|
Orthokeratology
Orthokeratology, also referred to as Night lenses, Ortho-K, OK, Overnight Vision Correction, Corneal Refractive Therapy (CRT), Accelerated Orthokeretology, Cornea Corrective Contacts, Eccentricity Zero Molding, and Gentle Vision Shaping System (GVSS), is the use of gas-permeable contact lenses that temporarily reshape the cornea to reduce refractive errors such as myopia, hyperopia, and astigmatism. History Doctors discovered the reshaping phenomena of glass lenses as early as the 1940s. This history of orthokeratology includes contributions made by multiple authors to the use of contact lenses for myopia reduction. George Jessen created what was probably the first orthokeratology design in the 1960s made from PMMA material, which he marketed as "Orthofocus". These early designs had generally unpredictable results, leading to the belief that applied orthokeratology was more art or luck than science. Many groups and individuals claim to have been the first to develop modern ortho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myopia
Myopia, also known as near-sightedness and short-sightedness, is an eye condition where light from distant objects focuses in front of, instead of on, the retina. As a result, distant objects appear blurry, while close objects appear normal. Other symptoms may include headaches and eye strain. Severe myopia is associated with an increased risk of macular degeneration, retinal detachment, cataracts, and glaucoma. Myopia results from the length of the eyeball growing too long or less commonly the lens being too strong. It is a type of refractive error. Diagnosis is by the use of cycloplegics during eye examination. Tentative evidence indicates that the risk of myopia can be decreased by having young children spend more time outside. This decrease in risk may be related to natural light exposure. Myopia can be corrected with eyeglasses, contact lenses, or by refractive surgery. Eyeglasses are the simplest and safest method of correction. Contact lenses can provide a rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Jessen
George Jessen (1916–1987) was an optometrist who was an early pioneer of the contact lens. He is credited with being one of the first to employ the concept of orthokeratology, a direct attempt to reduce refractive error with the use of a contact lens, under the term ''orthofocus''.McQueen, Adrienn ''Orthokeratology'' Eyewitness No. 4 2003. Career Jessen received his training at the Chicago College of Optometry, now called the Illinois College of Optometry. In 1976, the Contact Lens Manufacturers Association awarded him The Dr. Josef Dallos Award for "outstanding contribution to the development and advancement of the contact lens industry and for service to humanity". Jessen worked closely with his mentor and partner, Newton K. Wesley. In Uptown Chicago, in the basement of Jessen's mother's apartment building, the two began researching a solution to Dr. Wesley's vision problems. Wesley suffered from keratoconus, a degenerative disease of the cornea that defies correction with glas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diopter
A dioptre ( British spelling) or (American spelling), symbol dpt or D, is a unit of measurement with dimension of reciprocal length, equivalent to one reciprocal metre, . It is normally used to express the optical power of a lens or curved mirror, which is a physical quantity equal to the reciprocal of the focal length, expressed in metres. For example, a 3-dioptre lens brings parallel rays of light to focus at metre. A flat window has an optical power of zero dioptres, as it does not cause light to converge or diverge. Dioptres are also sometimes used for other reciprocals of distance, particularly radii of curvature and the vergence of optical beams. The main benefit of using optical power rather than focal length is that the thin lens formula has the object distance, image distance, and focal length all as reciprocals. Additionally, when relatively thin lenses are placed close together their powers approximately add. Thus, a thin 2.0-dioptre lens placed close to a th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contact Lens
Contact lenses, or simply contacts, are thin lenses placed directly on the surface of the eyes. Contact lenses are ocular prosthetic devices used by over 150 million people worldwide, and they can be worn to correct vision or for cosmetic or therapeutic reasons. In 2010, the worldwide market for contact lenses was estimated at $6.1 billion, while the US soft lens market was estimated at $2.1 billion.Nichols, Jason J., et a"ANNUAL REPORT: Contact Lenses 2010" January 2011. Multiple analysts estimated that the global market for contact lenses would reach $11.7 billion by 2015. the average age of contact lens wearers globally was 31 years old, and two-thirds of wearers were female.Morgan, Philip B., et al"International Contact Lens Prescribing in 2010" ''Contact Lens Spectrum''. October 2011. People choose to wear contact lenses for many reasons. Aesthetics and cosmetics are main motivating factors for people who want to avoid wearing glasses or to change the appearance or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acanthamoeba
''Acanthamoeba'' is a genus of amoeboid, amoebae that are commonly recovered from soil, fresh water, and other habitat (ecology), habitats. The genus ''Acanthamoeba'' has two stages in its life cycle, the metabolically active trophozoite stage and a dormant, stress-resistant Microbial cyst, cyst stage. In nature, ''Acanthamoeba'' species are generally free-living bacterivores. However, they are also opportunistic pathogens able to cause serious and potentially fatal infections in humans and other animals. Distribution ''Acanthamoeba'' spp. are among the most prevalent protozoa found in the environment. They are distributed worldwide, and have been isolated from soil, air, sewage, seawater, chlorinated swimming pools, domestic tap water, bottled water, dental treatment units, hospitals, air-conditioning units, and contact lens cases. Additionally, they have been isolated from human skin, nasal cavities, throats, and intestines, as well as plants and other mammals. Role in disea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haemophilus Influenzae
