TikTok’s cat vision filter is unsophisticated and misleading. I’ll explain why. TikTok has introduced another ‘filter’. What that means is the platform a alters the reality or filters the video that you make and, in this instance, they make the video look as if it was through the eyes of a cat. And in simplistic terms, TikTok are right because cats are, crudely speaking, colourblind to red. This means that what they see is missing the colour red which results in a cyan caste. Cyan is opposite to red. That’s about as far as it goes for TikTok. However, it’s actually more sophisticated than that.
Firstly, although humans have photopic trichromatic vision which means that there are three different types of “cones” in their retina, which are colour sensitive photoreceptors, cats have dichromatic vision. One form of the cones that they have are sensitive to shades of blue-violet while the others are sensitive to shades of yellow-green. That means that red colours cannot be picked up as accurately.
But cats also lack colour vibrancy in their vision as I understand it. And they have a wider field of vision than humans (see above). Also, the clarity of their vision is slightly lower than that of the average human with something approaching 20/200 vision compared to human 20/20 vision in a person with good vision.
Also, cats are believed to be nearsighted. That means they don’t see things sharply at a distance. This adds to the general softness of the image they see. But also, at very near range their eyesight is not great in my experience which is why you see them sniffing their food. They use their nose to “see” the food to ensure that it is palatable. Their muzzle gets in the way too!
One reason why I’m keeping this article fairly short is because we don’t know for sure that what I’ve stated above is entirely accurate. It’s not really possible to go into deep scientific explanations about domestic cat eyesight because we don’t have that information to hand at the moment.
I conducted a search on Google Scholar before typing this and there is nothing really there to rely upon in writing an article like this.
In short, the outstanding difference between human cat eyesight is that cats are going to see a world which is more blue-green (cyan) than humans because of their inability to detect the colour red and also the image formed by their eyes are going to be softer and of a wider field of view.
The last point to make is that cats see better at night. This is because they have a greater number of another sort of photoreceptor in their retinas called a ‘rod’ which is truly colourblind and sees things in black and white. But these cells are more sensitive than their colour photoreceptors.
As I understand it, with a greater proportion of rods to cones in their eyes compared to humans this must affect their day-to-day vision mainly at night time but also in the day. This is another factor which affects how we try and work out how domestic cats see compared to humans.
It is very complicated and we don’t know the true answer. Many years ago, I produced a comparison between human and cat eyesight in two images which you can see again below and which you can also see on the earlier page which you can reach by clicking on this link.
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