sparśhān kṛitvā bahir bāhyānśh chakṣhuśh chaivāntare bhruvoḥ
prāṇāpānau samau kṛitvā nāsābhyantara-chāriṇau||27||

Meaning : Withdrawing all sense contacts from external objects (sparśān bahir kṛtvā bāhyān), and fixing the gaze between the eyebrows (cakṣuḥ ca eva antare bhruvoḥ),regulating the incoming and outgoing breaths (prāṇa and apāna), to move evenly within the nostrils such a yogi practices deep inward concentration and breath control.