Creating ocular prosthetics using parametric modelling

Abstract

In the Netherlands roughly 20.000 people wear an ocular prosthetic as a consequence of losing their eye due to an accident or disease. An ocular prosthetic is a type of facial prosthesis that replaces an absent natural eye. The main goal of an ocular prosthetic is to provide an aesthetic replacement of a real eye. It does not restore the ability to see. During surgery the eye is removed and a empty socket is left. An ocular prosthetic is custom made to fit that socket.

These prosthetic eyes are made by highly-skilled professionals who are called ocularists. They do this through a labour-intensive manual production process. This process consists of several steps such as obtaining the shape of the empty socket, consulting with patients and painting a realistic iris, sclera and pupil by hand. Traditionally these prosthetics are made with an acrylate called PMMA using a series of plaster moulds.

However the industry is moving towards digital production. The starting point for this thesis was an article written in 2021 by a research team from the Amsterdam Medical Centre consisting of Annabel L.W. Groot, Jelmer S. Remmers, and Dyonne T. Hartong. This article featured a proof-of-concept of a fully coloured 3D-printed ocular prosthetic. This showed that creating an realistic prosthetic using 3D-printing is possible. The next steps are integrating this knowledge into the daily work of an ocularist.

The goal of this thesis was to develop a new workflow for an ocularist in order to create an ocular prosthetic suited for 3D-printing by using computer aided design. To increase the efficiency of production and to help the ocularist with digitalization a custom tool was developed in the form of a parametric model. This parametric model is able to automatically generate 3D-geometry of an ocular prosthetic using 3D-scans of ocular impressions or digital reference models. By inputting manual measurements, photographs and parameters the ocularist is able to create eyes which offer a personalized fit for every patient. Five ocular prosthetics have been made using the new workflow and parametric model. These were then validated by comparing the results with prosthetics who are made using the same input but with the traditional method. The 3D-prints showed great promise for a new fully digital way of creating ocular prosthetics having low surface deviations with the original prosthetics .

The next steps are testing with real patients and further developing the parametric model into a dedicated software tool for ocularists.

Most ocularists seem to be far away from producing fully 3D-printed prosthetics for customers but this thesis is a good first step in the digitalization of the ocularist practice.