(*Click on photo to see a larger image of Radha Shyamasundara in Vrindavan.)
"The form of Krishna is visible to that eye in proportion to its purification by the practice of devotion. When the devotion of the neophyte reaches the stage of bhava-bhakti the pure eye of that devotee is tinged with the salve of love by the grace of Krishna, which enables him to see Krishna face to face. The phrase 'in their hearts' means Krishna is visible in proportion as their hearts are purified by the practice of devotion. The sum and substance of this sloka is that the form of Krishna, who is Shyamasundara, Natavara (Best Dancer), Muralidhara (Holder of the Flute) and Tribhanga (Triple-bending), is not a mental concoction but is transcendental, and is visible with the eye of the soul of the devotee under trance."
(Sri Brahma-Samhita 5.38, Purport)
.