An interventional study of Horizontal Strabismus Reoperation in Strabismus, Esotropia and Exotropia, sponsored by Assiut University. Not yet recruiting at 1 site in Egypt. Per ClinicalTrials.gov, last updated 2026-03-09.
Sponsored by Assiut University · Not applicable, Interventional, and Treatment
Horizontal strabismus, commonly known as inward or outward deviation of the eyes, is a frequent eye condition that may require surgical correction. Although the first surgery is often successful, some patients develop residual or recurrent eye misalignment and require a second operation (reoperation).
This study aims to identify the clinical and surgical factors that may increase the risk of undercorrection, overcorrection, or recurrence after the first surgery. It also evaluates the outcomes and success rate of repeat surgery in patients with horizontal strabismus.
Patients undergoing reoperation will receive a complete ophthalmological examination before surgery. The surgical plan will be individualized based on previous surgical history and current eye findings. All procedures will be performed under general anesthesia by the same surgeon. Participants will be followed for three months after surgery to assess eye alignment, movement, and possible complications.
The results of this study may help improve surgical planning and predict which patients are at higher risk of requiring additional surgery in the future.
Horizontal strabismus, including esotropia and exotropia, represents the most common form of ocular misalignment requiring surgical intervention. Despite advances in surgical techniques, a proportion of patients experience residual deviation, overcorrection, or recurrence after primary surgery, necessitating reoperation. Reoperation presents unique surgical challenges due to altered anatomy, scar tissue formation, possible muscle slippage, and variability in postoperative healing response.
Reported reoperation rates vary across studies and clinical settings, with multiple patient-related and surgical factors implicated in surgical failure. These factors may include age at primary surgery, magnitude of deviation, amblyopia, number of operated muscles, surgical technique, and time interval between surgeries. However, data regarding predictive risk factors and standardized outcome evaluation in reoperated horizontal strabismus remain limited in the local setting.
This prospective interventional study will be conducted at Assiut University Hospital. It will include patients undergoing repeat surgery for correction of horizontal strabismus. Patients with vertical deviations, paralytic or restrictive strabismus, neurological or syndromic associations, or incomplete previous surgical data will be excluded.
Preoperative assessment will include measurement of visual acuity, cycloplegic refraction, anterior and posterior segment examination, evaluation of ocular motility in nine diagnostic positions of gaze, and measurement of angle of deviation using prism and alternate cover test or Krimsky test when appropriate. Documentation of conjunctival scarring and previous surgical details will be performed.
The surgical approach will be individualized according to preoperative findings and prior operative records. Exploration of previously operated muscles will be performed when clinically indicated. Intraoperative forced duction testing will assess muscle tightness. All surgeries will be conducted under general anesthesia by the same surgeon to reduce inter-operator variability.
Participants will be followed postoperatively at 1 day, 1 week, 1 month, and 3 months. Surgical success will be defined as postoperative alignment within ±10 prism diopters of orthotropia at final follow-up. Secondary outcomes include stability of alignment and postoperative complications such as limitation of ocular motility or conjunctival scarring.
Statistical analysis will evaluate associations between demographic and clinical variables and surgical outcomes using multivariate regression to identify independent risk factors for reoperation outcomes.
The findings of this study aim to improve risk stratification, optimize surgical planning, and enhance long-term outcomes in patients undergoing horizontal strabismus reoperation.
142 studies on the registry are indexed under Strabismus; 31 are open to participants now.
This study's planned enrollment of 62 is close to the median of 60 across 82 interventional studies indexed under Strabismus.
Browse Strabismus studies →Assiut University is the lead sponsor of 5,078 studies on the registry; 2,178 are open to participants now.
Of its 14 completed or terminated interventional studies of FDA-regulated products, 0 (0%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Patients diagnosed with horizontal strabismus (esotropia or exotropia).
Exclusion Criteria:
Combined vertical and horizontal strabismus.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
All enrolled participants undergo repeat surgery for correction of horizontal strabismus (esotropia or exotropia). The surgical approach is individualized based on preoperative clinical evaluation and prior operative records. Exploration of previously operated muscles is performed when indicated, particularly in cases of limited ocular motility or suspected scarring. Otherwise, surgery is performed on unoperated horizontal rectus muscles when appropriate. Intraoperative forced duction testing is conducted to assess muscle tightness, and scar tissue release is performed if necessary. All procedures are performed under general anesthesia by the same surgeon. Participants are followed postoperatively to evaluate alignment, ocular motility, and surgical outcomes.
Procedure: Horizontal Strabismus Reoperation
Horizontal strabismus reoperation is performed to correct residual or recurrent esotropia or exotropia following previous strabismus surgery. The surgical plan is individualized based on preoperative assessment and prior operative records. Previously operated muscles are explored when limited ocular motility, scarring, or suspected muscle slippage is present. In other cases, surgery may be performed on unoperated horizontal rectus muscles when appropriate. Intraoperative forced duction testing is conducted to assess muscle tightness, and scar tissue is released when indicated. All procedures are performed under general anesthesia by the same surgeon. Postoperative alignment and ocular motility are evaluated during follow-up visits.
Also known as: Strabismus Reoperation, Repeat Strabismus Surgery, Horizontal Rectus Muscle Reoperation
Rate Of Surgical Success After Horizontal Strabismus Reoperation
Percentage of participants achieving postoperative ocular alignment within ±10 prism diopters of orthotropia measured using the Prism and Alternate Cover Test at distance fixation.
Time frame: 3 months postoperative
Preoperative Angle Of Deviation
Angle of ocular deviation measured in prism diopters using the Prism and Alternate Cover Test at distance fixation before surgery.
Time frame: Baseline (preoperative)
Age At Primary Strabismus Surgery
Age of the participant at the time of initial strabismus surgery obtained from medical records.
Time frame: Baseline
Presence Of Amblyopia
Presence of amblyopia determined by best corrected visual acuity assessment during preoperative evaluation.
Time frame: Baseline
Number Of Extraocular Muscles Operated During Reoperation
Number of horizontal rectus muscles surgically operated during the reoperation procedure.
Time frame: Intraoperative
Plan to share: No
Start is estimated for Mar 2026; primary completion for May 2027, 14 months later.
Of 35 non-industry interventional studies with no phase under Strabismus, half reached primary completion within 17 months of starting (the median), counting those still running; a quarter within 8 and three quarters within 46. This study's planned 14 months is below that.
Counting every sponsor, half of 35 studies reached it within 17 months; a quarter within 8 and three quarters within 46.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
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