Crossword Genius

And eighty able minds knew LSD use without limits leads to vision impairment (5,9)

Ross

I believe the answer is:

night blindness

'and eighty able minds knew lsd use without limits leads' is the definition.
I can't tell whether this definition defines the answer.

'vision impairment' is the wordplay.
'vision' becomes 'night' (night vision is a kind of vision).
'impairment' becomes 'blindness' (blindness is a kind of impairment).
'night'+'blindness'='NIGHT-BLINDNESS'

'to' acts as a link.

(Another definition for night blindness that I've seen is " Inability to see in the dark".)

I've seen this clue in The Independent.
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