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Refractive Surgery
Refractive eye surgery is optional eye surgery used to improve the refractive state of the eye and decrease or eliminate dependency on glasses or contact lenses. This can include various methods of surgical remodeling of the cornea (keratomileusis), lens implantation or lens replacement. The most common methods today use excimer lasers to reshape the curvature of the cornea. Refractive eye surgeries are used to treat common vision disorders such as myopia, hyperopia, presbyopia and astigmatism. History The first theoretical work on the potential of refractive surgery was published in 1885 by Hjalmar August Schiøtz, an ophthalmologist from Norway. In 1930, the Japanese ophthalmologist Tsutomu Sato made the first attempts at performing this kind of surgery, hoping to correct the vision of military pilots. His approach was to make radial cuts in the cornea, correcting effects by up to 6 diopters. The procedure unfortunately produced a high rate of corneal degeneration, howeve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophthalmology
Ophthalmology ( ) is a surgical subspecialty within medicine that deals with the diagnosis and treatment of eye disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a medical degree, a doctor specialising in ophthalmology must pursue additional postgraduate residency training specific to that field. This may include a one-year integrated internship that involves more general medical training in other fields such as internal medicine or general surgery. Following residency, additional specialty training (or fellowship) may be sought in a particular aspect of eye pathology. Ophthalmologists prescribe medications to treat eye diseases, implement laser therapy, and perform surgery when needed. Ophthalmologists provide both primary and specialty eye care - medical and surgical. Most ophthalmologists participate in academic research on eye diseases at some point in their training and many include research as part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tsutomu Sato (ophthalmologist)
Tsutomu Sato (1902 – June 9, 1960) was a Japanese ophthalmologist who performed an early version of the radial keratotomy and was the first professor at the Research Institute of Ophthalmology at Juntendo University School of Medicine. Biography Sato was the first professor at the Research Institute of Ophthalmology at Juntendo University School of Medicine, where he researched the treatment of eye conditions such as trachoma and myopia. In the mid-1930s, Sato devised a glass scleral lens, but it never came into wide usage. Within a few years, higher-quality glass scleral lenses from Carl Zeiss were available in Japan. In 1939, Sato became the first physician to report the use of radial keratotomy for myopia. Sato knew that the cornea flattened out in patients with keratoconus who suffered corneal hydrops from the leakage of fluid through Descemet's membrane. His idea was to create numerous breaks in that membrane through anterior and posterior approaches. His initial pati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rangaswamy Srinivasan
Rangaswamy Srinivasan (born February 28, 1929 in Madras, India) is a physical chemist and inventor with a 30-year career at IBM Research. He has developed techniques for ablative photodecomposition and used them to contribute to the development of LASIK eye surgery. He received the National Medal of Technology from President Obama on February 2, 2013 for his contributions to laser eye surgery. Education Srinivasan was born in India on February 28, 1929. Srinivasan received both bachelor's and master's degrees in science from the University of Madras, in 1949 and 1950. In 1953 he moved to the United States to attend graduate school. He earned a doctorate in physical chemistry at the University of Southern California in 1956, studying protein chemistry with chemical kineticist Sidney W. Benson. He held postdoctoral positions at the California Institute of Technology in 1956, and at the University of Rochester from 1957 to 1961. Career Srinivasan has spent a thirty-year career, f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light which is ''coherent''. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances (collimation), enabling applications such as laser pointers and lidar (light detection and ranging). Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum. Alternatively, temporal coherence can be used to produce ultrashort pulses of ligh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halogen
The halogens () are a group in the periodic table consisting of five or six chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts). In the modern IUPAC nomenclature, this group is known as group 17. The word "halogen" means "salt former" (or "salt maker"). When halogens react with metals, they produce a wide range of salts, including calcium fluoride, sodium chloride (common table salt), silver bromide and potassium iodide. The group of halogens is the only periodic table group that contains elements in three of the main states of matter at standard temperature and pressure. All of the halogens form acids when bonded to hydrogen. Most halogens are typically produced from minerals or salts. The middle halogens—chlorine, bromine, and iodine—are often used as disinfectants. Organobromides are the most important class of flame retardants, while elemental halogens are dangerous and can be toxic. History The fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noble Gas
