Three-Dimensional Computer-Aided Design of a Full-Color Ocular Prosthesis with Textured Iris and Sclera Manufactured in One Single Print Job

Abstract

Three-dimensional (3D) printing of ocular prosthesis has been scarcely described in medical literature. Although ocular prostheses have been 3D printed successfully, iris colors are often manually added to the final product afterward. The objective was to produce a 3D-printed ocular prosthesis with textured iris and sclera in one single print job. We designed an average 3D model of an ocular prosthesis in 3D software, and took a high-resolution digital photograph of a human eye, which was processed in graphical software. By using functions called "displacement mapping" and "UV mapping" on the 3D model, the extent of height displacement was used to digitally produce a textured and colored iris and sclera on the 3D model. By using a polyjet 3D printer, different colors and materials could be used for different prosthesis components. We were able to design and 3D print a lifelike ocular prosthesis with realistic iris and sclera texture. The process took less than 4 h, of which 2.5 h are "printing time," reducing labor time compared with conventional methods. This proof-of-concept adds valuable knowledge to the future manufacture of 3D-printed ocular prostheses, which has several benefits over the conventional production method: 3D printing is much faster, reproducible, and prostheses can easily be digitally adjusted and reprinted. This study is an important step in the development of a full-fledged 3D workflow to produce lifelike custom eye prostheses.

Keywords: 3D printing; and computer-aided manufacturing; computer-aided design; displacement mapping; eye prosthesis; innovations; ocular prosthetics.

FIG. 1.

.stl file from Meshmixer showing a cross section of the prosthesis model.

FIG. 2.

3D design of a lifelike, textured, and full-color iris. (A) The high-resolution digital photograph. (B) The iris is isolated from the photograph using Adobe Photoshop and postprocessed. (C) Duplicate grayscale image. (D) The displacement mapping function in the 3D-design program Blender creates height displacement and therefore a texture on the selected iris of the core geometry. (E) UV mapping the colored image onto the texture creates a full-color and textured 3D iris; (F) The procedure was repeated for the sclera. (G) Core geometry with textured and colored iris and sclera. (H) Rendered, photorealistic image of the (full-color) core and (transparent) exterior geometry combined, showing the result. The final prosthesis model is now ready to print. 3D, three dimensional.

FIG. 3.

Left: a digital photograph (cross section) of the 3D-printed ocular prosthesis, where the different layers, hollow pupil, and color can be clearly seen. Right: a schematic model where (A, B) make up the transparent exterior (cornea and anterior chamber with a maximum depth of 3 mm at the center of the model, as indicated by the arrow). (C, D) The core geometry (iris and sclera, respectively).

FIG. 4.

The final prosthesis (a large and normal size version) and a large version of the textured iris.

FIG. 5.

One of the researchers holding a cross section of the 3D-printed prosthesis.