Devices, systems, and methods for monitoring hair

A device for examining a microfiber, comprising:

• a first plate, a second plate, and a groove, wherein:
• (i) the first and second plates are movable relative to each other into different configurations, including an open configuration and a closed configuration;
• (ii) the groove is on the surface of the second plate, wherein the groove is configured to accommodate one or a plurality of microfibers, wherein the groove has a depth of 3 mm or less and a length at least 5 mm;
• (iii) a part or the entire area of one or both the plates is transparent;
• wherein, in the open configuration, the two plates are configured to be partially or completely separated apart, so that a microfiber sample from a subject is deposited in the groove,
• wherein in the closed configuration, which is configured after the microfiber sample is deposited in the open configuration, the first plate is placed on top of the second plate, covering the groove,
• wherein the position of the groove on the second plate is configured to make at least a part of the microfiber sample placed in the groove being imaged in the field of view of an imager, wherein the imager is configured to view at least a part of the surface of the second plate, and
• wherein the microfiber is a diameter of 500 μm or less and a length of 4 mm or longer.