Natyashastra
शङ्कायां शङ्किता ज्ञेया विषादार्थे विषादिनी । निद्रास्वप्नसुखार्थेषु मुकुला दृष्टिरिष्यते ॥ ९१॥
The Śaṅkitā (apprehensive) gaze is to be used in states of apprehension, and the Viṣaṇṇā (dejected) gaze in despair. The Mukulā (bud-like) gaze is prescribed for sleep, dreams, and happiness.
english translation
zaGkAyAM zaGkitA jJeyA viSAdArthe viSAdinI । nidrAsvapnasukhArtheSu mukulA dRSTiriSyate ॥ 91॥
hk transliteration by Sanscript