One in five pairs of sunglasses tested in Hong Kong has been found to be potentially harmful or dangerous. Twenty-two out of 110 pairs of sunglasses tested by the Consumer Council either let through more than the safe limit of one per cent of ultra-violet rays or failed a traffic signal recognition test, meaning wearers could not adequately distinguish colours. The council's publicity and community relations committee vice-chairman, Larry Kwok Lam-kwong, yesterday said grey and brown-coloured lenses were generally better at filtering harmful rays. 'Certain blue colours may create more harm, but just because it's blue doesn't mean it's harmful,' he said. 'A dark lens is also no more effective than a light one in protecting the eyes. What's most important is the lenses' ability to filter out the UV light.' According to the test, eight of the samples - six adult and two child models - failed to conform to the American National Standards Institute (ANSI) standard. In addition, 14 samples - 13 adult pairs and one child model - failed the ANSI requirement for reading traffic signals. 'Substandard sunglasses cause motorist confusion when viewing traffic signals. For example, green may be mistaken for amber or amber for red,' Mr Kwok said. A police spokesman said they had been notified of the problem but there was nothing they could do about it because legislation did not dictate what sunglasses drivers were allowed to wear. The defective models were bought from hawkers, although not all those bought from hawkers were of poor quality. Those from optical shops and department stores were free of defects. But Mr Kwok said there was no correlation between price and safety. He advised consumers to check the labelling of sunglasses. Those that comply with standards in countries such as the United States or Australia should be safe to wear. Lifelong exposure to UV is widely believed to be associated with the formation of certain types of cataracts, a condition due to a loss of transparency of the lens of the eye. It is the leading cause of blindness.