The development of Optical Coherence Tomography (OCT), a technique that uses echoes of light to image microscopic structure of tissues, had a powerful impact in healthcare. OCT brought a new paradigm to ophthalmic examination and is now regarded essential in ophthalmology. Dr. James G. Fujimoto, Elihu Thomson Professor of Electrical Engineering, Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology (MIT), led the research developing OCT, together with a multidisciplinary team of clinician scientists and engineers. This collaborative approach for medical-engineering joint research was very unusual at that time.
OCT enables high resolution imaging of subsurface structure in tissue (from the surface to a few millimeters deep). Our eyes perceive images formed by light coming through the lens onto the retina at the back of the eye, particularly on the macula which enables the highest visual acuity. The retina is susceptible to a variety of diseases that can lead to partial or total vision impairment, such as diabetic retinopathy, age-related macular degeneration (AMD), and glaucoma. The retina is only 0.1 to 0.5 mm thick and OCT is the only technique for obtaining high resolution cross-sectional and three-dimensional images of the retina in vivo. OCT is also an extremely safe procedure as it only projects a weak beam of light into the eye, without requiring injected dyes, which can be uncomfortable for patients.

Prior to OCT, ophthalmologists used slit-lamp biomicroscopes and ophthalmoscopes to examine the retina. Any abnormalities could also be examined using photography and fluorescein angiography. However, images obtained through these methods were limited to two-dimensional (2D) frontal images that provided only limited information.
In the 1980s, Dr. Fujimoto conceived the idea of visualizing the tissue microstructure at high resolution using interferometry. Jointly, with Dr. Carmen Puliafito, a retinal specialist then at Harvard Medical School, Dr. Fujimoto began his research, soon to be joined by Dr. Eric Swanson, an expert in fiber-optics and satellite communications. Then, with input from David Huang, a Harvard-MIT MD-PhD student, they built a prototype of an OCT instrument for ophthalmology.
In 1996, the first generation of instruments that used “time-domain OCT” (TD-OCT) were commercialized. These instruments created cross-sectional images of the retina and other tissues by building up slices of optical scans. TD-OCT advanced the understanding of many retinal diseases, improving diagnosis, and guiding treatment.
In 2006, a second generation of OCT technologies, “Fourier-domain OCT” (FD-OCT), was commercialized which achieved dramatic increases in imaging speed. A laser scans the retina to generate a 3D volumetric image in real time, visualizing depth resolved retinal structure, providing detailed images as well as quantitative measurements for ophthalmologists. With the development of new pharmaceuticals for age related macular degeneration and diabetic retinopathy, OCT was used to measure treatment response and guide retreatment. This drove the adoption of OCT in ophthalmic clinics across the world. OCT perfectly matched the needs of ophthalmologists, who wanted precise images of retinal structure, without imposing an excessive burden on their patients.

OCT has become a standard of care in ophthalmology, with 20 to 30 million imaging procedures performed worldwide every year. OCT examination of the eye has the potential to detect systemic diseases such as diabetes, hypertension, and neurological disease. Many diseases do not produce noticeable symptoms in their early stages, but early treatment is important to prevent disease progression and future morbidity and mortality. Companies are developing OCT for use in optometrists shops, drug stores, and primary care physicians offices. The ability to screen the population, to detect and treat early disease, can dramatically improve health.
OCT is also being developed for multiple other clinical specialties. In combination with optical fibers catheters, laparoscopes and endoscopes, OCT can provide high-resolution subsurface imaging of structures inside the body. Intravascular OCT of the coronary arteries is an emerging application and studies have shown the OCT treatment guidance for patients with myocardial infarction can improve outcomes, reducing rates of future major adverse cardiac events.
Today there are over 100 academic research groups and companies developing OCT technology and clinical applications worldwide. Advances by researchers, engineers, clinical thought leaders and industry promise improve healthcare and quality of life.