Source:http://linkedlifedata.com/resource/umls/id/C3203769
UMD: Devices designed to support and keep the patient's head in a fixed position and distance from an ophthalmic diagnostic device. These devices typically consist of frames with a head rest against which the forehead rests and a chin rest (e.g., U shaped or cup shaped) on which the chin rests. The height of the chin rest can be adjusted. These devices can be floor-standing independent devices or table-mounted; they may also be a part of an assembly of an ophthalmic diagnostic device (e.g., slit lamp). Ophthalmic test head and chin rests are used for patients during ophthalmic examinations.