the iris is the part of eyes where there is no sense of vision.
the iris is the part of eyes where there is no sense of vision.
at which part of eyes there is no sense of vision?
the iris
like other ichthyosaurs, "temnodontosaurus" likely had high visual capacity and used vision as its primary sense while hunting. "temnodontosaurus" had the largest eyes of any ichthyosaur, and of any animal measured. the largest eyes measured belonged to the species "t. platyodon". despite the enormous size of its eyes, "temnodontosaurus" had blind spots directly above its head due to the angle at which its eyes were pointed. the eyes of "temnodontosaurus" had sclerotic rings, hypothesized to have provided the eyes with rigidity. the sclerotic rings of "t. platyodon" were at least 25 cm in diameter.
temnodontosaurus
the overlapping of vision occurs due to the position of the eyes on the head (eyes are located on the front of the head, not on the sides). this overlap allows each eye to view objects with a slightly different viewpoint. as a result of this overlap of vision, binocular vision provides depth. stereopsis (from stereo- meaning "solid" or "three-dimensional", and opsis meaning “appearance” or “sight”) is the impression of depth that is perceived when a scene is viewed with both eyes by someone with normal binocular vision. binocular viewing of a scene creates two slightly different images of the scene in the two eyes due to the eyes' different positions on the head. these differences, referred to as binocular disparity, provide information that the brain can use to calculate depth in the visual scene, providing a major means of depth perception. there are two aspects of stereopsis: the nature of the stimulus information specifying stereopsis, and the nature of the brain processes responsible for registering that information. the distance between the two eyes on an adult is almost always 6.5 cm and that is the same distance in shift of an image when viewing with only one eye. retinal disparity is the separation between objects as seen by the left eye and the right eye and helps to provide depth perception. retinal disparity provides relative depth between two objects, but not exact or absolute depth. the closer objects are to each other, the retinal disparity will be small. if the objects are farther away from each other, then the retinal disparity will be larger. when objects are at equal distances, the two eyes view the objects as the same and there is zero disparity.
binocular vision