Optical Coherence Tomography (OCT) is an imaging method used to generate a picture of the back of the eye, called the retina. The picture is made by precisely measuring the amount of a dim red light that reflects off the retina. OCT is routinely used to image the eyes of patients with glaucoma.
OCT is used for medical imaging and industrial nondestructive testing (NDT). Optical coherence tomography is based on low-coherence interferometry, typically employing near-infrared light. The use of relatively long wavelength light allows it to penetrate into the scattering medium. Confocal microscopy, another optical technique, typically penetrates less deeply into the sample but with higher resolution.