Our data indicate that at least five and possibly as many as eight distinct K2P channels may be expressed within RGCs, including inward rectifying TWIK-type channels, acid sensitive TASK-type channels and arachidonic acid mechanosensitive TREK/TRAAK type channels. Based on levels of immunoreactivity, and the number of positively stained cells, TASK-1 is seemingly expressed at the highest levels, followed by TREK-1, TWIK-2, TWIK-1 and TWIK-3, with TREK-2 and TRAAK detected at only at low levels and TRESK only rarely (and inconsistently) detected. Based on the high number of positively stained cells observed for several K2P channel antibodies, it is highly likely that individual RGCs express multiple K2P channels simultaneously - likely generating complex profiles of K+ leak conductances within these cells36. Further work will be required to determine the precise functional roles performed by K2P channels within RGCs. However, based on their biophysical properties and known roles in other cell types we might expect K2P channels to make significant contributions to setting resting membrane potential and the regulation of action potential firing, as well as potentially performing roles in signal desensitisation and adaptation111666. In addition to their originally prescribed role as background leak channels it is now becoming clear that the function of many K2P channels is far more complex16. K2P channels may contribute directly to action potential waveforms and drive repolarisation of rapidly firing neurones16, with TASK-1 and TREK-1 capable of supporting action potential generation in the absence of voltage gated K+ channels67. It is therefore possible that K2P channels perform a number of diverse roles in RGCs, regulating both the likelihood and also the nature of electrical signalling events.