Anna Brouwer

Discussion & future perspectives Is there a role for the ERG in the diagnostic work-up of uveitis? This thesis describes in several chapters ERG abnormalities in uveitis. We even observed a characteristic ERG abnormality in uveitis: the prolonged cone b-IT. One might speculate that this typical ERG abnormality may be useful to diagnose uveitis. But, in our opinion an ERG is not necessary to diagnose uveitis. Ophthalmologist have no problems to make the diagnosis uveitis, and adding a time consuming test such as the ERG, would only burden patients. However, the ERG can be rather useful to diagnose or to exclude certain masquerade syndromes whichmimic uveitis. Exclusion of thesemasquerade symptoms is important in the diagnostic work-up of uveitis. The reason to record ERGs in children with uveitis in Chapter 5 was to exclude a retinal dystrophy. In retinal dystrophies the ERG is much more affected than in uveitis. 2 Some retinal dystrophies, notably those that are caused by mutations in CRB1, RP1 and USH2A may present with intermediate uveitis. 2 It is important to diagnose these patients, because they will not benefit from treatment with immunomodulating drugs. Therefore, they should not be exposed to the possible side-effects of treatment. In patients with a severely affected ERG, additional mutation analyses can be done to confirm a diagnosis of retinal dystrophy. It is useful to perform an ERG first in children where RD is suspected, because deoxyribonucleic acid (DNA) tests, are both expensive and it often takes more time before the tests results are known. The ERG can also be used in the work-up to diagnose or exclude diseases such as melanoma associated retinopathy (MAR) and carcinoma associated retinopathy (CAR). In both CAR and MAR malignancies produce antigens that are directed at the retina, thereby causing a retinopathy. Fundus examination is usually unremarkable, but some cells in the vitreous may be seen. In some cases, the retinopathy can improve with treatment. Therefore it is important that there is no diagnostic delay. 12 In rare cases of MAR and CAR the visual complaints of patients can be the first sign of the malignancy. 13 The typical, severely abnormal ERG responses can aid in the diagnosis. 14–16 Autoretinal antibodies in MAR are often directed at the ON-bipolar cells, which result in ERG abnormalities similar to congenital stationary night blindness. 17–19 Is there a role for the ERG in the monitoring of uveitis? This thesis describes in several chapters an association between the severity of the inflammation in uveitis and retinal dysfunction, as shown by ERG abnormalities. One can speculate that due to this association, there may be a role for the ERG in the monitoring or diagnosis of uveitis. 164 Chapter 8