The eyes of barn owls are important to the bird's ability to fly and hunt in the dark and the proportionately large eyes with large pupils are obviously a help with this. In addition the retina at the back of each eye is packed with more low light sensitive cells than most other birds. The disadvantage of this is that barn owls can only see in black and white and although their vision is superb, detailed research reveals that the differences between barn owl vision and that of other animals is not as startling as was once supposed, although they are far more sensitive than the eyes most diurnal birds.
Unlike most birds, the eyes of barn owls are fixed in their sockets and are forward facing set in the large heart shaped facial disk. This arrangement means that there is a large blind area behind the head but provides a wide area of binocular vision in front. The blind area is not really a disadvantage as the bird has a very flexible neck that allows it to rotate it's head through 300 degrees.