Instruments
This column is about instruments in commonly clinical use
Principles of aberrometers
May 31st
Principles of aberrometers:
Aberrometers are usually classified into three types. The first type is the outgoing wavefront aberrometer as in the Hartmann–Shack sensor, and the second type is the ingoing retinal imaging aberrometer as in the cross-cylinder aberrometer, Tscherning aberrometer and the sequential retinal ray tracing method. The third type is the ingoing feedback aberrometer as used in the spatially resolved refractometer11 and the optical path difference method.
Four anterior segment analysis intruments
Apr 14th
Four ocular anterior segment analysis intruments
1. Pentacam introduced by Oculus
Equipped with an automatically rotating Scheimpflug camera the Pentacam performs a complete measurement of the anterior eye segment in less than 2 seconds. A precise analysis of the central cornea is carried out in the process. During measurement extraneous eye movements are detected with a second pupil camera and automatically corrected during the calculation process. The software analyses and evaluates all the data acquired. These data then provide the basis for a three-dimensional model of the complete anterior eye segment.
The Pentacam analyses the entire cornea, anterior chamber and crystalline lens. This includes an objective determination of the central radii, corneal asphericity, various coloured maps of curvature and elevation, chamber angle, chamber volume and chamber elevation as well as lens transparency. Tomography shows the individual levels of the anterior eye segment in a freely rotating model. Measurement is non-contact and entirely agreeable to the patient.
2. Orbscan
The Orbscan IIz topographer analyses the physical shape/contours of your cornea and allows a surgeon to decide if it has a suitable shape, is healthy and thick enough for treatment.
It is the only topographer currently available that measures the shape of both the front and back surface of the entire cornea (other systems only measure the front surface) and can therefore provide a complete picture of the thickness of cornea. The Orbscan IIz is able to provide such high precision information as it captures data within seconds from 9000 points on the cornea during each measurement.
3. UBM
The abbreviation of ultrasound biomicroscopy. It is a new technology that uses very high frequency ultrasound (20~55 MHz or even higher, compared to 3~15 MHz in conventional clinical ultrasound systems) to non-invasively image the small animals in biological research. The spatial resolution of a two-dimensional image is up to ~50 μm, with penetration depth of ~20 mm. The functional modalities include B mode, M mode and Doppler mode, etc.
4. A-OCT Zeiss
Carl Zeiss Meditec’s technological expertise in the diagnosis and monitoring of retinal disease became apparent with revolutionary instruments such as the Stratus OCT™ system. Now, with the introduction of the Visante OCT system, this same expertise is being applied to high-resolution, non-contact optical coherence tomography customized for the anterior segment.
Currently Available Spectral Domain (SD) OCTs
Mar 26th
| Currently Available Spectral Domain (SD) OCTs | ||||
| System | B-scan | Axial
Resolution |
Scanning
Speed |
Additional Features |
| 3D OCT-1000 | yes | 6um | 27,000 | Fundus camera,
True Map 3D software, networks with EyeRoute |
| Bioptigen SD OCT
(Bioptigen, Triangle Park, NC) |
yes | 10um | N/a | N/a |
| Cirrus
(Carl Zeiss Meditech, Jena, Germany) |
yes | 5um | 27,00 | Line scanning laser
ophthalmoscope |
| Copernicus
(Optopol, Zabria, Poland) |
yes | 6um | 25,000 | Near IR |
| OTI OCT/SLO | yes | 6um | 28,000 | Scanning Laser |
| RTVue-100
(Optovue Corp., Fremont, Calif) |
yes | 5um | 26,000 | Near IR |
| Spectralis
(Heidelberg Engineering, Vista, Calif.) |
yes | 7um | 40,000 | Scanning laser
ophthalmoscope, fluorescein angiography, indocyanine green angiography, autofluorescence |
Contrast Glaretester: CSV-1000 VS. CGT-1000
Mar 25th
Contrast Glaretester: CSV-1000 VS. CGT-1000
CSV-1OOOE
The CSV-1OOOE contrast sensitivity chart test face is the most widely used contrast sensitivity test in the world. This test provides for four (4) rows of sine-wave gratings. At the recommended test distance of 8 ft (2.5 meters), these gratings test the spatial frequencies of 3, 6, 12 and 18 cycles/degree. The CSV-1OOOE provides a full contrast sensitivity curve, which is very useful for the evaluation of ocular disease (particularly cataracts, glaucoma, optic neuritis, diabetes and macular degeneration), contact lenses and refractive surgery. For cataract evaluation/documentation, a functional acuity score can be obtained directly from the test scoring sheet.
