Do our eyes truly act as the gateway to the world, as poets suggest? Not quite. We see the world through tiny pupils that act as spy holes. Our brain is like a creative ‘camera obscura‘, constantly comparing differences between images received by each eye and individual elements within each image. This makes our eyes highly sensitive to contrasts in brightness, sharpness, and depth. Sometimes, our brain tries to correct what we see.

Try this experiment: Look at the blurry face below next to the sharp one for 20-30 seconds (staring at the fixation star between them), then quickly shift your gaze to the same scene further below. You’ll notice that the previously clear face now appears blurry while the previously blurry face appears clearer. This illusion, called contrast adaptation or contrast gain control, occurs because prolonged exposure to blurry images affects our visual acuity and sensitivity to contrast.

blurred faces and contrast adaptation
© Gianni A. Sarcone