Red eyes may be among the more annoying things to happen to people capturing photos of their loved ones. But for a mother in Illinois, a photo of her 2-year-old son with red eyes, or rather, a single red eye, saved his life. That’s because only one of this eyes appeared in the photo as red; the other showed up white. It ended up being cancer.

“Probably a couple [of] months [ago] I would notice when I was looking at Avery in a light, I would see something in the back of his eye,” Julie Fitzgerald told CNN about her son. Unsure of what it was, she began researching and found articles about other people taking photos showing white eyes instead of red eyes. They suggested the white could be a sign of cancer.

Though her husband Patrick dismissed her concerns, saying it was probably nothing, she ended up taking a picture anyway — one of each of her kids. “I took a picture and I did not want to take the picture because I had this dreaded feeling in the pit of my stomach,” she said. “I took the picture and boom, his whole pupil was just white, and that’s when I knew.”

Specialists found that 75 percent of his left eye was covered in tumors called retinoblastomas, and said they had probably only begun growing six weeks earlier. Though it’s a rare form of eye cancer, retinoblastoma is the most common form of cancer in the eye among children, according to Mayo Clinic. It affects the retina, which senses light and transmits that information through the optic nerve to the brain. That information is then interpreted as images.

Doctors said Avery had most likely been blind since birth. They removed his eye to prevent the cancer from spreading further in to his brain and blood. He’ll eventually get a prosthetic eye and is undergoing further testing to determine if he’s at risk of other cancers.

You can watch the video below to learn more about Avery’s story. – Rockford’s News Leader