More than 800 people have had the device implanted since Florence Woodward became the first recipient 25 years ago. This month, she returned to Auckland and met surgeons Bill Baber and Ron Goodey - but alongside the cake and celebrations was an unspoken undertone.
The small electronic miracle that is the cochlear implant should, one would think, be welcomed as one of the great medical inventions of the past century, but it has received a mixed reception from the deaf community.
One faction supports traditional sign language and lip-reading over cochlear implants because it sees implants as killing off their beloved deaf community.
And that faction's opposition can be fierce.
Some argue the surgical intervention erodes the proud identity of the deaf and that children should be given the choice of whether to learn sign language or have to spend years adapting to the hearing world.
The most radical adherents of "manualism" over "oralism" even accuse their opponents of a kind of "cultural genocide".
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Cochlear implants are surgically placed under the skin behind the ear. The external part of the device includes one or more microphones, a speech processor and a transmitter.
The internal part features a receiver and stimulator which converts signals into electric impulses, sending them to electrodes in the cochlea which then make their way to the brain through the auditory nerve system.
Cairns believes he lost his hearing partly as a result of time spent in a noisy freezing works as a young man, working with machinery without wearing ear protectors, but thinks there could also be a genetic factor.
"I lost listening to music when I was 18. I was a big rock 'n' roll fan and the Beatles had just come on the scene. I lost 35 or 40 years."
His increasing deafness didn't prevent him thumping boundaries with his bat Excalibur but, after his sports career ended, the disability stopped him taking part in many activities, including being a cricket selector.
He had never heard of cochlear implants but, by the time he had just 7 per cent of hearing left, he was told by a doctor he should try it and has never looked back.
"I spoke to Chris on the phone for the first time ever. I can take part in groups now, I can listen and hear - it's 100 per cent better. But the thing that grates is, to qualify for an implant you have to be almost deaf."
Earlier this year, his granddaughter was diagnosed as profoundly deaf, something Cairns somehow believed was his fault, but father Chris immediately decided to get implants for Isabel. Watching the baby as she heard sound for the first time was a special moment for the proud grandfather. "It was brilliant," says Cairns. "They filmed her at the time and the fright she got was unreal."
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Josh Foreman, the 20-year-old son of prominent businesswoman Dianne Foreman, was also born profoundly deaf and had his first cochlear implant at the age of 2. He recalls learning to use the implant, first at the National Audiology Centre then at the Hearing House in Auckland, as an "arduous process".
"At times, I just complained and kicked and screamed and shouted. My mum says she would have to repeat every word 1000 times. It's about constant repetition of words, trying to get the mouthing right and create the words. But it all paid off well. I think it's a fantastic thing.
"It enables you to participate in a hearing world. It's fabulous."
Foreman is now taking physical education at Auckland University. He has had a second implant, but says it can be difficult to get two of them to work perfectly together when they are put in years apart.
The extraordinary thing about these men is that, speaking to them on the phone, it is impossible to tell that they are almost completely deaf. They can hear and speak as well as anyone.
Another thing they have in common is that they have experienced the depth of feeling about cochlear implants within the deaf community.
"I certainly see that division," says Foreman. "They say it's against nature and you should be like you are - it's better to be deaf. If that's the way they want to be that's fine but, by having an implant, I am gaining something that is positive. I would always say consider that option."
Cairns can't comprehend why there is such a controversy. "Some groups detest each other," he says. "I don't understand it. Something about keeping sign language alive. For the life of me, I can't believe a parent would keep their child in a silent world when, with CI, they can lead a full life."
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But the issue is a challenging one for many deaf people. One American parent went to court when told she had to offer her deaf children cochlear implants to improve their lives.
This posting by an anonymous New Zealand mother on an international website sums up the dilemma of some deaf parents. "We found out our daughter is severely to profoundly deaf at the age of 4 weeks old.
"I am an interpreter and my husband is deaf and we, of course, are signing to her. We have been offered a cochlear implant for her.
"We don't really want her to have one because of our strong connection to the deaf community and our beliefs, but we live in New Zealand and there aren't any other babies that will be growing up signing with her so I am afraid that she will have no peers."
Deaf Aotearoa president Kellye Bensley was raised to speak and did not fully embrace sign language until she was 18. "Now I prefer to sign, if it is in public, because I feel the information that I want to bring forth is better communicated that way. I have never been implanted nor worn hearing aids."
But Bensley says her organisation is not opposed to cochlear implants, although "initially there was a great deal of misunderstanding and fear. "More deaf people are accepting implants and also confirming their status as deaf people valuing sign language and deaf culture."
Bensley does not view the implant versus sign language issue as a "debate" and Deaf Aotearoa's focus is ensuring all deaf children have access to sign language and deaf culture.
"We know deaf youth who have grown up with sign language and a cochlear implant," she says. "They are well-adjusted, confident individuals with fantastic futures ahead of them.
"Some people do enjoy having access to sounds, hearing birds and so on. As deaf people are visual people, sign language is a natural language for communication. It is a rich language and we are proud that our language is one of New Zealand's three official languages."
The deaf community has mobilised itself politically, modelling itself on the American civil rights movement or the gay rights activism. In 2006, New Zealand was the first country to adopt sign language as an official language.
According to that year's census, nearly 25,000 people use NZ sign language. The Government now uses sign language interpreters in Parliament and for major speeches and announcements - including, notably, briefings in the aftermath of the Christchurch earthquake in February. And last week, special votes elevated Green candidate Mojo Mathers into Parliament as New Zealand's first deaf MP.
But statistics also show that more deaf families are seeking cochlear implants, especially for babies and children. Technology, it seems, is posing a challenge to the customs and culture of the deaf in New Zealand.
Bensley says: "We know that implants will change the dynamics of the community over time."
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CURE COMES SLOWLY
Learning that her second son, Aaron, was profoundly deaf came "like a bolt out of the blue" for Auckland mother Shona Gilby.
She says neither she nor her husband, Mike, have any deafness in their families - but screening showed they are both carriers of the Connexin 26 gene, which dramatically increases the chance of having a deaf child.
And so it proved when daughter Isla was also born deaf. "It was pretty devastating, really," says Gilby. "We knew the path ahead wasn't going to be easy."
After researching the options available, they made a "definite decision" to seek cochlear implant treatment. Health authorities only fund one implant per person. Insurance paid for a third implant, but they had to find $45,000 to ensure both children had hearing in both ears.
Aaron, 4, received his implants at 17 months and 3-year-old Isla at 5 months. Initially, it was traumatic for all of them when the implants were switched on.
"It was obvious that they were hearing, but it wasn't exactly pleasant for them," says Gilby. "Their response was to cry at the start. You feel like a terrible parent for forcing them to wear this device when they are ripping it off."
And the decision to opt for transplants attracted unexpected criticism. "I had people coming up to me and making judgments as to whether Aaron should get an implant, saying we had no right to do it until he was 18. People said we were taking away his culture. I find that hard to understand."
Learning to understand the strange noises coming through the implant and to be able to speak is a long and sometimes frustrating journey.
The children have been doing therapy and audiology at the Hearing House in Auckland for four years and the process is never-ending at home.
"You have week after week of therapy and activities at home and you are wondering if it's really working," says Gilby.
"It's only when you start getting the sounds and the first babbles and words that you realise it is working."
The children are now doing as well or better than others of their age in listening skills and Aaron is attending mainstream kindergarten.
Gilby is still amazed when she sees Aaron and Isla playing and chatting together. "They are both deaf, yet they are having full conversations. It just blows me away."
The Hearing House relies on independent funding to provide its services to deaf children. www.hearinghouse.co.nz
