Auckland Cataract Study Going Strong

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.

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