Optical coherence tomography or OCT is an interferometric, non-invasive optical tomographic imaging technique offering millimeter penetration which approximately 2-3 mm in tissue, with micrometer-scale axial and lateral resolution. The technique was first demonstrated in sometime 1991. Since then, OCT or Optical coherence tomography has achieved sub-micrometre resolution in 2001 due to introduction of wide bandwidth light sources. These sources had been reported to be emitting wavelengths over a hundred nm range. By now OCT has found its place as a widely accepted imaging technique, especially in ophthalmology and other biomedical applications. OCT, an emerging technology based on fiber optics, often uses a compact diode light source similar to those used in compact disc players. As a result, OCT technology can be robust, portable, low cost, and readily interfaced with optical fiber techniques to catheters, endoscopes, laparoscopes, and surgical probes. These attributes make it very attractive for medical and surgical diagnostics.
There are many advantages for using OCT in medical diagnostics, an example is to provide images of tissue structure at the micron scale in real time, and also to function as a type of optical biopsy, and unlike the conventional histopathology that requires removal of tissue specimens for microscopic examination. Oct was also built in hoping to replace standard excisional biopsy when it is perilous or impossible, possibly reducing sampling errors, enable surgical guidance and enabling imaging of organ systems inside the body and provide image resolutions that are one to two orders above conventional ultrasound. As said in this article, when we say interferometric, we mean that it is the science and technique of superposing or interfering two or more waves, which creates an output wave different from the input waves; this in turn can be used to explore the differences between the input waves. Because interference is a very general phenomenon with waves, interferometry can be applied to a wide variety of fields, including astronomy, fiber optics, optical metrology, oceanography, seismology and various studies of quantum mechanics. Interferometry can be applied to both one-dimensional waves such as time varying signals, or to multi-dimensional waves such as coherent images produced by laser illumination.
A scientist somewhere in southern California, Los Angeles has dedicated a research to evaluate or reveal changes in anterioir segment morphology by gonioscopy before and after laser peripheral iridotomy or LPI. Laser peripheral iridotomy with the aid of medical microscope is a surgical procedure that is performed on the eye to treat angle closure glaucoma, a condition of increased pressure in the front chamber, anterior chamber that is caused by sudden or acute or slowly progressive blockage of the normal circulation of fluid within the eye. The block occurs at the angle of the anterior chamber that is formed by the junction of the cornea with the iris. All one needs to do to see this angle is to look at a person’s eye from the side. Angle closure of the eye occurs when the iris blocks the trabecular meshwork, the drainage site for ocular fluid. Laser iridotomy with the help of medical microscope was first used to treat angle closures in sometime in the early 50s. During this procedure, a hole is made in the iris of the eye, changing its configuration. When this occurs, the iris moves away from the trabecular meshwork, and proper drainage of the intraocular fluid is enabled. Original article