D, Bostantjopoulou S, Katsarou Z, Karlovasitou A. Pupil light reflex in Parkinson’s disease: Evaluation with pupillometry. Int J Neurosci. 2011;121:37–43. doi: 10.3109/00207454.2010.526730. PubMed DOI

Ulep R, Khan F, Houghton D. Comparison of quantitative measures of Pupil Light Reflex measured using Automated Pupillometer in patients with Parkinson’s disease and controls. Neurology. 2017;88(16 Suppl):P1.014. doi: 10.1212/WNL.88.16_supplement.P1.014. DOI

Hamrakova A, Ondrejka I, Sekaninova N, Bona Olexova L, Visnovcova Z, Cesnekova D, Hrtanek I, et al. Central autonomic regulation assessed by pupillary light reflex is impaired in children with attention deficit hyperactivity disorder. Physiol Res. 2020;69(Suppl 3):S513–S521. doi: 10.33549/physiolres.934589. PubMed DOI PMC

Bär KJ, Greiner W, Jochum T, Friedrich M, Wagner G, Sauer H. The influence of major depression and its treatment on heart rate variability and pupillary light reflex parameters. J Affect Disord. 2004;82:245–252. doi: 10.1016/j.jad.2003.12.016. PubMed DOI

Bakes A, Bradshaw C, Szabadi E. Attenuation of the pupillary light reflex in anxious patients. Br J Clin Pharmacol. 1990;30:377–381. doi: 10.1111/j.1365-2125.1990.tb03787.x. PubMed DOI PMC

Fan X, Miles JH, Takahashi N, Yao G. Abnormal transient pupillary light reflex in individuals with autism spectrum disorders. J Autism Dev Disord. 2009;39:1499–1508. doi: 10.1007/s10803-009-0767-7. PubMed DOI