Perception of non-physical images is a power of consciousness expressed through the pineal and pituitary glands. Humanity of this era has these glands completely atrophied. Through sexual transmutation those glands are gradually strengthened.

Even if someone has those glands completely damaged and meditation is thereby limited, meditation is still important and helps the consciousness, and meditation also develops the ability to awaken consciousness in dreams. So even if one struggles to "see" in meditation, in dreams you can, and there you can acquire the information you need.

So the short answer is, keep meditating and transmuting.