Optical Coherence Tomography (OCT)

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Optical Coherence Tomography (OTC) is an imaging technique that uses the interference of light to capture tomographic images of the eye. 

 Light has wave properties, and interference is when two waves overlap to result in a wave with greater or lower amplitude. Interference is more likely when waves are similarly shaped and less likely when they are not. The likelihood of this interference is referred to as coherence. 

 OCT systems use the interference of light. Various wavelengths of light are sent from the light source and a device called an optical coupler, which combines and splits multiple optical fibers, is used to send some of the light to a mirror and some of it to the retina at the back of the eye. The light reflected by the mirror is used as a reference, and the strength of the interference between this light and the light reflected by each layer of the retina is measured and processed to create an image. In this way, OCT can be used to output images of the 3D structure of the retina.