A method of processing optical coherence tomography (OCT) scans through a subject's skin, the method comprising: receiving at least one OCT scan through the subject's skin, each scan representing an OCT signal in a slice through the subject's skin； processing each OCT scan so as to determine a set of parameters comprising at least a measure of the atrophy of the vascular structure in the epidermis； in which the processing produces a measurement of skin condition dependent upon each of the set of parameters, and the method comprises outputting the measurement of skin condition.
