In this paper we propose the use of underlying ITO/glass or ITO/PET electrode structures for reliable conductivity measurements of transparent organic thin films. This technique avoids any mechanical damage of the organic thin film and furthermore preserves its optical transparency. Thin PEDOT:PSS layers with various secondary dopant concentrations of dimethyl sulfoxide (DMSO) have been studied. In particular, the degeneration under UV exposure has been investigated by electrical probing and atomic force microscopy. We find that the conductivity degeneration of PEDOT:PSS under UV exposure is reduced by a factor of two for the layers with DMSO doping.