La Texican,

The lines you see may be ocular migraine variants. They are created by patterns of rhythmic neuronal firing in the visual cortex. The can occur by themselves, or be part of the aura that leads up to a migraine. Hildegard of Bingen had them, and interpreted them as angelic messengers. I know lots of people who have them, and I don't see a problem with having personal interpretations anywhere along the whole spectrum from odd physical artifact to spiritual manifestation.