A method that allows a plurality of variables to be measured with the aid of an integrated optical sensor module. Because all the components necessary for carrying out the method are integrated on the same substrate, the sensor becomes small, compact, stable, malfunction-free and economical. The sensor module substantially comprises a sensor field, an analyzer, and an information field. The method comprises making the variables to be measured interact in sensor fields with guided waves, analyzing the effect on the wave, determining from that the value of the measuring variables, and displaying the results in the information field.