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..
However it is to be noted that in episode 1 The Phantom Menace C-3PO is unable to see with only one photoreceptor activate.
- Star Wars: The Power of the Force (1995)
- The Essential Guide to Droids
- 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