Intermittent ExotropiaNCT07642687
Near Vergence Training for Distance Control in Intermittent Exotropia
A study testing Home-based near eye training program in people with Intermittent Exotropia, run by The Hong Kong Polytechnic University at 1 site in Hong Kong.
Trial summary
Intermittent Exotropia (IXT) is a common type of eye misalignment where one eye periodically turns outward, and control is typically much worse when looking at objects far away than close up. However, most currently available training programme are focused on near-viewing tasks. Read more about this study
- Who is it for?
- Ages 6 to 25 years
- Conditions the study is for
- Intermittent Exotropia
- What is being tested?
- Home-based near eye training program
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 42 participants
- Where
- 1 siteHong Kong
- Study dates
- 10 Jun 2026to Dec 2028
- 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 6 to 25 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- Age and Diagnosis: Participants must be aged 6 to ≤ 25 years at the time of screening, with a confirmed clinical diagnosis of either Basic or Divergence Excess (DE) Intermittent Exotropia (IXT).
- Ocular Alignment Magnitude: Distance exodeviation measuring between 10 and 40 prism diopters (pd) inclusive, determined by the prism and alternate cover test (PACT).
- Distance-Near Disparity Limits: Near exodeviation must not exceed the distance exodeviation by more than 10 pd (to exclude Convergence Insufficiency type exotropia).
- Baseline Distance Control: A baseline distance IXT Office Control Score (OCS) between Grade 2 and Grade 4 inclusive, based on the mean of 3 standardized assessments.
- Baseline Near Control: A baseline near IXT control score less than or equal to the distance IXT control score, based on the mean of 3 standardized assessments.
- Visual Acuity: Best-corrected visual acuity (BCVA) of Logarithm of the Minimum Angle of Resolution (logMAR) 0.1 or better in each eye at both distance and near fixation.
Show all 15Show fewer
- Sensory Status: Measurable near stereoacuity of 400 arc seconds or better on the Preschool Randot stereoacuity test.
- Refractive Correction Stability: Compliance with wearing a stable, appropriate spectacle correction for ≥ 4 months prior to formal baseline assessment if the participant meets any of the following refractive thresholds:
- Myopia < -0.50D spherical equivalent (SE) in either eye.
- Hyperopia > +2.50D SE in either eye.
- Anisometropia > 1.00 SE.
- Astigmatism > 1.50D cylinder in either eye.
- Treatment History: No history of prior non-surgical interventions for IXT, including patching, vision therapy/orthoptics, or overminus lens therapy (≥ 0.50 D).
- Surgical History: No prior history of strabismus surgery, extraocular muscle botulinum toxin injections, intraocular surgery, or refractive surgery.
- Trial Commitment: No planned strabismus surgery or conflicting ocular therapies during the 24-week study period.
Who cannot join
- Amblyopia and Co-morbid Strabismus: Presence of amblyopia, nystagmus, restrictive strabismus, or paretic strabismus.
- Vertical Misalignment: Presence of an associated vertical ocular deviation > 5 pd.
- Significant Pathologies: Co-existing significant ocular disease or neurological disorders (e.g., cerebral palsy) that could confound oculomotor or sensory evaluations.
- Confounding Medications: Regular use of systemic or topical ocular medications known to alter accommodative or vergence function within the 3 months prior to screening (including, but not limited to, atropine, pirenzepine, or systemic anti-epileptic agents).
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Hong Kong1 site, 1 recruiting
- Recruiting
The Optometry Clinic, The Hong Kong Polytechnic University
Hong Kong
Horace Ho-yin Wong, MClinOptom, BSc (Hons) Optom, 852-63384048, horace.wong@polyu.edu.hk
About this study
Official title: Evaluating Near Vergence Training for Distance Control in Basic and Divergence Excess Intermittent Exotropia
Intermittent Exotropia (IXT) is a common type of eye misalignment where one eye periodically turns outward, and control is typically much worse when looking at objects far away than close up. However, most currently available training programme are focused on near-viewing tasks. The goal of this clinical trial is to investigate if a new, structured, home-based near eye training program works to improve distance eye alignment control in children and young adults with IXT.
The main questions the study aims to answer are:
Read more
- Does a 12-week near eye training program improve a participant's ability to control their eye alignment when looking at a distance?
- Does using a special reading glasses during near training help to control distance eye alignment better than doing the training without the reading glasses?
- Do the benefits of this eye training last after the training has stopped?
This is a two- phase, single- masked (examiner masked), randomized clinical trial with crossover design. The entire study duration is about 24 weeks. A total sample size of 42 participants, aged 6 to 25 years with diagnosed Basic (distance deviation is within 10 prism diopters of the near deviation) or Divergence excess (distance deviation is at least 10 prism diopters greater than the near deviation) IXT, will be recruited.
