Letter: The outer limits

My thanks go to the authors of the article on UV protection by spectacle lenses (Optician, September 21) and for details of the potential problems in the 380nm to 400nm wavelength band.

I am very pleased that Zeiss has been able to extend its UV protection in clear spectacle lenses up to 400nm. The confusion over claims for ‘absorbs all UV’ on whether the upper limit for UV-A limit is taken as 380 or 400nm has been longstanding.1 Even now, there is strong objection by some members in industry to changing the upper limit of the UV-A band to 400nm, even for the purposes of occupational eye protection.