And they secrete that fluid through a canal known as the canal of schlem. So we have this anterior cavity that contains our aqueous humor, that is a fluid that maintains that pressure inside this region of our eye. Now, the next portion is our pupil. So the pupil is the opening of the eye. The pupil is the opening that actually allows light to pass through this region and into this large cavity that contains another type of gellike fluid known as our vitreous humor. So what exactly is this pupil?