Anterior segment OCT (AS-OCT) enables the precise visualization of anterior segment structure; thus, it can be used in various corneal and ocular surface disorders. In this review, the authors will discuss the application of AS-OCT for diagnosis and management of various corneal and ocular surface disorders.

What is the difference between anterior and posterior segment OCT?

Anterior segment OCT utilizes higher wavelength light than traditional posterior segment OCT. This higher wavelength light results in greater absorption and less penetration. In this fashion, images of the anterior segment (cornea, anterior chamber, iris and angle) can be visualized.

What can an OCT diagnose?

An optical coherence tomography scan (OCT scan) is a critical tool for early diagnosis of macular degeneration, glaucoma, retinal detachment, and diabetic retinal disease.

What are the different types of OCT?

There are currently two distinct OCT technologies commercially available: the older time domain technology and the newer spectral or Fourier domain OCT technology.

What is anterior segment?

The anterior segment refers to the front-most region of the eye, and includes the cornea, iris, and lens. Typically, the phrase “anterior segment surgery” refers to surgery performed on the iris and lens (either natural lens, or synthetic intraocular lens placed during cataract surgery).

How does OCTA work?

OCTA works by detection of erythrocyte motion, so any extraneous movement during the image-capturing process may result in motion artifacts, which appear as white or black lines in the flow angiograms, and/or misalignment of the retinal vasculature.

What type of scan is OCT?

Optical coherence tomography (OCT) is an imaging technique that uses low-coherence light to capture micrometer-resolution, two- and three-dimensional images from within optical scattering media (e.g., biological tissue). It is used for medical imaging and industrial nondestructive testing (NDT).

What does drusen look like on Oct?

Drusen is the earliest AMD sign that is detected clinically in fundus examinations. On OCT, drusen appear as RPE deformation or thickening that may form irregularities and undulations (Figure 2).

What are OCT images?

Optical coherence tomography (OCT) is a non-contact imaging technique which generates cross-sectional images of tissue with high resolution. Therefore it is especially valuable in organs, where traditional microscopic tissue diagnosis by means of biopsy is not available—such as the human eye.

Why do I need an OCT scan?

Why should I have an OCT scan? Having an OCT scan in combination with your normal eye test will allow us to obtain the most detailed information about your overall eye health. Early detection will lead to timely treatment and better outcomes for the health of your eye.

Can glaucoma be detected by October?

SD-OCT is a valuable clinical tool for glaucoma diagnosis and detection of progression. RNFL parameters have been demonstrated to provide accurate information for disease diagnosis and sensitive method for disease progression.

Are OCT scans safe?

Is an OCT scan safe? The OCT scanner is CE marked and the low powered laser light is safe, and cannot harm your eye. The OCT scan is suitable for use with people fitted with pacemakers or metallic implants and you can wear your hearing aid throughout the procedure.

What is optic nerve OCT?

Optical coherence tomography (OCT) is a non-invasive imaging technique routinely used in ophthalmology to visualize and quantify the layers of the retina. It also provides information on optic nerve head topography, peripapillary retinal nerve fiber layer thickness, and macular volume which correlate with axonal loss.

How do you read an OCT retina?

What is OCT test for glaucoma?

Optical coherence topography (OCT) tests obtain a topographical map of the optic nerve, using non-invasive light waves to take cross-section pictures of the retina. An OCT test measures the thickness of the nerve fiber layer, which is the portion of the optic nerve most vulnerable to eye pressure elevation.

What is posterior segment OCT?

Intraoperative optical coherence tomography (OCT) of the posterior segment is a relatively new application of a familiar imaging modality that promises to improve surgeons’ ability to visualize intraocular structures and to provide qualitative and quantitative information that has previously not been available during …

What is the anterior of the eye?

Anterior chamber: The anterior chamber is the front part of the eye between the cornea and the iris. The iris controls the amount of light that enters the eye by opening and closing the pupil. The iris uses muscles to change the size of the pupil.

What is anterior disease?

Anterior segment dysgenesis (ASD) refers to a spectrum of disorders that affect the development of the front of the eye (the anterior segment), which includes the cornea, iris, ciliary body, and lens.

What is the difference between OCT and OCTA?

The important difference between OCT and OCTA is: OCT images anatomical structure, OCTA images vascular structure. A large amount of burden is placed on the imager-usually technicians-because the amount of data captured in a scan is more than the clinician, or interpreter of the images, can feasibly decipher.

What is a scan and B scan in OCT?

In OCT many one-dimensional scans (a-scans) are performed at several depths to create a two-dimensional image (b-scan). Those b-scans, if acquired closely and rapidly, can be translated into a volumetric image (c-scan) of a retina, for example.

Who invented OCTA?

Makita et al. OCTA was first described in some form in 2006 by Makita et al. using an 18.7 kHz spectral-domain OCT (SD-OCT) system. [11] With further improvement of OCT hardware and advancement in data processing techniques, higher quality OCT angiograms could be generated with less image artifacts.

Can an OCT scan detect retinal detachment?

OCT can detect signs of glaucoma, retinal detachment, macular degeneration, diabetic retinopathy and more at an incredibly early stage. Any one of these eye diseases is potentially sight threatening.

Is drusen serious?

Developing a few small drusen as you get older is usually a harmless and normal part of aging, but having large numbers of drusen could mean you have AMD. Over time, AMD can degrade your central vision, making it difficult to see things that are right in front of you.

What causes Cnvm?

CNVM occurs when new blood vessels start to grow in the choroid and break through the barrier between the choroid and the retina. When CNVM leak in the retina, they cause vision loss. CNVM are associated with many serious eye diseases, most commonly wet age-related macular degeneration.

What causes drusen in the eye?

Drusen is a German word that means “rock” or “geode.” They are like tiny pebbles of debris under the retina. The cause of the drusen deposits is related to a type of “garbage” disposal problem. Retinal cells dump unwanted material, and immune cells normally clean up most of it.

Can an OCT scan detect a brain tumor?

The researchers are using OCT imaging to determine the tumor boundaries.

What is RNFL?

Retinal nerve fiber layer (RNFL) thinning – reflecting loss of ganglion cell axons that leave the retina as the optic nerve and synapse onto the lateral geniculate nucleus – as revealed by OCT, is thought to be a good model of brain neurodegeneration, since retinal cells are unmyelinated, and so any thinning directly …

What is OCT RNFL?

Optical coherence tomography (OCT) is a non-contact optical technique that allows imaging and measurement of the retinal nerve fiber layer (RNFL). Since 1991,1 OCT has undergone rapid evolution for use in detection and monitoring of glaucoma and macular diseases.