Most cheap sunglasses sold by fashion retailers on the high street do not meet EU safety standards according to latest testing.
The Optical Appliances Testing Service at City University London also found little correlation between investment and quality at a price range between £1 and £25.
Of the 100 sunglasses it tested last month, 57 pairs failed EU standards.
Failures ranged from the uniformity of transmittance to the robustness of the lenses, with ball drop, uniformity and scatter tests all carried out.
In total, 49 per cent of all failures were on the drop ball impact test, which involves dropping a metal ball of specific dimensions from a specified height on the lens.
Twenty per cent of the sunglasses failed the uniformity test, when there was a transmittance difference between the two lenses of more than 20 per cent, while 14 per cent of the sunglasses failed the 'scatter' test, which measures the surface quality of the lenses.
The findings suggested that consumers have no way of knowing whether they are buying products that fail the sunglass standard even when the product carries the CE mark and reference to the sunglass standard.
It added that a lack of industry enforcement meant that products were failing even the most basic of tests.
Priti Kotecha, practice manager of Roger Pope and Partners, said: 'CE marking is the responsibility of the retailer who buys in product, and if they want to import goods of this standard they still need to be tried and tested.
'Irrespective of the price point retailers should still demand a genuine CE marking.'
Read this month's UV & The Eye supplement for further coverage on the sunglass market, together with CET articles on the need for ocular UV protection.