Normal orbital volumes and its pathology in orbital socket surgery

Abstract

The present article reviews current knowledge on orbital volumes in the anophthalmic socket and presents the authors' own results on the volumetry of the bony and soft tissue compartments following enucleation. These results provide strong evidence that enucleation in both children and adults is associated with a reduction of bony orbital volume and that this decrease in orbital volume increases with time. However, the reduction is smaller than generally assumed and does not cause obvious facial asymmetry. It is more related to the time interval since enucleation than the age at enucleation, which makes a mechanism of volume adaptation more likely than just retardation of growth. However, based on animal studies, the extent and consequences of bony orbital changes after early enucleation in childhood have until now been overstimated. Loss of the eyeball takes major responsibility for soft tissue volume reduction and can be variable due to marked inter-individual variations. Primarily, there is no shortage of orbital fat in the anophthalmic socket. The post-enucleation socket syndrome is therefore caused by a lack of adequate eyeball volume replacement and possibly a redistribution, but no shortage of orbital fat. However, chronic inflammation, radiation and secondary orbital implantation can induce orbital fat artophy and contribute to the development of a post-enucleation socket syndrome. Extraocular muscle volumes play a minor role in volume changes.