The evaluation of scar treatment benefits from exact structural measurements. Accurate assessment of thickness, surface area, and relief is crucial in routine clinical follow-up. From an experimental perspective, precise visualization of the microstructural organization is necessary for a better understanding of the mechanisms underlying pathological scarring. Structural proteins in scars differ from healthy skin in terms of amount, type, and importantly, organization. The precise quantification of this extracellular matrix (ECM) organization was, until recently, limited to two-dimensional images from fixated and stained tissue. Advances in optical techniques now allow high-resolution imaging of these structures, in some cases in vivo. The enormous potential of these techniques as objective assessment tools is illustrated by a substantial increase in available devices. This chapter describes currently used devices and techniques used in the clinical follow-up of scar progression from a volumetric standpoint. Furthermore, some of the most powerful techniques for microstructural research are described including optical coherence tomography, nonlinear optical techniques such as second harmonic generation microscopy, and confocal microscopy.