25 October 2005
Study to investigate sleep disturbances in blind and vision-impaired.
Researchers from The University of Auckland are about to begin a study to find how to better help blind and
vision-impaired people manage the chronic sleeping disorders many face.
Dr Guy Warman, a lecturer at the Department of Anaesthesiology in the Faculty of Medical and Health Sciences is leading
the study. He says they will investigate the prevalence of disturbances in the circadian rhythms of blind people, and
how the hormone melatonin is being used to treat this.
“Although the primary problem associated with blindness is loss of vision, a secondary problem which can have a major
impact on the health and well-being of blind people is the disruption of their sleep-wake cycles. This problem results
from the inability of light to adjust their internal biological clock to a period 24 hours. As a result they can have
disrupted sleep at night”.
The study is funded by a grant from the Health Research Council of New Zealand and is being carried out in association
with the Royal New Zealand Foundation of the Blind (RNZFB).
Chris Orr, an RNZFB member who has been blind for the past 30 years, is likely to be one of the benefactors of the
study. He has been suffering disrupted sleep since he lost all sight and conscious light perception in an accident 30
“I regularly wake at around 1.30 in the morning, and then can’t get back to sleep. Over the years I have accepted it,
and now just listen to the radio or read when I am awake at night. But I would obviously prefer a more regular sleep
“When I first became blind, no one could offer a good explanation for the problem. It is only in recent years that we
have come to understand the underlying cause of the problem.”
Dr Warman says the problem is caused because the human circadian clock (or body clock) ticks with a slightly longer than
a 24-hour day.
“Light perception in sighted people allows them to make daily adjustments to this which keeps their sleep patterns in
line. However those with poor or no light perception can find their body clock, and thus their sleep patterns
Melatonin has been successfully used to treat this problem when given at the correct dose and time of the day. Despite
the success of melatonin treatment, there is very little information on the overall prevalence of sleep timing problems
in blind and vision-impaired people and whether people suffering from circadian disturbances are using melatonin in an
Dr Warman says New Zealand is an ideal country for this sort of study.
“Unlike in many other countries, the RNZFB has a comprehensive list of our blind and vision impaired population. By
working with the RNZFB and its members who are keen to help out, we will be able to gain a good understanding of the
extent of sleep timing disorders, and the number of people taking melatonin to combat them.”
Potential health outcomes of this study include programmes to educate practitioners, pharmacists and patients on the
appropriate and effective use of melatonin.