Eye movements include voluntary or unconscious eye movements, helping to acquire, repair, and track visual stimuli. Specialized systems are used in maintaining fixation, while reading and reading music. A special type of eye movement, rapid eye movement, occurs during REM sleep.
The eye is the visual organ of the human body, and it moves using a six muscle system. The retina, a special type of tissue that contains photoreceptors, senses light. These special cells convert light into electrochemical signals. These signals travel along the optic nerve fibers to the brain, where they are interpreted as visual visions in the cortex.
Primates and many other vertebrates use three types of voluntary eye movements to track interesting objects: subtle pursuits, vergence shifts and saccade. These movements seem to be initiated by small cortical regions in the frontal lobe of the brain. This is corroborated by frontal lobe removal. In this case, the reflex (like a reflex that diverts the eye to the moving light) is still intact, although voluntary control is obliterated.
Video Eye movement
Anatomi
Otot
Six extraocular muscles facilitate eye movement. These muscles arise from the general tendon ring in orbit, eye socket, and attached to the eyeball. The six muscles are the lateral, medial, inferior and superior rectus muscles, and the inferior and superior oblique muscles. The muscles, when contracting, cause the movement of the eyeball, by pulling the eyeball toward the muscle. For example, the lateral rectus is on the lateral side of the eyeball. When contracting, the eyeball moves so the pupil looks out. The medial rectus causes the eyeball to look inward; the inferior rectus downward and the superior rectus upward. Superior oblique muscles and inferior oblique muscles are attached at an angle to the eyeball.
Kebanyakan otot tidak hanya memindahkan mata ke arah mata angin, tetapi juga sedikit memutar pupil.
The muscles are supplied by the oculomotor nerve, with the exception of the superior oblique, supplied by the troklear nerve, and the lateral rectus, supplied by the nerve abducens.
Three pairs of antagonist muscles control eye movement: the lateral and medial rectus muscles, superior and inferior rectus muscles, and superior and inferior tilt muscles. These muscles are responsible for eye movement along three different axes: horizontally, either toward the nose (adductive) or away from the nose (kidnapping); vertical, either elevation or depression; and torsional, movements that bring the top of the eye to the nose (intorsion) or away from the nose (twist). Horizontal movement is controlled entirely by the medial and lateral rectus muscles; the medial rectus muscle is responsible for adduction, the lateral rectus muscle for abduction. Vertical movement requires coordinated action of superior and inferior rectus muscles, as well as oblique muscles. The relative contribution of the rectus and oblique groups depends on the horizontal position of the eye. In a prime position (straight forward eye), both groups contribute to vertical movement. Improvement is caused by superior rectus action and inferior tilting muscles, while depression is caused by inferior rectus action and superior tilting muscles. When the eye is abducted, the rectus muscles are the main vertical movers. Improvement is caused by superior rectus action, and depression is caused by inferior rectus action. When the eye is in adduction, the oblique muscles are the main vertical movers. Improvement is caused by oblique inferior muscle action, while depression is caused by superior tilt muscle action. The oblique muscles are also primarily responsible for torsional movements.
Neuroanatomy
The brain gives supreme control over both voluntary and unconscious eye movements. Three cranial nerves carry signals from the brain to control the extraocular muscles. Three nerves control the eye muscles. It is the oculomotor nerve, which controls most of the muscles, the trochlear nerve, which controls the superior tilting muscles, and the nerve abducens, which control the muscles of the lateral rectus.
In addition to muscle movement, many areas of the brain contribute to unintentional and voluntary eye movement. This includes providing a conscious perception of the vision, as well as areas that facilitate tracking.
- Brain
- Cerebral cortex
- Frontal lobe - frontal eye area (FEF), medial eye area (MEF), additional eye area (SEF), dorsomedial frontal cortex (DMFC)
- The parietal lobe - the lateral intraparietal region (LIP), the middle temporal area (MT), the medial superior temporal area (MST)
- The occipital lobe
- Visual cortex
- Cerebellum
- Cerebral cortex
- Middle brain
- Pretectal area - Pretectal core
- Colliculus superior
- Brainstem
- Colliculus superior (SC)
- Priority core in the formation of reticular (PMN)
- Paramedian of reticular pontine formation
- The vestibular nucleus
- Medium longitudinal fasciculus
- Nucleus prepositus hypoglossi
Maps Eye movement
Physiology
Eye movements can be classified according to several systems:
- This can be classified according to one or both eyes' involvement; involves one eye they can be classified as duction, and both eyes either version, if moving in the same direction, or vergence, if moving in the opposite direction.
