Novel 3d-printed Coaxial Light Microscope Adapter for Ophthalmic Wet Lab.

Purpose: To compare the usability and training effectiveness of a 3D-printed coaxial illumination system mounted on an off-the-shelf stereo-microscope to a professional ophthalmic surgical microscope, in cataract surgery simulation.

Setting: Ophthalmology Lab, Ophthalmology Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy.

Design: Prospective randomized crossover study.

Methods: Twenty ophthalmology residents performed simulated cataract surgery steps, including corneal incisions, capsulorhexis, hydrodissection, and corneal suturing, on porcine eyes using an off-the-shelf stereo-microscope and a Zeiss OPMI Lumera 700. The stereo microscope was equipped with a 3D-printed coaxial light adapter. After each simulation, participants completed a 5-item evaluation questionnaire (5-point Likert scale) and the System Usability Scale (SUS).

Results: The Zeiss microscope received significantly higher scores for image quality (4.15 vs. 3.40, p < 0.001) and red reflex visibility (4.10 vs. 3.25, p < 0.001). No significant differences were observed in depth perception, ergonomics, or ease of instrument handling. The stereo microscope scored higher in the SUS (80.5 ± 5.48 vs. 66.6 ± 4.95, p < 0.001).

Conclusion: The modified stereo microscope with 3D-printed coaxial illumination represents a cost-effective alternative for ophthalmic wet lab training. Despite lower optical performance, its usability and affordability make it a valuable tool for simulation-based education, particularly in low-resource settings.