الفهرس 
Optical Principle of OCTOnly 14 pages are availabe for public view
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Abstract
Assessment of anterior segment structures is an integral part of
ophthalmic examination. Objective quantitative assessment of anterior segment
structures is limited and direct iridocorneal angle visualization can only be
carried out with the use of diagnostic contact lenses.
OCT is a non-invasive optical imaging technique. It uses the property of
optical reflectivity to give a cross-sectional imaging of biological tissue with
high resolution and micrometer scale (Hrynchak, 2000).
AS-OCT can detect quantitatively subtle changes to the eye caused during
the early stages of ocular disease, such as glaucoma, and by procedures like
cataract surgery. It can measure residual stromal thickness in LASIK patients
who are candidates for re-treatment. This capability has made OCT an attractive
imaging and measurement technique to aid photorefractive surgery for the
correction of myopia, hyperopia and astigmatism. It is used to investigate and
monitor post-op side-effects (Tomlins and Wang, 2005).
AS-OCT has also been used to measure intraocular dimensions, such as
anterior chamber width, prior to phakic IOL implantation. Also it is used to
study the dynamic nature of phakic IOLs during accommodation and to
demonstrate contact of the IOL with the anterior surface of the crystalline lens
(Konstantopoulos et al., 2007).
Such investigative tool performs a type of optical biopsy, with a micronscale
imaging of tissue morphology in-situ and in real time. Image information
is available immediately without the need for excision and histological
processing of a specimen. This allows pathology to be monitored on screen and
stored on high-resolution video tape. Real-time imaging can enable real-time
diagnosis, and coupling this information with surgery, it can enable surgical
guidance (Fujimoto et al., 2000).
AS-OCT system provides clear, highly detailed, in-depth cross-sectional
images of the anterior segment -including the angle- without the need for ocularanesthesia or a messy, time-consuming water bath. It is so easy to use and
efficient to operate that it will seamlessly take its place in daily workflow. This
dramatically expands the potential for diagnostic confidence and therapeutic
precision (Zeiss 1, website