Currently, ophthalmic replacements are manually manufactured out of glass or acrylic, which bring their own unique problems to the table – acrylic eye prosthetics are hard to individualize, and glass is easily breakable and can even cause an allergic reaction. While prostheses made of polymethyl methacrylate (Plexiglas) are a little more durable, the iris color is pale in the light, often requiring the wearer to wear sunglasses.
“It requires a lot of practice and not always shade has to go,” said Ondřej Vocílka, a visually impaired engineering student at the Technical University in Brno (VUT), in a translated quote about the lengthy manual production of an artificial iris. “In computer production, you can adjust it using filters so that it matches the healthy eye as much as possible in color and shape.”
23-year-old Vocílka lost sight in his left eye as a child. During a lecture on 3D printing at VUT, he thought that the technology could be used to more easily produce ophthalmic prostheses, at less cost, that were tailored to individual patients. After a discussion with his teacher, he began researching the topic for his bachelor’s thesis.
According to the abstract for his thesis, “This Bachelor’s thesis deals with a production of a prototype of an eye prosthesis using 3D printing on the base of a model given by scanning of an PMMA handmade prosthesis. Model was modified in a program 3ds Max 2017. The core of the prosthesis with texture was created using this procedure. Additive technology PolyJet and 3D printer Stratasys J750 was used for production. Printed core was covered with biocompatible material to create biocompatible surface. The Bachelor’s thesis was ended with a discussion, in which problematic steps of the production were described. The discussion also includes economic analysis and suggested procedure of future production of eye prostheses using 3D printing.”
Vocílka decided to use his old ophthalmic prosthesis as a jumping-off point. After first meeting with representatives from a 3D printing company at a local engineering fair, he then attempted to take a 3D scan of his old ophthalmic prosthesis. Using the scan data, he adjusted and modified the shape in 3D modeling program 3ds Max, and the final model was able to apply the texture of the eye from the scan. Vocílka then exported the model and used polyjet technology to 3D print the full-color prosthesis, out of photopolymer material, on the company’s Stratasys J750, which can offer high-resolution creations.
“The whole process works by applying layers of material up to 14 microns in thickness and curing them with light,” said Vocílka.
The hardest part of making an eye prosthetic is the iris, as it needs to resemble a person’s healthy eye as much as possible. This is hard to achieve with conventional methods of manufacturing, but the 3D printer had better results, in a reduced amount of time.
While Vocílka was content with how his first print turned out, he was sorry to see that it was lacking a red vein; additionally, no surface treatment was added to mimic the gloss and plasticity of a real human eye.
Vocílka explained, “This was solved at the conclusion of a plexiglass layer on the prototype, as with current acrylic dentures.”
He plans to make the second version of his 3D printed prosthetic eye with biocompatible material, which is better for the environment and less expensive.
“The material is either white or transparent. White would be white and form a transparent layer that would overlap the prosthesis,” Vocílka said. “The whole production would be done in 3D, and the price would be drastically reduced without final adjustments. In addition, biocompatible material is health-conscious.”
Typically, eye prostheses in the the Czech Republic cost between 2,000 to 3,000 crowns (about USD$95-$145), while that amount goes up to 90,000 crowns (about USD$4,380) in England. But, Vocílka’s 3D printed prosthetic cost less than 850 crowns (about USD$40), and it took less time to manufacture as well.
“My method takes less than an hour and a half,” Vocílka said. “Production of an acrylic prosthesis takes around eight hours. While a glass prosthesis can be ready for a patient in two hours, there is no possibility to modify it.”
Vocílka’s 3D printed eye prosthetic is only a simple prototype, and would not pass any health tests. But, he is currently working to develop an even less expensive, more efficient method, and the eventual goal is to store a patient’s 3D eye prosthesis in a computer, and then be able to easily 3D print a replacement when necessary.
“When a patient calls for a new prosthesis in two years’ time, he does not even need to ride in,” Vocílka said. “Essentially, just print and send the artificial eye to his post, for example.”
The engineering student has received a Bosch award for his innovative work.
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