Giant cell (temporal) arteritis (GCA) is the most common systemic vasculitis in Western countries. It involves large and medium-sized vessels with predisposition to the cranial arteries in the elderly. Cranial ischemic complications, in particular permanent visual loss, constitute the most feared aspects of this vasculitis. Although the use of corticosteroids and a higher physician awareness may have contributed to a decrease in the frequency of severe ischemic complications, permanent visual loss is still present in 7%-14% of patients. To investigate further the incidence, trends, and clinical spectrum of visual manifestations in patients with GCA, we examined the features of patients with biopsy-proven GCA diagnosed at the single reference hospital for a defined population in northwestern Spain during an 18-year period. Predictive factors for the development of any visual manifestation, not only permanent visual loss, were also examined. Between 1981 and 1998, 161 patients were diagnosed with biopsy-proven GCA. Visual ischemic complications were observed in 42 (26.1%), and irreversible blindness, mainly due to anterior ischemic optic neuropathy and frequently preceded by amaurosis fugax, was found in 24 (14.9%). Despite a progressive increase in the number of new cases diagnosed, there was not a significant change in the proportion of patients with visual manifestations during the study period (p = 0.37). Patients with visual ischemic complications had lower clinical and laboratory biologic markers of inflammation. Indeed, during the last years of the study, anemia was associated with a very low risk of visual complications. Also, HLA-DRB1*04-positive patients had visual manifestations more commonly. Patients with other ischemic complications developed irreversible blindness more frequently. The best predictors of any visual complication were HLA-DRB1*04 phenotype (odds ratio [OR] 7.47) and the absence of anemia at the time of admission (OR for patients with anemia = 0.07). The best predictors of irreversible blindness (permanent visual loss) were amaurosis fugax (OR 12.63) and cerebrovascular accidents (OR 26.51). The present study supports the claim that ocular ischemic complications are still frequent in biopsy-proven GCA patients from southern Europe. The presence of other ischemic complications constitutes an alarm for the development of irreversible blindness. In contrast, a higher inflammatory response may be a protective factor against the development of cranial ischemic events.