What’s That All About – Eyesight
Ever wondered how our pets see? Pet Insurance Australia investigates the incredible ways our pets view the world and the science behind it.
When it comes to how our pets see, there have been many misconceptions circling. At one point it was determined that dogs only see in black and white and shades of grey. However, thanks to science this myth has been abolished and it’s now well accepted that our dogs can see a small range of colour.
For our canine companions, they have two types of colour receptors commonly referred to as ‘cones’. Humans have three cones, being blue, green and red. This allows us to see a host of different colours including purple and orange, and everything between.
These cones are responsible for day vision and colour. While ‘rods’ are responsible for peripheral and night vision.
For dogs, they are missing the ‘red cone’ so they only have the two receptors being yellow and blue. This means that they only see colours related to yellow and blue, being light yellow, dark yellow, greyish blue, dark blue, greyish yellow. So, red yellow and green are seen as one colour – being primarily shades of yellow. As colours like magenta are perceived as a grey hue.
So, for a dog, they see like a human who has red/green colour blindness.
However, the two-legged variety (AKA humans) may win in the colour, but when it comes to motion dogs win paws down. Studies have indicated that dogs are 10 to 20 times more sensitive than humans. PLUS – their eyesight is much better during dawn and dusk.
Dogs also have a higher incident of rod cells in their eyes which allows them to see shades of black, white and grey. This is why dogs are champions when it comes to night vision.
Then there is the peripheral vision. Because our lovable hounds have eyes that are placed on either side of the head this allows them to have an impressive visual field of around 250 degrees compared to approximately 180 degrees for humans. Meaning your canine companion has a whopping 70-degree advantage when it comes to peripheral vision.
But this great peripheral vision comes at the cost of binocular vision being the visual area where both eyes meet. In dogs it’s around 75 degrees as with humans it’s approximately 120. This is due to our eyes being on the front of the head and not at the sides. Short nosed dogs have an even smaller field of vision.
Cats also have different vision compared to humans and just like their canine companions they are less able to see vibrant colours but are masters when it comes to night and peripheral vision.
Having around eight times more rod cells than humans, a cat is super sensitive to low light and can see with impressive clarity and motion. The shape of the eye also helps. This elliptical shape and larger corneas and tapetum (a layer of tissue that reflects light back into the retina) can help gather more light during dusk and dawn.
Humans certainly have the edge when it comes to colour and daylight viewing. The two-legged kind can also view objects clearly even at 50 meters away, as your friendly feline can only see things sharply at around six metres. This is due to the difference in the shape of our eye lenses. Their clearest zone is between 10cm-80cm. Any closer or further away and the sharpness of the object becomes distorted.
Cats also have an impressive peripheral vision with some experts hinting at closer to 280 degrees compared with the 180 degrees of humans!