By Leilani

LifeBuzz Staff

These Unusual Cat Twins Are The Prettiest Cats On The Internet.

Iriss and Abyss, known together as @sis.twins on Instagram, are two blond twin sister cats based in Saint-Petersburg, Russia. Besides their beautiful white coats, you will be enchanted by their matching cases of complete heterochromia.

Complete heterochromia describes the condition in which one iris is completely different from the other. It can be hereditary, but it can also develop soon after birth. A cat with complete heterochromia is commonly referred to as an 'odd-eyed cat.'

Other types of the condition include partial heterochromia, when part of one iris is different from the rest, and central heterochromia, when the inner ring of the iris is different from the outer area.

According to the American Academy of Opthalmology, most of those born with the condition won't bear any other symptoms. In some cases, however, heterochromia may be a symptom of another condition.

It can also be acquired later in life through eye injuries, diabetes, and other causes. In the case of actress Mila Kunis, a surgery to correct her cataracts and poor vision resulted in acquired heretochromia.

Think you're seeing double? Think again! These pretty kitties are blond twin sisters from Russia.

They were born on 11/11/2015, a date some believe to have an auspicious sign.

Their names are perfectly unique, just like them. Say 'Hello' to Iriss and Abyss!

Here's a closer look at Abyss. Meow!

Here's her beautiful sister, Iriss. No Photoshop edits needed here!

The sisters have complete heterochromia, which means their eyes are different colors.

While you might confuse them with angoras, turkish van, or other breeds, their human says they have no distinct breed.

"The fact that we have no distinct breed and got all these fantastic features is truly amazing," said their owner on Instagram.

Their Instagram account @sis.twins has generated nearly 40K followers.

They've even been featured on the most popular cat page @cats_of_Instagram.

Here's a few more fun facts about them. They love to admire pretty things like flowers.

Turns out they are big Trekkies! 'Live long and prospurr.'

They can also sport amazing costumes with very little effort.

And even though they look the same, they have different personalities.

Time for these two to take a much needed nap. Aren't they precious?

If you loved Iriss & Abyss, make sure to follow their Instagram page @sis.twins today.

Source: sis.twins / Instagram