In Phase I (Weeks 0 to 12), participants will be randomly allocated into one of three groups, with 14 individuals in each group:
- Group 1 does eye training while wearing special plus-power reading glasses that remove the need to focus up close, mimicking how the eyes look at a distance.
- Group 2 does the exact same eye training but wears regular distance glasses without the special reading addition.
- Group 3 serves as a control group that does not do training during the first 12 weeks, but will receive the training in the second phase.
In Phase II (Weeks 13 to 24), which is a crossover phase, groups 1 and 2 will stop training to see if the visual improvements last, while group 3 will be re-randomized into two subgroups (group 3A, with special plus-power reading glasses, and group 3B with regular glasses with distance correction) that will undertake daily eye training for 12 weeks to ensure ethical treatment access. All participants will have a final eye exam at 24 weeks.
During home training, participants will:
- Wear standard glasses provided by the study.
- Practice daily, home-based eye exercises for 12 weeks using a standardized software program on a computer or tablet.
- Complete 3 training sessions every day, lasting 7 minutes per session.
- Wear red-blue 3D glasses during training and press arrow keys or swipe the screen to play a visual game that dynamically changes in difficulty.
Preliminary test and binocular vision assessment with fixed and uniform sequence will be performed at baseline visit, 6th week interim visit, 12th and 24th week evaluation. All eye examinations will be carried out in The Optometry Centre (A034), the School of Optometry, The Hong Kong Polytechnic University.
The following data will be statistically analyzed. The primary outcome data is distance Office Control Score (OCS) at 12-week visit. Secondary outcomes data include change in deviation angle, near and distance stereopsis and patient- / parent- reported health-related quality-of-life questions at 12-week.
- Conditions
- Intermittent Exotropia
- Being tested
- Home-based near eye training program
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Home-based near eye training programOther
Standardized home-based near vergence training platform with data visualization tools and communication platforms
| Study group | Role | What they receive |
|---|---|---|
| Active training group with reading glasses | Active comparator | Receiving training in Phase I (Weeks 0 to 12), stop training in Phase II (Weeks 13 to 24) to study the effect persistence Receives: Other: Home-based near eye training program |
| Active training group without reading glasses | Active comparator | Receiving training in Phase I (Weeks 0 to 12), stop training in Phase II (Weeks 13 to 24) to study the effect persistence Receives: Other: Home-based near eye training program |
| Control group | No intervention | No training will be received in Phase I (Weeks 0 to 12); Will receive training in Phase II of the study (Weeks 13 to 24) to ensure ethical treatment access |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change of Distance Office Control Score
Objective and quantitative office control scale, based on the frequency of deviation and the recovery speed followed by occlusion. Ranged from 0 to 5, with score 0 represents the best control (phoria with excellent control), and score 5 represents the worst control (constant exotropia during the 30-second observation)
Measured: Baseline, 6-week, 12-week and 24-week
Secondary outcomes (5)
Change of exodeviation magnitude angle
measured by Prism and Alternate Cover Test, ranged from 1 to 50 prism diopter. The higher the value, the worse is the magnitude angle of the exodeviation
Measured: Baseline, 6-week, 12-week and 24-week
Change of Distance stereoacuity
measured by Distance Randot® stereotest, ranged from 400 seconds of arc (the worst measurable stereoacuity) to 60 seconds of arc (the best measurable stereoacuity )
Measured: Baseline, 6-week, 12-week and 24-week
Change of Near stereoacuity
measured by Preschool Randot® stereoacuity test, ranged from 800 seconds of arc (the worst measurable stereoacuity) to 40 seconds of arc (the best measurable stereoacuity )
Measured: Baseline, 6-week, 12-week and 24-week
Change of Quality of Life (QoL) measures - Chinese Intermittent Exotropia Questionnaire (CIXTQ) for children aged 5 to 17 and parents of children aged 2 to 17
Part a: Child CIXTQ - 12 items completed by children, simplified 3-point scale (0, 50 and 100); Part b: Proxy CIXTQ - 12 items completed by parents to evaluate their child's health-related quality-of-life (HRQoL) from a parental perspective, 5-point Likert-type (0, 25, 50, 75, and 100); Part c: Parent CIXTQ - 17 items to measure the parent's own HRQoL, 5-point Likert-type (0, 25, 50, 75 and 100). The higher the score, the better the outcome (QoL).
Measured: Baseline, 12-week and 24-week
Change of Quality of Life (QoL) measures - The Chinese Adult Strabismus Quality of Life Questionnaire (CAS-20) for adult participants aged 18 or above
20 items to assess psychosocial impact and visual function, 5-point Likert-type (0, 25, 50, 75 and 100). Higher scores indicating better perceived QoL.
