visual axis


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Related to visual axis: fovea, pupillary axis

axis

 [ak´sis] (pl. ax´es)
1. a line through a center of a body, or about which a structure revolves.
the second cervical vertebra. adj., adj ax´ial.
2. the position of the cylindrical part of a lens, used for correcting astigmatism; the range of values is from 0° to 180°.
celiac axis celiac trunk.
dorsoventral axis one passing from the posterior to the anterior surface of the body.
electrical axis of heart the preponderant direction of current flow through the heart, a consequence of the electromotive forces within the heart. It may be computed on either an instantaneous basis or a mean basis.
frontal axis an imaginary line running from right to left through the center of the eyeball.
axis of heart a line passing through the center of the base of the heart to the apex.
instantaneous electrical axis the electrical axis of the heart determined at a given point in time.
lead axis the imaginary direct line between the two electrodes of the bipolar leads or between the positive electrode and the reference point of the unipolar leads.
mean electrical axis the average direction of the activation or repolarization process during the cardiac cycle; it may be determined for any deflection (P, QRS, ST-T) and in the frontal, transverse, or sagittal plane.
optic axis
1. a line connecting the center of the anterior curvature of the cornea (anterior pole) with that of the posterior curvature of the sclera (posterior pole).
2. the hypothetical straight line passing through the centers of curvature of the front and back surfaces of a simple lens.
phlebostatic axis a point located by drawing an imaginary line from the fourth intercostal space at the sternum and finding its intersection with an imaginary line drawn down the center of the chest below the axillae.
Phlebostatic axis.
sagittal axis an imaginary line extending through the anterior and posterior poles of the eye.
visual axis an imaginary line passing from the midpoint of the visual field to the fovea centralis.
Axes of the eye. From Dorland's , 2000.

vis·u·al ax·is

the straight line extending from the object seen, through the center of the pupil, to the macula lutea of the retina.
Synonym(s): line of vision

vis·u·al a·xis

(vizh'ū-ăl ak'sis)
The straight line extending from the object seen, through the center of the pupil, to the macula lutea of the retina.

axis

pl. axes [L., Gr.]
1. a line through a center of a body, or about which a structure revolves.
2. the second cervical vertebra.

celiac axis
celiac trunk.
axis cylinder
axon.
dorsoventral axis
one passing from the back to the belly surface of the body.
electrical axis of heart
the resultant of the electromotive forces within the heart at any instant. See also mean electrical axis.
external bulbar axis
the optical axis that connects the anterior and posterior poles of the eyeball. Called also optic axis.
frontal axis
an imaginary line running from right to left through the center of the eyeball.
axis of heart
a line passing through the center of the base of the heart and the apex.
optic axis
see external bulbar axis (above).
orbital axis
a line passing through the apex of the bony orbit and the center of the opening of the orbit.
sagittal axis
an imaginary line extending through the anterior and posterior poles of the eye.
visual axis
an imaginary line passing from the midpoint of the visual field to the fovea centralis.
References in periodicals archive ?
In-plane ultrasound-guided needle insertion ALONG or ACROSS the visual axis hand positions.
Patients will present with varying reduction to visual acuity if the deposits cross the visual axis with severity dependent on location and density of deposits.
If it is not on the visual axis it is better to leave it alone rather than to start lifting a flap that has settled well.
7] It should be sensitive enough to pinpoint small differences in PCO obscuring the visual axis as also PCO progression, yet be specific enough to avoid registering artefacts such as lens edge, capsulorrhexis edge, flash reflections and poorly illuminated areas of capsule.
The temporal location is farthest from the visual axis and thus the effect of any flattering around the wound is less likely to effect the corneal curvature at the visual axis.
Stage 3 DLK appears as dense, white, clumped cells located at the visual axis with relative peripheral clearing and decreased VA by 1 or 2 lines.
Later stages may cause irritation, grittiness or intense pain (from sharp exposed edges of calcium plaques) and/or reduction of vision as it encroaches the visual axis.
A recurrent pterygium can be associated with decreased visual acuity due to involvement of visual axis and/or irregular astigmatism, extra ocular motility restriction and Symblepharon formation.
In later stages, the superficial opacities become translucent and flattened like breadcrumbs, and coalesce, causing a reduction in vision as the visual axis is affected.
Cause for improvement was decrease in astigmatism, clearing of visual axis, regular and a stable tear film.

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