An apparatus to illuminate a target includes a lens having a lens side to be positioned in opposing relation to the target. The apparatus includes a lightguide that circumscribes at least a portion of the periphery of the lens. The lightguide has an input end to receive light and a length along which the receive light propagates. The apparatus includes outcoupling elements that are spaced out along the length of the lightguide. The outcoupling elements couple light out of the lightguide at respective positions along the length of the lightguide. The outcoupling elements are oriented to direct the outcoupled light towards the target when the lens side is positioned in opposing relation to the target. An eye tracking apparatus including the illumination apparatus and a method of eye tracking are disclosed.