Measured: Baseline, 12-week and 24-week
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Jun 2026
- Study start10 Jun 2026
- Primary completionJun 2028 (estimated)
- Study completionDec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Intermittent ExotropiaStudies of the same condition, open and under way.
- More trials run by The Hong Kong Polytechnic UniversityThe 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
- Triple blind
- Who is masked
- Care provider, Investigator, Outcomes assessor
- Enrolment
- 42 participants (estimated)
Sponsor and investigators
- Lead sponsor
- The Hong Kong Polytechnic University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, LEUNG Tsz Wing, The Hong Kong Polytechnic University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07642687
- Sponsor's protocol ID
- HSEARS20251213004
- Status last verified
- May 2026
- First submitted
- 3 Jun 2026
- Last updated
- 28 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Mohney BG, Holmes JM. An office-based scale for assessing control in intermittent exotropia. Strabismus. 2006 Sep;14(3):147-50. doi: 10.1080/09273970600894716.
PubMed 16950743Ma MM, Kang Y, Scheiman M, Chen Q, Ye X, Pan L, Deng J, Su G, Zhang G, Chen X. Office-based vergence and anti-suppression therapy for the treatment of small-to-moderate angle intermittent exotropia: A randomised clinical trial. Ophthalmic Physiol Opt. 2024 Mar;44(2):356-377. doi: 10.1111/opo.13264. Epub 2023 Dec 26.
PubMed 38146812
Study at a glance
From the registry record, last updated by the sponsor on 28 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluating Near Vergence Training for Distance Control in Basic and Divergence Excess Intermittent Exotropia
- ClinicalTrials.gov ID
- NCT07642687
- Acronym / sponsor ID
- HSEARS20251213004
- Conditions
- Intermittent Exotropia
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 42 participants (estimated)
- Lead sponsor
- The Hong Kong Polytechnic UniversityUniversity, hospital or other
- Study start
- 10 Jun 2026 (actual)
- Primary completion
- Jun 2028 (estimated)
- Study completion
- Dec 2028 (estimated)
- First posted
- 11 Jun 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.
Intermittent Exotropia (IXT) is a common type of eye misalignment where one eye periodically turns outward, and control is typically much worse when looking at objects far away than close up. However, most currently available training programme are focused on near-viewing tasks. The goal of this clinical trial is to investigate if a new, structured, home-based near eye training program works to improve distance eye alignment control in children and young adults with IXT.
The main questions the study aims to answer are:
- Does a 12-week near eye training program improve a participant's ability to control their eye alignment when looking at a distance?
- Does using a special reading glasses during near training help to control distance eye alignment better than doing the training without the reading glasses?
- Do the benefits of this eye training last after the training has stopped?
This is a two- phase, single- masked (examiner masked), randomized clinical trial with crossover design. The entire study duration is about 24 weeks. A total sample size of 42 participants, aged 6 to 25 years with diagnosed Basic (distance deviation is within 10 prism diopters of the near deviation) or Divergence excess (distance deviation is at least 10 prism diopters greater than the near deviation) IXT, will be recruited.
In Phase I (Weeks 0 to 12), participants will be randomly allocated into one of three groups, with 14 individuals in each group:
- Group 1 does eye training while wearing special plus-power reading glasses that remove the need to focus up close, mimicking how the eyes look at a distance.
- Group 2 does the exact same eye training but wears regular distance glasses without the special reading addition.
- Group 3 serves as a control group that does not do training during the first 12 weeks, but will receive the training in the second phase.
In Phase II (Weeks 13 to 24), which is a crossover phase, groups 1 and 2 will stop training to see if the visual improvements last, while group 3 will be re-randomized into two subgroups (group 3A, with special plus-power reading glasses, and group 3B with regular glasses with distance correction) that will undertake daily eye training for 12 weeks to ensure ethical treatment access. All participants will have a final eye exam at 24 weeks.
During home training, participants will:
- Wear standard glasses provided by the study.
- Practice daily, home-based eye exercises for 12 weeks using a standardized software program on a computer or tablet.
- Complete 3 training sessions every day, lasting 7 minutes per session.
- Wear red-blue 3D glasses during training and press arrow keys or swipe the screen to play a visual game that dynamically changes in difficulty.
Preliminary test and binocular vision assessment with fixed and uniform sequence will be performed at baseline visit, 6th week interim visit, 12th and 24th week evaluation. All eye examinations will be carried out in The Optometry Centre (A034), the School of Optometry, The Hong Kong Polytechnic University.
