Anna Brouwer

12 Chapter 1 uveitis), 10,14 and HLA-B51 (Behçet’s disease). 15 Lastly, there are several diseases which can mimic symptoms of uveitis, known as masquerade syndromes. 16–18 One of the diseases that can be mistaken for uveitis are retinal dystrophies (RD), a group of genetic diseases that are characterized by progressive rod and cone dysfunction and degeneration. Unfortunately there is currently no treatment for RD. Therefore it is important to distinguish RD from uveitis, because uveitis can be be treated with immunomodulating medication to prevent retinal damage. This treatment is not useful in RD, so patients should not be exposed to the possible harmfull side- effects. 18 Despite all the known causes and associations for uveitis, often no underlying cause for the inflammation can be found. 19,20 This thesis focusses on the electrophysiology of the retina in non-infectious uveitis, and includes all anatomical localizations of uveitis as well as all the underlying causes. Epidemiology and treatment of uveitis The prevalence of each of the different uveitis diagnoses is quite rare. However, as a group, uveitis is a much more common disease. The prevalence of uveitis varies around 85-204 cases per 100.000 cases, and the incidence is around 17-52 cases per 100.000 person-years. 21–23 The peak incidence of uveitis is around 25-44 years of age, but some forms of uveitis present typically in childhood, whereas others manifest later in life. Because uveitis affects many people in the working population, the visual impact is quite high: uveitis causes about 10-15% of the total blindness in the United States. 24–26 Treatment of uveitis depends on the severity and underlying cause. In case of infectious uveitis, the underlying pathogen needs to be tackled. In case of non- infectious uveitis, the treatment is often focused on reducing the inflammation to prevent permanent damage to ocular tissue. Depending on the severity, localization and laterality of the inflammation, treatment can start with steroid eye droplets, streroid injections, or systemic medication. 20,27 Systemic steroids are usually not administered for a long time, because the long- term treatment has negative side-effects. Therefore, if an ophthalmologist expects that long-term treatment is necessary, a disease-modifying antirheumatic drug (DMARD) (e.g. methotrexate, azathioprine, mycophenolate mofetil, mycophenolate sodium, cyclosporine, cyclophosphamide) or a biologic ((adalimumab or infliximab) is usually commenced as well. 20,28