Combating VR Sickness
in Immersive Installation for Public Spaces, pt. 2/2

A few users self-reported discomfort, light hangover, mild pain and illness prior to testing. In all cases, their pre-test scores for VR Sickness symptoms were either mild or nonexistent. Although it would have been preferable to test on users with no symptoms presented in the pre-test questionnaire, none were evaluated to be too ill for trying VR, and no one stopped the installation out of discomfort.

The most reported pre-test symptoms were, in order of frequency: Fatigue, "Fullness of the Head", Eye Strain, General Discomfort, Difficulty Focusing Vision, Difficulty Concentrating, Headache, Blurred Vision and Sweating. These were therefore also expected to be high in the post-test questionnaire results.

Most were related to Oculomotor Disturbances and all symptoms were mild, except for Fatigue, Eye Strain and "Fullness of the Head", which were moderate in under 12% of cases. The majority of the pre-test symptoms could likely be attributed to studying or working hard before the end of the school semester and the holidays.

PREEXISTING SYMPTOMS:

Among the 42 users in the quantitative VR Sickness test, there was from the start a possible problem that a good portion of the group presented some symptoms already in the pre-test questionnaire. To get more accurate results, it would be a good idea to conduct the test with a larger group of healthy people.

If users had no preexisting symptoms before trying the installation, they also reported no or low symptoms in the post-test questionnaire. However, if they did have symptoms before, these usually increased in severity in the post-test questionnaire, particularly for Eye Strain, Dizziness with Eyes Open and Blurred Vision. It is logical that trying VR would be uncomfortable for an already unwell body.

The questionnaires were filled in on different times and days over a six day period. The time of day and the activities prior to the test would likely be a significant contributing factor to the differences in physical state of the users prior to starting the test.

INTERPRETING RESULTS:

Based on the results, Version 3.0 of the installation caused symptoms which might be related to VR Sickness in 21% of users, but none experienced severe enough symptoms to ask to stop the installation and test.

Oculomotor symptoms were the most widely reported. These show disturbances in visual processing, which often arise from not viewing the VR simulation clearly.

Disorientation and Nausea symptoms had low scores, and at least 1 of the symptoms (Sweating) could also be attributed to the tendency in users to walk around, kneel, reach and use their bodies to explore the playspace of the VR installation and thus might not have anything to do with VR Sickness.

It is difficult to assess how many of the symptoms were affected by Amaryllis VR : Ocean and how many were caused by preexisting or external factors, or the HMD itself. Particularly in the case of Oculomotor disturbances, it is worth noting that fogging of the VR lenses, light reflections from below the HMD, and wrong focus settings are common problems. For comparative data analysis it would be interesting to examine a comprehensive study of the HTC Vive HMD where a variety of different simulations are tested.

ISSUES WITH THE QUESTIONNAIRE:

A number of problems were experienced with the questionnaire itself. Firstly, the questions had to be translated to Danish for users
with poor English language skills, and secondly, the questions in the questionnaire are so brief, that some of them may have been misinterpreted by users. For example, the test does not contain precise explanations of what is meant by the different symptoms, and many could be misinterpreted.
One user thought that “Stomach Awareness” could include menstrual cramps, and it was necessary to add the word “vision” to the “Difficulty Focusing” question, as it was unclear whether the user was being asked about their eyes or their concentration in general.

Importantly, the users who noted symptoms related to Disorientation, such as Vertigo, explained that their symptoms were caused by the rising waves of the Ocean in the installation, giving them a feeling of "floating", but that the induction of Vertigo was NOT a negative symptom for them. The wording of the questionnaire should thus perhaps be more precise in asking of users about negative symptoms rather than something that might contribute to a positive feeling of presence in VR.

Arguably, the most important thing to note is that the questionnaire was developed for the US Navy for military aviators -a population of people less prone to experience the symptoms of VR Sickness. This greatly influences the suggested categorization of symptoms into mild, medium or severe. Symptoms which may seem negligible to aviators might indeed be felt as severe to non-aviators.

SELF-REPORTING:

The reliability and accuracy of the data in questionnaires is not fully accurate, in that people’s accounts of what they feel may not always correspond to what they actually feel. Furthermore, the reaction of the same user may vary every time they use VR, e.g. because of adaptation to the technology and changes in their health and general fitness from day to day.

PRIMING:

Finally, it is important to note the problem of priming. Theoretically, it is possible that having users fill in a questionnaire of symptoms before testing may have resulted in them feeling more aware of their symptoms, which could result in higher reports of symptoms post-test.
In the future, it would be ideal to only select users for the test if they report no symptoms in the pre-test questionnaire. This was not possible due to limited time and availability.