Illumination matters Part III: Impact of light obstruction on illuminance from flexible ureteroscopes — a comparative PEARLS analysis

Artifacts from poor ureteroscopes’ light design with shadowing and dark areas in the field of view have been reported. The aim was to quantify effects of light obstruction in a kidney calyx model. We evaluated a series of contemporary flexible ureteroscopes including the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, as well as OTU Wiscope using an enclosed 3D-printed pink in vitro kidney calyx model submerged in saline, where the field of light was intentionally partially obstructed alternatively at 12, 3, 6, and 9 o’clock. A color spectrometer was used for illuminance measurements at a 45° opening position in the background of the model. Overall and mean background illuminance for each obstructive situation were significantly different between scopes for both 50