The noble gases (historically also the inert gases; sometimes referred to as aerogens) make up a class of chemical elements with similar properties; under standard conditions, they are all odorless, colorless, monatomic gases with very low chemical reactivity. The six naturally occurring noble gases are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and the radioactive radon (Rn). Oganesson (Og) is a synthetically produced highly radioactive element. Although IUPAC has used the term "noble gas" interchangeably with "group 18" and thus included oganesson, it may not be significantly chemically noble and is predicted to break the trend and be reactive due to relativistic effects. Because of the extremely short 0.7 ms half-life of its only known isotope, its chemistry has not yet been investigated. For the first six periods of the periodic table, the noble gases are exactly the members of group 18. Noble gases are typically highly unreactive except when u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimer (chemistry)
A dimer () ('' di-'', "two" + ''-mer'', "parts") is an oligomer consisting of two monomers joined by bonds that can be either strong or weak, covalent or intermolecular. Dimers also have significant implications in polymer chemistry, inorganic chemistry, and biochemistry. The term ''homodimer'' is used when the two molecules are identical (e.g. A–A) and ''heterodimer'' when they are not (e.g. A–B). The reverse of dimerization is often called dissociation. When two oppositely charged ions associate into dimers, they are referred to as ''Bjerrum pairs'', after Niels Bjerrum. Noncovalent dimers Anhydrous carboxylic acids form dimers by hydrogen bonding of the acidic hydrogen and the carbonyl oxygen. For example, acetic acid forms a dimer in the gas phase, where the monomer units are held together by hydrogen bonds. Under special conditions, most OH-containing molecules form dimers, e.g. the water dimer. Excimers and exciplexes are excited structures with a short lifetime. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenon
Xenon is a chemical element with the symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized. Xenon is used in flash lamps and arc lamps, and as a general anesthetic. The first excimer laser design used a xenon dimer molecule (Xe2) as the lasing medium, and the earliest laser designs used xenon flash lamps as pumps. Xenon is also used to search for hypothetical weakly interacting massive particles and as a propellant for ion thrusters in spacecraft. Naturally occurring xenon consists of seven stable isotopes and two long-lived radioactive isotopes. More than 40 unstable xenon isotopes undergo radioactive decay, and the isotope ratios of xenon are an important tool for studying the early history of the Solar System. Radioactive xenon-135 is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diamond Knife
A diamond knife is a very sharp knife in which the edge is made from diamond, invented by Humberto Fernández-Morán in 1955. Diamond knives are used for medical and scientific applications where an extremely sharp and long-lasting edge is essential. The knives are very expensive to purchase, depending on the quality and size of the knife; in addition the knives must be professionally sharpened as the edge dulls. Eye surgery Diamond knives are used in eye surgery, specifically in refractive surgery. In particular they are the main tool, together with the microscope, for the radial keratotomy invented by Svyatoslav Fyodorov to correct myopia and for the Mini Asymmetric Radial Keratotomy (M.A.R.K.), invented by Marco Abbondanza to correct astigmatism and cure the first and second stages of keratoconus. Ultramicrotomy Metal microtome knives or razor blades are too soft and dull to cut ultrathin sections. In 1950, Latta and Hartmann discovered that the edge of broken glass could be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Svyatoslav Fyodorov
Svyatoslav Nikolayevich Fyodorov (; August 8, 1927 – June 2, 2000) was a Russian ophthalmologist, politician, professor, full member of the Russian Academy of Sciences and Russian Academy of Medical Sciences. He is considered to be a pioneer of refractive surgery. He was also one of the candidates in the 1996 Russian presidential election, running as a member of the Party of Workers' Self-Government. Life and career Fyodorov was born in ''Proskurov'', Ukrainian SSR (now Khmelnytskyi, Ukraine), to ethnic Russian parents. Fyodorov graduated from Rostov Medical Institute in Rostov on Don, then worked as a practicing ophthalmologist in a small town in Rostov Oblast. Cataract surgery In the 1960s he studied the pioneering work of the English ophthalmic surgeon Sir Harold Ridley, the inventor of the intraocular lens (IOL). Fyodorov began to use Ridley's intraocular lenses in his treatment of cataract. At first he used lenses manufactured by the Rayner company in England but h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jose Barraquer
José Ignacio Barraquer Moner (24 January 1916 – 13 February 1998) was a Spanish ophthalmologist and inventor born in Barcelona who did most of his life's work in Bogotá, Colombia. His original pioneering investigations on corneal transplants and correction of corneal refraction led him to be designated as “Father of modern Refractive Surgery”. His ophthalmological surgical techniques and inventions are now in routine use by the ophthalmic community. Biography He was born in Barcelona, first son of Ignacio Barraquer (March 25, 1884 – May 13, 1965) and Josefa Moner Raguer (1893-1987). His grandfather, José Antonio Barraquer i Roviralta (1852-1924) was a pioneer of modern ophthalmology in Spain and a great histopathologist, and the brother of Lluis Barraquer i Roviralta (1855-1928), a pioneer of neurology and the founder, in 1882, of the first department of clinical neurology and electrotherapy in Spain; his son Lluis Barraquer Ferré (1887-1959) and his grandson Llui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
