Final answer:
The image focused on the retina is inverted and reversed due to the optics of the eye, yet we perceive the world right-side-up because the visual cortex corrects it by actively processing and interpreting the signals received from the retina.
Step-by-step explanation:
The visual cortex must correct the image that is focused on the retina because the image is inverted and reversed.
When we observe our surroundings, the lens of the eye projects an image onto the retina that is inverted and reversed. This is due to the way the optics of the eye work, bending the light so that the image lands on the retinal surface in this upside-down and flipped state. However, our conscious perception does not see the world upside down, thanks to the visual cortex, which interprets the signals from the retina and corrects the orientation.
An example of this is demonstrated by experiments with prism glasses which, when worn, initially cause the visual field to be perceived as upside down. With adaptation over time, the subjects were able to interact with their environment correctly, indicating the remarkable flexibility and processing abilities of the visual cortex. Such findings show that the brain is actively creating a coherent picture from the inverted, reversed signals it receives, allowing for our perception of a right-side-up world.