- this can be classified as fixation, stabilizing gaze , or switching view . Motion stabilization movements may include vestibulo-ocular reflexes and optokinetic reflexes, and the mechanism of sight transfer as a saccade and chase movement.
Vergence Movement or convergence is the movement of both eyes to ensure that the image of the sighted object falls to the appropriate point on both retinas. This type of movement helps in a deep perception of the object
Pursuit Movement or fine pursuit is a movement made by the eye when tracking the movement of the object, so that the moving image can be retained in the fovea.
Saccades
Eyes never really rest. They make fast jittering random gestures even when we are fixated on one point. The reason for this random movement is related to photoreceptors and ganglion cells. It seems that a constant visual stimulus can make photoreceptors or ganglion cells unresponsive; on the other hand a stimulus that changes will not. Therefore, random eye movements constantly alter the stimuli that fall on the photoreceptors and ganglion cells, making the picture more pronounced.
Saccades are fast-eye movements used when scanning visual scenes. In our subjective impression, the eye does not move smoothly on the printed page while reading. Instead, our eyes make short and fast motions called saccades . As long as each saccade eye moves as fast as they can and speed can not be consciously controlled between stops. This movement is worth a few minutes arc, moving at regular intervals of about three to four per second. One of the main uses of saccadic eye movements is being able to scan larger areas with high resolution eye fovea.
Vestibulo-ocular System
The vision system in the brain is too slow to process the information if the images sneak in the retina more than a few degrees per second. Thus, to be able to see as we move, the brain must balance the head movement by rolling the eyes. Another specialty of the visual system in many vertebrate animals is the development of small areas of the retina with exceptionally high visual acuity. This area is called the fovea, and includes about 2 degrees of view in humans. To get a clear view of the world, the brain must rotate the eye so that the image of the object seen falls on the fovea. Therefore, eye movement is essential for visual perception, and any failure can cause serious visual disabilities. To see a quick demonstration of this fact, try the following experiment: raise your hand, about one foot (30 cm) in front of your nose. Keep your head fixed, and wiggle your hand from side to side, slowly at first, and then faster and faster. At first you will be able to see your fingers quite clearly. But since the vibration frequency runs about 1 Hz, the radius will become blurry. Now, keep your hands fixed, and shake your head (up and down or left and right). No matter how fast you shake your head, the picture of your fingers stays clear. This suggests that the brain can move the opposite eye to the head movement much better than one that can follow, or pursue, hand gestures. When your chase system fails to follow hand gestures, the image slips on the retina and you see a fuzzy hand.
The brain must direct both eyes quite accurately so that the corresponding object falls at the appropriate point of two retinas to avoid the perception of double vision. In most vertebrates (humans, mammals, reptiles, birds), the movement of different parts of the body is controlled by the striated muscles that work around the joint. The movement of the eye is slightly different because the eye is not tightly bound to anything, but is held in orbit by six extraocular muscles.
- Legal Vocabulary on the same innervation
- Sherrington's law on reciprocal innuendability
Reading
While reading, the eye moves along the lines of the text, but makes a short quick movement (saccade) mixed with a short stop (fixation). There are many variations in fixation (the point where saccade jumps to) and saccade between the reader and even for the same person reading one part of the text.
Music reading
Movement of the eye in reading music is scanning the music score by the eyes of a musician. This usually happens when music is read during a performance, although musicians sometimes scan music secretly to learn it, and sometimes perform from memory without a score. The movement of the eye in reading music may at first seem similar to that in the reading of the language, because in both activities the eye moves over the page in fixation and saccade, picking up and processing the meaning of the code. However, music is nonlinguistic and involves strict and continuous time constraints on the output generated by the continuous stream of instructions.
Scene view
The eye movement in viewing the scene refers to the visual processing of information presented in the scene. The core aspect of the study in this field is the division of eye movements into eye movement (saccade), and the focus of the eye on the point (fixation). Several factors can affect eye movements in viewing scenes, including audience duties and knowledge (top-down factors), and image properties seen (bottom-up factors). Usually, when presented with a scene, the viewer shows short fixation duration and long saccade amplitude in the initial phase of viewing the image. This is followed by a longer fixation and a shorter saccade in the final phase of the scene display processing. It has also been found that the behavior of eye movements in the scene scene is different from the level of cognitive development - the duration of fixation is considered to shorten and amplify the amplitude lengthwise with increasing age.
