Stability of Photo-Printed and Oil-Painted Irises in Ocular Prostheses Subjected to Weathering

Introduction Iris fabrication is central to ocular prosthesis aesthetics, yet comparative evidence on oil‑painting versus photo‑printing under environmental stressors remains limited. This study evaluated colour stability, dimensional stability and objective acceptability of conventionally oil‑painted and photo‑printed irises in ocular prostheses following exposure to weathering conditions. Methods Forty ocular prostheses were fabricated, comprising 20 oil‑painted and 20 photo‑printed irises. Ocular prostheses fabricated with each method were divided into two subgroups: 10 were subjected to outdoor weathering conditions for two weeks, and 10 were maintained in a dark room as controls, yielding four experimental groups: oil-painted weathered, oil-painted non-weathered, photo-printed weathered, and photo-printed non-weathered. Colour change was quantified using CIELAB colour difference formula values in Adobe Lightroom Classic (Adobe Inc., San Jose, California, USA), and iris size was assessed with Adobe Photoshop (Adobe Inc.). A researcher‑designed questionnaire compared the acceptability of oil-painted and digitally printed irises in ocular prostheses. Results Photo-printed non-weathered prostheses demonstrated the smallest mean colour value of all other groups. Following exposure to outdoor weathering conditions, colour changes in photo-printed irises were significantly larger than those in oil-painted irises (p<0.001). Photo-printed weathered irises were significantly smaller than oil-painted non-weathered irises (p=0.004), photo-printed non-weathered irises (p<0.001), and oil-painted weathered irises (p=0.002). In general, respondents rated oil-painted irises as more acceptable than photo-printed irises when compared with a natural human iris. Conclusions Oil-painted irises in ocular prostheses exhibited greater colour and dimensional stability compared with photo‑printed irises in ocular prostheses following exposure to outdoor weathering conditions. Oil‑painted irises were consistently judged more aesthetically acceptable than photo‑printed irises when compared with the natural human iris, underscoring their suitability for achieving durable and aesthetically pleasing prosthetic outcomes. Despite the efficiency and reproducibility offered by digital fabrication techniques, conventional oil‑painting methods currently remain the more reliable iris fabrication option for achieving durable and clinically acceptable aesthetic outcomes in ocular prostheses. Further research evaluating long‑term performance and advances in digital printing is warranted to enhance the viability of photo‑printed iris fabrication.