An Investigation of Topical Ophthalmic Low-Dose Atropine on Pupil Size and Accommodation

June 23, 2026 updated by: University of California, Berkeley

The goal of this clinical study is to learn about the short-term physiological effects of low-dose atropine in healthy volunteers. The study seeks to examine three questions related to low-dose topically applied ophthalmic atropine:

  1. Does applying two drops of 0.01% atropine sulfate solution cause the same clinical effects as one drop of 0.02% atropine?
  2. How quickly do the pupil responses and accommodative amplitudes recover following a dose of 0.01% atropine, 0.02% atropine, and 0.05% atropine?
  3. Does applying a single drop of 0.02% atropine sulfate solution cause the same clinical effects in participants with light vs. dark iris colors? Participants will have their pupil size and accommodative status measured at appropriate intervals to answer the questions above.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
24

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • California
      • Berkeley, California, United States, 94720-2020
        • University of California, Berkeley

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Subjects may be male or female, of any race, and between 18-40 years old at the time of screening.
  2. Patients must have best spectacle corrected visual acuity of at least 0.10 logMAR (20/25) in each eye.
  3. Subjects must be willing and able to apply eye drops to their non-dominant eye and to return for all scheduled follow-up visits.

Exclusion Criteria:

  1. Subjects with any contraindication to atropine use (as listed on package insert). At the time of this submission, the only contraindication listed is: "Hypersensitivity or allergic reaction to any ingredient in formulation"
  2. Subjects using monamine oxidase inhibitors (MAOIs). These are: Isocarboxazid (Marplan), Phenelzine (Nardil), Selegiline (Emsam), and Tranylcypromine (Parnate).
  3. Subjects with a history of any of the following medical conditions: collagen vascular disease, autoimmune disease, immunodeficiency diseases, ocular herpes zoster or simplex, endocrine disorders (including, but not limited to active thyroid disorders and diabetes), lupus, and rheumatoid arthritis.
  4. Subjects with a history of intraocular or corneal surgery (including cataract extraction), active ophthalmic disease or abnormality (including but not limited to, blepharitis, recurrent corneal erosion, dry eye syndrome, neovascularization >1mm from limbus), clinically significant lens opacity, clinical evidence of trauma (including scarring). This includes any patient with open-angle glaucoma, regardless of medication regimen or control. Additionally, any patient with an intra-ocular pressure (IOP) greater than 21 mm Hg at baseline is specifically excluded from eligibility. Subjects with narrow angles (less than Van Herick angle of 3) will also be excluded.
  5. Subjects who are pregnant, planning to become pregnant or breastfeeding during the course of the study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Single drop of 0.02% atropine sulfate solution
Participants received one drop of 0.02% atropine sulfate solution in one eye.
Drug: Atropine 0.02% Ophthalmic Solution
One drop of 0.02% atropine sulfate solution
Experimental: Two drops of 0.01% atropine sulfate solution
Participants received two drops of 0.01% atropine sulfate solution in one eye, spaced five minutes apart.
Drug: Atropine 0.01% Ophthalmic Solution
Two drops of 0.01% atropine sulfate solution
Other: observation of pupil responses
Subjects will be observed until pupils fully recover from a single dose of one of the atropine concentrations used.
Drug: Atropine 0.02% Ophthalmic Solution
One drop of 0.02% atropine sulfate solution
Drug: Atropine 0.01% Ophthalmic Solution
Two drops of 0.01% atropine sulfate solution
Drug: Atropine 0.05% Ophthalmic Solution
Atropine 0.05% Ophthalmic Solution

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Minimum pupil size
Time Frame: 1-24 hours after drop application
Dynamic pupil responses to a single pulse of light were measured 1 hour, 2 hours, 4 hours, 8 hours, and 24 hours after instilling the drop(s). The smallest pupil size (maximum pupil restriction) was used as the primary outcome measure.
1-24 hours after drop application

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Accommodative Amplitude
Time Frame: 1-24 hours after drop application
Subjective accommodative response was measured via the pull-away AA method.
1-24 hours after drop application

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of California, Berkeley

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Sarah E Singh, OD, PhD, University of California, Berkeley

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 16, 2022

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
October 9, 2022

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
October 9, 2022

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 23, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 23, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 30, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 30, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 23, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2021-09-14611

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

All IPD variables, including data dictionaries, will be available to other researchers upon request to the principal investigator and completion of a signed data sharing agreement.

IPD Sharing Time Frame

As this study is being registered retroactively (and the study is complete), all data can be made available upon request at this time (March 2026).

IPD Sharing Access Criteria

IPD can be accessed by emailing the PI who will make arrangements with appropriate UC Berkeley personnel to manage sharing.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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