EsophoriaNCT06729710
Prism Adaptation in Symptomatic Esophoria - Effect of Shorter Time Intervals and Surgical Outcomes Based on Prism Adaptation
A study testing Prism adaptation test and other in people with Esophoria, run by Copenhagen University Hospital, Rigshospitalet at 1 site in Denmark.
Trial summary
This study is a prospective randomized study aiming to investigate the effect of prism adaptation before surgery for symptomatic esophoria on the number of reoperations, the occurrence of over- and under-correction after the first surgery, and symptom resolution. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Esophoria
- What is being tested?
- Prism adaptation test and other
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 1 siteDenmark
- Study dates
- 19 May 2025to 1 Jan 2030
- Phase
- Interventional
- 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 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patients with symptomatic esophoria who meet one or more of the following criteria:
- Double vision
- Asthenopia (eye strain)
- Headaches related to esophoria
- Worsening of symptoms during fatigue, sleep deprivation, reading, illness, or alcohol consumption.
Who cannot join
- Age between 18 and 65 years at date of inclusion.
- Accommodative esotropia or esophoria
- Myopia exceeding 10 diopters in the most myopic meridian
- Treatment with botulinum toxin in an eye muscle within four months prior to inclusion
- Inability to undergo reliable orthoptic measurements or prism adaptation
- Previous strabismus surgery
Show all 12Show fewer
- Pregnancy or breastfeeding within 12 months prior to inclusion
- Myogenic disorders (including Myasthenia Gravis)
- Restrictive strabismus (including previous eye muscle trauma or Graves' orbitopathy)
- Eye muscle paresis
- Maximum prism-adapted deviation angle >40 prism diopters (PD) in any gaze direction for distance
- Maximum prism-adapted deviation angle with ≥20 PD difference between near and distance measurements
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Denmark1 site, 1 recruiting
- Recruiting
Rigshospitalet
Copenhagen, 2600
Mikael Hofsli, MD, +4538634755, mikael.hofsli@regionh.dk
About this study
This study is a prospective randomized study aiming to investigate the effect of prism adaptation before surgery for symptomatic esophoria on the number of reoperations, the occurrence of over- and under-correction after the first surgery, and symptom resolution. Additionally, we aim to define the optimal duration of prism adaptation.
Read the detailed description
SUBSTUDY 1 The Optimal Duration of Prism Adaptation in Symptomatic Esophoria Study Design: Prospective, randomized controlled study Patient Group: 100 participants with symptomatic esophoria, randomized into two groups of 50 participants each to undergo either one hour or four hours of prism adaptation.
The purpose of this study is to determine the optimal duration of prism adaptation.
The hypothesis is that the measured deviation angle is expected to increase after one hour of prism adaptation compared to before prism adaptation. Furthermore, it is expected that the measured deviation angle will not differ significantly between the two randomization groups. The primary endpoint is the measured deviation angle at the conclusion of prism adaptation.
The results are highly relevant for accurate surgical dosing (and thus postoperative symptoms and reoperation rates), efficient use of hospital resources, and reduced patient waiting times in the outpatient clinic.
SUBSTUDY 2 Strabismus Surgery for Symptomatic Esophoria Based on Prism Adaptation Study Design: Prospective, randomized controlled study Patient Group: 100 participants with symptomatic esophoria, using the same patients and randomization groups as in Substudy 1.
The purpose of this study is to investigate the effectiveness of strabismus surgery for symptomatic esophoria based on prism adaptation. Patients randomized in Substudy 2 to either one or four hours of prism adaptation will undergo surgery based on the full prism-adapted angle.
The hypothesis for this substudy is that surgical dosing based on one hour of prism adaptation will be equivalent to dosing based on four hours of prism adaptation. The primary endpoint will be the reoperation rate. Secondary endpoints will include comparisons of preoperative surgical planning metrics (target deviation and number of eye muscles operated), symptom resolution after the first surgery, and prism measurements (including rates of over- and undercorrections).
- Conditions
- Esophoria
- Being tested
- Prism adaptation test, other
- Keywords
- Esophoria, prism adaptation, strabismus surgery
- Medical subject headings
- Esotropia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Prism adaptation testProcedure or surgery
Prism Adapation test for 1 hour in one group, and 4 hours in second group
otherProcedure or surgery
Also called Surgery based on prism adaptation test
Surgery based on prism adaptation test of 1 hour in one group and 4 hours in second group
| Study group | Role | What they receive |
|---|---|---|
| 1 hour prism adaptation | Active comparator | Patients who receive one hour of prism adaptation. Receives: Procedure: Prism adaptation test; Procedure: other |
| 4 hours of prism adaptation | Active comparator | Patients who receive four hour of prism adaptation. Receives: Procedure: Prism adaptation test; Procedure: other |
What is being measured
The primary outcome is the main question the study is designed to answer.
Reoperation rate
Number of patients in need of reoperation after initial surgery for symptomatic esophoria
Measured: Up to 5 years
Measured deviation angle at the conclusion of prism adaptation.
Measured deviation angle in prism diopters at the conclusion of prism adaptation.
Measured: Up to 5 years
Secondary outcomes (3)
Motor success
Motor success: 10 prism diopters of esophoria to 5 prism diopters of exophoria measured with prism alternating cover test.
Motor failure: Manifest strabismus measured with prism alternating cover test
Measured: 1 year from date of surgery
Sensory success
Sensory success: Postoperative unchanged or improvement in stereopsis measured in seconds of arc with the same method (LANG I/II or TNO) in compared to baseline.
