Secondary outcome measures
nausea, headache
DOUBLE VISION
The perceived visual quality, body-part discomfort, and subjective evaluation of the user experience was evaluated by a survey after the trial of each loupe and at the end of the whole experiment.The perceived visual quality was measured by a survey that contains indirect and direct comparison after the use of each pair of loupes. For the indirect comparison, a 5-point Likert-type scale (from –2, very bad, to +2, very good) was employed to measure the overall visual function, image brightness, spatial orientation, and image depth, and a 4-point scale (from –3, severe, to 0, nothing) was used for assessing double vision, headache, and nausea (The perceived discomfort was assessed by Borg’s CR-10 scale for the neck, right shoulder, left shoulder, upper back, and lower back (Subjective evaluation of the user experience contained two parts – a single-choice question on the preferred loupes and an open question asking for any comments on the three pairs of loupes were included (see Additionally, surgical performance was assessed by task completion time and counting the number of surgical errors. The errors were rated by two independent surgeon examiners. An error was counted when the participant missed one dot or did not go through one dot in the suture for BS and when the participant cut outside the black line for PC. Errors were not counted in PT.