Healthy ParticipantsNCT07746167
Pupillary Dilation Reflex in Healthy Volunteers
An observational study of Healthy Participants, run by Children's National Research Institute at 1 site in United States.
Trial summary
This a single site, observational study that will examine how the pupil responds to neurostimulation under different conditions in healthy adults. The objective is to measure pupillary dilation reflex (PRD) in response to increasing neurostimulation intensities using the AlgometRx device. Read more about this study
- Who is it for?
- Ages 18 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy Participants
- How many people
- 60 participants
- Where
- 1 siteUnited States
- Study dates
- 29 Apr 2026to Jun 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Study population: This study will enroll up to 60 healthy adult volunteers between the ages of 18 and 60
Who may be able to join
- Age 18-60 years.
- In good general health (self-reported).
- Able and willing to provide written informed consent.
Who cannot join
- Eye pathology that prevents accurate pupillometry.
- Pregnancy (Self-Report)
- Diagnosis of autoimmune disorders.
- Diagnosis of any neuropathic disorder
- Inability to complete questionnaires.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Children's National Hospital
Washington D.C., District of Columbia, 20010
Julia Finkel, MD, 202-476-4867, jfinkel@childrensnational.org
About this study
Official title: The Relationship Between Neurostimulation Intensity and Pupillary Dilation Reflex (PRD) in Healthy Volunteers
This a single site, observational study that will examine how the pupil responds to neurostimulation under different conditions in healthy adults. The objective is to measure pupillary dilation reflex (PRD) in response to increasing neurostimulation intensities using the AlgometRx device.
- Conditions
- Healthy Participants
- Being tested
- No intervention (observational study)
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
No intervention (observational study)Other
No intervention
| Study group | Role | What they receive |
|---|---|---|
| Healthy Volunteers | Not described Receives: Other: No intervention (observational study) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Pupillary Dilation Amplitude in Response to Increasing Neurostimulation Intensity Measured by AlgometRx Infrared Pupillometer
Pupillary dilation amplitude is defined as the maximum increase in pupil diameter from the pre-stimulus baseline, measured in millimeters (mm) using the AlgometRx infrared pupillometer. Pupil diameter is recorded before, during, and for 10 seconds following each 1-second stimulus. Amplitude is assessed at each stimulation intensity, beginning at 1.0 mA and increasing in 1 mA steps until participant perception, followed by measurements at 2 mA and 4 mA above the perception threshold, at each of three frequencies (5 Hz, 250 Hz, and 2000 Hz). Reported as the mean pupillary dilation amplitude in millimeters at each intensity and frequency combination.
Measured: Day 1
Secondary outcomes (5)
Baseline Pupil Diameter Variability During the Pre-Stimulation Period Measured by AlgometRx Infrared Pupillometer
Variability of pupil diameter recorded by the AlgometRx infrared pupillometer during the pre-stimulation baseline period, while participants fixate on a visual marker in a quiet room under controlled lighting for up to 5 minutes. Variability is calculated as the standard deviation of pupil diameter, in millimeters (mm), across the final 30 seconds of the baseline recording. Reported as the mean standard deviation in millimeters.
Measured: Day 1
Area Under the Pupillary Dilation Curve (AUC) Measured by AlgometRx Infrared Pupillometer
Area under the curve (AUC) is calculated from the pupil diameter-time curve recorded over the 10-second period following each 1-second stimulus, using the AlgometRx infrared pupillometer, and is expressed in millimeter-seconds (mm*s). AUC is assessed at each stimulation intensity, beginning at 1.0 mA and increasing in 1 mA steps until participant perception, followed by measurements at 2 mA and 4 mA above the perception threshold, at each of three frequencies (5 Hz, 250 Hz, and 2000 Hz). Reported as the mean AUC in millimeter-seconds at each intensity and frequency combination.
Measured: Day 1
Difference in Pupillary Dilation Amplitude Between Ambient Lighting Conditions Measured by AlgometRx Infrared Pupillometer
Within-participant difference in pupillary dilation amplitude, measured in millimeters (mm) by the AlgometRx infrared pupillometer, between testing under approximately 100 lux and approximately 400 lux ambient lighting. Amplitude is defined as the maximum increase in pupil diameter from the pre-stimulus baseline. Reported as the mean within-participant difference in millimeters.
