A sterile field encroachment indicator apparatus of a surgical lighting system , the apparatus comprising: one or more encroachment indicators configured to indicate encroachment of a predetermined proximity to a surgical lighthead by a foreign entity and contact of the encroaching foreign entity with the surgical lighthead , the surgical lighthead being configured to provide illumination in order to illuminate a surgical environment ; one or more sensor units positioned in the surgical lighthead , the sensor units being configured to sense proximity of the foreign entity to the surgical lighthead and the contact of the encroaching foreign entity with the surgical lighthead ; and one or more controllers configured to control the encroachment indicators based on the sensed proximity of the foreign entity to the surgical lighthead and the sensed contact of the foreign entity with the surgical lighthead , the controllers being further configured to activate the encroachment indicators when the sensor units sense that the foreign entity has encroached the predetermined proximity to the surgical lighthead or has contacted the surgical lighthead , wherein at least one of the encroachment indicators is positioned in the surgical lighthead , wherein the at least one of the encroachment indicators comprises one or more surgical light sources of the surgical lighthead , the surgical light sources being configured to illuminate a surgical environment in which a surgical procedure is conducted, wherein the controllers are further configured to flash the surgical light sources when the sensor units sense that the foreign entity contacts the surgical lighthead , and wherein the at least one of the encroachment indicators further comprises one or more light emitting devices of a first color positioned in a handle of the surgical lighthead covered by a translucent handle skin . one or more encroachment indicators configured to indicate encroachment of a predetermined proximity to a surgical lighthead by a foreign entity and contact of the encroaching foreign entity with the surgical lighthead , the surgical lighthead being configured to provide illumination in order to illuminate a surgical environment ; one or more sensor units positioned in the surgical lighthead , the sensor units being configured to sense proximity of the foreign entity to the surgical lighthead and the contact of the encroaching foreign entity with the surgical lighthead ; and one or more controllers configured to control the encroachment indicators based on the sensed proximity of the foreign entity to the surgical lighthead and the sensed contact of the foreign entity with the surgical lighthead , the controllers being further configured to activate the encroachment indicators when the sensor units sense that the foreign entity has encroached the predetermined proximity to the surgical lighthead or has contacted the surgical lighthead , wherein at least one of the encroachment indicators is positioned in the surgical lighthead , wherein the at least one of the encroachment indicators comprises one or more surgical light sources of the surgical lighthead , the surgical light sources being configured to illuminate a surgical environment in which a surgical procedure is conducted, wherein the controllers are further configured to flash the surgical light sources when the sensor units sense that the foreign entity contacts the surgical lighthead , and wherein the at least one of the encroachment indicators further comprises one or more light emitting devices of a first color positioned in a handle of the surgical lighthead covered by a translucent handle skin . <EOS>