Spatial variation
Where eye movements are glued are influenced by bottom-up and top-down factors. Even the initial glimpse of the scene has an influence on the next eye movement. At the bottom-up factor, the contrast or superiority of local features in an image, such as large contrast in lighting or greater edge density, can affect eye movement. However, the top-down factor of the scene has a greater impact on where the eyes are transfixed. Areas containing more meaningful features, or areas where colors help object discrimination, can affect eye movement. Images associated with the previous image being displayed can also have an effect. Eye movements can also be directed toward an item when they are heard verbally at the same time by viewing it. Cross-culturally, it has been found that Westerners have a tendency to concentrate on objects of focus in a scene, while East Asians pay more attention to contextual information.
Temporary variation
The last average fixation duration for about 330 ms, although there is great variability in this approximation. This diversity is largely due to the properties of an image and in the current task, which impacts both bottom-up and top-down processing. Image concealment and other degradation, such as decreased luminance, during fixation (factors affecting bottom-up processing) have been found to increase the length of fixation duration. However, the increased image with these factors also increases the duration of fixation. Factors that affect top-down processing (eg blur) have been found both to increase and decrease the duration of fixation.
Disturbance
Symptoms
- Patients with eye movement disorders may report diplopia, nystagmus, poor visual acuity or cosmetic patches from the eyes of the squint.
Cause
- Innervational
- Supranuclear
- Nuclear
- Nerves
- Synapse
- Muscle anomaly
- Maldevelopment (eg Hypertrophy, atrophy/dystrophy)
- Malinsertion
- Secondary scars for sync operations
- Muscle diseases (eg Myasthenia gravis)
- Orbital anomalies
- Tumors (eg rhabdomyosarcoma)
- Excess fat behind the globe (eg thyroid condition)
- Bone fracture
- Check the ligaments (eg Brown syndrome, or tendon tendon superior syndrome)
Distractions selected
- The fourth congenital nerve paralysis
- Duane's Syndrome
- Internuclear ophthalmoplegia
- Nystagmus
- Ophthalmoparesis
- Opsoclonus
- Sixth (abducent) nerve palsy
Vision therapy
In psychotherapy
Terminology
The following terms can be used to describe eye movements:
- Incyclotorsion is a term applied to inward, torsional (rotational) eye movement, mediated by the superior oblique muscle of the eye. The superior oblique muscle is innervated by the IV cranial nerve (the trolear nerve). Insiklotorsion may also be used to describe one part of the eye condition when a patient has oculomotor nerve paralysis. The oculomotor nerve (cranial nerve III) supplies the inferior oblique muscle (along with the other four eye muscles - the superior rectus, the medial rectus, the inferior rectus and the straight levator palpebrae superioris muscle), and when this muscle does not work (as in oculomotor palsy) > incyclotorts ; ie bend/spin inward.
- Excyclotorsion is a term applied to outward, torsional (rotational) eye movements, mediated by the inferior oblique muscle of the eye. The inferior oblique muscle is innervated by the cranial nerve III (oculomotor nerve). Excyclotorsion can also be used to describe the condition or state of the eye when a patient has a cranial nerve IV (troklear nerve) palsy. The troklear nerves supply superior oblique muscles, and when these muscles do not work (as in troklear palsy) eyes excyclotorts ; ie bend/spin out. This excyclotorsion can be repaired via operation using the Harada-Ito procedure.
- An version is an eye movement involving both eyes simultaneously moving and symmetrical in the same direction. Examples include:
- True attraction/view
- Laevoversion/left view
- Surumversion/elevation/up gaze
- Deorsumversion/depression/down gaze
- Declarations/stares up and right
- Extraction/gaze down and right
- Laevegelevation/upward and left view
- Laevodepresi/gaze down and left
- Dextrocycloversion - the top of the eye spins to the right
- Laevocycloversion - the top of the eye spins to the left
See also
- Convergence micropsia
- Dissociated vertical deviation
- Eye tracking
- Gaze-contingency paradigm
- Listing law
- Microsaccade
- Ocular Vibration
- Biometric eye movement
- Orthoptist
- Oculesics
- Strabismus
- Progressive supranuclear palsy
- Computer body language processing
References
- Wehner R (2005). "Sensory physiology: The eye without the brain". Nature : 157-159.
External links
- eMedicine - Extra muscle, Action
- Oculomotor Control - Nistagmus and Dizziness Department of Otolaryngology - Queen's University in Kingston, Canada
- Eye Fixation Movement
- System software for simulating eye disorders and surgical correction
- Eye movement simulator, which shows changes in eye movement for any muscle or nerve damage.
Source of the article : Wikipedia
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