Researchers say more children with arthritis than previously recognized may be at high risk for a devastating eye condition called uveitis, which causes blindness in up to 45 percent of cases.

Their study, which was published in the June 2010 issue of Arthritis & Rheumatism, has the potential to change eye-screening recommendations for kids with juvenile idiopathic arthritis (JIA), who often get uveitis as a complication of their disease.

Uveitis is the inflammation of the middle layer of the eye, which houses the colored iris and the lens.

In children, the most common disease associated with uveitis is JIA – approximately 1 in 8 diagnosed with arthritis will also develop the eye condition.

The condition often has no symptoms in its early stages, when it is most treatable. That’s why catching it early, with frequent eye screenings, is critical for saving sight.

Current guidelines, published in 2006 in the journal Pediatrics, recommend eye exams every three months for children diagnosed with juvenile arthritis before age 6 who also test positive for anti-nuclear antibodies, or ANAs. From four to seven years after diagnosis, the recommended frequency of screening drops to every six months; and after seven years, experts recommend eye screening once each year.

But the current study has called those guidelines into question, suggesting that kids diagnosed with JIA before age 5 should get quarterly eye exams until seven years after their diagnoses, instead of just four.

The researchers also stressed that gender appears to play a greater role in the development of uveitis than previously realized. Girls who were diagnosed with arthritis before age 2 comprised the highest risk group of all children in the study.

Traudel Saurenmann, MD, the study’s lead author and head of the Pediatric Rheumatology Unit at University Children's Hospital in Zürich, Switzerland, says she wanted to better understand risk factors associated with the development of uveitis because the condition can be difficult to recognize.

Dr. Saurenmann and her international team analyzed data on more than 1,000 children with a diagnosis of JIA who had been followed for many years through the Hospital for Sick Children in Toronto, Canada. Of the 1,081 patients with juvenile arthritis included in the study, 142, or 13.1 percent, eventually developed uveitis.

“This is the largest cohort of patients from a single center reported so far,” Dr. Saurenmann says, adding that a large patient population is one of the only reliable ways to spot patterns of risk factors related to a disease.

One of those patterns was related to age. “Age at diagnosis of juvenile arthritis was a much more important factor than we had previously thought,” she says.

Other red flags related to gender – girls seemed to be more susceptible to uveitis than boys, and to the presence of antinuclear antibodies (ANAs), in the blood. ANAs are proteins that may signal an autoimmune attack on the body.