For those interested in using the CSV-1OOOE in research studies, the test face is available in two versions. The CSV-1OOOE Contrast Sensitivity Chart 1 provides randomized locations for the grating targets.
CGT-1000
CGT-1000 is effectively available for diagnosis before and after the cataract surgery, observing the progress after the surgery of the corneal refractive power correction, relatively examining the contrast sensitivity and glare sensitivity for loss of the visual function.
CGT-1000 has four merits:
1. No need to read the operation manual repeatedly. Immediately you may be an expert operator.
2. Just press the start button. No complicated setting of the targets. The CGT 1000 will automatically perform examinations with presentation of 6 kinds of targets and 12 levels of the contrast thresholds. Buzzer will notice the completion of the examinations. (Refer to the operation procedure)
3. After finish, just press the print button. The examination results will be printed out through the built-in printer.
4. Less patient’s fatigue with short time of examination. Examination time is approximately 2 minutes per eye.
The CGT 1000 was produced by Takagi seiko co. LTD.
Thirty five free full text websites in the world
Mar 7th
Free full text website in the world
1.
The NASA Astrophysics Data System – the world’s largest free full text of web site, more than 300,000 full-text
Major disciplines: Astrophysics
2.
HighWire Press – the world’s second-largest free full text of web site, more than 235,812 full-text
Major subjects: biology, medicine
3.
arXiv.org
Major subjects: physics, mathematics, nonlinear science, computer science. PostScript-based file format, If there is no corresponding reading software, you can choose to generate PDF file format.
4.
Behavioral and Brain Sciences
Major disciplines: behavioral science, brain science
5.
Centers for Disease Control and Prevention (CDC)
Major disciplines: medical
6.
CogPrints
Major subjects: psychology, neuroscience, behavioral science, linguistics, artificial intelligence, philosophy,
7.
GPO Access
The U.S. government documents
8.
Inter-university Consortium for Political and Social Research (ICPSR)
The world’s largest social science literature site
9.
National Academy Press
U.S. National Academy of Sciences, the National Academy of Engineering, medical associations, agencies reported
10.
National Center for Health Statistics (NCHS)
U.S. National Center for Health Statistics of the statistical report
11.
NCSTRL
Computer science research reports and papers
12.
Project Gutenberg Electronic Public Library
E-books, 10,000 kinds of available before the 2002 full-text electronic books
13.
Thomas Legislative Information on the Internet
U.S. Library of Congress provided by the reports and historical documents of the United States Congress
14.
UNESCO
UNESCO to provide documentation
15.
United States Geological Survey
Report of the U.S. Geological Survey
16.
World Development Sources (World Bank)
World Bank report
17.
Delphion
Countries in the world patents, you can see full text of the former 13 pages
18
American Mathematical Society (AMS) of the three kinds of free journals
Bulletin
Electronic Research Announcements
Notices of the American Mathematical Society
19
Physics Today
American Institute of Physics (American Institute of Physics) will provide free magazines
20
Frontiers in Bioscience
Biological sciences journals and books, articles have been Biosis, CA, Medline and other important secondary literature database reference
21
The World Wide Web Journal of Biology
Cited by Biosis Previews
22
Proceedings of the National Academy of Sciences (PNAS)
Free of charge to developing countries, offers full-text browsing.
23
Scientific American
24
Issues in Science and Technology
Founded in 1984, the year 4, ISSN 0748-5492, National Academy of Sciences, to explore and elaborate science, technology and the development of health policy issues.
25
Bulletin of Symbolic Logic
Founded in 1995, the year 4, ISSN 1079-8986, published in mathematics, philosophy, computers, linguistics and other fields relating to symbolic logic of the papers, book reviews and conference abstracts.
26
Progress of Theoretical Physics Japan.
Founded in 1946, the year 12, ISSN 0033-068X, published by Japan’s theoretical physics research.Articles in English, German, French published.
27
Australian Journal of Physics , Australia.
Founded in 1948, the year 6, ISSN 0004-9506, published in physics (from elementary particles to astrophysics) the area of research papers, newsletters and comment.
28
New Journal of Physics , United Kingdom.
