How Do Dogs See the World?
You may be under the assumption that because dogs can hear better than us, they can probably see better than us, too. But that’s not necessarily the case. Let’s take a look at the anatomy of a dogs eye and how a dog’s eyesight compares to ours—from seeing colors to side vision and seeing in the dark. Dog Eye Anatomy The anatomy of a dog’s eye is very similar to that of a human eye. Dogs have an upper and lower eyelid, the same as people. There are many other similarities, including: Sclera: Tough, fibrous layer that’s often referred to as the “white” of the eye Cornea: Thin, clear layer at the front of the eye that can be injured easily Conjunctiva: Lining of the eyelids that can become inflamed and pink in color when dogs get excited, have allergies, or have an eye infection Iris: Colored part of the eye that contains smooth muscle and controls the size of pupil, regulating how much light enters the eye Pupil: Black area in the center of the iris; It contracts (gets smaller) in bright light or dilates (gets bigger) in dim light Lens: Located behind the iris; it changes shape to focus light on the retina Retina: Located in the back of the eye; it contains photoreceptors called rods, which sense light and movement, and other photoreceptors called cones, which sense colors Dogs also have eye structures that people lack: Tapetum lucidum: Located behind the retina, the tapetum lucidum reflects light through the retina, increasing the light available to the photoreceptors. This why animals see better at night, and it makes an animal’s eyes appear to glow at night when lights reflect from the animal’s eye. Third eyelid: Known as the nictitating membrane, the third eyelid is whitish in color and is located at the corner of the eye, near the nose. It helps protect the eye from scratches and also moves across the eye when a dog blinks to help produce tears.
