Nowadays, modern cameras have a setting which actually makes it relatively easy to prevent ending up with red eyes in photographs. As a result, this problem has practically become a thing of the past, but more recently, people have been getting frustrated about this again because when they take photos in darker conditions, at least one person inevitably ends up with those annoying red eyes. And then the photo is useless.
You can already guess that this is because of the lighting. But the person in the photo and the photographer themselves are also responsible because red eyes only show up when a photograph is taken directly from the front.
The peculiarities of the anatomy of the eye
In order to better understand why this happens, we first have to look at a schematic representation of the eye. The eyeball is covered by the cornea under which the aqueous humour is located and then the pupil surrounded by the iris. Behind this is the lens, then a large orb, namely the vitreous humour that surrounds the retina. And then finally you have the macula lutea, which in Latin translates as ‘yellow spot'.
Now let's take a closer look at the pupil. The pupil is an opening in the middle of the iris that functions as a shutter does on a camera. But what is it for? It regulates the amount of light that enters the eye. Our eyes capture the light by letting it pass through the cornea and the pupil. The pupil gets smaller and shrinks when it is exposed to light that is too bright to avoid being blinded, but in darker conditions, it opens up and becomes wider in order to allow as much light as possible into the eye.
When you take photos with the flash on, you are doing so because the environment you are in is too dark for the camera to see and pick up everything in the shot. This light penetrates the dilated pupils and goes directly into your eye. This happens so quickly that the pupil isn’t able to contract quick enough and this results in the concentrated light beam entering the eye and hitting a small spot in the middle of the retina at the back of the eye - the macula lutea.
What makes your eyes red in pictures?
But what does this have to do with red eyes in photos? The explanation is simple. The macula is at the same height as the pupil in the eye and is also a part of the eye through which several blood vessels from the retina run. And you can probably imagine what colour it is!
As a result, this red spot in your eye ends up reflecting the flash the camera generates in these darker conditions. Consequently, your photo ends up being spoiled by the ocular fundus and the blood vessels that are located in this part of the eye.
But then why do cats have green eyes in photos that are taken with the flash on? This is because a cat’s eye is made of special light-reflecting crystals, which is also what allows these animals to see in the dark. Therefore, it is these crystals that create the fascinating pale green colour that cats’ eyes are famous for in photos. The more you know!
They say that eyes are the windows to the soul but as it turns out, they also say a lot about your health. Check out this article to find out more.