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Updated: Jun 28, 2026
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Objective Nociceptive Assessment in Ventilated ICU Patients: A Feasibility Study Using Pupillometry and the Nociceptive Flexion Reflex
Published on: July 4, 2018
Using a hand-held pupillometer to quantify pupil constriction as part of the accommodation reflex
DaiWai M Olson1, Anjali Perera1, Abdulkadir Kamal1
1University of Texas Southwestern Medical Center, 5353 Harry Hines Blvd, Dallas, TX, USA.
Summary
Quantitative pupillometry (QP) objectively measures the pupil accommodation reflex (P-AR) by detecting changes in pupil diameter with gaze fixation distance. This new method can assess autonomic function and neurophysiological integrity.
Area of Science:
- Ophthalmology
- Neuroscience
- Physiology
Background:
- Quantitative pupillometry (QP) reliably measures the pupillary light reflex.
- The pupil accommodation reflex (P-AR) involves pupil diameter changes with visual focus shifts.
- Measuring P-AR with handheld QP has not been previously described.
Purpose of the Study:
- To explore if handheld quantitative pupillometry (QP) can objectively detect pupil diameter changes related to gaze fixation distance.
- To assess the feasibility of using QP for quantifying the pupil accommodation reflex (P-AR).
Main Methods:
- A prospective study involving 100 healthy adult volunteers.
- Bilateral QP measurements were taken for near and far gaze fixations.
- Time-series data analysis was performed on pupil diameter readings.
Main Results:
- 178 out of 200 observations yielded reliable pupil measurements.
- Pupil diameter significantly decreased from far to near fixation (P < 0.0001).
- Pupil diameter significantly increased when returning to far fixation (P < 0.0001), confirming P-AR.
Conclusions:
- Quantitative pupillometry (QP) is established as an objective method for quantifying the pupil accommodation reflex (P-AR).
- This technique offers a potential tool for evaluating autonomic function, brain arousal, and neurophysiological integrity.
