What is optical coherence tomography?
Optical coherence tomography (OCT) is a procedure used for non -invasive examination of introocular structures. It is primarily used to analyze the retina and optical nerve, OCT focuses on the amount of light absorption or scattering that occurs when light passes through the tissue layer. Optical coherence tomography uses a diode laser that emits light at a wavelength of about 840 nanometers. Two rays of light, reference beam focused on mirror and detection beam focused on eye tissues, measure and analyze. Oct allows doctors to develop cross -sectional images of the front chamber of the eye and three -dimensional retinal images.
Oct images allow doctors to detect anatomical changes in eye structures that occur in glaucoma and retinal disease. Ophthalmologists can determine the overall thickness of the retina as well as the thickness of the individual layers of the retina to identify macular swelling, macular degeneration, amacular holes. They can easily recognize epiretinal membranes on the surface of the retina. ExceptThis makes the optical coherence tomography easier to evaluate the horizontal and vertical cup on the size of the disk for long -term monitoring of glaucoma damage.
barriers in achieving satisfactory scanning of optical coherence of tomography include corneal or lens clouds, lack of patient cooperation and excessive flashing. The OCT device gets approximately 27,000 scans per second, allowing increased resolution and details with a minimum amount of time required. Although it is possible to obtain high quality scanning through a small pupil, sometimes pupils must be expanded. It is also useful for the patient to use artificial lubricants on the surface of the eye before examination.
Examination with optical coherence tomographic scanning often provides valuable information concerning structural abnormality. For example, subretinal tumors such as melanomas can increase the entire retina and produce ascending bow tiltICE visible on Oct. The epirectinal membrane appears as a clear line overlapping retina with wavy folds below the line due to lateral traction on the surface of the retina by the membrane. The macular opening full of thickness appears as the obvious discontinuity in the retina of the macula with liquid pockets in the neighboring retina.
In addition, OCT scratches offer useful information about changes in the tissue light pattern. High reflectivity of light can occur in choroidal non -resentment, mole -like structure deep to retina, due to brown pigment in it. The scar tissue will also be highly reflective. On the other hand, liquid pockets, such as cysts or ward, appear on the scanning of dark. The degree of reflectivity depends on the depth of tissue, the composition of the tissue and the orientation of The Tissue. Horizontal structures are more reflected than vertically oriented structures.