Supplementary Material for: Surgical Videos with Synchronised Vertical 2-Split Screens Recording the Surgeons' Hand Movement

<b><i>Purpose:</i></b> To improve the state-of-the-art teaching system by creating surgical videos with synchronised vertical 2-split screens. <b><i>Methods:</i></b> An ultra-compact, wide-angle point-of-view camcorder (HX-A1, Panasonic) was mounted on the surgical microscope focusing mostly on the surgeons' hand movements. In combination with the regular surgical videos obtained from the CCD camera in the surgical microscope, synchronised vertical 2-split-screen surgical videos were generated with the video-editing software. <b><i>Results:</i></b> Using synchronised vertical 2-split-screen videos, residents of the ophthalmology department could watch and learn how assistant surgeons controlled the eyeball, while the main surgeons performed scleral buckling surgery. In vitrectomy, the synchronised vertical 2-split-screen videos showed the surgeons' hands holding the instruments and moving roughly and boldly, in contrast to the very delicate movements of the vitrectomy instruments inside the eye. <b><i>Conclusions:</i></b> Synchronised vertical 2-split-screen surgical videos are beneficial for the education of young surgical trainees when learning surgical skills including the surgeons' hand movements.