Military order lacks republican vision (8)

I believe the answer is:

eyesight

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'vision' is the definition.
(eyesight is your vision)

I don't understand how the rest of the clue works.

(Other definitions for eyesight that I've seen before include "Yes, eight required for vision" , "quality of viewing" , "Seeing faculty" , "Power of vision" , "Seeing ability" .)

I've seen this clue in The Irish Times.

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