Aim: To evaluate the efficacy of periocular triamcinolone acetonide for the tr eatment of thyroid associated ophthalmopathy (TAO), and the presence of ocular o r systemic adverse effects. Methods: A multicentre prospective pilot study was p erformed on patients diagnosed with Graves’ophthalmopathy less than 6 months be fore entry to the study. Patients were admitted to the study and were randomised into two groups: treatment and control. The treatment group received four doses of 20 mg of triamcinolone acetate 40 mg/ml in a peribulbar injection to the inf erolateral orbital quadrant. Both groups were evaluated by measuring the area of binocular vision without diplopia on a Goldmann perimeter and the size of the e xtraocular muscles on computed tomography (CT) scans. Ophthalmological and syste mic examinations were done to rule out ocular and systemic adverse effects. Foll ow up was 6 months for both groups. Results: 50 patients were eligible for the s tudy. 41 patients completed the study. There was an increase in the area of bino cular vision without diplopia in the treatment group (Σinitial: mean 231.1 (SD 99.9) and final absolute change, mean 107.1 (SD 129.0) compared to the control g roup (Σinitial: mean 350.7 (SD 86.5) and final absolute change, mean-4.5 (SD 6 7.6)). The sizes of the extraocular muscles were reduced in the treatment group (mean (inferior rectus initial values): 1.3 (0.7), final percentage change:-13. 2 (25.7), medial rectus initial values: 1.2 (0.6), final percentage change:-8.2 (20.7), superior rectus levator palpebrae initial values: 1.2 (0.6), final per centage change:-9.5 (29.1), lateral rectus initial values: 1.0 (0.4), final per centage change:-11.5 (20.6)) compared to the control group (inferior rectus ini tial values: 0.9 (0.3), final percentage change:-4.0 (21.5), medial rectus init ial values: 0.9 (0.3), final percentage change: 0.6 (22.4), superior rec tus l evator palpebrae initial values: 0.9 (0.3), final percentage change: 12.5 (37.5) , lateral rectus initial values: 0.9 (0.4), final percentage change:-0.5 (31.6) . Both measurements (degree of diplopia and muscle thickness) were statistically significant between groups (initial final). No systemic or ocular adverse effe cts were found. Conclusions: Triamcinolone administered as a periocular injectio n is effective in reducing diplopia and the sizes of extraocular muscles in TAO ophthalmopathy of recent onset. This form of treatment is not associated with sy stemic or ocular side effects. Aim: To evaluate the efficacy of periocular triamcinolone acetonide for the tr eatment of thyroid associated ophthalmopathy (TAO), and the presence of ocular or systemic adverse effects. Methods: A multicentre prospective pilot study was p erformed on patients diagnosed with Graves’ opthalmopathy less than 6 months be fore entry to the study. Patients were admitted to the study and were randomized into two groups: treatment and control. The treatment group received four doses of 20 mg of triamcinolone acetate 40 mg / ml in a peribulbar injection to the inf Both groups were evaluated by measuring the area of ​​binocular vision without diplopia on a Goldmann perimeter and the size of the e xtraocular muscles on computed tomography (CT) scans. Ophthalmological and syste mic examinations were done to rule out ocular and systemic adverse effects. Foll ow up was 6 months for both groups. Results: 50 patients were eligible for the tudy. 41 patients completed the There was an increase in the area of ​​bino cular vision without diplopia in the treatment group (Σinitial: mean 231.1 (SD 99.9) and final absolute change, mean 107.1 (SD 129.0) compared to the control g roup (Σinitial: mean 350.7 (SD 86.5) and final absolute change, mean-4.5 (SD 6 7.6)). The sizes of the extraocular muscles were reduced in the treatment group (mean (inferior rectus initial values): 1.3 The final percentage change: -8.2 (20.7), superior rectus levator palpebrae initial values: 1.2 (0.6), final per centage change: -9.5 (29.1), Lateral rectus initial values: 1.0 (0.4), final per centage change: -11.5 (20.6)) compared to the control group (inferior rectus ini tial values: 0.9 (0.3), final percentage change: -4.0 Initial ial values: 0.9 (0.3), final percentage change: 0.6 (22.4), superior rec tus l evator palpebrae initial values: 0.9 (0.3), final percentage change: 12. 5 (37.5), lateral rectus initial values: 0.9 (0.4), final percentage change: -0.5 (31.6). Both measurements (degree of diplopia and muscle thickness) were significantly different from groups were found. Conclusions: Triamcinolone administered as a periocular injectio n is effective in reducing diplopia and the sizes of extraocular muscles in TAO ophthalmopathy of recent onset. This form of treatment is not associated with sy stemic or ocular side effects.