Frag Out! Magazine
Issue link: https://fragout.uberflip.com/i/1407740
INVISIBLE DANGER Good news: you've got an involuntary blink response. Bad news: The blink response only occurs if the offending light is in the visible spectrum, and cheap lasers are often contaminated with invisible, IR and near-IR light. This means a dim, 5mW visible laser could be pumping out hundreds of mW of light in the near-IR spectrum, and you won't know it until you feel your eyes itching and burning for no appar- ent reason. By that point, that light is cooking your retina. HOW DO YOU STOP A LASER At the simplest level, a laser's color is its Achilles heel. Want to stop a red laser? Put a red-absorbing filter in its path. Generally laser protective lenses will look the opposite of the color they absorb. Of course there's more to blocking a laser than that, but a key consideration when looking for laser eye pro is knowing the color of the light you want to block. Eye pro manufacturers list this spec as a specific wavelength or a range of wavelengths in nanometers (nm). LENS CONSTRUCTION MATTERS To make a lens that stops a laser means choosing a dye that absorbs light at the same wavelength as the laser and incorpo- rating it into the lens. This can be in the form of a coating ap- plied after a glass or polymer lens is made, or by mixing the dye into the base material of a polymer lens before it's molded into shape. The later method of construction results in a much more durable form of laser protection, since the dye is impregnated into the lens and can't be scratched off. Most laser protective lenses are made for use in a laboratory or on a manufacturing line where getting punched in the face or fragged by a BB-covered M-80 isn't a concern. Keep that in mind when looking for laser eye pro that'll be used on the street and on the battlefield. There are only a few companies making laser eye pro that also provides mil-spec ballistic protection, and Revision offers the widest range of ballistic laser eye protection solutions across the spectrum of threats. CHOOSING THE RIGHT LENS It'd be great if there was one lens that could block all laser wavelengths, but there isn't. Knowing that blocking a laser is accomplished by filtering its particular wavelength of light, the practical cost of protection for a given color of laser is limiting the ability to see that color. So, a lens that would block all laser colors would need to filter out all colors of light, and that lens would essentially be impossible to see through. Because each lens can only provide laser protection in a cer- tain wavelength, or range of wavelengths, determining what color lasers you're likely to face is critical in choosing a protective lens. LASER EYE PRO SPECS Carefully consider the time of day you'll use the laser eye pro. Nighttime is the right time for laser use, so you're going to want to get lenses that aren't so dark that they can't be used at night. The spec that tells you how much light a lens allows through is called its visible light transmission (VLT.) VLT tells you how much regular light a lens allows to pass though it as a percentage. Higher percentages allow more light to pass. Another important spec you'll see is a lens's optical density (OD). OD tells you how much of a laser's light is blocked by the lens. It's given as a number from 0 generally up to around 7, with higher numbers offering the most protection. Each additional OD absorbs ten times as much laser light, so a lens with OD 3 ab- sorbs 10 times as much light as a lens with OD 2. Practically speaking, the higher the OD, the more laser energy a lens can absorb. The higher the VLT, the more natural light is passing through the lens. BEWARE OF IR ONLY LENSES Before heading out to work a protest with the eye pro that came with your IR aiming lasers, confirm those lenses also provide pro- tection in the visible light spectrum. IR rated lenses are general- ly only good for stopping lasers in the IR/Near-IR spectrum and won't necessarily offer protection against visible lasers. LOOKING FORWARD The current limitations of protective laser lens technology means the need for situational awareness and broad spectrum protection are at odds with each other. Want to see everything? You have to give up protection. Want to be protected from the widest range of threats? You're going to have to decide how much visual awareness to give up. The threat of lasers is still emerging, as is the response from companies making eye protection. Cutting edge research and development in tactical laser eye protection is focused on find- ing a no-compromise solution that provides full spectrum laser protection, uninhibited vision, and mil-spec ballistic protection 83 www.fragoutmag.com TACTICAL GEAR