Sanitiser is discarded on the counter, important for seeing membranes (7)

I believe the answer is:

retinas

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'membranes' is the definition.
(I know this)

'sanitiser is discarded on the counter' is the wordplay.
'discarded' indicates named letters should be taken away.
'on the counter' is a reversal indicator (counter can mean in the opposite direction).
'sanitiser' with 'is' taken out is 'saniter'.
'saniter' in reverse letter order is 'RETINAS'.

'important for seeing' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.

Can you help me to learn more?

I've seen this clue in The Independent.

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