Optical shops are sites for sore eyes
Intense lighting at eyewear outlets is putting employees' sight at risk, survey finds
Stores selling products to improve eyesight are, ironically, threatening the eyesight of their employees through excessive display lighting, a University of Hong Kong survey has found.
A green group and opticians say the problem is also found in goldsmiths and other shops, and has urged the government to set a maximum limit for store lighting.
The survey was conducted in April by HKU students from the Intensified Learning Opportunity Programme researching problems of indoor light pollution.
Under the guidance of lighting expert Henry Chung Shu-hung of City University, the students gained permission from nine optical stores in five shopping malls - Harbour City, China Hong Kong City, Times Square, Windsor Plaza and the Westwood - to record their average lighting levels with a photometer.
Shops surveyed included major optical chain stores. Eight of the nine stores were found to have intensive indoor illumination levels exceeding the optimal level - 500 lux (a unit measuring the intensity of light) - recommended by the Labour Department for shops in its occupational safety guidelines issued in 2000.
Only one store at the Westwood complied with the recommended level. Average lighting levels of the eight other stores ranged from 1,100 lux to more than 2,500 lux.
The survey also found a stark contrast - sometimes as much as four times - between lighting levels at the display desk and the shop floor.
'Under the mixed lighting environment, the pupils of the eyes stretch and contract frequently, which might result in tearful eyes, sore eyes, headache or even glaucoma,' said eye specialist Chow Pak-chin, president of the Hong Kong Association of Private Eye Surgeons.
He added that eye problems caused by excessive lighting in shops and offices had become an increasing trend, and he received two or three similar cases each week on average.
'When examining the patients, I did not find their eyes had structural problems. But when I looked into their working conditions, their working environment is usually over-illuminated,' said Dr Chow.
Friends of the Earth environmental affairs manager Chu Hon-keung said indoor light pollution at optical stores was just the tip of the iceberg.
'It is not only a health issue, the shops are wasting energy,' he added.
The Electrical and Mechanical Services Department figures show 39 per cent of the energy used by retailers was for illumination in 2004, an increase of 13.5 per cent since 1997. Energy used for air-conditioning had increased by 8.6 per cent.