Charles Ellicott Commentary Psalms 119:82

"Mine eyes fail for thy word, While I say, When wilt thou comfort me?" — Psalms 119:82 (ASV)

My eyes fail. —The failing of the eyes is evidently to be understood here as the effort of straining to catch or keep sight of a distant object, not, as so frequently in the Psalms (see Psalms 6:7 and following), from sickness or even grief. Compare:

“I would have broke my eye-strings, cracked them, but
To look upon him.”—SHAKESPEARE: Cymbeline.