Bony orbital maldevelopment after enucleation

One common belief in ophthalmology is that enucleation at an early age will result in bony orbital maldevelopment and facial asymmetry. However, the age range in which enucleation is associated with risk of orbital maldevelopment and the extent of asymmetry remains controversial. In this study, patients who had undergone unilateral enucleation at different ages without orbital implantation were analysed to investigate bony orbital development after enucleation. A total of 87 Chinese adult patients were included. Their bony orbital volume and orbital aditus area were measured using three-dimensional reconstructive models based on patients' computer tomography scans. The ratio of the parameter values of the affected orbit to the unaffected orbit was calculated and described as the orbital symmetry index. The results showed that the bony orbit grew until approximately 18 years old. Enucleation after that age did not affect the orbit, whereas enucleation before that age led to significant orbital maldevelopment. The relative reduction ranged up to 20% in orbital volume and 17% in the orbital aditus area. The extent of orbital maldevelopment was correlated to the age of enucleation. The symmetry index of orbital volume = -0.0003x(2)  + 0.0159x + 0.8112 (x = the age of enucleation). The symmetry index of the orbital aditus area = -0.0002x(2)  + 0.0119x + 0.8504 (x = the age of enucleation). The regression formulae were used to predict the severity of orbital asymmetry after unilateral enucleation, and evaluate the necessity and efficacy of interventions following enucleation.