Dear Daisy Dog: I breed golden retrievers, and I’ve noticed that when the puppies are young, their eyes shine red in photos. Should I be concerned?

Daisy Responds: You are very observant, an important quality in a breeder. Rest assured that what you’re seeing is normal.

The red glow is the reflection of light off the blood vessels in the retina, near the back of the eye.

Behind the retina is a layer called the tapetum lucidum, which is colorless or pale blue-gray at birth. In mature dogs, the tapetum lucidum reflects light back onto the retina, allowing us to see better in dim light than you humans, who don’t have the structure.

As puppies grow, the tapetum lucidum changes color, becoming iridescent yellow, orange, green or blue. This process generally occurs by four months of age, but it can take as long as seven months, depending on the breed.

Once the tapetum lucidum attains its adult color, the eyes may reflect that color when you take a photo.

The iris also changes color with age, as we puppies are born with blue-gray eyes.

Unlike in humans, our eyelids are closed at birth, opening at 10 to 16 days. Our retinal blood vessels develop by 14 days. The cornea, the usually clear covering of Eyesight is precious, so if you notice your dog’s eyes don’t look right, contact your veterinarian immediately.