Laser Protection

Laser Protection Eyewear is designed to protect the wearer against harmful levels of laser radiation in either the ultraviolet, visible or infrared parts of the spectrum.  Typically lasers with a classification above that of a class II / 2 such as Class IIIB / 3B or Class IV / Class 4 it is required that laser protective eyewear is worn.

Infrared laser wavelengths are particularly dangerous in that they are invisible to the human eye and therefore no protection is afforded by the blink response of the human eye or by visual avoidance. 

Laser protection eyewear can either completely cut out the laser beam which is generally desirable with invisible / infrared laser beams or it can partially cut down the laser power to a safe level while still allowing some visibility of the laser beam, which is often desirable for visible red , green or blue lasers where they are used for alignment purposes. 

The lenses used in laser protection eyewear can be either made from a lightweight polycarbonate lens or from a glass lens.  Polycarbonate lenses are most popular due to cost as well as being lightweight however some lasers require laser safety eyewear out with the wavelengths that can be stopped by polycarbonate filters such as Holmium lasers, which require a filter glass lens, or desire high visibility at a certain wavelength in which case glass lenses with specific coatings can be used. 

When choosing laser protection eyewear the various technical aspects that need to be are the Optical Density (OD), the Wavelength in nm (nanometers) and the visible Light Transmission (VLT). 

The OD is basically the number of zeros the laser protection eyewear will cut down the laser beam by.  For example an OD of 5+ means the laser protection level will reduce the laser power by 100,000X and an OD of 3+ means it will cut the laser power down by 1000X. 

The wavelength basically specifies the part of the electromagnetic spectrum that the laser safety glasses cover.  For example if laser protection eyewear states it has an OD of 5+ at 635-660nm then this tells you it has 100,000X power reduction from 635nm up to 660nm which is the visible red part of the spectrum. 

Lastly the VLT is specified in a % and indicates the percentage of visible light that transmits through the filters of the laser protection glasses, therefore it lets you know how well you will be able to see through them.  Typically if the VLT % of the laser safety eyewear is <25% then you may need to use extra light in the area however, it does depend on the light levels you are working in so each case is different.

For Information on IPL Protection Eyewear click here