Maharaja Prthu developed spiritual eyes by his pure devotional service. Here (in SB 4.20.38), therefore, the Lord is described as sandarsitatma, for He reveals Himself to the vision of the devotee, although He is not visible to ordinary eyes

Expressions researched:
"Mahārāja Pṛthu, however, developed spiritual eyes by his pure devotional service. Here, therefore, the Lord is described as sandarśitātmā, for He reveals Himself to the vision of the devotee, although He is not visible to ordinary eyes"

Srimad-Bhagavatam

SB Canto 4

The Supreme Lord is not visible to material eyes, but when the material senses are inclined to the transcendental loving service of the Lord and are thus purified, the Lord reveals Himself to the vision of the devotee. Avyakta means "unmanifested." Although the material world is the creation of the Supreme Personality of Godhead, He is unmanifested to material eyes. Mahārāja Pṛthu, however, developed spiritual eyes by his pure devotional service. Here, therefore, the Lord is described as sandarśitātmā, for He reveals Himself to the vision of the devotee, although He is not visible to ordinary eyes.

SB 4.20.38, Translation and Purport

King Pṛthu then offered his respectful obeisances unto the Supreme Personality of Godhead, who is the Supreme Lord of all demigods. Although not an object of material vision, the Lord revealed Himself to the sight of Mahārāja Pṛthu. After offering obeisances to the Lord, the King returned to his home.

The Supreme Lord is not visible to material eyes, but when the material senses are inclined to the transcendental loving service of the Lord and are thus purified, the Lord reveals Himself to the vision of the devotee. Avyakta means "unmanifested." Although the material world is the creation of the Supreme Personality of Godhead, He is unmanifested to material eyes. Mahārāja Pṛthu, however, developed spiritual eyes by his pure devotional service. Here, therefore, the Lord is described as sandarśitātmā, for He reveals Himself to the vision of the devotee, although He is not visible to ordinary eyes.