Creutzfeldt-Jakob disease and ERG

Visual impairment can be one of the symptoms of Creutzfeldt-Jakob disease (CJD). We report three cases of idiopathic CJD with visual symptoms and review previous reports of visual symptoms in CJD. Patient 1 initially visited our ophthalmology department complaining of blurred vision. Even before she was diagnosed with CJD, electroretinography (ERG) showed a selective reduction in the b-wave. Patient 2 appeared to have visual disturbances but, due to severe dementia, had no such complaints. At this time he had severely advanced CJD but normal ERG results; however, a reduction of the b-wave was observed 1 month before he died. Patient 3 had visual disturbances at the initial visit, but the ERG result was normal even after the CJD had advanced. Atrophy of the visual cortex was later observed. CJD can alter vision in various ways. The selective reduction in the b-wave we observed on ERG indicates retinal involvement; however, visual disturbances may occur without retinal implications. Ophthalmologists should be aware that visual impairment may be the first symptom of CJD.