Evaluation of Echothiophate in Pediatric Patients With Refractory Amblyopia

April 20, 2026 updated by: University of Oklahoma

The goal of this clinical trial is to see if a medicine called echothiophate iodide (Phospholine Iodide) can help treat children with refractory amblyopia. Amblyopia (also called lazy eye) is when one eye doesn't see as well as it should because the brain isn't using that eye correctly. Refractory amblyopia means a lazy eye that's very difficult to treat and it doesn't improve even after using common treatments, such as putting atropine eye drops in the stronger eye to encourage use of the weaker eye.

The main questions this study aims to answer are:

  • Can adding echothiophate iodide eye drops help children who stopped improving with atropine alone start making progress again?
  • Does using atropine and echothiophate iodide eye drops together work better for older children and adolescents who typically do not respond well to atropine alone?
  • Besides improving eyesight, can echothiophate iodide eye drops also help with things like depth perception, seeing in crowded spaces, or noticing motion

Participants will be asked to:

  • Participate in the study for a total of 14 weeks
  • Attend four clinic visits
  • Use atropine drops in the stronger eye nightly for a total 12 weeks
  • Use of echothiophate iodide eye drops in the weaker eye in addition to atropine use in the stronger eye, if vision does not improve after 4 weeks of use of atropine alone in the stronger eye
  • Upload weekly photos of the eyes
  • Have a slit lamp exam performed at each visit
  • Have Best Corrected Visual Acuity (BCVA) eye measurements taken at each visit.
  • Have Optical Coherence Tomography Angiography (OCTA) images taken at at each visit.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

20

Phase

  • Phase 2

Contacts and Locations

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

Study Contact

Study Locations

  • United States
    • Oklahoma
      • Oklahoma City, Oklahoma, United States, 73104
        • Dean McGee Eye Institute
        • Contact:
        • Principal Investigator:
          • Tammy Yanovitch, MD, MHSc
        • Sub-Investigator:
          • Rachel Dolan

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

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Children/adolescents between 3 and <18 years old with amblyopia who are currently undergoing atropine treatment who are deemed to no longer be improving.
  • Diagnosis of amblyopia associated with strabismus, anisometropia, or mixed types (as defined by previous PEDIG studies).
  • Wearing appropriate spectacle correction based on cycloplegic refraction using PEDIG protocol recommendations.
  • Currently undergoing atropine treatment (either 2x a week or every other day) with visual acuity in the amblyopic eye that has not improved with atropine treatment from participant's previous visit.
  • Cycloplegic refraction that has been completed within 6 months of enrollment.
  • Ability to measure visual acuity using standardized testing protocols.
  • Visual acuity in the amblyopic eye 20/40 to 20/100. Visual acuity in the non-amblyopic eye 20/30 or better with intraocular difference greater than or equal to 2 lines.

Exclusion Criteria:

