A Prospective Observational Study of Adult Strabismus

Study Overview
=================
Brief Summary
-----------------
The purpose of this study is to describe clinical characteristics, treatments, and one-year outcomes of adults with convergence insufficiency, divergence insufficiency, or small angle hypertropia.

Detailed Description
-----------------
The purpose of this study is to describe clinical characteristics, treatments, and one-year outcomes of adults with convergence insufficiency, divergence insufficiency, or small angle hypertropia. Treatment comparisons within the studied conditions will also be done to help develop future studies.

Official Title
-----------------
A Prospective Observational Study of Adult Strabismus

Conditions
-----------------
Convergence Insufficiency, Divergence Insufficiency, Hypertropia

Intervention / Treatment
-----------------
* Device: Prism
* Other: Orthoptic Exercises
* Procedure: Eye Muscle Surgery
* Procedure: Botox Injection


Participation Criteria
=================
Eligibility Criteria
-----------------
Eligibility Criteria for Convergence Insufficiency (CI) Group: The following inclusion criteria must be met for the subject to be enrolled into the study: Adults ≥18 years of age (adult onset of CI not required) No strabismus surgery within the past 10 years CI Symptom Survey score ≥21 points Near exodeviation of ≥4∆ and at least 4∆ larger than at distance by PACT Distance exodeviation ≤15∆ by PACT Vertical deviation ≤2∆ at distance and near by PACT No constant exotropia at distance or near Reduced positive fusional vergence (PFV) at near (<20∆ or fails Sheard's criterion that the PFV measures less than twice the magnitude of the near phoria) Near point of convergence (NPC) of ≥6 cm break Visual acuity 20/50 or better in both eyes by ETDRS or Snellen No paralytic strabismus (e.g., 3rd, 4th, or 6th cranial nerve palsies, skew deviation, Duane syndrome) No restrictive strabismus (e.g., blowout fracture, thyroid eye disease, post scleral buckle, Brown syndrome) No monocular diplopia No paretic strabismus, thyroid eye disease, myasthenia gravis, chronic progressive external ophthalmoplegia, or eye movement abnormalities associated with known neurological disease. Patients with Parkinson's disease can be enrolled if non-paretic deviation. No inferior or superior oblique overaction defined as 2+ or greater Ability to fuse with prism in space (see section 2.4.1) Ability to understand and complete a survey Investigator is initiating treatment with prism, orthoptic exercises, botulinum toxin injection or surgery If initiating treatment with botulinum toxin or surgery, planned injection or surgery to be within 60 days of enrollment Single treatment modality is planned (e.g., no combined prism and orthoptic exercises) Treatment to be initiated has not been used within the past one year Eligibility Criteria for Divergence Insufficiency (DI) Group: The following inclusion criteria must be met for the subject to be enrolled into the study: Adults ≥18 years of age Adult-onset DI (at ≥18 years of age) No prior strabismus surgery Symptoms of diplopia at distance with a frequency of sometimes or worse in primary position (in current glasses if wearing glasses) Distance esodeviation of 2∆ to 30∆ and at least 50% larger than at near by PACT No more than 5∆ difference between right and left gaze by PACT No more than 10∆ difference between the primary position at distance and either upgaze or downgaze ≤10∆ by PACT Any coexisting vertical deviation must be less than distance esodeviation and ≤10∆ by PACT Visual acuity 20/50 or better in both eyes by ETDRS or Snellen No paralytic strabismus (e.g., 3rd, 4th, or 6th cranial nerve palsies, skew deviation, Duane syndrome) No restrictive strabismus (e.g., blowout fracture, thyroid eye disease, post scleral buckle, Brown syndrome) No monocular diplopia No paretic strabismus, thyroid eye disease, myasthenia gravis, chronic progressive external ophthalmoplegia, or eye movement abnormalities associated with known neurological disease. Patients with Parkinson's disease can be enrolled if non-paretic deviation No inferior or superior oblique overaction defined as 2+ or greater Ability to fuse with prism in space (see section 2.4.2) Ability to understand and complete a survey Investigator is initiating treatment with prism, orthoptic exercises, botulinum toxin injection or surgery If initiating treatment with botulinum toxin or surgery, planned injection or surgery to be within 60 days of enrollment Single treatment modality planned (e.g., no combined prism and orthoptic exercises) Treatment to be initiated has not been used within the past one year Eligibility Criteria for Small-angle Hypertropia (HT) Group: The following inclusion criteria must be met for the subject to be enrolled into the study: Adults ≥18 years of age Adult-onset HT (at ≥18 years of age) No prior strabismus surgery Symptoms of diplopia at distance or near with a frequency of sometimes or worse in primary or reading position (in current glasses if