StrabismusRSORNCT07446621
Risk Factors And Surgical Outcomes Of Strabismus Reoperation
A study testing Horizontal Strabismus Reoperation in people with Strabismus and Esotropia, run by Assiut University at 1 site in Egypt.
Trial summary
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). Read more about this study
- Who is it for?
- Any age
- Conditions the study is for
- Strabismus, Esotropia, Exotropia
- What is being tested?
- Horizontal Strabismus Reoperation
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 62 participants
- Where
- 1 siteEgypt
- Study dates
- Mar 2026to Jul 2027
- 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 Any age
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Patients diagnosed with horizontal strabismus (esotropia or exotropia).
- Patients undergoing repeat surgery for correction of residual, recurrent, undercorrected, or overcorrected horizontal strabismus.
- Availability of sufficient medical records documenting previous strabismus surgery.
- Ability to attend scheduled postoperative follow-up visits.
- Written informed consent obtained from the patient or legal guardian.
Who cannot join
- Combined vertical and horizontal strabismus.
- Paralytic strabismus.
- Restrictive strabismus.
- Strabismus associated with neurological or syndromic conditions.
- Patients with incomplete or insufficient documentation of previous surgical procedures.
- Patients unwilling or unable to complete follow-up.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Egypt1 site
Assiut university
Asyut
Assiut University, 08822080150, vp_grad@aun.edu.eg
About this study
Official title: Risk Factors And Surgical Outcomes Of Strabismus Reoperation: A Clinical Study
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.
Read more
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.
Read the detailed description
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.
- Conditions
- Strabismus, Esotropia, Exotropia
- Being tested
- Horizontal Strabismus Reoperation
- Keywords
- Horizontal strabismus, Strabismus reoperation, Recurrent strabismus, Ocular alignment, Prism diopters, Paediatric strabismus surgery, Orthotropia, Ocular motility
- Medical subject headings
- Strabismus, Esotropia, Exotropia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Horizontal Strabismus ReoperationProcedure or surgery
Also called Strabismus Reoperation, Repeat Strabismus Surgery, Horizontal Rectus Muscle 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.
| Study group | Role | What they receive |
|---|---|---|
| Horizontal Strabismus Reoperation | Experimental | 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. Receives: Procedure: Horizontal Strabismus Reoperation |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 3 months postoperative
Secondary outcomes (4)
Preoperative Angle Of Deviation
Angle of ocular deviation measured in prism diopters using the Prism and Alternate Cover Test at distance fixation before surgery.
Measured: Baseline (preoperative)
Age At Primary Strabismus Surgery
Age of the participant at the time of initial strabismus surgery obtained from medical records.
Measured: Baseline
Presence Of Amblyopia
Presence of amblyopia determined by best corrected visual acuity assessment during preoperative evaluation.
Measured: Baseline
Number Of Extraocular Muscles Operated During Reoperation
Number of horizontal rectus muscles surgically operated during the reoperation procedure.
Measured: Intraoperative
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Mar 2026
- Study startMar 2026 (estimated)
- Primary completionMay 2027 (estimated)
- Study completionJul 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (7)Papers the sponsor has linked to this study.
- Other trials for StrabismusStudies of the same condition, open and under way.
- More trials run by Assiut 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
- Not applicable
- Intervention model
- Single group
- Model description
- This is a prospective single-group interventional study in which all enrolled participants undergo horizontal strabismus reoperation. Outcomes are evaluated postoperatively, and clinical and surgical variables are analyzed to identify risk factors associated with surgical success or recurrence.
- Masking
- None (open label)
- Enrolment
- 62 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Assiut University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Rehab Safwat Hamza, Assiut University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07446621
- Sponsor's protocol ID
- AUH-STRAB-REOP-2026
- Acronym
- RSOR
- Status last verified
- Mar 2026
- First submitted
- 24 Feb 2026
- Last updated
- 9 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Rajavi Z, Gozin M, Sabbaghi H, Behradfar N, Kheiri B, Faghihi M. Reoperation in Horizontal Strabismus and its Related Risk Factors. Med Hypothesis Discov Innov Ophthalmol. 2018 Summer;7(2):73-82.
PubMed 30250856Heo H, Lambert SR. Effect of age on reoperation rate in children undergoing exotropia surgery. Acta Ophthalmol. 2021 Nov;99(7):e1206-e1211. doi: 10.1111/aos.14771. Epub 2021 Feb 2.
PubMed 33529446Yetkin AA. Factors Affecting Surgical Success Rates in Pediatric Horizontal Strabismus Surgery. Cureus. 2024 Nov 29;16(11):e74758. doi: 10.7759/cureus.74758. eCollection 2024 Nov.
PubMed 39734963Akbari MR. Preoperative factors associated with multiple strabismus surgeries: a large retrospective database study. Optom Vis Sci. 2026;103(1):45-52.
Olitsky SE, Coats DK. Complications of Strabismus Surgery. Middle East Afr J Ophthalmol. 2015 Jul-Sep;22(3):271-8. doi: 10.4103/0974-9233.159692.
