A smart contact lens, comprising: one or more, preferably concentric, rings (410-1, 410-2,..., 410-N) of a liquid crystal display, LCD, type, each ring being operable between a state having a lower attenuation of light and a state having a higher attenuation of light; a circuit (420, 100, 101) for detecting a ratiometric change in an incident light intensity, said circuit (420, 100, 101) comprising: an operational amplifier; a light sensor configured to induce a photocurrent (I PD) through it as a function of an intensity of an incident light, and connected to an inverting input of the operational amplifier; a feedback loop connecting an output of the operational amplifier to the inverting input of the operational amplifier, said feedback loop comprising at least one circuit element having a logarithmic voltage-current dependence; a high-pass filter configured to filter a signal (V AMP) output from the operational amplifier to generate a high-pass filtered signal (V HPF), and a comparison element configured to compare the high-pass filtered signal with at least a first threshold value and to output a signal (V OUT) which, as a response to an amplitude of the high-pass filtered signal passing the at least a first threshold value, changes to indicate a ratiometric change in the intensity of the incident light; and a controller configured to operate the one or more rings based on an intensity of an incident light, to receive the signal (V OUT) output from the comparison element and to, as a response to said signal indicating a ratiometric change in the intensity of the incident light from a higher intensity state to a lower intensity state indicating that at least a beginning of a blinking of an eye of a user has occurred, initiate a re-polarization of the one or more rings. one or more, preferably concentric, rings (410-1, 410-2,..., 410-N) of a liquid crystal display, LCD, type, each ring being operable between a state having a lower attenuation of light and a state having a higher attenuation of light; a circuit (420, 100, 101) for detecting a ratiometric change in an incident light intensity, said circuit (420, 100, 101) comprising: an operational amplifier; a light sensor configured to induce a photocurrent (I PD) through it as a function of an intensity of an incident light, and connected to an inverting input of the operational amplifier; a feedback loop connecting an output of the operational amplifier to the inverting input of the operational amplifier, said feedback loop comprising at least one circuit element having a logarithmic voltage-current dependence; a high-pass filter configured to filter a signal (V AMP) output from the operational amplifier to generate a high-pass filtered signal (V HPF), and a comparison element configured to compare the high-pass filtered signal with at least a first threshold value and to output a signal (V OUT) which, as a response to an amplitude of the high-pass filtered signal passing the at least a first threshold value, changes to indicate a ratiometric change in the intensity of the incident light; and an operational amplifier; a light sensor configured to induce a photocurrent (I PD) through it as a function of an intensity of an incident light, and connected to an inverting input of the operational amplifier; a feedback loop connecting an output of the operational amplifier to the inverting input of the operational amplifier, said feedback loop comprising at least one circuit element having a logarithmic voltage-current dependence; a high-pass filter configured to filter a signal (V AMP) output from the operational amplifier to generate a high-pass filtered signal (V HPF), and a comparison element configured to compare the high-pass filtered signal with at least a first threshold value and to output a signal (V OUT) which, as a response to an amplitude of the high-pass filtered signal passing the at least a first threshold value, changes to indicate a ratiometric change in the intensity of the incident light; and a controller configured to operate the one or more rings based on an intensity of an incident light, to receive the signal (V OUT) output from the comparison element and to, as a response to said signal indicating a ratiometric change in the intensity of the incident light from a higher intensity state to a lower intensity state indicating that at least a beginning of a blinking of an eye of a user has occurred, initiate a re-polarization of the one or more rings.