Measured: 1 year from date of surgery
Symptomatic success
Symptomatic success: Single vision (defined as the absence of double vision in daily life) and/or absence of asthenopia (defined as eye strain that is significant in daily life)
Measured: 1 year from date of surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Dec 2024
- Study start19 May 2025
- Primary completion1 Jan 2028 (estimated)
- Study completion1 Jan 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for EsophoriaStudies of the same condition, open and under way.
- More trials run by Copenhagen University Hospital, RigshospitaletThe 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Copenhagen University Hospital, Rigshospitalet
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Mikael Hofsli, Copenhagen University Hospital, Rigshospitalet
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06729710
- Sponsor's protocol ID
- H-24017032
- Status last verified
- Jul 2025
- First submitted
- 4 Dec 2024
- Last updated
- 22 Jul 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 22 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Prism Adaptation in Symptomatic Esophoria - Effect of Shorter Time Intervals and Surgical Outcomes Based on Prism Adaptation
- ClinicalTrials.gov ID
- NCT06729710
- Acronym / sponsor ID
- H-24017032
- Conditions
- Esophoria
- Keywords
- Esophoria, prism adaptation, strabismus surgery
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Copenhagen University Hospital, RigshospitaletUniversity, hospital or other
- Study start
- 19 May 2025 (actual)
- Primary completion
- 1 Jan 2028 (estimated)
- Study completion
- 1 Jan 2030 (estimated)
- First posted
- 11 Dec 2024 (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 study is a prospective randomized study aiming to investigate the effect of prism adaptation before surgery for symptomatic esophoria on the number of reoperations, the occurrence of over- and under-correction after the first surgery, and symptom resolution. Additionally, we aim to define the optimal duration of prism adaptation.
Detailed description
SUBSTUDY 1 The Optimal Duration of Prism Adaptation in Symptomatic Esophoria Study Design: Prospective, randomized controlled study Patient Group: 100 participants with symptomatic esophoria, randomized into two groups of 50 participants each to undergo either one hour or four hours of prism adaptation.
The purpose of this study is to determine the optimal duration of prism adaptation.
The hypothesis is that the measured deviation angle is expected to increase after one hour of prism adaptation compared to before prism adaptation. Furthermore, it is expected that the measured deviation angle will not differ significantly between the two randomization groups. The primary endpoint is the measured deviation angle at the conclusion of prism adaptation.
The results are highly relevant for accurate surgical dosing (and thus postoperative symptoms and reoperation rates), efficient use of hospital resources, and reduced patient waiting times in the outpatient clinic.
SUBSTUDY 2 Strabismus Surgery for Symptomatic Esophoria Based on Prism Adaptation Study Design: Prospective, randomized controlled study Patient Group: 100 participants with symptomatic esophoria, using the same patients and randomization groups as in Substudy 1.
The purpose of this study is to investigate the effectiveness of strabismus surgery for symptomatic esophoria based on prism adaptation. Patients randomized in Substudy 2 to either one or four hours of prism adaptation will undergo surgery based on the full prism-adapted angle.
The hypothesis for this substudy is that surgical dosing based on one hour of prism adaptation will be equivalent to dosing based on four hours of prism adaptation. The primary endpoint will be the reoperation rate. Secondary endpoints will include comparisons of preoperative surgical planning metrics (target deviation and number of eye muscles operated), symptom resolution after the first surgery, and prism measurements (including rates of over- and undercorrections).
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| 1 hour prism adaptation | Active comparator | Procedure: Prism adaptation test, Procedure: otherPatients who receive one hour of prism adaptation. |
| 4 hours of prism adaptation | Active comparator | Procedure: Prism adaptation test, Procedure: otherPatients who receive four hour of prism adaptation. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Double vision
- Asthenopia (eye strain)
- Headaches related to esophoria
- Worsening of symptoms during fatigue, sleep deprivation, reading, illness, or alcohol consumption.
Key exclusion criteria (12 listed)
- Age between 18 and 65 years at date of inclusion.
- Accommodative esotropia or esophoria
- Myopia exceeding 10 diopters in the most myopic meridian
- Treatment with botulinum toxin in an eye muscle within four months prior to inclusion
- Inability to undergo reliable orthoptic measurements or prism adaptation
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 |
|---|---|---|
| Prism adaptation testPrism Adapation test for 1 hour in one group, and 4 hours in second group | Procedure or surgery | 1 hour prism adaptation, 4 hours of prism adaptation |
| otherAlso: Surgery based on prism adaptation testSurgery based on prism adaptation test of 1 hour in one group and 4 hours in second group | Procedure or surgery | 1 hour prism adaptation, 4 hours of prism adaptation |
Primary outcome
Reoperation rate
Time frame: Up to 5 years
Number of patients in need of reoperation after initial surgery for symptomatic esophoria
Measured deviation angle at the conclusion of prism adaptation.
Time frame: Up to 5 years
Measured deviation angle in prism diopters at the conclusion of prism adaptation.
3 secondary outcomes
Motor success
Time frame: 1 year from date of surgery
Sensory success
Time frame: 1 year from date of surgery
Symptomatic success
Time frame: 1 year from date of surgery
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 22 Jul 2025.
- Individual participant dataSharing planned: No
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?
A study testing Prism adaptation test and other in people with Esophoria, run by Copenhagen University Hospital, Rigshospitalet at 1 site in Denmark.
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 5 inclusion and 12 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 22 Jul 2025. 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 Denmark. 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?
Contact Mikael Hofsli, M.D (004538634381, mikael.hofsli@regionh.dk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Reoperation rate (time frame: Up to 5 years). The study lists 2 primary outcomes in all. 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 22 Jul 2025.