System replaces assortment of military-issued protection
A mixed assortment of protective eyewear is on its way to being replaced by the streamlined Military Eye Protection System (MEPS) developed at the U.S. Army Soldier Systems Center (Natick).
The Army and Marine Corps have used a combination of the Ballistic/Laser Protective Spectacles (BLPS), Special Protective Eyewear, Cylindrical System (SPECS) and Sun, Wind and Dust Goggles (SWDG) since the mid-1990s to shield troops from eye injury.
With the new eye protective gear, the number of lenses is cut in half and the level of protection is increased. Troops will have one system in sleek goggles or spectacles with interchangeable lenses for both.
“Soldier acceptability is tough,” said Michelle Markey, project officer at Product Manager-Soldier Equipment. “It is difficult to get soldiers to wear eye protection, especially those who are not used to wearing glasses. They are more likely to wear their eye protection if it is something they look good in, and I think these goggles and spectacles will be well-accepted.”
Of course, by wearing them they’ll have much more than a fashionable profile.
An estimated 10 percent of battlefield casualties are from eye injuries, a figure that has steadily increased since the Civil War, according to Harold Moody, project engineer. Explosive fragments, tree branches, blowing sand and rocks, and lasers are major battlefield hazards.
“A soldier’s eye is easily damaged by fragmentation from a nearby blast,” Markey said. “Even small particles such as sand can injure the eye. These injuries are also easy to protect against using polycarbonate. Our eye protection is designed to stop a .15 caliber, 5.7 grain fragment simulating a projectile traveling at 640-660 feet per second.”
The new protection system carries over the lightweight yet tough polycarbonate used in the BLPS, SPECS and SWDG that passed tests for ballistic resistance, but now the new spectacles bring peripheral coverage that was limited with the SPECS. Like SPECS and BLPS, they also meet the American National Standards Institute requirements for occupational eye and face protection.
Another military requirement is protection from laser range finders and designators used to acquire targets on the battlefield.
BLPS, SPECS and SWDG use four lenses designed for each item: clear, sunglass, three-line laser protective and two-line laser protective. When lasers are not a hazard, soldiers can use the clear lens to protect against ballistic and ultraviolet rays day or night, or use a darkened sunglass lens during the day that adds sun glare protection.
When lasers are a danger, soldiers currently switch to a green lens that blocks two wavelengths for use in dim light or a dark lens that shields three wavelengths for use in daylight. Special coloring and coatings absorb the laser to eliminate or minimize injuries.
“The problem with (the daytime lens) is that it’s dye-based and very dark. It is not suitable for use at night, which is why there is a separate two-wavelength lens, which has better transmission properties, for nighttime use,” Markey said. “The third wavelength wouldn’t likely be used at night anyway because it would be visible.”
The new system uses two types of laser reflective technologies sandwiched between two layers of polycarbonate for durability, and it covers a wider band of near-infrared wavelength energy than the current systems. Separate daytime and nighttime lenses are gone.
“We’re looking at blocking broad bands of laser while minimizing the impact on color vision,” Markey said. “This is critical in order to maintain the soldiers’ ability to read maps and use devices such as image intensifiers. We also wanted better light transmission than the current systems, and ultimately would like to have tunable laser protection that adjusts to the hazard.”
Other improvements are in fit, comfort and logistical efficiency.
The BLPS was designed to accommodate prescription eyeglass wearers.
They were one size and difficult to properly fit across the user population. SPECS comes in two sizes for a more precise fit, but they can be worn only by those with normal vision. Military-issued eyeglasses fit inside the SWDG, but often with just enough room.
The new system can be worn by anyone and comes in two spectacle sizes for an improved fit while retaining a single size for the goggles. A prescription lens carrier snaps into the goggles and spectacles frames if needed.
Clear, sunglass and laser lenses, all with ballistic protection, are interchangeable between the large spectacles and goggles for simpler supply and storage. Spectacles or goggles, along with two extra lenses, are stored and carried in a rigid foam case with a green cloth cover.
The Military Eye Protection System was tested with more than 26 pieces of equipment to ensure optical and structural compatibility, Moody said.
Markey demonstrated how easily the goggles tighten and loosen for fall-to-the-chest capability, a feature important to a gunner looking through his tank or infantry vehicle’s internal sights. Currently used goggles have a simple elastic strap and are stowed on the helmet, which interferes with the proper use of the sighting system in the tank, said Moody.
Goggles are undergoing user evaluation at the Marine Corps Air Ground Combat Center at Twentynine Palms, Calif., and both goggle and spectacle prototypes are being evaluated at Fort Campbell, Ky. Fielding is expected to begin in 2005.