Optical coherence tomography also known as OCT is an instrument and a diagnostic imaging technique which had its primary medical usage in the field of ophthalmology. It is a relatively new technique that has found its place in the clinical and diagnostic medicine only in the last fifteen years. The first scientific reports about usage of OCT were introduced in 1991. OCT is completely modern, non-contact and non-invasive diagnostic technique. The basic part of the OCT is the Michelson interferometer, which was constructed by American physicist and Nobel Prize winner Albert Abraham Michelson in the late 19ᵗʰ century. The first version of the Michelson interferometer was pretty simple considering that it was constructed using few mirrors, beamsplitter, a light source and a simple detector. The construction of today’s modern Michelson interferometer is radically modernised by replacing the simple mirrors and the beamsplitter with modern fiberoptic components, which has dramatically increased the speed, quality and precision of the whole system. As its light source is from the infra-red spectrum, the OCT offers high resolution of the image taken, very precise scanning of extremely small structures and also a greater diagnostic quality compared to the ultrasound and radio waves diagnostic methods. The usage of the OCT, which made a revolution in clinical ophthalmology, is not limited to that field anymore. Its usage is now spread throughout many medical fields and it is becoming a new diagnostic standard. In few years, many of older diagnostic methods might become obsolete because of the OCT.