**2.3. Juvenile idiopathic arthritis**

Juvenile idiopathic arthritis is the most common form of chronic inflammation of the con‐ nective tissue in children. Prevalence in the population is 43-148 cases per 100 000 persons [29,30,31]. The diagnosis of JIA is based on the 1997 ILAR criteria. For the arthritis do be di‐ agnosed as JIA the onset of the disease must take place until 16 years of age, arthritis symp‐ toms must last more than 6 weeks and other diseases in which arthritis occurs have to be excluded ( e.g.infectious, reactive, toxic and allergic and neoplastamatic diseases and other conditions with joint involvment). Ocular complications - mainly uveitis - occur in approxi‐ mately 12-17% of juvenile patients [32]. Treatment, as in RA, is based on DMARDs and bio‐ logical agents.
