  This paper proposes a computer-assisted system for the surgical treatment of
exophthalmia. This treatment is classically characterized by a de-compression
of the orbit, by the mean of an orbital walls osteotomy. The plan-ning of this
osteotomy consists in defining the size and the location of the de-compression
hole. A biomechanical model of the orbital soft tissues and its in-teractions
with the walls are provided here, in order to help surgeons in the definition
of the osteotomy planning. The model is defined by a generic Finite Element
poro-elastic mesh of the orbit. This generic model is automatically adapted to
the morphologies of four patients, extracted from TDM exams. Four different FE
models are then generated and used to simulate osteotomies in the maxillary or
ethmoid sinuses regions. Heterogeneous results are observed, with different
backwards movements of the ocular globe according to the size and/or the
location of the hole.
