Three-dimensional design of a geometric model for an ocular prosthesis in ex vivo anophthalmic socket models.

PURPOSE: Fitting a customized ocular prosthesis for anophthalmic patients entails an artisanal labour-exhausting process and is standardly based on impression moulding of the socket, which may be anatomically inaccurate. The objective of the study was to design an impression-free socket mould with three-dimensional (3D) technology. METHODS: The ex vivo anophthalmic socket models included one silicone, one fresh pig cadaver head and three fresh-frozen human cadaver heads. After intra-socket application with iodine substance, five observers obtained eighteen low-dose cone beam computed tomography (CBCT) scans and one observer one high-dose CBCT scan of each model. The observers designed non-impression 3D moulds of the socket with 3D software. For the human cadaver sockets 3D geometric models of the ocular prosthesis were rendered from the 3D mould of the socket and the mirrored cornea of the contralateral eye. RESULTS: The posterior surface of the 3D mould was highly accurate, with a mean absolute deviation of 0.28 mm, 0.53 mm, 0.37 mm and mean upper deviation of 0.53 mm, 0.86 mm, 1.17 mm, respectively, for the phantom, pig and human model. The intra- and interobserver repeatability and reproducibility of the 3D moulds and designs was good (<0.35 mm). The largest variation in the 3D geometric model was found at the junction of the 3D mould and mirrored cornea. CONCLUSION: 3D design of an impression-free geometric model for an ocular prosthesis with low-dose CBCT is highly accurate in ex vivo anophthalmic socket models. This novel method is a critical step towards the manufacturing of 3D printed ocular prostheses and requires validation in anophthalmic patients.

The prevalence of anophthalmic socket syndrome and its relation to patient quality of life.

BACKGROUND: Following removal of the eye, soft tissue changes of the eyelids and orbit may develop into an anophthalmic socket (AS) syndrome, which is often attributed to orbital volume deficiency. While adequate primary orbital volume replacement is nowadays standard of care, patients may still present with facial asymmetry. The aim of this study is to provide insights into these changes and their impact on patient quality of life (QoL). METHODS: Cross-sectional study of 59 patients with longstanding ocular prosthetic wear after enucleation or evisceration surgery. The alignment, function, and laxity of the eyelids of the anophthalmic side were compared to those of the fellow side. The QoL was assessed with a 4-item questionnaire specific for the prosthetic condition. The different aspects of AS syndrome were analysed in relation to disease-specific and prosthetic data and to the patient QoL scores. RESULTS: Clinical AS syndrome was prevalent in 53% of patients with acquired anophthalmia. The anophthalmic side was statistically significantly different from the fellow side for the known AS syndrome features such as superior sulcus depression, margin reflex distance 1, and enophthalmia, but also for new features such as levator muscle function and lagophthalmia (P < 0.05). The difference was correlated with duration of prosthetic wear, prior orbital radiotherapy, and size of the prosthesis (P < 0.05). QoL scores were not correlated to the separate features of AS syndrome, except for a positive correlation between wearing comfort of the prosthesis and upper eyelid ptosis (P < 0.05). CONCLUSION: Patients with an ocular prosthesis show a relatively high prevalence of one or more distinct clinical features of AS syndrome, which do not negatively affect patient QoL. These findings underscore the importance to tailor prosthetic and surgical treatment to the patient's perceived QoL rather than to the objective clinical findings.

Applications of three-dimensional printing in orbital diseases and disorders.

PURPOSE OF REVIEW: To comprehensively review the applications of advanced three-dimensional printing technology in the management of orbital abnormalities. RECENT FINDINGS: Three-dimensional printing has added value in the preoperative planning and manufacturing of patient-specific implants and surgical guides in the reconstruction of orbital trauma, congenital defects and tumor resection. In view of the costs and time, it is reserved as strategy for large and complex craniofacial cases, in particular those including the bony contour. There is anecdotal evidence of a benefit of three-dimensional printing in the manufacturing of prostheses for the exenterated and anophthalmic socket, and in the fabrication of patient-specific boluses, applicators and shielding devices for orbital radiation therapy. In addition, three-dimensional printed healthy and diseased orbits as phantom tangible models may augment the teaching and learning process of orbital surgery. SUMMARY: Three-dimensional printing allows precision treatment tailored to the unique orbital anatomy of the patient. Advancement in technology and further research are required to support its wider use in orbital clinical practice.