Vision is not about the eyes seeing, but also the brain interpreting what’s in front of us. Light enters the eye through the cornea, which bends it toward the lens. The lens fine-tunes the focus, directing the light onto the retina at the back of the eye. The retina contains photoreceptor cells that convert light into electrical signals, which then travel to the brain via the optic nerve. The brain processes this information and turns it into the images we perceive. Sometimes when we don’t see things it’s often because of how our brain processes visual input rather than a failure of our eyes.