Adbhutasagara 48.88

48.88

yena pratyarke phūtkṛtya jalakaṇaughamadhye śakradhanuḥ pratyahaṃ ddaśyate sa yadā tanna paśyati tadā tasya riṣṭaṃ bhavatītyarthaḥ|
liṅgapurāṇavrahmāṇḍapurāṇayoḥ|
divā vā yadi vā rātrau pratyakṣe yo nihanyate|
hantāraṃ na sa paśyecca sa gatāyurna jīvati||

The meaning is: when he by whom a rainbow is seen every day facing the sun by blowing out [water] in the midst of a spray of water droplets no longer sees it, then a sign of death occurs for him.
In the Liṅgapurāṇa and Brahmāṇḍapurāṇa:
"He who is struck down in plain sight either by day or by night,
and does not see the striker, his life has ended; he does not live."