The authors wish to demonstrate on the case of a 52-year-old female patient who suffered fromnon-specific symptoms and impaired visual functions, typical changes on the fundus which may be due to some serious haematological diseases. In the case of the mentioned patient the haematological disease (Waldenström’s disease) was manifested by hyperviscous and anaemic syndrome. The ophthalmological finding in the general picture was not dominant but on the whole typical and contributed to a more rapid diagnosis of the fundamental disease. Changes on the fundus by which the hyperviscous syndrome ismanifested must be known and in the differential diagnosis the possibility of haematological disease should be taken into account as in the majority patients are involved who are at risk of sudden loss of eyesight and sudden death.

        Key words: primary macroglobulinaemia, Waldenström’s disease, fundus paraproteinemicus, hyperviscous syndrome