An optical coherence tomography (OCT) system to produce both longitudinal and transversal images of the in vivo human eye is presented. For the first time, OCT transversal images collected from the living eye at 50-μm depth steps show details unobtainable with the state-of-the-art scanning laser ophthalmoscope. Images of up to 3×3 mm are produced from the retina in less than a second. For images larger than 1.6×1.6 mm, a path modulation is introduced by the galvanometric scanning mirror and is used as an effective phase modulation method.© 1998 Society of Photo-Optical Instrumentation Engineers.