Red lasers operating around 635nm and 650nm are commonly encountered in alignment, measurement, positioning, scientific and industrial applications. Although red laser light is visible to the human eye, high-power sources can still create a serious eye hazard.

The wavelength is one of the first specifications to check when selecting laser safety glasses. Eyewear designed for a particular red wavelength may provide different levels of protection across the surrounding spectrum.

Optical density should also be considered. OD describes the attenuation provided by the filter at a specified wavelength or wavelength range. The appropriate OD depends on the laser's output and operating conditions.

Laser safety glasses for red wavelengths are available in different filter designs and levels of visible light transmission. A darker lens is not necessarily a better choice if it unnecessarily reduces visibility for the task being performed.

Some filters also cover additional wavelengths, which can be useful in workplaces where several laser sources are used.

Before using laser safety glasses with a 635nm or 650nm laser, compare the laser's specifications with the eyewear's wavelength and OD ratings. The frame design and coverage should also be suitable for the working environment.

Selecting eyewear based on documented performance rather than lens colour provides a more reliable approach to laser eye protection.