Govert Veldhuijzen

143 Virtual reality distraction for patients to relieve pain and discomfort during colonoscopy towards a better customized VR system instead of the used off-the-shelf VR sets to resolve this issue. 36,37 Indeed, patients reported that the effect of the VR distraction was less immersive probably because of the content showed. Other studies found that content is relevant to the level of distraction 12,15 . Low pixel resolution of the VR content influenced the experience of at least one participant and previous studies showed that low resolution videos reduce the quality of experience. 38 The literature on VR for patients in endoscopy is scarce. A retrospective study of 190 patients found that VR allowed unsedated transnasal gastroscopy in children and young adults. In this study VR assisted transnasal gastroscopy was safe and cost-effective for staging of eosinophilic esophagitis. 39 The argument has been made that VR allows avoiding sedation for colonoscopy which fuels patients’ experience. 40 Therefore it is probable that in selected patients VR during colonoscopy will be the preferred option. 29 Strengths and limitations Our study was performed in a real life setting and selected a representative sample of patient which adds to the external validity of the study. By using Samsung Gear VR to provide distraction, we have chosen a widely available and relatively inexpensive VR device, enhancing the generalizability of the study. Our study also comes with limitations. First, the small sample size does not allow robust statements on clinically relevant endpoints like reducing anxiety or pain or improving patient satisfaction. Also, recent literature points out that our sample size computation carries the risk of overestimation of the required sample size when designing a main trial to confirm our results. 41 Secondly, the physicians who performed the procedure were not blinded, because the patients in the control group did not wear VR glasses. Although we did not observe a difference in administration of drugs in the control group and intervention group, this could have affected the choice and dose of sedatives. The ideal set-up is a direct comparison of sedation vs VR, instead of VR combined with sedation as done in our pilot. We used patient reported measures for pain and comfort after patients were recovering from sedative administration. The post amnesia effect of midazolam might have had some effect, but the Gloucester scale rated by the nursing staff revealed no differences between groups. Because of the low costs of the VR device, VR distraction may easily be deployed in colonoscopy. There are several technical shortcomings such as low resolution, 7