Shatapatha Brahmana 14.1.3.21

14.1.3.21

suṣadā paścādivti nātra tirohitamivāsti devasya saviturādhipatya iti devamevāsyai savitāramadhipatiṃ karoti nāṣṭrāṇāṃ rakṣasāmapahatyai cakṣurme dā iti cakṣurevātmandhatte tatho ha cakṣuṣmānbhavati

'Well to live on behind (towards the western region),'--in this there is nothing hidden, so to speak;--'in god Savitri's over-lordship;'--the god Savitri he thus makes her over-lord for the warding off of the fiends, the Rakshas;--'grant thou eyesight unto me!'--he thus secures eyesight for himself, and accordingly he becomes possessed of eyesight.