To access the data, click or select the words “Appendix 14.” RPE flat mounts from 15-month-old WT and Bicdl1 KI mice were incubated with secondary antibodies alone (without primary antibodies) to serve as negative controls for the dual immunofluorescence experiments. Images were acquired using identical microscope settings as experimental groups, confirming the absence of nonspecific background signal in both channels. Scale bar = 100 µm.