## Step6

Study the text and do the assignment below.

Upside down The lens focuses the image but also turns it upside down. This is no problem for our brain because it can just flip it right side up again. After all we are seeing everything right side up right now? right? Watch the video to see how the lens works. Blind spot There are two important parts of the retina, the macula lutea and the blind spot. The macula lutea is the part where the light falls when we focus on something. The blind spot is where the optic nerve enters the eye and we can't see anything. Then how come we dont have a blind spot in our vision? We do! but our brain fills it in for us. Don't believe me? Cover your right eye with your hand while sitting about 50cm away from your screen. Now with your left eye focus on the eyes of the girl. Now slowly move your face (while holding your hand over your right eye) towards your screen. If you keep focusing on the eyes, at a certain moment the flower will disapear! The reason this happens is the light from the eyes is falling directly onto your macula lutea, so you see it clearly. However the light from the flower is falling directly onto your blind spot and you can't see it at all.