Efficacy of 3D-printed eye model to enhance retinoscopy skills

We conducted a prospective study to evaluate the efficacy of simulation-based education using a three-dimensional (3D)-printed schematic eye model in improving the retinoscopy refraction skills of medical students. A schematic eye model was printed using a fused deposition modeling-based 3D printer. Twenty medical students randomized into 3D (n = 10) and control (n = 10) groups received a 1-h lecture on the principles and methods of manifest refraction and were shown how to use the retinoscope and sciascope bars. The 3D group additionally attended a tutorial on the schematic eye. Both groups performed refractive examinations on four eyes of volunteer patients, and the results were recorded as a baseline. Instructor feedback and refraction practice was provided with the 3D group or with control group. To account for subject fatigue, patients spent no more than 8 min on the examination. After a 1-h break to allow for fatigue and familiarity, refraction tests were repeated on four randomly selected eyes of patients. Students' refraction readings were compared with the autorefractor values using a spherical equivalent value and blur strength. All participants measured the time required to complete the refraction test and reported their subjective confidence in the results of each refraction test. Refractive errors before and after training did not differ between the control and 3D groups, with a significant improvement in errors observed in both groups (p = 0.005 and 0.008, respectively). The time to complete refraction before and after training did not differ between the two groups, both of which showed a significant reduction in time (p = 0.005 and 0.028, respectively). Pre- and post-training confidence scores for the accuracy of each refraction on a 10-point Likert scale were not significantly different. However, when comparing score changes between pre- and post-training, only the control group showed a significant increase in confidence (p = 0.005). Tests for the non-inferiority of refractive errors after training indicated that the 3D group was non-inferior to the control group. In conclusion, training in retinoscopy refraction skills using a 3D-printed eye model resulted in significant improvement in accuracy and speed compared to practice with real patients. Except for better confidence in the control group, schematic eye model training was not inferior to practice with real patients.