WOONSOCKET - On Dec. 19, Manda Buck became concerned when she looked at a photo of her then-7-month-old son, Kaydn, and saw a yellowish glow in one of his pupils.

Manda took Kaydn to an optometrist in Mitchell that day. The next day, he was taken to the University of Minnesota's hospital in Minneapolis, where an opthamologist said that his eye was already so sick that it would be best to have it removed. On Dec. 28, after spending Christmas at the family's home in Woonsocket, the procedure was done.

About a month later, Kaydn was diagnosed with Coats' Disease, a rare eye condition that affects fewer than 200,000 people in the U.S., or about 0.05 percent of the population, according to the Jack McGovern Coats' Disease Foundation's website.

"We're trying to make the best of it," Manda Buck told The Daily Republic. "He's going to grow up with not having vision in that eye, which is easier on him, because that will be his normal."

Coats' Disease involves abnormal development of the blood vessels behind the eye, which causes retinal capillaries to break open and the serum portion of blood to leak into the back of the eye. That causes swelling in the retina, eventually causing it to detach. It's almost always only found in one eye.

While there are some forms of treatment that can help people with the condition retain some of their vision if the disease is caught in its earlier stages, there is no known cause, cure or way to bring back vision that's already been lost.

Kaydn's case progressed so rapidly that although his mother took him to a doctor as soon as she suspected something might be wrong, doctors said his retina had already detached by the time they got to Minneapolis.

In March, he'll be fitted for a prosthetic eye, which can be replaced as needed as he gets older. Manda Buck said that one upside of her son's situation is that his eye and the information doctors have gathered while studying his case will go toward research for the disease.

Before Kaydn's diagnosis, his family, which has been hit hard by cancer in recent years, feared that he had a rare eye tumor known as a retinoblastoma which, like other eye diseases, share some symptoms with Coats' Disease. When they got the news on Jan. 24 that the issue wasn't a tumor, they were relieved, but they said that getting to that point was not easy.

Kaydn's father, Bryan Buck, who is a truck driver, said that when Manda Buck first called him to let him know something was wrong, he was hours away.

"I instantly fell apart," he said.

Manda Buck said getting through the period in which her son was being diagnosed would not have been possible without the help of family and friends.

Her father, Bill Bell, said that when he was told his grandson was having medical problems, he was at first angry, but then knew that the only way through the process was for family members to "pony up" and help out, both financially and with caring for Kaydn's three sisters, who are 9, 6 and 3 years old.

While the family's emotional struggle may have been eased by getting a more concrete and non-cancerous diagnosis, their financial burden is not likely to end any time soon. Because the condition is so rare, Kaydn has to be taken to Minnesota to see specialists who can address Coats' Disease. Although his visits will likely become less frequent as he gets older, he'll have to be driven between Woonsocket and Minneapolis every few months to both fit and maintain a prosthetic eye and make sure that his other eye isn't affected, resulting in between $700 and $800 in travel expenses per trip for the Bucks.

Manda Buck said that she's frustrated about the lack of awareness of and research on Coats' Disease, and she hopes more people will learn to recognize early warning signs of the condition, such as leukocoria, the effect that looks similar to red eye in photos but is instead white, yellow or orange. Other symptoms include loss of depth perception or of central or peripheral sight.

More than two-thirds of people with Coats' Disease are male, and about two-thirds have symptoms start before age 10.

"Unfortunately, now, we won't be able to have a cure for (Kaydn). But my goal, long term, would be to raise awareness for it for other families that might have to go through this process," Manda Buck said. "... I can't stress it enough. Take pictures of your family. Take pictures with the flash on. If you see anything off, get them into the doctor, because this could happen. Your child could be without an eye for the rest of their life."

Those interested in helping to offset the Bucks' expenses can contribute to accounts under Manda and Bryan Buck's names at Dakotaland Federal Credit Union and an account for Kaydn Buck/Manda Bell/Buck at the Black Hills Federal Credit Union or by donating to a GoFundMe entitled "Go Fund Me for Baby Kaydn."