Madhvaon Brahma Sūtra 4.1.10
Dvaita Vedānta
Sūtra
स्मरन्ति च
smaranti ca
Sūtra translation
(Krishna and others) also have thus enunciated (it) in Bmriti.
" For the purification of self, he shall be engaged in meditation holding his body, head and neck erect and motionless, keeping his mind firm, directing his eyes to the tip of his nose and controlling them (the eyes) from straying in the various directions (i.e., withdrawing bis looks from all the cardinal points),” and so on.