Playful judge going off about vision? (6)

I believe the answer is:

ocular

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'about vision?' is the definition.
(I've seen this in another clue)

I can't explain the remainder of the clue.

(Other definitions for ocular that I've seen before include "Eyepiece" , "Of the eye - visible" , "not to be seen - due to this trouble?" , "Of the eyes, visual" , "Glaucoma's such" .)

I've seen this clue in The Irish Times.

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