Thesis-2004-Clemes.pdf (21.62 MB)
The influence of the menstrual cycle on visually-induced discomfort
thesis
posted on 2014-07-07, 09:07 authored by Stacy A. ClemesSince the introduction of immersive virtual reality (VR) equipment, a number of
studies have found that users can experience unpleasant side effects. A major focus
of VR research and development has been on head-mounted display (HMD) based
systems. Incorporation of an HMD provides the user with a sensation of immersion
and presence in the virtual environment (VE), and it has been these systems that have
attracted the most attention from both the media and human factors researchers over
the last ten to fifteen years. Health and safety concerns associated with the use of this
technology include symptoms experienced by users which resemble those of motion
sickness (for example, disorientation, pallor, stomach awareness and nausea) and
reports of visual discomfort, particularly eyestrain. The motion sickness-like
symptoms have been referred to as virtual simulation sickness (VSS), and VSS is
considered to be a form of visually-induced motion sickness.
Susceptibility to motion sickness varies immensely, however females are generally
regarded as being more susceptible than males to all forms of motion sickness, and it
has been suggested that this heightened susceptibility in females could be attributed to
the functioning of the female endocrine system. Changes to many of the body's
systems have been reported to occur over the menstrual cycle, and it is reasonable to
suggest that changes in susceptibility to nauseogenic visual stimuli may also occur.
The first piece of research conducted in this thesis examined the influence of the
menstrual cycle on susceptibility to VSS. 16 naturally cycling females were
immersed in a nauseogenic YE on specific days (5, 12, 19 and 26) of their menstrual
cycle, these days were chosen because they fall in line with peaks and troughs of
ovarian hormone levels. The menstrual cycle phase of participants was confirmed by
the measurement of salivary oestradiol and progesterone levels. The responses from
the naturally cycling females (the experimental group) were compared to those from
two control groups, consisting of 16 pre-menopausal females taking a combined
monophasic oral contraceptive, and 16 men. Susceptibility to VSS did vary over the
menstrual cycle, with susceptibility increasing on day 12, this was seen as both an
increase in symptom severity and a decrease in symptom onset time. No consistent
variation was seen in the females taking a combined monophasic oral contraceptive.
In addition to susceptibility to VSS changing over the menstrual cycle, variations in
reports of visual discomfort were also apparent, with visual discomfort also increasing
on day 12. As no previous research has investigated the influence of the menstrual
cycle on susceptibility to visual discomfort, two studies were conducted to determine
whether such a relationship exists in other situations. The first was a laboratory based
experiment whereby visual discomfort was induced by prolonged accommodative effort, and the second was a field study whereby reports of visual discomfort were
examined in individuals performing intensive VDU work. Unlike the changes in
visual discomfort seen over the menstrual cycle in females viewing a nauseogenic VE
through an HMD, no changes in visual discomfort were found over the menstruaJ
cycle when visual discomfort was induced by prolonged accommodative effort, or by
intensive VDU work. It was concluded from this research that the previously seen
changes in susceptibility to visual discomfort over the cycle, in females viewing a
nauseogenic VE, were not a consequence of susceptibility to visual discomfort
changing over the cycle. In the first experiment, susceptibility to VSS was seen to
increase on day 12, as manifest by an increase in the severity of nausea reported on
this day, and increases in general bodily discomfort. It is suggested that the change in
visual discomfort reported over the cycle is a consequence of these general changes
rather than having a specific ocular origin. This idea was supported in a fourth
experiment which examined symptom reports collected from 88 participants
immersed in a nauseogenic virtual environment at weekly intervals. A relationship
was found between the severity of symptoms of VSS reported and the amount of
visual discomfort reported.
History
School
- Sport, Exercise and Health Sciences
Publisher
© Stacy Anne ClemesPublication date
2004Notes
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.415921Language
- en