''Haemophilus influenzae'' (formerly called Pfeiffer's bacillus or ''Bacillus influenzae'') is a Gram-negative, Motility, non-motile, Coccobacillus, coccobacillary, facultative anaerobic organism, facultatively anaerobic, Capnophile, capnophilic pathogenic bacterium of the family Pasteurellaceae. The bacteria are Mesophile, mesophilic and grow best at temperatures between 35 and 37 °C. ''H. influenzae'' was first described in 1893 by Richard Friedrich Johannes Pfeiffer, Richard Pfeiffer during an influenza pandemic when he incorrectly identified it as the causative microbe, which is why the bacteria was given the name "influenzae". ''H. influenzae'' is responsible for a wide range of localized and invasive infections, typically in infants and children, including pneumonia, meningitis, or bloodstream infections. Treatment consists of antibiotics; however, ''H. influenzae'' is often resistant to the penicillin family, but amoxicillin/clavulanic acid can be used in mild cases ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudomonas Aeruginosa
''Pseudomonas aeruginosa'' is a common Bacterial capsule, encapsulated, Gram-negative bacteria, Gram-negative, Aerobic organism, aerobic–facultative anaerobe, facultatively anaerobic, Bacillus (shape), rod-shaped bacteria, bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, ''P. aeruginosa'' is a multiple drug resistance, multidrug resistant pathogen recognized for its ubiquity, its Intrinsic and extrinsic properties, intrinsically advanced antibiotic resistance mechanisms, and its association with serious illnesses – hospital-acquired infections such as ventilator-associated pneumonia and various sepsis syndromes. ''P. aeruginosa'' is able to selectively inhibit various antibiotics from penetrating its outer membrane'' ''– and has high resistance to several antibiotics. According to the World Health Organization ''P. aeruginosa'' poses one of the greatest threats to humans in terms of an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corneal Ulcer
Corneal ulcer, often resulting from keratitis is an inflammatory or, more seriously, infective condition of the cornea involving disruption of its epithelial layer with involvement of the corneal stroma. It is a common condition in humans particularly in the tropics and in farming. In developing countries, children afflicted by vitamin A deficiency are at high risk for corneal ulcer and may become blind in both eyes persisting throughout life. In ophthalmology, a corneal ulcer usually refers to having an infection, while the term corneal abrasion refers more to a scratch injury. Types Superficial and deep corneal ulcers Corneal ulcers are a common human eye disease. They are caused by trauma, particularly with vegetable matter, as well as chemical injury, contact lenses and infections. Other eye conditions can cause corneal ulcers, such as entropion, distichiasis, corneal dystrophy, and keratoconjunctivitis sicca (dry eye). Many micro-organisms cause infective corneal ulce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
US Food And Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food safety, tobacco products, caffeine products, dietary supplements, prescription and over-the-counter pharmaceutical drugs (medications), vaccines, biopharmaceuticals, blood transfusions, medical devices, electromagnetic radiation emitting devices (ERED), cosmetics, animal foods & feed and veterinary products. The FDA's primary focus is enforcement of the Federal Food, Drug, and Cosmetic Act (FD&C). However, the agency also enforces other laws, notably Section 361 of the Public Health Service Act as well as associated regulations. Much of this regulatory-enforcement work is not directly related to food or drugs but involves other factors like regulating lasers, cellular phones, and condoms. In addition, the FDA takes control of diseases ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoxia (medical)
Hypoxia is a condition in which the body or a region of the body is deprived of an adequate oxygen supply at the tissue (biology), tissue level. Hypoxia may be classified as either ''Generalized hypoxia, generalized'', affecting the whole body, or ''local'', affecting a region of the body. Although hypoxia is often a pathological condition, variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise. Hypoxia differs from hypoxemia and anoxemia, in that hypoxia refers to a state in which oxygen present in a tissue or the whole body is insufficient, whereas hypoxemia and anoxemia refer specifically to states that have low or no Oxygen saturation (medicine), oxygen in the blood. Hypoxia in which there is complete absence of oxygen supply is referred to as anoxia. Hypoxia can be due to external causes, when the breathing gas is hypoxic, or internal causes, such as reduced effectiveness of gas transfer in the lung ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Off-label Use
Off-label use is the use of pharmaceutical drugs for an unapproved indication or in an unapproved age group, dosage, or route of administration. Both prescription drugs and over-the-counter drugs (OTCs) can be used in off-label ways, although most studies of off-label use focus on prescription drugs. Off-label use is very common and generally legal unless it violates ethical guidelines or safety regulations. The ability to prescribe drugs for uses beyond the officially approved indications is commonly used to good effect by healthcare providers. For example, methotrexate is commonly used off-label because its immunomodulatory effects relieve various disorders. However, off-label use can entail health risks and differences in legal liability. Marketing of pharmaceuticals for off-label use is usually prohibited. Indications and labeling laws An '' indication'' is when a drug is medically appropriate for a given condition; an approved indication is when a government drug regula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
