Watch this senior cat's beautiful eyes change from gorgeous blue to emerald green (Gallery)

This beautiful cat had always had the bluest eyes until about a year ago, when one of his eyes began to change its color.

Meet Biggie the cat!

biggie the cat
reddit/rbend

"Our neighbors found him as a stray and asked if we wanted to take him," reddit user rbend said. They couldn't say no.

Though he's a bit of a scaredy cat, once he's warmed up to you, he a very affectionate, loud purrer, and a big cuddler.

Biggie had the bluest eyes, until one of his eyes started to change.

biggie the cat
reddit/rbend

It happened gradually over a year. His eye changed from blue to emerald green.

They took Biggie to the vet to get him checked out, but the vets couldn't find anything abnormal.

"They said it's nothing. I guess it's something that happens with age. I'm not completely sure why it changed but vets have never been worried about it."

biggie the cat
reddit/rbend

Eye color change normally occurs in kittens. "Most kittens are born with blue eyes. As a kitten's sense of sight develops over the next several weeks, his eyes begin to take on a variety of other colors," according to vetinfo.

For older cats, eyes changing color could be a sign of an underlying medical condition or eye damage.

But Biggie is as happy and healthy as can be, so his condition is a mystery.