wearing glasses) Vertical deviation ≥1∆ to ≤10∆ at distance and near by PACT No more than 4∆ difference from the primary in any gaze position by PACT Any coexisting esodeviation must be less than the vertical deviation Any coexisting exodeviation ≤10∆ by PACT No convergence insufficiency as defined in section 2.2.1 Visual acuity 20/50 or better in both eyes by ETDRS or Snellen No paralytic strabismus (e.g., 3rd, 4th, or 6th cranial nerve palsies, skew deviation, Duane syndrome) No restrictive strabismus (e.g., blowout fracture, thyroid eye disease, post scleral buckle, Brown syndrome) No monocular diplopia No paretic strabismus, thyroid eye disease, myasthenia gravis, chronic progressive external ophthalmoplegia, or eye movement abnormalities associated with known neurological disease. Patients with Parkinson's disease can be enrolled if non-paretic deviation. No inferior or superior oblique overaction defined as 2+ or greater Ability to fuse with prism in space (see section 2.4.3) Ability to understand and complete a survey Investigator is initiating treatment with prism, orthoptic exercises, botulinum toxin injection or surgery If initiating treatment with botulinum toxin or surgery, planned injection or surgery to be within 60 days of enrollment Single treatment modality planned (e.g., no combined prism and orthoptic exercises) Treatment to be initiated has not been used within the past one year Exclusion Criteria for Convergence Insufficiency (CI) Group: The following criteria exclude a subject from enrollment into the study: Strabismus surgery within the past 10 years CI Symptom Survey score ≥21 points Near exodeviation of ≤4∆ and at least 4∆ larger than at distance by PACT Distance exodeviation ≥15∆ by PACT Vertical deviation ≥2∆ at distance and near by PACT Constant exotropia at distance or near Near point of convergence (NPC) of ≤6 cm break Visual acuity worse than 20/50 either eye by ETDRS or Snellen Paralytic strabismus (e.g., 3rd, 4th, or 6th cranial nerve palsies, skew deviation, Duane syndrome) Restrictive strabismus (e.g., blowout fracture, thyroid eye disease, post scleral buckle, Brown syndrome) Monocular diplopia Paretic strabismus, thyroid eye disease, myasthenia gravis, chronic progressive external ophthalmoplegia, or eye movement abnormalities associated with known neurological disease. Patients with Parkinson's disease can be enrolled if non-paretic deviation. Inferior or superior oblique overaction defined as 2+ or greater Inability to fuse with prism in space (see section 2.4.1) Inability to understand and complete a survey Treatment to be initiated has already been used within the past one year Exclusion Criteria for Divergence Insufficiency (DI) Group: The following criteria exclude a subject from enrollment into the study: No adult-onset DI (at ≥18 years of age) Prior strabismus surgery Distance esodeviation outside the range of 2∆ to 30∆ and less than 50% larger than at near by PACT More than 5∆ difference between right and left gaze by PACT More than 10∆ difference between the primary position at distance Any coexisting vertical deviation more than distance esodeviation and ≥10∆ by PACT Visual acuity worse than 20/50 in either eye by ETDRS or Snellen Paralytic strabismus (e.g., 3rd, 4th, or 6th cranial nerve palsies, skew deviation, Duane syndrome) Restrictive strabismus (e.g., blowout fracture, thyroid eye disease, post scleral buckle, Brown syndrome) Monocular diplopia Paretic strabismus, thyroid eye disease, myasthenia gravis, chronic progressive external ophthalmoplegia, or eye movement abnormalities associated with known neurological disease. Inferior or superior oblique overaction defined as 2+ or greater Inability to fuse with prism in space (see section 2.4.2) Inability to understand and complete a survey Treatment to be initiated has already been used within the past one year Exclusion Criteria for Small-angle Hypertropia (HT) Group: The following criteria exclude a subject from enrollment into the study: No adult-onset HT (at ≥18 years of age) Prior strabismus surgery Vertical deviation ≤1∆ or ≥10∆ at distance and near by PACT More than 4∆ difference from the primary in any gaze position by PACT Coexisting esodeviation must not be less than the vertical deviation Coexisting exodeviation ≥10∆ by PACT Convergence insufficiency as defined in section 2.2.1 Visual acuity worse than 20/50 in either eye by ETDRS or Snellen Paralytic strabismus (e.g., 3rd, 4th, or 6th cranial nerve palsies, skew deviation, Duane syndrome) Restrictive strabismus (e.g., blowout fracture, thyroid eye disease, post scleral buckle, Brown syndrome) Monocular diplopia Paretic strabismus, thyroid eye disease, myasthenia gravis, chronic progressive external ophthalmoplegia, or eye movement abnormalities associated with known neurological disease. Inferior or superior oblique overaction defined as 2+ or greater Inability to fuse with prism in space (see section 2.4.3) Inability to understand and complete a survey Treatment to be initiated has already been used within the past one year

