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Ophthalmotrope
An ophthalmotrope is an apparatus for demonstrating the movements of the eye and the action of the different muscles which produce them, consisting essentially of a model eyeball to which are attached strings and pulleys to duplicate the line force of the muscles. Movements of the eye are kinematically complex and can be described as a combination of rotations about changing rotation centers. But even when ocular mechanics are simplified to pure rotations about a head-fixed rotation center, their noncommutative property makes them difficult to visualize. Ruete, Listing, Donders, Helmholtz, von Graefe, Volkmann and many others have provided the broad outline of an answer to the question how the eye rotates during eye movements. History Historically, mechanical representations of oculomotor mechanics have been used for visualization of eye movements and their interaction with visual geometry. Many mechanical models of eye movements have been constructed and studied in the ni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Christian Georg Theodor Ruete
Christian Georg Theodor Ruete (2 May 1810 – 23 June 1867) was a German ophthalmologist born in Scharmbeck, Lower Saxony. In 1833 obtained his medical doctorate from the University of Göttingen, later serving as an assistant to Karl Gustav Himly (1772–1837). In 1841 he became an associate professor at Göttingen, receiving the title of "full professor" in 1847. Afterwards he was a professor of ophthalmology at the University of Leipzig from 1852 to 1867. Christian Ruete was a pioneer of German ophthalmology, and made several significant contributions in this field. In 1845 he designed the first ophthalmotrope, a device that serves as a mechanical model of the eye and its muscles, and is used to clarify movements of the eye. In 1857 he constructed an improved version of his earlier prototype. He made modifications to Hermann von Helmholtz's ophthalmoscope by implementing a concave focusing mirror, and thereby introduced "indirect ophthalmoscopy" to allow for a stereoscopic a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermann Jakob Knapp
Jacob Hermann Knapp (March 17, 1832 – April 30, 1911), also known as Hermann Knapp, was a German-American ophthalmologist and otolaryngologist. Biography Knapp was born in Dauborn, Nassau. He earned his medical degree from the University of Giessen in 1854. As a young physician he studied with Franciscus Cornelis Donders in Utrecht, William Bowman in London, Albrecht von Graefe in Berlin and Hermann von Helmholtz in Heidelberg. From 1860 until 1868 he was a professor of ophthalmology at Heidelberg. He emigrated to New York City, where he worked as a surgeon. In 1869 he founded the New York Ophthalmic and Aural Institute, which from 1913 to 1939 was called the Herman Knapp Memorial Hospital. In 1882, he was made professor of the New York University Medical College. In 1888, he was appointed professor of ophthalmology at the College of Physicians and Surgeons, Columbia University, and in 1902 he became emeritus professor. His son, Arnold Knapp (1869–1956) was also a noted op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eye Movement (sensory)
Eye movement includes the voluntary or involuntary movement of the eyes. Eye movements are used by a number of organisms (e.g. primates, rodents, flies, birds, fish, cats, crabs, octopus) to fixate, inspect and track visual objects of interests. A special type of eye movement, rapid eye movement, occurs during REM sleep. The eyes are the visual organs of the human body, and move using a system of six muscles. The retina, a specialised type of tissue containing photoreceptors, senses light. These specialised cells convert light into electrochemical signals. These signals travel along the optic nerve fibers to the brain, where they are interpreted as vision in the visual cortex. Primates and many other vertebrates use three types of voluntary eye movement to track objects of interest: smooth pursuit, vergence shifts and saccades. These types of movements appear to be initiated by a small cortical region in the brain's frontal lobe. This is corroborated by removal of the fr ... [...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] |
Kinematics
