Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
But they must never he fixed or protruding, languid or sluggish, lifeless, lascivious, restless, nor swim with a moist voluptuous glance, nor look aslant nor leer in amorous fashion, nor yet must they seem to promise or ask a boon. As for keeping them fully or partially closed while speaking, surely none save an uneducated man or a fool would dream of doing such a thing.
And in addition to all these forms of expression, the upper and lower eyelids can render service in support of the eyes.
The eyebrows also may be used with great effect. For to some extent they mould the expression of the eyes and
Complete immobility in the eyebrows is a fault, as also is excess of mobility or the tendency to raise one and lower the other, as in the comic mask which I mentioned just now: while it is a further blemish if they express a feeling out of keeping with the words we utter. For they show anger by contraction, grief by depression and cheerfulness by their expansion. They are also dropped or raised to express consent or refusal respectively.