Background:Visual involvement is one of the most feared complication of Giant Cell Arteritis (GCA).Tocilizumab (TCZ) has shown efficacy and safety in large-vessel vasculitis (LVV) including GCA (1-4).Objectives:To assess the efficacy of TCZ to: a) prevent the appearance of new ocular involvement, and b) to improve visual symptoms if present.Methods:Observational, multicenter study of 312 patients with GCA treated with TCZ. Patients were diagnosed with GCA accordingly to a) ACR criteria, and/or b) biopsy of temporal artery, and/or c) presence of LVV by imaging.Patients were divided into two subgroups: a) with, and b) without visual involvement at any time. Visual manifestations were classified as: a) Transient visual loss (TVL) (amaurosis fugax), b) Permanent visual loss (PVL) (longer than 24 hours) (partial or complete; unilateral or bilateral), c) diplopia, and d) blurred vision. Accordingly to visual duration up to TCZ onset, we considered: a) 1-10 days, b) 11-30 days, and c) more than 30 days.Results:We studied 312 (218 women/94 men; mean age73.4±9.6 years). Visual manifestations at any time (before and/or after TCZ) were observed in 78 (25%). In 47 of them visual manifestations were present at TCZ onset, and in the remaining 31 patients had had a complete recovery. Main clinical features of GCA with and without visual involvement are shown in TABLE. Patients with visual involvement were older, with other ischemic complications, and requiring more corticosteroids dose.Table 1.Main features of 312 patients at TCZ onset.OverallN= 312GCA with visual involvement(n= 78)GCA without visual involvement(n=234)pGeneral featuresAge (mean±SD)73.4±9.676.6±8.072.4±9.80.001*Female/Male(% of female), n218/94 (70)47/31 (60)171/63(73)0.046*Time from GCA diagnosis to TCZ onset (months), median [IQR]8 [3-24]5 [1-14]10 [3-24]0.040*Positive TAB, n (%)137/229 (60)33/60 (55)104/169 (61)0.444Ischemic manifestationsVisual involvement, n (%)47 (15)47 (60)00.000*Headache, n (%)166 (53)59 (76)107 (46)0.000*Jaw claudication60 (19)26 (33)34 (14)0.001*Systemic manifestationsFever, n (%)27 (9)8 (10)19 (8)0.743Constitutional syndrome, n (%)115 (37)30 (38)85 (36)0.878PmR, n (%)188 (60)46 (59)142 (61)0.830Acute phase reactantsESR, mm/1st hour, median [IQR]27 [10-50]34.5 [15.2-58]26.0 [10.0-48.0]0.193CRP (mg/dL), median [IQR]1.4 [0.4-3.3]1.5 [0.3-5.5]1.3 [0.4-2.9]0.134Prednisone dose, mg/day, mean±SD22.3±16.627.1±18.620.8±15.60.008*TCZmono/TCZcombo, n (%)211/10157/21154/800.295Follow-up (months), mean±SD28.4±21.825.8±22.429.3±21.60.119After TCZ onset, none patient developed new visual involvement. At TCZ onset 47 patients had the following visual manifestations; PVL (n= 28; unilateral/bilateral; 22/6), TVL (n=15; unilateral/bilateral; 9/6), diplopia (n=2) and blurred vision (n=2).None of the patients with TVL presented new episodes after TCZ onset, while 8 out of 28 patients with PVL experienced partial improvement (FIGURE). The 2 patients with diplopia and 1 of 2 patients with blurred vision improved.Figure 1.Efficacy of TCZ in 47 patients with GCA and visual involvement at TCZ onset.Conclusion:TCZ seems to prevent the appearance of new ocular manifestations. When they are present, TCZ may improve totally TVL and partially PVL.