Imported sunglasses could contain poor UV light filters leading to eye damage, the Association of Optometrists has warned.
A Brazilian-led study published in Biomedical Engineering Online has found the ageing test used to determine safety standards for sunglasses is not sufficient to ensure protection for the average length of time a person keeps a pair of sunglasses.
Researchers want sunglasses' UV light filters to be more rigorously tested, and say the current test is unrealistic, especially for people living in the Southern Hemisphere.
Association of Optometrists president Callum Milburn said the sunglasses standard testing should be mandatory in New Zealand, and the testing regime needed improvement.
"It will be disappointing for New Zealanders to know that sunglasses sold here are not tested to ensure they meet even the current standard.
The Association would welcome compliance with the AS/NZS 1067 standard for sunglasses and eye protection becoming mandatory to protect New Zealanders' eyes.
"The lenses need to provide adequate UV filters because sun damage can lead to cataracts, cancers, retina damage and perhaps even blindness. Much of the tissue damage from UV radiation is irreversible making prevention an important consideration for people.
"Preventing loss of vision should not be left to chance and the hope that your sunglasses are providing sufficient protection. New Zealand already has a high burden of vision loss and blindness," Mr Milburn said.
He said the New Zealand Disability Survey showed that number of people with vision impairment that could not be corrected by glasses or contact lenses doubled from 81,000 in 2006 to 168,000 in 2013.
"Vision impairment carries a heavy burden for society, especially as people age and they lose their independence and quality of life.
"In advocating for a mandatory standard for sunglasses, the association would also encourage that research like this be taken into account to ensure the best protection for New Zealanders."
There was no guarantee sunglasses in New Zealand should meet the acceptable standard, whereas in Australia they must to be defined as sunglasses, he said.
"You're relying on the person selling the sunglasses to be selling you to a standard so some people are motivated by eye health and some people are motivated by sales," he said.
"Some sunglasses are just made for wearing outside, some are made for a work environment, but if it's compliant with the AS/NZS106 that will dictate whether it meets the UV requirements.
"Not all sunglasses would be say 85 percent filter. Some would only be 60 or 20 percent, but they might still provide 100 percent UV protection - the important factor is the UV protection.
"You just have to look at our skin cancer rates to know we are exposed to a lot of UV and the eyes are no different," said Mr Milburn.