Glass does block out the sun's UVB rays, but about 50 percent of UVA rays, associated with burning and ageing, do get through. Leading dermatologists and photobiologists warn that daily exposure to ultraviolet rays means the skin can age more than twice as quickly as skin that is protected. There will be more lines and wrinkles, and these will be much deeper around the eyes, nose and mouth.

　　玻璃確實能阻擋太陽光中的中波紫外線，但卻無法抵擋50%的長波紫外線（正是這種紫外線催生了燃燒和老齡化）穿堂入室。著名皮膚病學家以及光生物學家警告人們，經常暴露于紫外線下意味著皮膚的老化速度比被保護時要快兩倍。屆時臉上會有更多溝壑褶皺，而眼睛、鼻子和嘴巴周圍的紋路會深得多。