The Collaborative International Dictionary of English v.0.48:

Blear \Blear\, v. t. [imp. & p. p. Bleared; p. pr. & vb. n.
   Blearing.] [OE. bleren; cf. Dan. plire to blink, Sw. plira
   to twinkle, wink, LG. plieren; perh. from the same root as E.
   blink. See Blink, and cf. Blur.]
   To make somewhat sore or watery, as the eyes; to dim, or
   blur, as the sight. Figuratively: To obscure (mental or moral
   perception); to blind; to hoodwink.
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         That tickling rheums
         Should ever tease the lungs and blear the sight.
                                                  --Cowper.
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   To blear the eye of, to deceive; to impose upon. [Obs.]
      --Chaucer.
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The Collaborative International Dictionary of English v.0.48:

Blear \Blear\, a. [See Blear, v.]
   1. Dim or sore with water or rheum; -- said of the eyes.
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            His blear eyes ran in gutters to his chin. --Dryden.
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   2. Causing or caused by dimness of sight; dim.
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            Power to cheat the eye with blear illusion.
                                                  --Milton.
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WordNet (r) 3.0 (2006):

blear
    adj 1: tired to the point of exhaustion [syn: bleary, blear,
           bleary-eyed, blear-eyed]
    v 1: make dim or indistinct; "The fog blurs my vision" [syn:
         blur, blear] [ant: focalise, focalize, focus,
         sharpen]