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Snellen Chart
A Snellen chart is an eye chart that can be used to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen, who developed the chart in 1862. Many ophthalmologists and vision scientists now use an improved chart known as the LogMAR chart. History Snellen developed charts using symbols based in a 5×5 unit grid. The experimental charts developed in 1861 used abstract symbols. Snellen's charts published in 1862 used alphanumeric capitals in the 5×5 grid. The original chart shows A, C, E, G, L, N, P, R, T, 5, V, Z, B, D, 4, F, H, K, O, S, 3, U, Y, A, C, E, G, L, 2. Description The normal Snellen chart is printed with eleven lines of block letters. The first line consists of one very large letter, which may be one of several letters, for example E, H, or N. Subsequent rows have increasing numbers of letters that decrease in size. A person taking the test covers one eye from 6 metres or 20 feet away, and reads aloud the letters of each row, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eye Chart
__NOTOC__ An eye chart, or optotype, is a chart used to subjectively measure visual acuity. Eye charts are often used by health care professionals, such as optometrists, physicians or nurses, to screen persons for vision impairment. Ophthalmologists, physicians who specialize in the eye, also use eye charts to monitor the visual acuity of their patients in response to various therapies such as medications or surgery. The chart is placed at a standardized distance away from the person whose vision is being tested. The person then attempts to identify the symbols on the chart, starting with the larger symbols and continuing with progressively smaller symbols until the person cannot identify the symbols. The smallest symbols that can be reliably identified is considered the person's visual acuity. The Snellen chart is the most widely used. Alternative types of eye charts include the logMAR chart, Landolt C, E chart, Lea test, Golovin–Sivtsev table, the Rosenbaum chart, and the Jae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Google Play
Google Play, also known as the Google Play Store and formerly the Android Market, is a digital distribution service operated and developed by Google. It serves as the official app store for certified devices running on the Android (operating system), Android operating system and Google Operating System, its derivatives, as well as ChromeOS, allowing users to browse and download applications developed with the Android software development, Android software development kit (SDK) and published through Google. Google Play has also served as a digital media store, offering games, music, books, movies, and television programs. Content that has been purchased on Google TV (service), Google Play Movies & TV and Google Play Books can be accessed on a web browser and through the Android (operating system), Android and iOS apps. Applications are available through Google Play either for free or at a cost. They can be downloaded directly on an Android device through the proprietary software, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Tests
A medical test is a medical procedure performed to detect, diagnose, or monitor diseases, disease processes, susceptibility, or to determine a course of treatment. Medical tests such as, physical and visual exams, diagnostic imaging, genetic testing, chemical and cellular analysis, relating to clinical chemistry and molecular diagnostics, are typically performed in a medical setting. Types of tests By purpose Medical tests can be classified by their purposes, the most common of which are diagnosis, screening and evaluation. Diagnostic A diagnostic test is a procedure performed to confirm or determine the presence of disease in an individual suspected of having a disease, usually following the report of symptoms, or based on other medical test results. This includes posthumous diagnosis. Examples of such tests are: * Using nuclear medicine to examine a patient suspected of having a lymphoma. * Measuring the blood sugar in a person suspected of having diabetes mellitus after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dutch Inventions
The Netherlands and its people have made contributions to the arts, science, technology and engineering, economics and finance, cartography and geography, exploration and navigation, law and jurisprudence, thought and philosophy, medicine. and agriculture. The following list is composed of objects, (largely) unknown lands, breakthrough ideas/concepts, principles, phenomena, processes, methods, techniques, styles that were discovered or invented by people from the Netherlands. Lists * List of Dutch inventions and innovations * List of Dutch discoveries * List of Dutch explorations See also * List of place names of Dutch origin * Australian places with Dutch names * Toponymy of New Netherland * New Holland * List of English words of Dutch origin * Japanese words of Dutch origin Japanese words of Dutch origin started to develop when the Dutch East India Company initiated trading in Japan from the factory (trading post), factory of Hirado in 1609. In 1640, the Dutch were t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diagnostic Ophthalmology
Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines, with variations in the use of logic, analytics, and experience, to determine " cause and effect". In systems engineering and computer science, it is typically used to determine the causes of symptoms, mitigations, and solutions. Computer science and networking * Bayesian networks * Complex event processing * Diagnosis (artificial intelligence) * Event correlation * Fault management * Fault tree analysis * Grey problem * RPR Problem Diagnosis * Remote diagnostics * Root cause analysis * Troubleshooting * Unified Diagnostic Services Mathematics and logic * Bayesian probability * Block Hackam's dictum * Occam's razor * Regression diagnostics * Sutton's law copy right remover block Medicine * Medical diagnosis * Molecular diagnostics Methods * CDR Computerized Assessment System * Computer-assisted diagnosis * Differential diagnosis * Medical di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charts
