A method comprising: emitting light with modulating intensity from a plurality of light sources towards an eye of a user; receiving light intensity data including a plurality of event messages indicative of an intensity change of the emitted light reflected by the eye of the user in the form of a plurality of glints; filtering, by a diplexer , the light intensity data according to a frequency range of the modulation of the intensity from the plurality of light sources, wherein filtering the light intensity data includes: generating target-frequency event messages that are inside of the frequency range of the modulation of the intensity from the plurality of light sources; and generating off-target-frequency event messages that are outside of the frequency range of the modulation of the intensity from the plurality of light sources; and determining an eye tracking characteristic of the user based on the filtered light intensity data, wherein determining the eye tracking characteristic of the user incudes: determining a target feature for detecting one or more of the plurality of glints based on the target-frequency event message; and determining an off-target feature for detecting a pupil of the eye of the user based on the offtarget-frequency event message. emitting light with modulating intensity from a plurality of light sources towards an eye of a user; receiving light intensity data including a plurality of event messages indicative of an intensity change of the emitted light reflected by the eye of the user in the form of a plurality of glints; filtering, by a diplexer , the light intensity data according to a frequency range of the modulation of the intensity from the plurality of light sources, wherein filtering the light intensity data includes: generating target-frequency event messages that are inside of the frequency range of the modulation of the intensity from the plurality of light sources; and generating off-target-frequency event messages that are outside of the frequency range of the modulation of the intensity from the plurality of light sources; and determining an eye tracking characteristic of the user based on the filtered light intensity data, wherein determining the eye tracking characteristic of the user incudes: determining a target feature for detecting one or more of the plurality of glints based on the target-frequency event message; and determining an off-target feature for detecting a pupil of the eye of the user based on the offtarget-frequency event message. generating target-frequency event messages that are inside of the frequency range of the modulation of the intensity from the plurality of light sources; and generating off-target-frequency event messages that are outside of the frequency range of the modulation of the intensity from the plurality of light sources; and determining an eye tracking characteristic of the user based on the filtered light intensity data, wherein determining the eye tracking characteristic of the user incudes: determining a target feature for detecting one or more of the plurality of glints based on the target-frequency event message; and determining an off-target feature for detecting a pupil of the eye of the user based on the offtarget-frequency event message. determining a target feature for detecting one or more of the plurality of glints based on the target-frequency event message; and determining an off-target feature for detecting a pupil of the eye of the user based on the offtarget-frequency event message. <EOS>