Near-eye training to improve distance eye alignment in intermittent exotropia
Official title: Evaluating Near Vergence Training for Distance Control in Basic and Divergence Excess Intermittent Exotropia
Run by The Hong Kong Polytechnic University · NCT07642687 · Data updated 2026-11-12
A home-based 12-week program tests whether training the eyes at a distance can improve control of outward eye turn in children and young adults with intermittent exotropia, and whether wearing reading glasses during training helps more.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 6 Years to 25 Years |
| Sex | All |
| Enrollment | 42 (estimated) |
| Sponsor | The Hong Kong Polytechnic University Academic / other |
| Locations | 1 site (Hong Kong) |
| Status | Recruiting |
| Started | June 10, 2026 |
| Main results expected | June 2028 |
| Study ends | December 2028 |
| Registry record updated | September 28, 2026 |
| Trial ID | NCT07642687 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal candidates are ages 6 to 25 with basic or divergence excess intermittent exotropia, 10–40 prism diopters of distance exodeviation, and baseline distance control in the defined range.
✕Probably not a fit
Patients with exodeviation outside the specified range, Convergence Insufficiency-type exotropia, or BCVA worse than the stated threshold may be less likely to benefit.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This randomized, two-phase, examiner-masked, crossover trial evaluates a structured near-eye training program for improving distance control in intermittent exotropia. Participants aged 6 to 25 with basic or divergence excess exotropia and specific distance-near alignment criteria will complete a 12-week home-based regimen. The study also compares training with and without reading glasses and looks at whether any improvements persist after training ends. Outcomes will focus on distance eye alignment control and the durability of benefits over time.
Why it matters
Potential benefit: If successful, the program could provide a practical home-based option to improve distance eye alignment in IXT and possibly reduce the need for more invasive treatments.
How similar studies have gone: Previous approaches in exotropia training have shown mixed results; this study adds a randomized, crossover design to test a home-based near-training regimen with a novel distance-focused component.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria * 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. * 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. Exclusion Criteria * 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).
Where it's running
-
The Optometry Clinic, The Hong Kong Polytechnic University
Hong Kong, Hong Kong Recruiting
Study contacts
- Study coordinator: Horace Ho-yin Wong, MClinOptom, BSc (Hons) Optom
- Email: horace.wong@polyu.edu.hk
- Phone: 852-63384048
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.