indir
Yayinci: googletechtalks
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PhotoTechEDU Day 3: Ray Tracing, Lenses, and Mirrors
Google Tech Talks
January 31, 2007
ABSTRACT
Photographic Technology Day 3: Ray Tracing, Lenses, and Mirrors
In this lecture, we will study the principles of ray tracing for simple optical components: thin spherical lenses and spherical mirrors. The notion of real/virtual object and real/virtual images will be highlighted as well as the computation of the position and magnification the image. The case of thick lenses will also be mentioned including the notion of nodal and cardinal points. Credits: Speaker:Rom Clement
Etiketler:[google] [howto] [phototechedu] [day] [ray] [tracing]
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indir
Yayinci: ojasCentre
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Ojas Laser Eye Centre - Implantable Lenses (Phakic IOLs )
Surgically implanted lenses, also called phakic IOLs (intra ocular lenses), are a new option for people seeking more permanent correction of common vision errors such as myopia (nearsightedness). These implants, which resemble contact lenses, are placed between the clear front covering of the eye (cornea) and the iris (colored portion of the eye) or just behind the iris.
Implantable lenses are a surgical alternative to LASIK. Both procedures alter the way light rays enter the eye to achieve sharper focus. LASIK does this by removing tissue from the eye's cornea to change its shape; implantable lenses function like glasses or contact lenses, except they do it from within your eye. Implantable lenses do not require tissue to be removed from the eye as with LASIK; these lenses are effectively added to the eye.
Prior to surgery, drops are placed in the eye to reduce pupil size. An instrument is attached to hold open the eyelids during the procedure, and a local anesthetic is given to numb the eye's surface. An incision then is made into the eye. The Verisyse phakic IOL is inserted and attached to the colored portion of the eye (iris).
Etiketler:[] [lasik] [eye] [centre] [india] [surgeon] [phakic] [iols]
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