The development of optical low-coherence reflectometry and optical low-coherence tomography, commonly called optical coherence tomography (OCT), are prime examples of the transfer of optical technology to the invention and development of medical imaging devices in the field of ophthalmology. Optical coherence tomography had its origin in femtosecond optics, but used optical communications technologies and required advanced engineering for early OCT prototypes, clinical feasibility studies, entrepreneurship, and corporate development in order to achieve clinical acceptance and clinical impact. Critical advances were made by early career researchers, clinician scientists, engineering experts, and business leaders, which enabled OCT to have a worldwide impact on health care. Low-coherence interferometry involves the precise measurement of the amplitude and the relative phase of the reflected or backscatter light. It is based on the Michelson interferometer with the following components: a light source, a beam-splitter that divides the light into a reference arm and a measurement arm, and a light detector. There were many technologies that were transferred to those investigators who invented and developed the prototypes of today’s clinical devices for clinical ophthalmology and also for other medical disciplines. The list begins with fiber optics, optical couplers, low-coherence light sources, desktop computers, and of course femtosecond lasers. Prior to the invention and development of various types of OCT instruments, the ophthalmologist could only view the surface of the retina for diagnostic purposes. OCT instruments provide images that are acquired from below the surface of the retina. OCT provides images with high axial and lateral resolution. The invention and continued development of OCT medical devices and their general worldwide acceptance by ophthalmologists is a monument to the advances in diagnostic clinical ophthalmology that has occurred in the last few decades.