Giant cell arteritis is characterized primarily by inflammation in certain large and medium-sized arteries. The major risk factors are age, female gender and Northern European descent. In this report we describe two cases of acute vision loss due to giant cell arteritis. In both cases the erythrocyte sedimentation rate (ESR) was below 50 mm/hr and the presenting complaint was foggy vision followed by acute blindness. The cases are to some extent different, for example in the former case the patient reported jaw claudication and ophthalmologic evaluation was consistent with anterior ischemic optic neuropathy. In the latter case there was narrowing and box-carring of blood cells in retinal arterioles, consistent with occlusion of the central retinal artery. This patient had recently finished a 2-year long treatment with glucocorticosteroids for polymyalgia rheumatica. The retina and the optic nerve do not survive for long without perfusion. If giant cell arteritis causes blindness in one eye there is significant risk for the other eye to go blind if no treatment is given. Corticosteroids can spare the other eye and suppress the underlying inflammatory disease process as well. It is vital to confirm the diagnosis of giant cell arteritis with a biopsy and start corticosteroid treatment as soon as possible, even before the biopsy is taken.