Randomized prospective clinical trial, aiming to compare two techniques of orbital decompression. Patients with Graves orbitopathy in the inactive phase for at least 6 months will be divided in two groups; one group will be submitted to orbital decompression by antro-ethmoidal technique; the other group will be submitted to orbital decompression by lateral wall technique. Patients will be followed up for a period of 6 months after the surgery, and will be evaluated about the effect of orbital decompression on ocular motility, proptosis, ocular surface and quality of life.

Graves' orbitopathy is the most relevant non-thyroid manifestation of Graves' disease. Its clinical status varies from subclinical to severe deformities. Clinical features include palpebral retraction, exophthalmos, restrictive strabismus, chemosis, ocular surface lesions and optic neuropathy. There are two stages of the disease. There is an active phase in which the inflammatory process is present and the orbital changes evolve. The inactive phase comprises a stable clinical picture regarding the sequelae of the active phase. Orbital decompression surgery is the main treatment procedure for this inactive phase for functional and cosmetic rehabilitation purposes. In the last decades, great advances in the techniques and indication of this surgery have been observed. However, a consensus about the ideal technique does not yet exist. The most commonly used techniques are antro-ethmoidal decompression and lateral wall decompression alone or associated with other walls. The present study will be based on patients with Graves' orbitopathy diagnosis for at least 2 years and who are already in the inactive phase for at least 6 months. There are no prospective studies comparing the 2 main orbital decompression techniques through a detailed analysis of surgical outcomes from computed tomography images, digital photographic images and ocular motility examination. These informations will be collected in the preoperative and postoperative periods. The investigators will evaluate the decompressive potential of each technique calculated by the tomographic images. Participants will be followed up for a period of 6 months after the surgical procedure and the effect of decompression on ocular motility, ocular bulb positioning, ocular surface, vertical palpebral fissure, and the patient's quality of life will also be analyzed. The findings of this work will bring important contribution to the improvement of this surgical procedure of great relevance in the rehabilitation of patients with Graves' orbitopathy.

Inclusion Criteria:

• Diagnosis of Graves orbitopathy for at least 2 years
• Clinical Activity Score (CAS) < 4 for at least 6 months
• Agreement with the Informed Consent Form, which will be signed during the selection visit
• Ability to come to periodic evaluations for 6 months after the orbital decompression
• Absence of ocular abnormalities such as degenerative myopia, microphthalmia or anophthalmic cavity
• Absence of orbital abnormalities such as previous fractures or congenital defects
• Good collaboration for the exams
• Euthyroidism
• Exophthalmus ≥ 20 mm in Hertel's exophthalmometry
• Preoperative clinical evaluation indicating absence of contraindications for a surgical procedure

Exclusion Criteria:

• Myasthenia gravis
• Pregnancy
• Previous orbital, strabismus or eyelid surgery
• Other abnormal eye conditions or symptoms that make it impossible to admit the patient to the study, according to the clinical judgment of the investigator.

Participants and investigators do not know which orbital decompression technique will be done until 6 months of postoperative period.