The following data will be statistically analyzed. The primary outcome data is distance Office Control Score (OCS) at 12-week visit. Secondary outcomes data include change in deviation angle, near and distance stereopsis and patient- / parent- reported health-related quality-of-life questions at 12-week.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (care provider, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Active training group with reading glasses | Active comparator | Other: Home-based near eye training programReceiving training in Phase I (Weeks 0 to 12), stop training in Phase II (Weeks 13 to 24) to study the effect persistence |
| Active training group without reading glasses | Active comparator | Other: Home-based near eye training programReceiving training in Phase I (Weeks 0 to 12), stop training in Phase II (Weeks 13 to 24) to study the effect persistence |
| Control group | No intervention | –No training will be received in Phase I (Weeks 0 to 12); Will receive training in Phase II of the study (Weeks 13 to 24) to ensure ethical treatment access |
Who may qualify
- Ages
- 6 to 25 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (15 listed)
- Age and Diagnosis: Participants must be aged 6 to ≤ 25 years at the time of screening, with a confirmed clinical diagnosis of either Basic or Divergence Excess (DE) Intermittent Exotropia (IXT).
- Ocular Alignment Magnitude: Distance exodeviation measuring between 10 and 40 prism diopters (pd) inclusive, determined by the prism and alternate cover test (PACT).
- Distance-Near Disparity Limits: Near exodeviation must not exceed the distance exodeviation by more than 10 pd (to exclude Convergence Insufficiency type exotropia).
- Baseline Distance Control: A baseline distance IXT Office Control Score (OCS) between Grade 2 and Grade 4 inclusive, based on the mean of 3 standardized assessments.
- Baseline Near Control: A baseline near IXT control score less than or equal to the distance IXT control score, based on the mean of 3 standardized assessments.
Key exclusion criteria (4 listed)
- Amblyopia and Co-morbid Strabismus: Presence of amblyopia, nystagmus, restrictive strabismus, or paretic strabismus.
- Vertical Misalignment: Presence of an associated vertical ocular deviation > 5 pd.
- Significant Pathologies: Co-existing significant ocular disease or neurological disorders (e.g., cerebral palsy) that could confound oculomotor or sensory evaluations.
- Confounding Medications: Regular use of systemic or topical ocular medications known to alter accommodative or vergence function within the 3 months prior to screening (including, but not limited to, atropine, pirenzepine, or systemic anti-epileptic agents).
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 |
|---|---|---|
| Home-based near eye training programStandardized home-based near vergence training platform with data visualization tools and communication platforms | Other | Active training group with reading glasses, Active training group without reading glasses |
Primary outcome
Change of Distance Office Control Score
Time frame: Baseline, 6-week, 12-week and 24-week
Objective and quantitative office control scale, based on the frequency of deviation and the recovery speed followed by occlusion. Ranged from 0 to 5, with score 0 represents the best control (phoria with excellent control), and score 5 represents the worst control (constant exotropia during the 30-second observation)
5 secondary outcomes
Change of exodeviation magnitude angle
Time frame: Baseline, 6-week, 12-week and 24-week
Change of Distance stereoacuity
Time frame: Baseline, 6-week, 12-week and 24-week
Change of Near stereoacuity
Time frame: Baseline, 6-week, 12-week and 24-week
Change of Quality of Life (QoL) measures - Chinese Intermittent Exotropia Questionnaire (CIXTQ) for children aged 5 to 17 and parents of children aged 2 to 17
Time frame: Baseline, 12-week and 24-week
Change of Quality of Life (QoL) measures - The Chinese Adult Strabismus Quality of Life Questionnaire (CAS-20) for adult participants aged 18 or above
Time frame: Baseline, 12-week and 24-week
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 28 Sep 2026.
- Background: PubMed 16950743Mohney BG, Holmes JM. An office-based scale for assessing control in intermittent exotropia. Strabismus. 2006 Sep;14(3):147-50. doi: 10.1080/09273970600894716.
- Background: PubMed 38146812Ma MM, Kang Y, Scheiman M, Chen Q, Ye X, Pan L, Deng J, Su G, Zhang G, Chen X. Office-based vergence and anti-suppression therapy for the treatment of small-to-moderate angle intermittent exotropia: A randomised clinical trial. Ophthalmic Physiol Opt. 2024 Mar;44(2):356-377. doi: 10.1111/opo.13264. Epub 2023 Dec 26.
- Individual participant dataSharing planned: Undecided
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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?
A study testing Home-based near eye training program in people with Intermittent Exotropia, run by The Hong Kong Polytechnic University at 1 site in Hong Kong.
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 15 inclusion and 4 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 28 Sep 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 Hong Kong. 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 Horace Ho-yin Wong, MClinOptom, BSc (Hons) Optom (852-63384048, horace.wong@polyu.edu.hk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change of Distance Office Control Score (time frame: Baseline, 6-week, 12-week and 24-week). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07642687, which also lists 2 linked publications.
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 28 Sep 2026.