Roving eyes

Gentleman. O, the noble conflict that 'twixt joy and sorrow was fought in Paulina. She had one eye declined for the loss of her husband, another elevated that the oracle was fulfilled. (Winter's Tale, 5.2)

Claudius. Have we, as 'twere with a defeated joy,
With an auspicious and a dropping eye,
With mirth in funeral and with dirge in wedding,
In equal scale weighing delight and dole,
Taken to wife. (Hamlet, 1.2)

Claudius's 'noble conflict 'twixt joy and sorrow' is not really noble; even in this early stage in the play, we suspect that his 'dropping eye' is not causing him too much bother. Paulina's conflict is, though, more troublesome. Her sadness pervades the ostensibly comic ending of the play, reminding us that some things are lost irrevocably: Hermione will never regain the chance to watch her daughter grow through childhood; Mamillius remains dead. Yet the Gentleman suggests more than simply an underlying sadness to the reunion of Perdita and Leontes. Rather, as one eye is elevated as the other declines, we must imagine an absolute co-existence of the two states of joy and sorrow. This paradox is enormous; even the image of roving eyes, used by both the Gentleman and Claudius, is an impossibility. Surely this image prompts us to ask whether the comic resolutions of marriage or reunion are possible or even desirable in the face of tragedy.
Edgar's narration of Gloucester's death suggests that the meeting of these two emotions is, indeed, unsustainable:

But his flawed heart,
Alack, too weak the conflict to support,
'Twixt two extremes of passion, joy and sorrow,
Burst smilingly. (King Lear, 5.3)