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Listing's Law
Listing's law, named after German mathematician Johann Benedict Listing (1808–1882), describes the three-dimensional orientation of the eye and its axes of rotation. Listing's law has been shown to hold when the head is stationary and upright and gaze is directed toward far targets, i.e., when the eyes are either fixating, making saccades, or pursuing moving visual targets. Listing's law (often abbreviated L1) has been generalized to yield the ''binocular extension of Listing's law'' (often abbreviated L2) which also covers vergence. Definition Listing's law states that the eye does not achieve all possible 3D orientations and that, instead, all achieved eye orientations can be reached by starting from one specific "primary" reference orientation and then rotating about an axis that lies within the plane orthogonal to the primary orientation's gaze direction (line of sight / visual axis). This plane is called Listing's plane. It can be shown that Listing's law implies that, if ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History One of the earliest known mathematicians were Thales of Miletus (c. 624–c.546 BC); he has been hailed as the first true mathematician and the first known individual to whom a mathematical discovery has been attributed. He is credited with the first use of deductive reasoning applied to geometry, by deriving four corollaries to Thales' Theorem. The number of known mathematicians grew when Pythagoras of Samos (c. 582–c. 507 BC) established the Pythagorean School, whose doctrine it was that mathematics ruled the universe and whose motto was "All is number". It was the Pythagoreans who coined the term "mathematics", and with whom the study of mathematics for its own sake begins. The first woman mathematician recorded by history was Hypati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extraocular Muscles
The extraocular muscles (extrinsic ocular muscles), are the seven extrinsic muscles of the human eye. Six of the extraocular muscles, the four recti muscles, and the superior and inferior oblique muscles, control movement of the eye and the other muscle, the levator palpebrae superioris, controls eyelid elevation. The actions of the six muscles responsible for eye movement depend on the position of the eye at the time of muscle contraction. Structure Since only a small part of the eye called the fovea provides sharp vision, the eye must move to follow a target. Eye movements must be precise and fast. This is seen in scenarios like reading, where the reader must shift gaze constantly. Although under voluntary control, most eye movement is accomplished without conscious effort. Precisely how the integration between voluntary and involuntary control of the eye occurs is a subject of continuing research."eye, human."Encyclopædia Britannica from Encyclopædia Britannica 2006 Ulti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afterimage
AfterImage is a Filipino rock band formed in 1986, best known for their songs "Habang May Buhay", "Next in Line", and "Mangarap Ka". They disbanded in 1997 and became active again in 2008 after they reunited and released their fourth studio album. After disbanding in 1997, Wency Cornejo, the band's vocalist, pursued a solo career. In January 1992, the band signed with Dyna Records, The band's first album, entitled ''Touch the Sun'', was released in July 1992. Among the eight songs that the album contained, four were released as singles: "Next in Line", "Bai (Sa Langit ang Ating Tagpuan)", "Only You", and "Pagtawid". The title of the album, which was the concluding part of the lyric to "Next in Line", was said to have just been a spontaneous utter of phrase which Cornejo made during the recording session for the said song. History The band was composed of five members: Bobit Uson on bass guitar, Chuck Isidro on lead guitar, Rogie Callejo on drums, Arnold Cabalza on keyboards and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermann Von Helmholtz
Hermann Ludwig Ferdinand von Helmholtz (31 August 1821 – 8 September 1894) was a German physicist and physician who made significant contributions in several scientific fields, particularly hydrodynamic stability. The Helmholtz Association, the largest German association of research institutions, is named in his honor. In the fields of physiology and psychology, Helmholtz is known for his mathematics concerning the eye, theories of vision, ideas on the visual perception of space, color vision research, the sensation of tone, perceptions of sound, and empiricism in the physiology of perception. In physics, he is known for his theories on the conservation of energy, work in electrodynamics, chemical thermodynamics, and on a mechanical foundation of thermodynamics. As a philosopher, he is known for his philosophy of science, ideas on the relation between the laws of perception and the laws of nature, the science of aesthetics, and ideas on the civilizing power of science. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eye Tracking On The ISS
The eye-tracking device (ETD) is a headmounted device, designed for measurement of 3D eye and head movements under experimental and natural conditions. The tracker permits comprehensive measurement of eye movement (three degrees of freedom) and optionally head movement (six degrees of freedom). It represents a tool for the investigation of sensorimotor behaviour, particularly of the vestibular and oculomotor systems in both health and disease. Eye-tracking device on ISS It was originally developed by the German Space Agency (DLR) for use on the International Space Station (ISS) and was uploaded to the station as part of the joint European / Russian space programme in early 2004. The device was designed by Prof. Dr. Andrew H. Clarke (Vestibular Lab, Charité Berlin) together with the companies Chronos Vision and Mtronix in Berlin and integrated for space utilisation by the Munich-based company Kayser-Threde. In the first set of experiments, conducted by Prof. Clarke’s tea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eye Tracking
