Table 3.
Qualitative evaluation using a 5-point Likert questionnaire. Central tendency summarized using median with dispersion measured by interquartile range (25°∼75°).
| Item | Questionnaire items | Median (25°∼75°) | P value (Eng. vs Clin.) | |||
|---|---|---|---|---|---|---|
| Engineers | Clinicians | All | ||||
| Visual and audio perception | A | The virtual content is correctly aligned to the real objects. | 5 (5∼4) | 4 (5∼3.75) | 5 (5∼4) | 0.280 |
| B | It is easy to perceive the spatial relationships between real and virtual objects. | 5 (5∼4) | 4.5 (5∼4) | 5 (5∼4) | 0.739 | |
| C | I did not notice motion of virtual content. | 4 (5∼4) | 4 (5∼3.75) | 4 (5∼4) | 0.436 | |
| D | I did not notice latency (lag, delay) between virtual content and objects real. | 4.5 (5∼4) | 4 (5∼4) | 4 (5∼4) | 0.353 | |
| E | I did not notice jitter (high-frequency shaking of the virtual content). | 4 (5∼2.75) | 4 (4.75∼3.75) | 4 (5∼3) | 0.912 | |
| F | I did not experience double vision. | 4.5 (5∼4) | 5 (5∼4) | 5 (5∼4) | 0.481 | |
| G | I did not notice colour separation. | 5 (5∼3.75) | 5 (5∼4.75) | 5 (5∼4) | 0.393 | |
| H | The field of view (FOV) is adequate for the application. | 4 (4.25∼2.75) | 3.5 (4∼2.0) | 4 (4∼2.25) | 0.579 | |
| I | Spatial sounds make the experience more immersive. | 4 (5∼4) | 5 (5∼3.75) | 4.5 (5∼4) | 0.796 | |
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| ||||||
| Interaction and ergonomics | J | I did not experience postural discomfort during the application. | 4 (4.25∼3.75) | 3 (4 ∼ 2) | 4 (4∼2.25) | 0.029 |
| K | I did not experience visual fatigue (eyestrain, dried mucus or tears around the eyelids, discomfort when the eyes are open, hot eyes, and headaches). | 4 (4.25∼2.75) | 2.5 (4.25∼2) | 3.5 (4∼2) | 0.393 | |
| L | Gesture interaction is easy and intuitive. | 4.5 (5∼4) | 5 (5∼4) | 5 (5∼4) | 0.631 | |
| M | Voice interaction is easy and intuitive. | 4 (5∼4) | 5 (5∼4) | 4.5 (5∼4) | 0.481 | |
| N | It is easy to aligning the surgical instrument to the AR viewfinders. | 5 (5∼4) | 3 (4∼2) | 4 (5∼3) | 0.023 | |
No statistically significant differences were found between groups with different experience with AR (Item A p=0.126; Item B p=0.219; Item C p=0.789; Item D p=0.653; Item E p=0.590; Item F p=0.085; Item G p=0.204; Item H p=0.466; Item I p=0.196; Item J p=0.204; Item K p=0.246; Item L p=0.469; Item M p=0.284; Item N p=0.193) and HoloLens (Item A p=0.606; Item B p=0.662; Item C p=0.772; Item D p=0.326; Item E p=0.986; Item F p=0.986; Item G p=0.772; Item H p=0.499; Item I p=0.364, item J p=0.470; Item K p=0.508; Item L p=0.739; Item M p=0.187; Item N p=0.760).