An artificial retina using thin-film photodiodes (TFPDs) and thin-film transistors (TFTs) is proposed, which is expected to be suitable for living bodies, low-emitting and cost-effective, and which is an improvement of the system-on-panel devices in which the in-pixel and pixel-to-pixel operations are executed using TFTs. The characteristics of a TFPD and TFTs are measured, and their models are made for a circuit simulator. Circuits of the retina pixel and retina array with some improvements are invented, and it is confirmed using a circuit simulator that the artificial retina using TFPDs and TFTs can operate. Edge enhancement is also confirmed, and its dependence on the characteristic deviations of TFTs is analyzed.