Optical coherence tomography is an imaging technology that can perform non-contact cross-sectional imaging of tissue structure in real time.It is analogous to ultrasound B-mode imaging, except that OCT measures the intensity of reflected light rather than acoustical waves. OCT has a number of features that make it attractive as a diagnostic imaging modality: 1.) It has micron-level resolution, which is not possible with any other non-contact technique; 2.) No potentially allergenic dyes or contrast agents are required; 3.) OCT images are generated in electronic form, which facilitates the use of digital image processing techniques to extract quantitative parameters regarding the imaged tissue anatomy. For these reasons, structural OCT is already routinely used to assess areas of macular edema and response to treatment. Novel functional OCT including Doppler OCT and OCT angiography may allow an assessment of retinal blood flow and obviate the need for the more invasive FA test.