Reliability and Reproducibility of Automated Angular Measurement in Strabismus

Study Overview
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Brief Summary
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Angular measurement of deviation is an essential element in the clinical evaluation of strabic patients. It is performed by orthoptic methods. However, studies show that the same patient presents a great variability of his angular measurement between 2 consultations, and between 2 observers. Automated angle measurement is a recent concept that aims to overcome the defects of subjective angle measurement by alternate occlusion test and prismatic bar. Improvements made by these devices would provide reliable, objective and reproducible measurements of the angle of deviation by increasing the accuracy of strabal angle assessment, improving decision making and surgical follow-up, decreasing inter-examiner variability and variability over time, and facilitating data comparison to improve scientific publication possibilities. The Gazelab® device is a video-oculograph combined with a laser projection system and an infrared camera. It allows an objective angular evaluation, in non-dissociating physiological conditions, possible even in the absence of binocular vision and allows an analysis of the deviation in all positions. There is extremely little data in the literature on automated measuring devices. The Gazelab tool is still little known in the strabology discipline and seems to have a number of advantages over other devices. The interest of this examination towards this pathology led the ophthalmology department to use it in the current practice, and since recently it is an act nomenclaturé.

Detailed Description
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The objective of this work is to evaluate the reliability and reproducibility of the automated angular measurement by the Gazelab® (ES12/13127) apparatus, compared to the standard gold which is the angular measurement by alternate occlusion test and prismatic bar, in horizontal strabisms (converging and diverging). Indeed in our daily practice the 2 examinations are carried out. To compare with the standard gold which denotes a strong inter-observer variability, the investigator will compare the results of the Gazelab to the alternate occlusion by prism bar (standard gold) 2 times with 2 trained examiners

Official Title
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Reliability and Reproducibility of Automated Angular Measurement in Strabismus

Conditions
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Strabismus

Intervention / Treatment
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* Other: Evaluate the reliability and reproductibility of the automated angular measurement by the Gazelab


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients over 18 years of age Strabic convergent or divergent patients or patients requiring an oculomotor check-up in their follow-up consultation Patient giving oral consent to this study Exclusion Criteria: Patient with medical follow-up impossible, Impossibility to install Gazelab equipment for anatomical reasons of the head (craniostenosis...) No ocular fixation. Major without freedom under guardianship or trusteeship

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: Evaluate the reliability and reproductibility of the automated angular measurement by the Gazelab|Compare the results of the Gazelab to the alternate occlusion by prism bar (standard gold) examiners.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Intra-class correlation coefficient | Intra-class correlation coefficient calculated on the 4 measures (2 of each technique) of each patient taken at time 1 by the same assessor. | 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Intra-class correlation coefficient using measurements | Intra-class correlation coefficient using measurements from each technique between 2 different evaluators at time 1 | 12 months | 
| Intraclass correlation coefficient using time 1 and time 2 measurements | Intraclass correlation coefficient using time 1 and time 2 measurements with the same investigator | 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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angle measurement, automated, strabismus