Thousands of children who can't see or hear properly are falling through the cracks because newborn and preschool checks only look for more serious issues.
As a result, children are going through primary school struggling to learn and thinking they are dumb - rather than knowing there's a reason they can't read.
A recent University of Auckland survey revealed one in 10 kids aged 8 and 9 need glasses but don't have them.
Our findings show:
• The Ministry of Health under-recording the number of 4-year-olds screened through the B4 School Checks for vision and hearing.
• A number of concerning eye and ear problems are not included in the before school screening, meaning children who are struggling to see or hear may be missed.
• Around 20 per cent of children are screened six months after they are meant to be meaning referrals for follow up assessment aren't being completed before school.
• Vision concerns are most prevalent in Asian children (16 per cent).
• Hearing concerns are most common in Pasifika children (17 per cent) then Māori (14 per cent).
Screentime for kids: Warning over 'alarming' toll on young Kiwi pre-schoolers
University of Auckland's Growing Up in New Zealand study director Susan Morton said there was concern the B4SCs may be under-reporting issues.
This was worrying because it was underestimating need and widening existing health inequalities, she said.
Of particular concern, the Ministry of Health only records the children who are signed up to a primary health organisation (PHO), which could be a GP or another community health provider- they are "the eligible population". Researchers estimate this to be around 96 per cent of 4-year-olds living in New Zealand.
Those children who are not signed up to a PHO, which is likely to be the most deprived population, are not included in the ministry's data collection.
The Herald calculated this to be at least 2440 children each year, based on government data that showed about 61,000 children were born in 2015.
University of Auckland optometry and vision science researcher Lisa Silva said there was also a gap in the system because there was no mandatory checking of children's hearing and vision after the age of 4.
At age 11 or 12 the Ministry of Health funds vision and hearing checks but parents need to be proactive about this.
This is concerning because children can develop problems after the age of 4 and as there's no national testing then it's often not picked up until high school or sometimes never, Silva said.
She has been leading a five-year survey showing one in 10 kids need glasses but don't have them.
Of around 3500 children included in this year's testing, 20 per cent of the children screened failed and were sent home with a note to visit the optometrist.
Of those, half went on to get glasses.
For 11-year-old Ethan, whose poor vision wasn't detected in the B4 School Check, this meant years of hating school and thinking "he was too dumb to learn".
The only reason he was picked up later was due to the University of Auckland screening.
Up until the age of 9, Ethan Harpur hated school.
He would tell his mum, "I hate reading and writing, I'm just too dumb and I can't do it."
His mother, Diane Harpur, said she never suspected the now 11-year-old was having trouble with his vision because he passed his B4 School Checks with flying colours.
"You don't think to take him for more testing because he'd passed his B4 School Checks so you assume it's not that," Harpur said.
She said watching him struggle was "really hard as a parent".
"He had lost a lot of confidence. It's difficult because you start thinking, 'why is he not picking up the skills like his older sibling?' And you hate to see your child with low self-esteem," Harpur said.
The Mt Roskill Primary School student was screened through the University of Auckland study when he was 9.
"They picked up his poor vision straight away, it was amazing. If it hadn't have happened then we wouldn't have known."
Harpur said Ethan's sight wasn't just mildly bad - "he was given quite a strong prescription".
Since getting his glasses two years ago, his confidence has picked up and his reading has improved dramatically.
"I like reading and writing and school is a lot easier than it was before I had glasses," Ethan told the Herald.
And he's not alone. Silva said hundreds had been picked up in the study and it had shown a huge effect on their learning.
A 12-year-old boy who had been "acting out" in the classroom was discovered to have "seriously poor vision". It's likely his frustration at not being able to see was causing his behaviour problems and struggle to learn, Silva said.
Tips for parents
Impact on learning:
A 6-year-old girl jumped 12 reading levels within one school term after she started wearing glasses, Nga Iwi School teacher Glenda Shipman told the Herald.