Eye tracking is the process of measuring either the point of gaze (where one is looking) or the motion of an eye relative to the head. An eye tracker is a device for measuring eye positions and eye movement. Eye trackers are used in research on the visual system, in psychology, in psycholinguistics, marketing, as an input device for human-computer interaction, and in product design. Eye trackers are also being increasingly used for rehabilitative and assistive applications (related,for instance, to control of wheel chairs, robotic arms and prostheses). There are a number of methods for measuring eye movement. The most popular variant uses video images from which the eye position is extracted. Other methods use search coils or are based on the electrooculogram. History In the 1800s, studies of eye movement were made using direct observations. For example, Louis Émile Javal observed in 1879 that reading does not involve a smooth sweeping of the eyes along the text, as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scleral Coil
A scleral lens, also known as a scleral contact lens, is a large contact lens that rests on the sclera and creates a tear-filled vault over the cornea. Scleral lenses are designed to treat a variety of eye conditions, many of which do not respond to other forms of treatment. Uses Medical uses Scleral lenses may be used to improve vision and reduce pain and light sensitivity for people with a growing number of disorders or injuries to the eye, such as severe dry eye syndrome, microphthalmia, keratoconus, corneal ectasia, Stevens–Johnson syndrome, Sjögren's syndrome, aniridia, neurotrophic keratitis (anesthetic corneas), complications post-LASIK, higher-order aberrations of the eye, complications post-corneal transplant and pellucid degeneration. Injuries to the eye such as surgical complications, distorted corneal implants, as well as chemical and burn injuries also may be treated by the use of scleral lenses. Sclerals may also be used in people with eyes that are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strabismus Surgery
Strabismus surgery (also: ''extraocular muscle surgery'', ''eye muscle surgery'', or ''eye alignment surgery'') is surgery on the extraocular muscles to correct strabismus, the misalignment of the eyes. Strabismus surgery is a one-day procedure that is usually performed under general anesthesia most commonly by either a neuro- or pediatric ophthalmologist. The patient spends only a few hours in the hospital with minimal preoperative preparation. After surgery, the patient should expect soreness and redness but is generally free to return home. History The earliest successful strabismus surgery intervention is known to have been performed on 26 October 1839 by Johann Friedrich Dieffenbach on a 7-year-old esotropic child; a few earlier attempts had been performed in 1818 by William Gibson of Baltimore, a general surgeon and professor at the University of Maryland. The idea of treating strabismus by cutting some of the extraocular muscle fibers was published in American newspapers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclodisparity
Cyclodisparity refers to the difference in the rotation angle of an object or scene viewed by the left and right eyes. Cyclodisparity can result from the eyes' torsional rotation (''cyclorotation'') or can be created artificially by presenting to the eyes two images that need to be rotated relative to each other for binocular fusion to take place. Human and animal vision The eyes and visual system can compensate for cyclodisparity up to a certain point; if the cyclodisparity is larger than a threshold, the images cannot be fused, resulting stereoblindness, and in double vision in subjects who otherwise have full stereo vision. When a human subject is presented with images that have artificial cyclodisparity, cyclovergence is evoked, that is, a motor response of the eye muscles that rotates the two eyes in opposite directions, thereby reducing cyclodisparity. Visually-induced cyclovergence of up to 8 degrees has been observed in normal subjects. Furthermore, up to about 8 degrees ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strabismus
Strabismus is a vision disorder in which the eyes do not properly align with each other when looking at an object. The eye that is focused on an object can alternate. The condition may be present occasionally or constantly. If present during a large part of childhood, it may result in amblyopia, or lazy eyes, and loss of depth perception. If onset is during adulthood, it is more likely to result in double vision. Strabismus can occur due to muscle dysfunction, farsightedness, problems in the brain, trauma or infections. Risk factors include premature birth, cerebral palsy and a family history of the condition. Types include esotropia, where the eyes are crossed ("cross eyed"); exotropia, where the eyes diverge ("lazy eyed" or "wall eyed"); and hypertropia or hypotropia where they are vertically misaligned. They can also be classified by whether the problem is present in all directions a person looks (comitant) or varies by direction (incomitant). Diagnosis may be made by obser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereopsis
Stereopsis () is the component of depth perception retrieved through binocular vision. Stereopsis is not the only contributor to depth perception, but it is a major one. Binocular vision happens because each eye receives a different image because they are in slightly different positions on one’s head (left and right eyes). These positional differences are referred to as "horizontal disparities" or, more generally, " binocular disparities". Disparities are processed in the visual cortex of the brain to yield depth perception. While binocular disparities are naturally present when viewing a real three-dimensional scene with two eyes, they can also be simulated by artificially presenting two different images separately to each eye using a method called stereoscopy. The perception of depth in such cases is also referred to as "stereoscopic depth". The perception of depth and three-dimensional structure is, however, possible with information visible from one eye alone, such as diffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
