Q. Since the visual images are projected in an inverted manner on the retina why don't we see things upside down?
Since the crystalline lens is a convex spherical lens it forms inverted images on the retina every converging lens forms inverted images the inverted information follows through the optical nerves until the occipital cerebral cortex that holds the visual area of the brain, in the brain the interpretation of the image takes place and the inverted information is reverted.