Founded In 1998 , ISSN 1367-2630, is a full-text electronic magazine, it is very authoritative in the field of physics. Editor of the magazine every effort through the publication of the useful and can cause physicists concerned about the high-quality articles, so the “New Journal of Physics,” the cost of the field to do the most important scientific journals.
29
Journal of Biological Chemistry ,” the United States.
Founded in 1905, the year 52, ISSN 0021-9258, Journal of Biological Chemistry Subscription, published in the field of biochemistry research. High Journal.
30
Chemical and Pharmaceutical Bulletin , Japan.
Founded in 1953, the year 12, ISSN 0009-2363, published bio-analytical chemistry, biochemistry, pharmacology, toxicology and bio-pharmaceutical research papers and reports published in English.
31
Journal of Micromechanics and Microengineering , the British.
Founded in 1991, the year 4, ISSN 0960-1317, published in MEMS, micro-mechanical and vacuum microelectronics technology research papers related to micro-system control, program and construction, micro-structures and devices, integrated circuits, electronic andphotonic devices such as basic structure, equipment and system design studies.
32
VDI-Z “Journal of the German Engineers Association Integrated Production”, Germany.
Founded in 1857, the year 12, ISSN 0042-1766, published in machine manufacturing, metal processing technology, production planning and management, production systems, production and evaluation as well as metal processing equipment and systems in the papers, and and industry news, new product introduction.
33
Modern Machine Shop . the United States.
Founded in 1928, the year 12, ISSN 0026-8003, comprehensive coverage of manufacturing and mechanical industry news and technical information, including engineering, industrial robots, research and development, program design, safety rules and equipment.
34
Process Engineering , United Kingdom.
Founded in 1920, the year 12, ISSN 0370-1859, published in chemical processing technology and equipment, materials and maintenance, etc. articles.
35
Signal, the United States.
Founded in 1946, the year 12, ISSN 0037-4938, the United States Armed Forces Communications and Electronics Association’s journal, published in the telecommunications, electronics and technology, photography articles in military applications, as well as command, control, communications and intelligence research progress reports.
Finding a CAD software for rebuilding tri-dimension model from clinical instrument
Feb 23rd
I am trying to Find a CAD software for rebuilding tri-dimension model from clinical instrument.
I posted a question in a forum: CAD softwares for rebuilding tri-dimension model in linux
1. I want to gather data from a equipment. Perhaps content millions of data.
2.Rebuilt these data by math method.
3.Use software to reconstruct the data in two-dimensional graphics, tri-dimensional graphics is the best.
4.Choose another model and by some technique to collect the tri-dimensional shape, then use the same method to reconstruct it in computer.
5.Match them to see if they are fit.Are there any CAD for build tri-dimension model in linux?
There four answers:
1. There are lots of CAD programs for Linux. I’ve personally only used Qcad, which is 2D only, but have a look through the following links for more information; of these, some are non-free, some 2D and some 3D, while some may be in various stages of completion/usefulness, but Google can point you to lots of other examples besides these:
http://www.linux.org/apps/all/Graphics/CAD/CAM.html
http://www.roseindia.net/linux/linux-cad-software.shtml
http://www.cycas.de/I found Qcad by Google + trial&error,
and found it to be somewhat complicated, but ultimately fairly decent.As to which, if any, program will fit *all* of your needs, I cannot comment. You might need to break the job(s) into sections, which then can each be dealt with by the most appropriately suited application.
2. Is the data analysis for the wavefront and corneal topography units on your sig’s link? If you are doing that kind of work, you might want to look at maxima or macsyma or whatever they’re calling themselves these days, or a commercial program such as Mathematica.
3. Free 3D CAD software :
http://www.craftsmanspace.com/resour…-software.htmlBRL-CAD 7.14.8
http://freshmeat.net/projects/brl-cad
4. If you know how the data points are arranged, it shouldn’t be hard to reconstruct an image. For example, topography images often are radii and heights at evenly spaced angles with underlying polar coordinates rather than cartesian triplets. The data set usually is grouped by each ring of data points. You can use the 3D plotting routines of any of the programs mentioned to reconstruct the image.
Six corneal thickness measurement methods
Feb 1st
Six corneal thickness measurement methods
1. Slit lamp gross measurement. Especilly used in evaluating the anterior chamber angle of glaucoma patient.
2. A Ultrasound
3. Anterior segment OCT
4. Pentacam
5.Obscan Ⅱ
6. Non-contact specular microscopy