"One of the problems we've got is low achievement in Northland, and if a third of our kids are walking around needing glasses that perhaps might be an indication why," he said.
The Ministry of Health's chief adviser of child and youth health, Pat Tuohy, said current testing, which included at-birth screening, B4 School Check vision screening for amblyopia (lazy eye), and Year 7 vision checks at school, which included distance visual acuity screening, was sufficient, however.
"They are sufficient for finding children with amblyopia, however it's important they are regularly reviewed and updated as new evidence is made available," he said.
"There's no evidence that more frequent screening leads to better health outcomes."
The undiagnosed conditions found in Whangarei ranged from hyperopia (long sightedness) and astigmatism ('rugby ball-shaped' eyes) to myopia (short sightedness) and binocular imbalances (where the eye muscles are under strain with close work).
Dr Tuohy said the statistics were not surprising, as B4 School Checks do not specifically screen for those conditions, as they did not lead to amblyopia. Many of them would have no impact on a child's health and development.
Mr Newman was unimpressed.
"They'll have headaches, they won't be able to see. Where the hell is common sense? If a kid can't see, then they don't learn," he said.
"I think it clearly points to the current testing regime in primary schools failing. Every child needs to be checked regularly at least twice during their primary school time, in schools. It should be a matter of right."
A spokesperson for Lowes & Partners Optometrists said one of the reasons eye conditions may have gone unidentified was because children did not know that their eyesight wasn't normal.