1. A method, of applying radiation to a patient's eye, comprising: identifying a first location of a fiducial marker, located on a contact lens that contacts an outer surface of the eye; identifying in a coordinate system, based on imaging data, a mapped location of a macula of the eye relative to the first location of the fiducial marker; positioning, based on the mapped macula location, a radiation source that applies radiation to the macula; and emitting the radiation from the positioned radiation source to the macula.