PubMed 26180463Niu R, Lv P, Hao R, Zhang W. Comprehensive analysis of strabismus reoperations: clinical insights and progression factors. BMC Ophthalmol. 2024 Oct 11;24(1):446. doi: 10.1186/s12886-024-03712-2.
PubMed 39394059Samplaski MK. Editorial Commentary. Urol Pract. 2019 Jan;6(1):44. doi: 10.1097/01.UPJ.0000552857.40544.a1. Epub 2018 Dec 27. No abstract available.
PubMed 37312345
Study at a glance
From the registry record, last updated by the sponsor on 9 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Risk Factors And Surgical Outcomes Of Strabismus Reoperation: A Clinical Study
- ClinicalTrials.gov ID
- NCT07446621
- Acronym / sponsor ID
- RSOR / AUH-STRAB-REOP-2026
- Conditions
- Strabismus, Esotropia, Exotropia
- Keywords
- Horizontal strabismus, Strabismus reoperation, Recurrent strabismus, Ocular alignment, Prism diopters, Paediatric strabismus surgery, Orthotropia, Ocular motility
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 62 participants (estimated)
- Lead sponsor
- Assiut UniversityUniversity, hospital or other
- Study start
- Mar 2026 (estimated)
- Primary completion
- May 2027 (estimated)
- Study completion
- Jul 2027 (estimated)
- First posted
- 3 Mar 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.
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.
Detailed description
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- This is a prospective single-group interventional study in which all enrolled participants undergo horizontal strabismus reoperation. Outcomes are evaluated postoperatively, and clinical and surgical variables are analyzed to identify risk factors associated with surgical success or recurrence.
| Arm | Type | Receives |
|---|---|---|
| Horizontal Strabismus Reoperation | Experimental | Procedure: Horizontal Strabismus ReoperationAll 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. |
Who may qualify
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (5 listed)
- Patients diagnosed with horizontal strabismus (esotropia or exotropia).
Key exclusion criteria (6 listed)
- Combined vertical and horizontal strabismus.
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 |
|---|---|---|
| Horizontal Strabismus ReoperationAlso: Strabismus Reoperation, Repeat Strabismus Surgery, Horizontal Rectus Muscle ReoperationHorizontal 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. | Procedure or surgery | Horizontal Strabismus Reoperation |
Primary outcome
Rate Of Surgical Success After Horizontal Strabismus Reoperation
Time frame: 3 months postoperative
Percentage of participants achieving postoperative ocular alignment within ±10 prism diopters of orthotropia measured using the Prism and Alternate Cover Test at distance fixation.
4 secondary outcomes
Preoperative Angle Of Deviation
Time frame: Baseline (preoperative)
Age At Primary Strabismus Surgery
Time frame: Baseline
Presence Of Amblyopia
Time frame: Baseline
Number Of Extraocular Muscles Operated During Reoperation
Time frame: Intraoperative
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 9 Mar 2026.
- Background: PubMed 30250856Rajavi Z, Gozin M, Sabbaghi H, Behradfar N, Kheiri B, Faghihi M. Reoperation in Horizontal Strabismus and its Related Risk Factors. Med Hypothesis Discov Innov Ophthalmol. 2018 Summer;7(2):73-82.
- Background: PubMed 33529446Heo H, Lambert SR. Effect of age on reoperation rate in children undergoing exotropia surgery. Acta Ophthalmol. 2021 Nov;99(7):e1206-e1211. doi: 10.1111/aos.14771. Epub 2021 Feb 2.
- Background: PubMed 39734963Yetkin AA. Factors Affecting Surgical Success Rates in Pediatric Horizontal Strabismus Surgery. Cureus. 2024 Nov 29;16(11):e74758. doi: 10.7759/cureus.74758. eCollection 2024 Nov.
- BackgroundAkbari MR. Preoperative factors associated with multiple strabismus surgeries: a large retrospective database study. Optom Vis Sci. 2026;103(1):45-52.
- Background: PubMed 26180463Olitsky SE, Coats DK. Complications of Strabismus Surgery. Middle East Afr J Ophthalmol. 2015 Jul-Sep;22(3):271-8. doi: 10.4103/0974-9233.159692.
- Background: PubMed 39394059Niu R, Lv P, Hao R, Zhang W. Comprehensive analysis of strabismus reoperations: clinical insights and progression factors. BMC Ophthalmol. 2024 Oct 11;24(1):446. doi: 10.1186/s12886-024-03712-2.
- Background: PubMed 37312345Samplaski MK. Editorial Commentary. Urol Pract. 2019 Jan;6(1):44. doi: 10.1097/01.UPJ.0000552857.40544.a1. Epub 2018 Dec 27. No abstract available.
- Individual participant dataSharing planned: No
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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 Horizontal Strabismus Reoperation in people with Strabismus and Esotropia, run by Assiut University at 1 site in Egypt.
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 6 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: opening soon, as of the sponsor's last update on 9 Mar 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 Egypt. 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 Rehab Safwat Hamza (01112603390, Rehabsafwat347@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Rate Of Surgical Success After Horizontal Strabismus Reoperation (time frame: 3 months postoperative). 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 NCT07446621, which also lists 7 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 9 Mar 2026.