Auckland Cataract Study Going Strong
Auckland’s elderly are providing
clues to some of the secrets of the world’s most common cause of
blindness – cataracts.
Professor Charles McGhee, the Chair of
Ophthalmology at The University of Auckland’s Faculty of Medical and
Health Science, leads a team studying cataracts in the Auckland
metropolitan area. The research began in 1999 with a study based in the
Rodney district, since then the project has evolved and led to a variety
of spin-off projects.
“Cataracts are not only a common
cause of blindness, but are thought to indirectly shorten people’s
lives through a reduced quality of life and the risks of visual
impairment.”
“Cataracts are a huge problem
throughout the world, and although New Zealand has representative
numbers of people with the condition, the cases do seem to be more
severe. This is partly connected to the high rate of diabetes in New
Zealand, particularly amongst Maori and Pacific Island people, which
leads to earlier diabetic cataracts.”
Professor McGhee, who is also the
Clinical Director in Ophthalmology for Auckland Healthcare, says New
Zealand has a high rate of hard nuclear cataracts, the most severe form
of cataracts, which are generally less common in developed countries.
“When I worked in Scotland I’d
probably see one such advanced hard cataract a month, whereas here I see
three or four a week. Partly this is because in the UK and the USA
people present with their cataract at a much earlier stage,” he says.
The Auckland Cataract Study started in
1999 and follows 500 people from the Auckland region. The research has
highlighted the link between diabetes and cataracts and shown that some
people are more likely to have the condition than others. Women are
generally more susceptible because of longer lives, as are diabetics and
Maori and Pacific Island people.
The subjects also had a high level of
other diseases: “More than half of those in the study had high blood
pressure, or diabetes, or they’d had a stroke in the past. But this is
partly a manifestation of their age, as the mean age of the participants
was 77,” he says.
Initially the participants had been on
waiting lists for a cataract operation for up to three years –
something Professor McGhee and his team quickly turned around.
“In a joint initiative, we assessed
patients and performed 500 cataract operations between the university
and hospital ophthalmology departments and got the waiting list down to
under six months. A spin-off from that was being able to involve
patients in ongoing research into the causes of cataract and the
outcomes of contemporary no stitch small incision surgery,” he says.
The participants have been closely
followed post operation and it was found that 98.5 percent of patients
had significant visual improvement post operation. They also reported a
significantly improved quality of life.
The team is now looking to extend the
study to further define factors that predispose people to cataracts.
“We are using the lens tissue that is
routinely removed to look at the nature of the cataract so that we can
work out the genetic protein, or structure of the cataract. That could
theoretically help us to develop a medicinal or drug cure rather than a
surgical operation for cataracts in the future,” Professor McGhee
says.
The team is also examining the
intra-ocular lenses (implants) which replace the cataract to enable the
person to see. Professor McGhee says it is important to discover whether
implants can be improved to minimise aberrations.
“The human eye has evolved over
millions of years to try and minimise distortions and we are replacing
that with a man-made acrylic lens which will obviously have its own
minor optical distortions.”
“The Auckland study, which is the
largest of its kind ever undertaken in New Zealand, is providing us with
some excellent data for trying to come up with more effective ways of
treating cataracts,” Professor McGhee says.
Six senior clinical and laboratory
researchers continue to be involved in the Auckland Cataract Study at
The University of Auckland.
