Sheep have panoramic vision of 330° to 360° and binocular vision of 25° to 50°. They are thought to have colour vision and are able to distinguish between a variety of colours: black, red, brown, green, yellow and white. They have no accommodation, so must lift their head to see distant objects. This also means that they are unable to judge depth as accurately as some other animals. Sheep eyes possess very low hyperopia with little astigmatism. Such visual characteristics are likely to produce a well-focused retinal image of objects in both the middle and long distance.