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Convergence insufficiency<br>Eligible adults with convergence insufficiency can be treated with prism, orthoptic exercises, eye muscle surgery, or botox injection, per the investigator's usual clinical practice. | Device: Prism<br>* Ground-in or Fresnel prism<br>Other: Orthoptic Exercises<br>* Orthoptic exercises- fusion, convergence, divergence, and others, including computer-based therapy<br>Procedure: Eye Muscle Surgery<br>* Bilateral medial rectus muscle resection surgery Single medial rectus muscle resection surgery Recess lateral rectus muscle resection medial rectus muscle surgery Bilateral lateral rectus muscle recession surgery Single lateral rectus muscle recession surgery Bilateral lateral rectus muscle resection surgery Single lateral rectus muscle resection surgery Recess medial rectus muscle resection lateral rectus muscle surgery Bilateral medial rectus muscle recession surgery Single medial rectus muscle recession surgery Vertical rectus muscle recession surgery Vertical rectus muscle mini-tenotomy (snip) surgery<br>Procedure: Botox Injection<br>* Botulinum toxin injection<br>* Other names: Botulinum toxin injection;|
| Divergence insufficiency<br>Eligible adults with divergence insufficiency can be treated with prism, orthoptic exercises, eye muscle surgery, or botox injection, per the investigator's usual clinical practice. | Device: Prism<br>* Ground-in or Fresnel prism<br>Other: Orthoptic Exercises<br>* Orthoptic exercises- fusion, convergence, divergence, and others, including computer-based therapy<br>Procedure: Eye Muscle Surgery<br>* Bilateral medial rectus muscle resection surgery Single medial rectus muscle resection surgery Recess lateral rectus muscle resection medial rectus muscle surgery Bilateral lateral rectus muscle recession surgery Single lateral rectus muscle recession surgery Bilateral lateral rectus muscle resection surgery Single lateral rectus muscle resection surgery Recess medial rectus muscle resection lateral rectus muscle surgery Bilateral medial rectus muscle recession surgery Single medial rectus muscle recession surgery Vertical rectus muscle recession surgery Vertical rectus muscle mini-tenotomy (snip) surgery<br>Procedure: Botox Injection<br>* Botulinum toxin injection<br>* Other names: Botulinum toxin injection;|
| Small-angle hypertropia<br>Eligible adults with small-angle hypertropia can be treated with prism, orthoptic exercises, eye muscle surgery, or botox injection, per the investigator's usual clinical practice. | Device: Prism<br>* Ground-in or Fresnel prism<br>Other: Orthoptic Exercises<br>* Orthoptic exercises- fusion, convergence, divergence, and others, including computer-based therapy<br>Procedure: Eye Muscle Surgery<br>* Bilateral medial rectus muscle resection surgery Single medial rectus muscle resection surgery Recess lateral rectus muscle resection medial rectus muscle surgery Bilateral lateral rectus muscle recession surgery Single lateral rectus muscle recession surgery Bilateral lateral rectus muscle resection surgery Single lateral rectus muscle resection surgery Recess medial rectus muscle resection lateral rectus muscle surgery Bilateral medial rectus muscle recession surgery Single medial rectus muscle recession surgery Vertical rectus muscle recession surgery Vertical rectus muscle mini-tenotomy (snip) surgery<br>Procedure: Botox Injection<br>* Botulinum toxin injection<br>* Other names: