SAN FRANCISCO (KCBS)— If you’re like me, you may be fascinated by the fact that some pets’ eyes can change colors. With puppies it’s normal, according to Dr. Jennifer Scarlett with the SF SPCA.

“They’re born with yellow or amber eyes and those will change to a dark brown by about eight weeks of age,” she said.

READ MORE: Wildfire Smoke, High Temperatures Prompt Spare The Air Alert For Bay Area On Tuesday

Scarlett said cats’ eye color changes with age and it’s something called iris atrophy. “Literally you’ll see this kind of cobwebby appearance to the iris.”

READ MORE: Stanford Infectious Disease Expert Angered By Nicki Minaj's COVID Vaccination Tweets

Other changes to eye color could indicate some sort of abnormality. There are types of diseases that can cause a change in eye color. Cataracts are a common cause, mainly in dogs and can cause changes either because of congenital reasons or because of diabetes.

MORE NEWS: Paradise Woman Pleads Guilty To Defrauding FEMA To Receive Camp Fire Disaster Relief

“Other changes of eye color can be due to conditions of the cornea or infections of the iris,” she said. “In old dogs, if you catch them in the right light you’ll see that their eyes kind of have a hazy blue. That’s called lenticular sclerosis or a hardening of the lens. The other reason for a blue eye is due to corneal inflammation, either due to an immune reaction or some type of infection or injury.”