FIGURE 9-4 Find Your Blind Spot Hold this book 30 centimeters (about 12 inches) away from your face. Shut your left eye and look at the cross with your right eye. Slowly bring the page toward you until the red spot in the center of the yellow disc disappears and the entire disc appears yellow. The red spot is now in your blind spot. Your brain replaces the area with the surrounding yellow to fill in the image. Turn the book upside down to test your left eye.