Botulinum toxin injection;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Symptom Success at 10 Weeks | In the convergence insufficiency group, the primary outcome will be symptom success at the 10-week and 12-month visit, defined as improvement of CI Symptom Survey (CISS) score of at least 9 points and an outcome score of <21 points. In the divergence insufficiency group, the primary outcome will be symptom success at the 10-week and 12-month visit, defined as diplopia rarely or never in primary position at distance on the diplopia questionnaire. In the small-angle hypertropia group, the primary outcome will be symptom success at the 10-week and 12-month visit, defined as diplopia rarely or never both in primary position at distance and in reading position on the diplopia questionnaire. | 10 weeks after enrollment | 
| Number of Participants With Symptom Success at 12 Months | In the convergence insufficiency group, the primary outcome will be symptom success at the 10-week and 12-month visit, defined as improvement of CI Symptom Survey (CISS) score of at least 9 points and an outcome score of <21 points. In the divergence insufficiency group, the primary outcome will be symptom success at the 10-week and 12-month visit, defined as diplopia rarely or never in primary position at distance on the diplopia questionnaire. In the small-angle hypertropia group, the primary outcome will be symptom success at the 10-week and 12-month visit, defined as diplopia rarely or never both in primary position at distance and in reading position on the diplopia questionnaire. | 12 months after enrollment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean of Near Point of Convergence in Convergence Insufficiency Group | Near point of convergence (convergence insufficiency group only). | 12 months after enrollment | 
| Mean Positive Fusional Vergence in Convergence Insufficiency Group | Positive fusional vergence (convergence insufficiency group only). | 12 months after enrollment | 
| Adult Strabismus 20 Questionnaire Score (DI) | Adult Strabismus Quality of Life Questionnaire (AS-20) For AS-20, scores are reported for the following subscales. A total score will not be reported. Self-perception score Interaction score Reading function score General function score Values for each subscale range from 0 to 100. 0 indicates poor quality of life (the patient reported always for all questions) and 100 represents good quality or life (patient reported never for all questions) | 12 months after enrollment | 
| Mean Convergence Insufficiency Symptom Survey Score | Mean Convergence Insufficiency Symptom Survey Score (convergence insufficiency group only) For CISS, the range is from 0 (having no symptoms of CI) to 60 (always showing all symptoms of CI). | 12 months after enrollment | 
| Adult Strabismus 20 Questionnaire Score (CI) | Adult Strabismus Quality of Life Questionnaire (AS-20) For AS-20, scores are reported for the following subscales. A total score will not be reported. Self-perception score Interaction score Reading function score General function score Values for each subscale range from 0 to 100. 0 indicates poor quality of life (the patient reported always for all questions) and 100 represents good quality or life (patient reported never for all questions) | 12 months after enrollment | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Convergence Insufficiency, Divergence Insufficiency, Small-angle Hypertropia, Strabismus