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kappa angle

Guilbert E, Saad A, Gatinel D. AcuTarget Measurements: Repeatability and Comparison to OPD-Scan III. J Refract Surg, 2014; 30 (3): 180-185.

This article looks at the study compared to the Acutarget (today renamed Veryon) and the OPDscan III regarding the measurement of the distance between the center of the pupil and corneal vertex (first Purkinje image). Due to the presence of an angle Kappa, the apparent Center of the entrance pupil is not confused [...]

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Centering corneal laser surgery (LASIK/PRK) with the Alcon/Wavelight EX 500 laser and Topolyzer Vario

Introduction This page explains the different steps that allow the surgeon to the ablation center we the desired location with the Alcon/Wavelight EX500 excimer laser, while preventing discrepancies between registration data (Topolyzer Vario) and the EX500 laser eye-tracking system. The EX500 excimer can be linked via local network to the Vario Topolyzer: this enables easy [...]

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Axes and remarkable angles of the eye

The existence of remarkable axes of the eye is linked to a peculiarity of the eye: the absence of a common axis for the main structures refractive: cornea, and crystalline. In addition, the fovea, the area of the precise central vision, is slightly temporal to the emergence of the optic nerve. If the eye was an optical system where the optical surfaces were centered on a [...]

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Pupillary axis, kappa angle

The pupillary axis is year axis of importance, as it serves to define several angles. The pupillary axis is defined as the line that joined the center of the entrance pupil to a point located at the anterior corneal surface, where the local tangent is perpendicular to it If the corneal was perfect spherical [...]

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Centering corneal refractive surgery based

Focus (or centering) of the surgical procedures is important area year in refractive surgery. While using the center of the entrance pupil did landmark for the broad treatment areas such as myopic laser photoablations may be sufficient for achieving good optical quality, smaller treatment areas such as hyperopic photoablations gold corneal inlays (ex: Acufocus KAMRA [...])

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Visual axis

The visual axis is a theoretical notion and in the case of the eye requires to take into account certain ocular characteristics such as the absence of a common axis linking the main refractive surfaces (cornea and crystalline). The visual axis corresponds intuitively to the path according to which the light rays from a point source observed would take the most direct route [...]

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What axis k?

The kératométrique axis is a term used in corneal topography. It is defined as the axis that connects the centre of curvature of the cornea to the fixation point. Due to the lack of a common centre of the refractive surfaces of the eye, and eccentricity of the fovea, this axis does not pass through the centre of the [...]

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Line of sight

Line of sight: "Aiming line": A line that connects the attachment point with the center of the pupil. It cuts the anterior surface of the cornea at the point called "Corneal sighting Center". This point is not readily identifiable in clinical practice, unlike the vertex (corneal reflection – image of Purkinje number 1). The [...]

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Pupillary axis

Eye angles are usually defined by specific branches. The pupillary axis is an axis of useful reference, which corresponds to a line perpendicular to the surface of the cornea and goes through the center of the pupil. To identify the pupillary axis, guide the eye in a way that the corneal reflection [...]

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