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EW NEWS & OPINION 28 October 2016 With 1 year of follow-up, there are no reported changes to the pros- thesis, and wearing comfort and re- constructive cosmesis were achieved, Prof. Mombaerts said. Where the technology is heading "3D technology has integrated in medicine, particularly in maxillofa- cial, cranial, dental, and orthopedic surgery. On a routine basis, surgeons and engineers join forces in the op- erating theatre to develop prostheses and implants tailored to the pa- tient," Prof. Mombaerts said. "While the bespoke prostheses are always preferred above standard prostheses, so far they still require the expertise of an ocularist. Anophthalmic socket rehabilitation will continue to re- quire close co-management between the ocularist and the ophthalmic plastic surgeon," she said. Prof. Mombaerts noted these are not the first reports of 3D printing being used to design ocular prosthe- ses, but the earlier versions created elsewhere described mass-produced eyes (three sizes, preselected hues) that lacked customized shapes. "Those were not tailored to the patient," she said. "Our current impression-free method requires the cone beam CT, which involves extremely low ionized radiation. Impression-free, radiation-free methods are more desirable." Prof. Mombaerts' group is researching alternatives to the cone beam CT. "3D printing has great potential in customizing the ocular pros- thesis," the group wrote. As each patient has a unique anophthalmic socket, technological advances that include 3D printing may be able to safely produce customized prosthe- ses, but more study is necessary. EW Reference 1. Ruiters S, et al. Computer-aided design and three-dimensional printing in the manufactur- ing of an ocular prosthesis. Br J Ophthalmol. 2016;100:879–881. Editors' note: Dr. Mombaerts has no financial interests related to her comments. Contact information Mombaerts: Ilse.Mombaerts@uzleuven.be by Michelle Dalton EyeWorld Contributing Writer serves as a start to finish off the prosthesis," which is still produced in the traditional, artisanal way, Prof. Mombaerts explained. First patient Prof. Mombaerts has described the first case of a 3D prosthe- sis, a 68-year-old male who had long-standing pain in his blind right eye as the result of congenital cata- ract, uveitis, glaucoma, and corneal melting. The subject underwent evisceration, and 6 weeks later a cone beam CT of both orbits was obtained. After the 3D computer model was designed, it was digitally delineated with the use of seg- mentation, the group wrote. They calculated the anterior curve of the 3D model from the mean standard values of normal eyes and printed the design in resin. That prototype was used as a trial prosthesis after the patient was fitted, and "further processing was performed in the standard way, with duplication to the polymethyl methacrylate (acrylic) prosthesis," the group said. Impression molding In this technique, an impression mold of the anophthalmic cavity is created. "We create a mold—or cast— of the socket by impression with materials injected through a tray," she said. "The procedure is uncom- fortable for the patient," creating additional difficulty in infants and children. "The mold may distort soft tis- sues, which can result in an equally distorted anophthalmic prosthesis," she said. 3D printing Prof. Mombaerts thinks 3D printing can overcome some of the obstacles presented with impression molding. Her group used computer-aided design/computer-aided manufactur- ing and rapid prototype modeling to outline the anophthalmic cavity. "The 3D virtual image of the anophthalmic socket is subsequent- ly 3D printed," she said. However, the 3D print is just the mold, "and Using the technology has enabled a group of researchers to create an ocular prosthesis I n an ideal world, faces are sym- metrical, and for people with only one eye, an ocular prosthe- sis may be able to restore that symmetry. There are challenges when fitting an ocular prosthesis, however, not the least of which is that some of the asymmetry re- mains, said Ilse Mombaerts, MD, PhD, University Hospitals Leuven, Belgium. "The fabrication is an artisanal process and is primarily based on an impression of the anophthalmic cavity," she said. Although the fabri- cation has routinely comprised im- pression molding, Prof. Mombaerts and colleagues have begun exploring the use of 3D printing to develop the prosthesis. 1 Three-dimensional printing: Opportunities in ophthalmology 3D scan of the anophthalmic socket with 3D design of the ocular prosthesis Source: Ilse Mombaerts, MD

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