Austin Manning has received life-changing surgery in America at St Louis Children Hospital.

His doctor was so positive about Austin's future he decided to do another procedure to stop his legs from scissoring as he walks.

Austin will start light physio this week before starting several weeks on intense physio.

The 8-year-old is one of 7000 in New Zealand with cerebral palsy. He suffers from periventricular leukomalacia (a brain injury), asymmetric spastic quadriplegia, developmental delay and has problems with his vision.

There are no operations available in New Zealand to relieve the spasticity of his limbs caused by the cerebral palsy. However, the surgery, which reduces muscle stiffness, is offered by Dr Park at St Louis Children's Hospital.

Nine other New Zealand children have had the operation at the same hospital and all had been successful.

More than $15,000 was raised for Austin's trip to America for the surgeries, as well as a major store getting behind the cause.

Specsavers Bayfair and Tauranga got behind the cause and donated $10 from every pair of children's glasses sold in-store, as well as throwing a fun day with face painting, balloon art and other activities.

Specsavers retail director Glenn Dunkerley said Austin had been coming into the store since he was a baby and he and others in the store had got to know the family really well.

The Tauranga Bridge Club donated $2885 to Austin's family while his primary, St Thomas More Catholic School, had raised $1785 from a bake sale.

Austin's mum Helen Manning said the school's bake sales normally raised about $600 so was thrilled with the amount raised for Austin.

"One man walked straight up to Thomas [Austin's brother] and gave him $200 and said, 'This is for your brother'.

"It's just amazing. It's mind blowing. We can't believe how many wonderful people there are out there and how many people you don't know are so willing to get behind Austin and his cause."

Ms Manning said that, after a traumatic birth with her second son, everything appeared normal in Austin's first few months. Yet, at 6 months old, Austin's eyes were going cross-eyed and rolling into the back of his head.

Plunket told her it would correct itself but it never did, she said.

"It got worse, we went to the GP, who referred us on to the eye specialist, who looked at his eyes and said there was nothing wrong with them and said it must be coming from his brain.

"It was the worst day of my life. We got a speedy appointment with a pediatrician, who offered an urgent MRI. He had brain damage. The worst thing was we didn't know what he was going to be able to do, a waiting game."

Learning her son had brain damage was devastating, she said.

"But having said that, he is such a pleasure. He is such a joy, a beautiful happy little boy. I think the way he is, that is what has made him the child he is."