A wearable apparatus (100) for directing electromagnetic radiation onto at least one tissue area is disclosed. The apparatus comprises at least one radiation collection surface (101) for receiving incident electromagnetic radiation and at least one radiation emitting surface (102) adapted to direct electromagnetic radiation onto at least one target area of tissue to be treated. A light guide (103) is adapted to receive electromagnetic radiation received by at least one radiation collection surface and to direct at least part of the electromagnetic radiation to at least one radiation emitting surface, wherein a total surface area of the or each radiation collection surface is larger than a total surface area of the or each radiation emitting surface. Coupling means increases the proportion of electromagnetic radiation received by at least one radiation collection surface which enters the light guide.
