Is it true that a hazy eye leads to irreversible vision loss? Why?

Delayed development . The visual system continues developing until age 10-12years. If something interferes with the vision in one eye (cataract, trauma, strabismus[crossed eyes]) the image it produces is confusing and the brain blocks the image out. The optic nerve and tracts in the brain stop developing if the image is blocked(suppressed). If the blocking continues to age 12 the lack of development becomes permanent .