  • Existing ocular conditions likely to interfere with treatment response (e.g., congenital cataract history, corneal opacities/scars, ptosis, retinal diseases).
  • Neurologic or systemic conditions that impact vision.
  • Severe developmental delays that might impact treatment adherence and outcome evaluation.
  • Current use of prisms or bifocals.
  • Active uveal inflammation or history of angle-closure glaucoma.
  • Concurrent use of other anticholinesterase medications.
  • Anticipated surgical procedures during the study period.
  • Prior surgical interventions for ocular conditions that could interfere with study outcomes.
  • Myopia with spherical equivalent >6D.
  • Any contraindications to the components of the medicine to be used in 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: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Atropine + Echothiophate Combination Therapy
Single-group interventional Arm - Atropine + Echothiophate Combination Therapy
Drug: Echothiophate Iodide 0.125% Ophthalmic Solution
Participants will receive echothiophate iodide eye drops in addition to standard atropine therapy to assess whether the combination improves visual function in refractory amblyopia.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Best Corrected Visual Acuity (BCVA)
Time Frame: Baseline, 4 weeks, 8 weeks, 12 weeks, 14 weeks.
Best Corrected Visual Acuity (BCVA) after 8 weeks of echothiophate iodide treatment and after a 2-week washout period (study-certified visual acuity tester masked to the patient's treatment group)
Baseline, 4 weeks, 8 weeks, 12 weeks, 14 weeks.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Interocular visual acuity difference
Time Frame: Baseline, 4 weeks, 8 weeks, 12 weeks, and 14 weeks.
Difference in BCVA between the amblyopic and fellow eye, measured in logMAR.
Baseline, 4 weeks, 8 weeks, 12 weeks, and 14 weeks.
Change in stereoacuity
Time Frame: 4 weeks, 8 weeks, 12 weeks, 14 weeks
Change in log arcseconds of stereoacuity assessed with the Randot Preschool Stereoacuity Test.
4 weeks, 8 weeks, 12 weeks, 14 weeks
Refractive error changes
Time Frame: 4 weeks, 8 weeks, 12 weeks (after completion of echothiophate treatment), 14 weeks (after two-week wash-out period).
Changes in spherical equivalent refraction from baseline in the amblyopic eye, measured in diopters.
4 weeks, 8 weeks, 12 weeks (after completion of echothiophate treatment), 14 weeks (after two-week wash-out period).
Ocular alignment
Time Frame: Baseline, 4 weeks, 8 weeks, 12 weeks, and 14 weeks.
This measure evaluates the presence and magnitude of ocular deviation measured in prism diopters, assessed at distance and near fixation
Baseline, 4 weeks, 8 weeks, 12 weeks, and 14 weeks.
Contrast sensitivity
Time Frame: Baseline, 4 weeks, 8 weeks, 12 weeks, 14 weeks
The ability of the amblyopic eye to distinguish an object from its background under varying levels of contrast, assessed using a standardized contrast sensitivity chart (e.g., Pelli-Robson) and reported in log contrast sensitivity units.
Baseline, 4 weeks, 8 weeks, 12 weeks, 14 weeks
Quality of life measures using the Pediatric Eye Disease Investigator Group (PEDIG) Pediatric Eye Questionnaire (PedEyeQ)
Time Frame: Baseline, 4 weeks, 8 weeks, 12 weeks, 14 weeks
The PedEyeQ is an instrument specific to pediatric eye conditions designed to evaluate health-related quality of life in children with eye conditions. The assessment values are Rasch calibrated and scaled to score from 0 (worst) to 100 (best)
Baseline, 4 weeks, 8 weeks, 12 weeks, 14 weeks
Treatment adherence
Time Frame: From baseline to the end of treatment at 14 weeks.
This measure assess the proportion of prescribed treatments completed as directed over the study period, including frequency and consistency of administration
From baseline to the end of treatment at 14 weeks.
OCT-A foveal avascular zone (FAZ) area changes
Time Frame: 4 weeks, 8 weeks, 12 weeks, 14 weeks
Examine difference/change in OCT-A foveal avascular zone (FAZ) area between amblyopic and non-amblyopic eye with treatment. Units are in square millimeters (mm^2)
4 weeks, 8 weeks, 12 weeks, 14 weeks
OCT-A foveal avascular zone (FAZ) perimeter changes
Time Frame: 4 weeks, 8 weeks, 12 weeks, 14 weeks
Examine changes in OCT-A foveal avascular zone (perimeter) changes between the amblyopic and non-amblyopic eye with treatment measured in millimeters (mm).
4 weeks, 8 weeks, 12 weeks, 14 weeks
OCT-A foveal avascular zone (FAZ) circularity index changes
Time Frame: 4 weeks, 8 weeks, 12 weeks, 14 weeks
Examine changes in foveal avascular zone (FAZ) circularity index between the amblyopic and non-amblyopic eye with treatment. Circularity is measured by utilizing the FAZ area and perimeter by multiplying the area by 4 pi and dividing by the squared perimeter. This measurement is unitless.
4 weeks, 8 weeks, 12 weeks, 14 weeks
OCT-A vessel density changes
Time Frame: 4 weeks, 8 weeks, 12 weeks, 14 weeks
Examine the differences in OCT-A between amblyopic and non-amblyopic eye with treatment. Measured as the proportion of the area occupied by vasculature.
4 weeks, 8 weeks, 12 weeks, 14 weeks
OCT-A vessel diameter index (VDI) changes
Time Frame: 4 weeks, 8 weeks, 12 weeks, 14 weeks
Examine the changes in the VDI between amblyopic and non-amblyopic eye with treatment. Measured as the average vessel caliber in micrometers (µm).
4 weeks, 8 weeks, 12 weeks, 14 weeks
OCT-A perfusion density (PD) changes
Time Frame: 4 weeks, 8 weeks, 12 weeks, 14 weeks
Changes in PD between the amblyopic and non-amblyopic eye with treatment. Measured as the total area of perfused vasculature per unit area (%)
4 weeks, 8 weeks, 12 weeks, 14 weeks
OCT-A retinal thickness changes
Time Frame: 4 weeks, 8 weeks, 12 weeks, 14 weeks
Examine changes in retinal thickness between amblyopic and non-amblyopic eye with treatment. Measured in microns.
4 weeks, 8 weeks, 12 weeks, 14 weeks

Collaborators and Investigators

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

Sponsor

University of Oklahoma

Collaborators

Fera Pharmaceuticals, LLC

Investigators

  • Principal Investigator: Tammy Yanovitch, MD, University of Oklahoma

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 (Estimated)

June 1, 2026

Primary Completion (Estimated)

December 1, 2026

Study Completion (Estimated)

December 1, 2026

Study Registration Dates

First Submitted

February 23, 2026

First Submitted That Met QC Criteria

April 20, 2026

First Posted (Actual)

April 28, 2026

Study Record Updates

Last Update Posted (Actual)

April 28, 2026

Last Update Submitted That Met QC Criteria

April 20, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 19462

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

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.

No

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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