So we're very first all of our channel checks that ophthalmologists are seeing Rhopressa and Rocklatan as the pure indications to some of the existing generic options, but we're also hearing prescribers are facing some challenges because you've been in cases where Rhopressa and Rocklatan are indicated as covered by a plan.
What is the relationship between 'pure' and 'channel' in the context of the input sentence.
Options: original broadcaster, headquarters location, founded by, product/material produced