Measured: Day 1
Inter-Ocular Agreement in Pupillary Dilation Amplitude Measured by AlgometRx Binocular Handheld Attachment
Agreement between left-eye and right-eye pupillary dilation amplitude recorded simultaneously using the AlgometRx binocular handheld attachment under identical stimulation and lighting conditions. Amplitude is defined as the maximum increase in pupil diameter from the pre-stimulus baseline, measured in millimeters. Agreement is expressed as an intraclass correlation coefficient (ICC) ranging from 0 to 1, where higher values indicate greater agreement between eyes. Reported as the ICC with a 95% confidence interval.
Measured: Day 1
Percentage of Participants With Successful Simultaneous Binocular Pupillary Recording Using the AlgometRx Binocular Handheld Attachment
The percentage of participants in whom the AlgometRx binocular handheld attachment successfully captures interpretable simultaneous pupillary recordings from both eyes. A recording is considered successful if both pupils are tracked continuously throughout the stimulus and post-stimulus recording period. Reported as the percentage of participants with successful binocular recording.
Measured: Day 1
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Aug 2026
- Study start29 Apr 2026
- Primary completionApr 2027 (estimated)
- Study completionJun 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy ParticipantsStudies of the same condition, open and under way.
- More trials run by Children's National Research InstituteThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case only
- Time perspective
- Cross-sectional
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Children's National Research Institute
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Julia Finkel, Children's National Research Institute
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07746167
- Sponsor's protocol ID
- STUDY00001697
- Status last verified
- Jul 2026
- First submitted
- 27 Jul 2026
- Last updated
- 4 Aug 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 4 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Relationship Between Neurostimulation Intensity and Pupillary Dilation Reflex (PRD) in Healthy Volunteers
- ClinicalTrials.gov ID
- NCT07746167
- Acronym / sponsor ID
- STUDY00001697
- Conditions
- Healthy Participants
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Children's National Research InstituteUniversity, hospital or other
- Study start
- 29 Apr 2026 (actual)
- Primary completion
- Apr 2027 (estimated)
- Study completion
- Jun 2027 (estimated)
- First posted
- 4 Aug 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This a single site, observational study that will examine how the pupil responds to neurostimulation under different conditions in healthy adults. The objective is to measure pupillary dilation reflex (PRD) in response to increasing neurostimulation intensities using the AlgometRx device.
Study design
- Observational model
- Case only
- Time perspective
- Cross-sectional
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Healthy Volunteers | – | Other: No intervention (observational study) |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- This study will enroll up to 60 healthy adult volunteers between the ages of 18 and 60
Key inclusion criteria (3 listed)
- Age 18-60 years.
- In good general health (self-reported).
- Able and willing to provide written informed consent.
Key exclusion criteria (5 listed)
- Eye pathology that prevents accurate pupillometry.
- Pregnancy (Self-Report)
- Diagnosis of autoimmune disorders.
- Diagnosis of any neuropathic disorder
- Inability to complete questionnaires.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| No intervention (observational study)No intervention | Other | Healthy Volunteers |
Primary outcome
Pupillary Dilation Amplitude in Response to Increasing Neurostimulation Intensity Measured by AlgometRx Infrared Pupillometer
Time frame: Day 1
Pupillary dilation amplitude is defined as the maximum increase in pupil diameter from the pre-stimulus baseline, measured in millimeters (mm) using the AlgometRx infrared pupillometer. Pupil diameter is recorded before, during, and for 10 seconds following each 1-second stimulus. Amplitude is assessed at each stimulation intensity, beginning at 1.0 mA and increasing in 1 mA steps until participant perception, followed by measurements at 2 mA and 4 mA above the perception threshold, at each of three frequencies (5 Hz, 250 Hz, and 2000 Hz). Reported as the mean pupillary dilation amplitude in millimeters at each intensity and frequency combination.
5 secondary outcomes
Baseline Pupil Diameter Variability During the Pre-Stimulation Period Measured by AlgometRx Infrared Pupillometer
Time frame: Day 1
Area Under the Pupillary Dilation Curve (AUC) Measured by AlgometRx Infrared Pupillometer
Time frame: Day 1
Difference in Pupillary Dilation Amplitude Between Ambient Lighting Conditions Measured by AlgometRx Infrared Pupillometer
Time frame: Day 1
Inter-Ocular Agreement in Pupillary Dilation Amplitude Measured by AlgometRx Binocular Handheld Attachment
Time frame: Day 1
Percentage of Participants With Successful Simultaneous Binocular Pupillary Recording Using the AlgometRx Binocular Handheld Attachment
Time frame: Day 1
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Aug 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Healthy Participants, run by Children's National Research Institute at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 4 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Pupillary Dilation Amplitude in Response to Increasing Neurostimulation Intensity Measured by AlgometRx Infrared Pupillometer (time frame: Day 1). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Aug 2026.