A chart (sometimes known as a graph) is a graphical representation for data visualization, in which "the data is represented by symbols, such as bars in a bar chart, lines in a line chart, or slices in a pie chart". A chart can represent tabular numeric data, functions or some kinds of quality structure and provides different info. The term "chart" as a graphical representation of data has multiple meanings: * A data chart is a type of diagram or graph, that organizes and represents a set of numerical or qualitative data. * Maps that are adorned with extra information (map surround) for a specific purpose are often known as charts, such as a nautical chart or aeronautical chart, typically spread over several map sheets. * Other domain-specific constructs are sometimes called charts, such as the chord chart in music notation or a record chart for album popularity. Charts are often used to ease understanding of large quantities of data and the relationships between parts of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1862 Introductions
Year 186 ( CLXXXVI) was a common year starting on Saturday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Aurelius and Glabrio (or, less frequently, year 939 ''Ab urbe condita''). The denomination 186 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Peasants in Gaul stage an anti-tax uprising under Maternus. * Roman governor Pertinax escapes an assassination attempt, by British usurpers. New Zealand * The Hatepe volcanic eruption extends Lake Taupō and makes skies red across the world. However, recent radiocarbon dating by R. Sparks has put the date at 233 AD ± 13 (95% confidence). Births * Ma Liang, Chinese official of the Shu Han state (d. 222) Deaths * April 21 – Apollonius the Apologist, Christian martyr * Bian Zhang, Chinese official and gener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sloan Letters
Sloan letters, designed by Louise L. Sloan, Louise Sloan in 1959, are a set of optotypes used to test visual acuity generally used in Snellen charts and logMAR charts. This set of optotypes consists of ten specially formed "letters", C, D, H, K, N, O, R, S, V and Z. These letters, unlike the ones used in older Snellen charts, are designed to give acuity testing results that are comparable to tests made using Landolt C, Landolt rings. Computer fonts for macOS and Microsoft Windows operating systems are available for research purposes. The fonts are based on Louise Sloan's design, which has been designated the US standard for acuity testing by the National Academy of Sciences, National Research Council, Committee on Vision (1980, Adv Ophthalmol, 41, 103–148). See also *Eye chart *Landolt C *Lea test *Snellen chart References [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoyer Chart
The Monoyer chart was created by Ferdinand Monoyer and is used to test visual acuity. He inserted his name in the chart; reading upwards on both ends, but ignoring the first line, the name "Ferdinand Monoyer" can be seen. See also *Snellen chart A Snellen chart is an eye chart that can be used to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen, who developed the chart in 1862. Many ophthalmologists and vision scientists now use an improved ... References {{Reflist Medical tests Ophthalmology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lea Test
The LEA Vision Test System is a series of pediatric vision tests designed specifically for children who do not know how to read the letters of the alphabet that are typically used in eye charts. There are numerous variants of the LEA test which can be used to assess the visual capabilities of near vision and distance vision, as well as several other aspects of occupational health, such as contrast sensitivity, visual field, color vision, visual adaptation, motion perception, and ocular function and accommodation (eye). History The first version of the LEA test was developed in 1976 by Finnish pediatric ophthalmologist Lea Hyvärinen, MD, PhD. Dr. Hyvärinen completed her thesis on fluorescein angiography and helped start the first clinical laboratory in that area while serving as a fellow at the Wilmer Eye Institute of Johns Hopkins Hospital in 1967. During her time with the Wilmer Institute, she became interested in vision rehabilitation and assessment and has been working in that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landolt C
The Landolt C, also known as a Landolt ring, Landolt broken ring, or Japanese vision test, is an optotype: a standardized symbol used for testing vision. It was developed by the Swiss-born ophthalmologist Edmund Landolt. The Landolt C consists of a ring that has a gap, thus looking similar to the letter C. The gap can be at various positions (usually left, right, bottom, top and the 45° positions in between) and the task of the tested person is to decide on which side the gap is. The size of the C and its gap are reduced until the subject makes a specified rate of errors. The minimum perceivable angle of the gap is taken as measure of the visual acuity. It is generally practised in the laboratory. The stroke width is of the diameter, and the gap width is the same. This is identical to the letter C from a Snellen chart. The Landolt C is the standard optotype for acuity measurement in most European countries. It was standardized, together with measurement procedures, by the Germa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jaeger Chart
The Jaeger chart is an eye chart used in testing near vision acuity. It is a card on which paragraphs of text are printed, with the text sizes increasing from 0.37 mm to 2.5 mm. This card is to be held by a patient at a fixed distance from the eye dependent on the J size being read. The smallest print that the patient can read determines their visual acuity. The original 1867 chart had a text containing seven paragraphs and a corresponding seven-point scale. Jaeger cards are not standardized, and the variability of the actual size of test letters on different Jaeger cards currently in use is very high. Therefore, test results with different Jaeger cards are not comparable. More commonly, distance vision acuity is tested using the Snellen chart A Snellen chart is an eye chart that can be used to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen, who developed the chart in 1862. Many ophthalmologists and vision scientists now use an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