Sangster said poor vision and hearing can have a significant effect on children's learning.
"One thing often missed in the B4 School Checks is binocular vision, which is how the eyes work together, and if that's affected it can have a huge impact on their reading.
"If children are struggling to perform, their vision must be considered and often it's not," Sangster said.
Mt Roskill Primary was one of a handful of Auckland schools participating in the University of Auckland survey.
The school's learning support teacher, Sonya Lamb, said about 28 of their students had ended up getting glasses each year since they first started taking part in the study.
She said the school set up its own system in collaboration with the university to ensure all children were picked up.
"When I started working here I would get referrals from teachers who were concerned about a child's reading ability and it became really simple that most were because of their vision."
If Lamb was concerned about the child's vision she would refer them to the university and if it was confirmed they needed glasses but the parents couldn't afford them, the school would pay.
Lamb said children slipping through the cracks for poor vision was a huge issue that needed to be addressed nationwide.
"There's a big gap because after B4 School Checks there's no more mandatory testing and as a parent, it's like you don't know what you don't know so it gets missed."
Tips for parents
Experts said the reasons children were still slipping through the cracks of the system included the cost of treatment, poor access to testing in low socio-economic areas and the quality of screening.
Ministry of Health data showed that in the past year 2967 children out of about 59,000 had failed the B4SC for vision and were referred for further assessment. For hearing, 2763 kids had failed and were referred for further assessment.
Authors of a University of Otago 2018 study, published in New Zealand Medical Journal, criticised the data collection for not showing the effects of the referrals and whether it had a positive result for these children.
They also said not all children who met the referral criteria were referred to other health services and the reasons for this needed further investigation.
Sangster said it was all very well identifying a child has a problem but the next challenge is ensuring they get treated.
After a meeting the NZOA had with Parliament's health select committee, the Children's Spectacle Subsidy was introduced in 2010 to help families with the cost of certain vision services for eligible children 15 years of age and under.
To be eligible parents must have a valid Community Services Card which shows they are on a low to middle income and cannot afford it.
The total subsidy amount available each year to a child until they turn 16 years old is $287.50 including GST.
Of the $287.50, a maximum of $138 can be used toward frames. Additional funding of $51.11 is available if the child requires adult-size frames.
In New Zealand, children's frames and lenses cost between $60 to $300 in total.
Last year, 26,660 claims for the subsidy were approved. Already this year, 12,951 have been approved.
"It's proved to be very effective, especially for the low socio-economic areas, but the number of claims coming through is just the tip of the iceberg," Sangster said.
He said there were still a lot of people who weren't accessing treatment.
"It boils down to funding, it is all very well expecting parents to take their child to an optometry clinic but often they can't afford it or don't know there is a problem."
This echoed calls from Mt Roskill Primary School saying screening in schools needed to be done nationwide and a system needed to be in place for teachers to be able to refer for free testing.
In the United States, all children are required to get their eyes and ears tested by an optometrist and audiologist before they start school.
In New Zealand children are screened by vision and hearing technicians who only test for serious issues such as lazy eye and glue ear and less severe issues aren't getting picked up. The Government is currently reviewing the effectiveness of this.
What needs to change?
Experts interviewed said a lot more needed to be done to make sure all New Zealand children's eyes and ears were working effectively. This included:
• Screening of vision and hearing at an older age, not just before school.
• A nationwide funded referral process for teachers to be able to flag students with hearing or vision concerns.
• Instead of spending money on behavioural learning programmes, invest more money into better testing and treating of children's vision and hearing. "It's a long-term investment."
• Funding for optometrists and audiologists to do the screening at school, rather than technicians.
• Widen the eligibility for the children's spectacle subsidy.
Monday: Hearing and vision
Tuesday: Child obesity
Wednesday: Breathing problems
Thursday: Behavioural problems
Friday: Diseases on the rise as immunisations rates drop