Final answer:
The flash of light or "stars" seen after a blow to the eye is caused by lateral inhibition, which sharpens edges and enhances contrast in the images.
Step-by-step explanation:
A blow to the eye causes us to see a flash of light or "stars" even though photoreceptors are not being activated by light. This can be explained by lateral inhibition. When a blow occurs, the photoreceptors in the retina are stimulated and send signals to the bipolar cells and ganglion cells. This activation can create lateral inhibition, where horizontal cells inhibit more distant photoreceptors and bipolar cells, sharpening edges and enhancing contrast in the images.