Natyashastra
त्रासोद्वृत्तपुटा या तु तथोत्कम्पिततारका । सन्त्रासोत्फुल्लमध्या च त्रस्ता दृष्टिरुदाहृता ॥ ८३॥
Trastā: The Glance in which the eyelids are drawn up in fear, the eyeballs are trembling and the middle of the eye is full-blown due to panic, is called Trastā (frightened).
english translation
trAsodvRttapuTA yA tu tathotkampitatArakA । santrAsotphullamadhyA ca trastA dRSTirudAhRtA ॥ 83॥
hk transliteration by Sanscript