Colour stability during production of printed ocular prostheses

Ocular prostheses have been used for centuries to restore patient confidence, psychosocial relationships and to improve quality of life. Methodology for producing accurate prostheses has improved with technological discoveries. Recently, hand painting ocular prostheses has been the go-to method for creating life like prostheses. However, digital printing a print to envelope around an acrylic prosthesis has been shown to decrease treatment and rehabilitation times, whilst still producing high-definition ocular prostheses. Despite these improvements, little is known about the colour stability of digitally printed ocular prostheses. To better understand the colour stability of digital prostheses 30 samples simulating ocular prostheses were created, containing 10 with blue iris, 10 combination/green iris and 10 with sepia (brown) irises. Colour measurements were taken using a data spectrophotometer, from two defined points, the iris and sclera for both pre-polymerisation and post-polymerisation to assess colour variance. Colour coordinate data was gathered and was analysed using a one-way analysis of variance test and a paired t-test, both with alpha = 0.05. Significant colour variations were found for each iris colour and for the sclera. The sclera showed the largest colour variation with a ΔE of 4.75, followed by the brown irises, the green irises and then blue irises with ΔE values of 3.29, 2.47 and 1.82, respectively. This is a significant decrease compared to current hand painting methods which have an average colour variance of ΔE = 20. This shows a large increase in colour stability which can drastically improve patient satisfaction and quality of life.