Kinematics is a subfield of physics, developed in classical mechanics, that describes the Motion (physics), motion of points, Physical object, bodies (objects), and systems of bodies (groups of objects) without considering the forces that cause them to move. Kinematics, as a field of study, is often referred to as the "geometry of motion" and is occasionally seen as a branch of mathematics. A kinematics problem begins by describing the geometry of the system and declaring the initial conditions of any known values of position, velocity and/or acceleration of points within the system. Then, using arguments from geometry, the position, velocity and acceleration of any unknown parts of the system can be determined. The study of how forces act on bodies falls within kinetics (physics), kinetics, not kinematics. For further details, see analytical dynamics. Kinematics is used in astrophysics to describe the motion of celestial bodies and collections of such bodies. In mechanical engin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Benedict Listing
Johann Benedict Listing (25 July 1808 – 24 December 1882) was a German mathematician. J. B. Listing was born in Frankfurt and died in Göttingen. He first introduced the term "topology" to replace the older term "geometria situs" (also called sometimes "Analysis situs"), in a famous article published in 1847, although he had used the term in correspondence some years earlier. He (independently) discovered the properties of the Möbius strip, half-twisted strip at the same time (1858) as August Ferdinand Möbius, and went further in exploring the properties of strips with higher-order twists (paradromic rings). He discovered topological invariants which came to be called Listing numbers.Charles Sanders Peirce, Peirce, C. S., 1992, ''Charles Sanders Peirce bibliography#RLT, Reasoning and the Logic of Things: The Cambridge Conference Lectures of 1898'', edited with introduction by Kenneth Laine Ketner and with commentary by Hilary Putnam, who discusses Listing numbers starting on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Franciscus Donders
Franciscus (Franz) Cornelius Donders FRS FRSE (27 May 1818 – 24 March 1889) was a Dutch ophthalmologist. During his career, he was a professor of physiology in Utrecht, and was internationally regarded as an authority on eye diseases, directing the Netherlands Hospital for Eye Patients. Along with Graefe and Helmholtz, he was one of the primary founders of scientific ophthalmology. Life He was born in Tilburg, the son of Jan Franz Donders and Agnes Elizabeth Hegh. He was educated at Duizel School and seminaries in both Tilburg and Boxmeer. By the age of seventeen, Franciscus Donders had started studying medicine in the School of Military in Utrecht. It was here that he discovered his passion for experimental study, specifically in the field of chemistry. By the age of twenty-two he entered the junior military in order to become a surgeon For several years, the young Donders studied at the Royal Dutch Hospital for Military Medicine in Utrecht, then earning his M.D. in 1840 ... [...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] |
Albrecht Von Graefe (ophthalmologist)
Friedrich Wilhelm Ernst Albrecht von Gräfe, often Anglicized to Graefe (22 May 182820 July 1870), was a Prussian pioneer of German ophthalmology. Graefe was born in Finkenheerd, Brandenburg, the son of Karl Ferdinand von Graefe (1787–1840). He was the father of the far right politician Albrecht von Graefe (1868–1933). Background At the University of Berlin, Graefe studied philosophy, logic, natural sciences and anatomy, under notable names such as Dove, H. Rose, Müller, and Schlemm, eventually obtaining his medical doctorate in 1847. He continued his studies at Prague, Paris, Vienna and London, and having devoted special attention to ophthalmology, in 1850, he began to practice as an oculist in Berlin. Here, he founded a private institution for the treatment of eyes. During the same year, he received his habilitation with the thesis ''Über die Wirkung der Augenmuskeln''. In 1858 he became an associate professor of ophthalmology at the Charité in Berlin, where in 18 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alfred Wilhelm Volkmann
Alfred Wilhelm Volkmann (1 July 1801, Leipzig – 21 April 1877, Halle an der Saale) was a German physiologist, anatomist, and philosopher. He specialized in the study of the nervous and optic systems. Biography Alfred Wilhelm Volkmann was born in Leipzig, and enrolled in medicine there in 1821. Together with Gustav Theodor Fechner, who got his degree in medicine in 1822, and Rudolph Hermann Lotze (1817–1881) they formed a small intellectual group which dissolved only in 1837 when Volkmann received his professorship in Dorpat. In 1826 he obtained his doctorate and in 1828 he was habilitated as '' Privatdozent'' at the University of Leipzig. It was there that he became professor extraordinary of zootomy in 1834. In 1837 he went to Dorpat (now Tartu) as professor of physiology, pathology and semiotics. However, his residence in Dorpat was short: he left for Halle as early as 1843. After moving to Halle, Volkmann helped Gustav Theodor Fechner, his brother-in-law (married to V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
