Studies of the Angle Kappa and the Angle Alpha

Study Overview
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Brief Summary
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Anatomical ophthalmological connections and their dynamics are still debated in the scientific community. However, their considering is essential in many surgeries (strabismus, cataract, refractive...) or in clinical practice. The correlation between these biometric values would make it possible to refine the knowledge related to these landmarks and thus offer better ophthalmological management by integrating these variables into the clinical examination. The aim of the study is to analyze the correlation between the angle alpha and the angle kappa in a healthy individual without ophthalmologic disorder.

Detailed Description
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The angle kappa corresponds to the angle formed between the visual axis (line between the point of fixation and the fovea: area of the retina allowing precise vision) and the pupillary axis (line passing through the center of the pupil and perpendicular to the cornea). The angle alpha corresponds to the angle formed between the visual axis and the optical axis (line passing through the nodal point of the eye and corneal center). In theory, the angle kappa and angle alpha are equal; but physiological corectopy in the nasal position induces a variation between these two angles; the angle kappa being generally less than the angle alpha without a correlation being established. Also, pupillary constriction causes a variation in the position of the center of the pupil. The angle kappa therefore exhibits a variation depending on the expansion. Anatomical ophthalmological connections and their dynamics are still debated in the scientific community. However, their considering is essential in many surgeries (strabismus, cataract, refractive ...) or in clinical practice. The correlation between these biometric values would make it possible to refine the knowledge related to these landmarks and thus offer better ophthalmological management by integrating these variables into the clinical examination. The aim of the study is to analyze the correlation between the angle alpha and the angle kappa in a healthy individual without an eye disorder.

Official Title
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Studies of the Characteristics of the Angle Kappa and the Angle Alpha in the Healthy Individual. Studies of the Angle Kappa and the Angle Alpha

Conditions
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No Eye Disorder

Intervention / Treatment
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* Other: Eye examination


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - Informed major subject not opposing to their participation in the study Exclusion Criteria: - Subject with strabismus or organic ophthalmologic pathology

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

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Healthy individual<br>Healthy individual | Other: Eye examination<br>* Multimodal fundus imaging (color fundus photography, optical coherence tomography (OCT)) orthoptic assessment (Visual acuity, Refraction, Cover test, Stereopsis evaluation ocular biometry corneal topography monocular photographs in photopic and scotopic condition<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Value of the angle Kappa | Semi-automatic digital method of measurement by eye photography | Day 0 | 
| Value of the angle Alpha | Semi-automatic digital method of measurement by eye photography | Day 0 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Variation of the Kappa angle depending on the pupillary diameter | Variation in the same individual. Value of the Kappa angle using the semi-automatic method of measurement by ocular photography in photopic and scotopic conditions & measurement of the pupillary diameter using the photographs obtained | Day 0 | 
| Correlation between the value of the angle Alpha and the Optic disc / fovea distance | Angle Alpha value using the semi-automatic method of measurement by eye photography and the distance between the optic disc and the fovea | Day 0 | 
| Correlation between the angle Kappa and the axial length | Value of the angle Kappa and Alpha using the semi-automatic method of measurement by eye photography and Value of the axial length measured by biometry IolMaster 500 (Carl Zeiss) | Day 0 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Angle Kappa, Angle Alpha, Pupillary axis, Visual axis, Optical axis