Reliability of Pupil Response to Acute Pain

Wake Forest University Health Sciences (Other)
Overall Status
Recruiting ID

Study Details

Study Description

Brief Summary

The purpose of this research study is to test whether researchers can reliably measure the response pupils have when an acute painful stimulus is experienced. Changes in the size of the pupil of the eye can be an indicator of brain activity in a region of the brain that is important for feeling pain.

Condition or Disease Intervention/Treatment Phase

    Detailed Description

    There is strong rationale to support a role for locus coeruleus (LC) responsivity to acute painful stimuli in regulating speed of recovery after surgery and for LC responsivity as a mechanistic link explaining the risks for slow recovery from weak Conditioned Pain Modulation (CPM), catastrophizing cognitive style, and low enzyme activity catecholamine-O-methyltransferase (COMT) genotype. Preliminary data show feasibility to perform the proposed study.

    Primary Hypothesis: An observational study of pupil responses to noxious stimuli shows strong intra-individual reliability over 8 weeks.

    Key secondary hypotheses: Compared to individuals homozygous for val at the val158met site of the catecholamine-O-methyltransferase (COMT) gene, those homozygous for met will show smaller pupil responses to noxious stimuli and weaker CPM.

    Study Design

    Study Type:
    Anticipated Enrollment :
    80 participants
    Observational Model:
    Time Perspective:
    Official Title:
    Reliability of Pupil Response to Acute Pain
    Actual Study Start Date :
    Aug 4, 2015
    Anticipated Primary Completion Date :
    Dec 1, 2022
    Anticipated Study Completion Date :
    Dec 1, 2022

    Arms and Interventions

    Arm Intervention/Treatment

    Study population to include adult men and women with osteoarthritis.

    Outcome Measures

    Primary Outcome Measures

    1. Percentage of change in pupil diameter [8 weeks]

      pupil diameter in response to 5 second presentation of noxious heat stimuli

    2. Change from Baseline Verbal Pain Scores [8 weeks]

      Verbal pain scores will be obtained during stimulus presentation

    Eligibility Criteria


    Ages Eligible for Study:
    18 Years to 70 Years
    Sexes Eligible for Study:
    Accepts Healthy Volunteers:
    Inclusion Criteria:
    • Adult (18-70)

    • Pain from hip or knee arthritis of moderate intensity

    • American Society of Anesthesiologists physical status 1-3

    Exclusion Criteria:
    • Inability to complete study questionnaires

    • Pregnancy

    • Litigation or workers compensation related to hip or knee pain

    • Taking > 50 mg morphine equivalents/day

    • History of Raynaud's disease of the feet

    • Psychotic disorder or a recent psychiatric hospitalization

    • History of eye surgery or topical eye medications that would would directly affect pupil diameter

    Contacts and Locations


    Site City State Country Postal Code
    1 Wake Forest Baptist Medical Center Winston-Salem North Carolina United States 27157

    Sponsors and Collaborators

    • Wake Forest University Health Sciences


    • Principal Investigator: James C Eisenach, MD, Wake Forest University Health Sciences

    Study Documents (Full-Text)

    None provided.

    More Information


    None provided.
    Responsible Party:
    Wake Forest University Health Sciences Identifier:
    Other Study ID Numbers:
    • IRB00033891
    First Posted:
    Dec 11, 2015
    Last Update Posted:
    Sep 29, 2021
    Last Verified:
    Sep 1, 2021
    Additional relevant MeSH terms:

    Study Results

    No Results Posted as of Sep 29, 2021