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مقاله
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Abstract
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Title:
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OCT Units: Which One Is suitable for each patient?
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Author(s):
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Heirani.Mohsen
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Presentation Type:
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Poster
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Subject:
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Posterior Segment and Uveitis
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Others:
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Presenting Author:
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Name:
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Mohsen Heirani
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Affiliation :(optional)
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Mashhad University of Medical Sciences
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E mail:
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heyranim931@mums.ac.ir
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Phone:
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05138641795
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Mobile:
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09126430156
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Purpose:
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A detailed look at the principles behind this spreading technology and the variety of instruments available
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Methods:
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Optical Coherence Tomography is a non-invasive technology developed more than 15 years ago as an optical biopsy to obtain high-quality, cross-sectional images of biological tissues.1 Since its discovery and integration into clinical medicine, it has become pervasive in the field of ophthalmology, specifically in managing retinal diseases, glaucoma, and the anterior segment via the anterior segment OCT. There are currently two distinct OCT technologies commercially available: the older time domain technology and the newer spectral or Fourier domain OCT technology.
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Results:
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The integration of Fourier transformation technology has dramatically increased the image acquisition speed of OCT devices from 400 A-scans/second in the standard time domain Stratus OCT (Carl Zeiss Meditec) to 18,000 to 50,000 A-scans/second in spectral/Fourier domain OCTs. The improved imaging decreases the presence of fixation drift while increasing the total retinal coverage of the OCT scan. The dense scans generated by the spectral domain OCT devices make 3D macular and optic nerve rendering and fly-through possible. These functions are now present in the majority of the commercially available devices for qualitative analysis of the retina.
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Conclusion:
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Commercial OCT devices utilize low-coherence superluminescent diode (SLD) light sources. Stratus OCT has a bandwidth of about 25 nm centered at 840 nm, giving it a resolution of 10 µm. Commercially available spectral/Fourier domain OCTs have bandwidths near infrared wavelengths, achieving about 3 to 5 µm axial resolution in tissue. The improved resolution allows for clear delineation of each retinal layer as distinct entities, like the ability to differentiate inner segment/outer segment (IS/OS) junction from the retinal pigment epithelium.
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Attachment:
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