yada manah svam virajam

 yogena susamahitam

kastham bhagavato dhyayet

 sva-nasagravalokanah

 

Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 

 

When the mind is perfectly purified by this practice of yoga, one should concentrate on the tip of the nose with half-closed eyes and see the form of the Supreme Personality of Godhead.

 

Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 

 

It is clearly mentioned here that one has to meditate upon the expansion of Visnu. The word kastham refers to Paramatma, the expansion of the expansion of Visnu. Bhagavatah refers to Lord Visnu, the Supreme Personality of Godhead. The Supreme Godhead is Krsna; from Him comes the first expansion, Baladeva, and from Baladeva come Sankarsana, Aniruddha and many other forms, followed by the purusa-avataras. As mentioned in the previous verses (purusarcanam), this purusa is represented as the Paramatma, or Supersoul. A description of the Supersoul, upon whom one must meditate, will be given in the following verses. In this verse it is clearly stated that one must meditate by fixing the vision on the tip of the nose and concentrating one’s mind on the kala, or the plenary expansion, of Visnu.