They were often sensitive to a wider visual spectrum than a typical humanoid eye. Droids could have many photoreceptors on their bodies, sometimes highly specialized.
The photoreceptors of droids were often made to resemble the eyes of species with which the droids would interact. The LOM-series protocol droid's photoreceptors were made to look familiar to insectoid species such as the Brizzits, Verpines, Gand, Yam'rii and Xi'Dec, while the CZ-series communications/business droid had optical sensors resembling the eyes of the Stacchati..
- Star Wars: The Roleplaying Game, First Edition (As "visual sensors" and "video sensors")
- The Star Wars Sourcebook
- Rebel Alliance Sourcebook, First Edition
- Star Wars: The Power of the Force (1995)
- The Essential Guide to Droids
- Star Wars Episode I: The Visual Dictionary
- Star Wars Customizable Card Game – Hoth Limited (Card: Probe Telemetry)
- Star Wars Customizable Card Game – Dagobah Limited (Card: Droid Sensorscope)
- The Official Star Wars Fact File 43 (ASS1–4)
- The Complete Star Wars Encyclopedia
- LEGO Star Wars Character Encyclopedia
- Dangerous Covenants