Table of Contents
What is Intorsion and extortion?
Inferior Oblique (IR) Rotates the top of the eye away from the nose (extorsion) Moves the eye upwards (elevation) Moves the eye outwards (abduction)
What does Intorsion of eye mean?
Medical Definition of intorsion : inward rotation (as of a body part) about an axis or a fixed point especially : rotation of the eye around its anteroposterior axis so that the upper part moves toward the nose — compare extorsion.
What is eye adduction?
When the eye is adducted, the oblique muscles are the prime vertical movers. Elevation is due to the action of the inferior oblique muscle, while depression is due to the action of the superior oblique muscle. The oblique muscles are also primarily responsible for torsional movements.
What are Ductions and versions?
2. Ductions are monocular rotations of the eye. 3. Versions are conjugate binocular eye movements.
Which explanation best describes Emmetropia?
Emmetropia is a state in which the eye is relaxed and focused on an object more than 6 meters or 20 feet away. The light rays coming from that object are essentially parallel, and the rays are focused on the retina without effort.
What is INO eye?
Introduction. Internuclear ophthalmoplegia or ophthalmoparesis (INO) is an ocular movement disorder that presents as an inability to perform conjugate lateral gaze and ophthalmoplegia due to damage to the interneuron between two nuclei of cranial nerves (CN) VI and CN III (internuclear).
What causes gaze deviation?
Common causes include strokes for horizontal gaze palsies, midbrain lesions (usually infarcts and tumors) for vertical gaze palsies, and progressive supranuclear palsy for downward gaze palsies. Treat the underlying disorder.
What is emmetropic vision?
Emmetropia is the refractive state of an eye in which parallel rays of light entering the eye are focused on the retina, creating an image that is perceived as crisp and in focus.
What happens in emmetropia?
When a person has emmetropia in both eyes, the person is described as having ideal vision. When an eye is emmetropic, light rays coming into the eye from a distance come to perfect focus on the retina. If the eye is an abnormal length or the cornea is abnormally shaped, chances are you will not be emmetropic.
What are eyeball movements?
The eyes are the visual organ and eyeball moves includes voluntary or involuntary movements to increase the field of vision, to reduce blurring. This movements are controlled by a set of extra-ocular muscles of each eye.
What is the principal intortor of the eye?
However, as the eye moves into an abducted position, the superior oblique muscle becomes the prime intortor, and in adduction, the superior rectus muscle is the principal intortor.
What is excycloduction (extorsion)?
Excycloduction (extorsion) is a torsional movement of the eye about the anteroposterior axis that displaces the superior pole of the eye laterally. Extorsion is the result of the combined contraction of the inferior oblique and inferior rectus muscles and the combined relaxation of the superior oblique and superior rectus muscles.
What is the difference between dextrocyloversion and torsional version?
Torsional versions are produced by combined contractions of intortors of one eye (SO and SR) and extortors of the other (IO and IR); dextrocyloversion results from right eye extortors and left eye intortors contracting, and le-vocycloversion results from right eye intortors and left eye extortors contracting.