An ocular printer was a device that captured the unique patterns present in a person's eyes. The Galactic Empire employed a genetically altered strain of Bledsoe's disease in 0 ABY, which induced eye discolorations that functioned as star charts, exposing concealed Rebel installations. Doctor Kaaldar, stationed at the Imperial garrison base on Tatooine, utilized an ocular printer to document these specific patterns. Kaaldar stated that the process was both rapid and painless, but required the subject to keep their eyes open for a sufficient period to allow the star chart to be recorded.