'Readiness' implies that a military service member can fulfill a mission from all aspects, including having trained properly to master the skills to undertake a given mission, as well as being in the right state of physical, psychological, and overall health.
Our senses have an important function in service members' health and readiness. They are interconnected, meaning they work with each other to allow us to function, move, and communicate.
In the case of hearing and sight, for example, the two dominant senses work together to create the perception of what we experience in the world, according to Dr. Mike Pattison, program manager of readiness and operations optometry at the Defense Department's Vision Center of Excellence (VCE) in Falls Church, Virginia.
"Studies involving sight have found that the visual cortex uses signals received from both the eyes and the ears when viewing the world," he said.
Added Dr. Felix Barker, VCE's director of rehabilitation and reintegration: "Vision and hearing guide nearly all human behavior - as two of our most important senses, they allow us to remotely sense opportunities and threats at great distances compared to other senses such as smell and touch.
"This ability extends to interaction with the environment at a safe distance," he said. "A great example of this is driving, where vision and hearing enable us to safely move through our environment using technological solutions that greatly enhance our access to our world."
Dr. Amy Boudin-George, a clinical audiologist at the DOD's Hearing Center of Excellence, at Lackland Air Force Base, Texas, said "our hearing allows us to listen to others, while our vision allows us to see their mouths, expressions, and gestures to help us confirm what they are saying."
And, said Pattison, "where the visual input is unclear such as at dusk or in a dark building, hearing takes on a more prominent role. Hearing helps us monitor our environment for potential threats or opportunities in directions other than where we are looking, which results in shifts in where we look when necessary."
In fact, he said, "studies have found that the brain has to work harder to hear when we are not looking at what we are listening to."
This is especially true with radio communications, which place all the emphasis on hearing, said Boudin-George.
In the military, this is important because hearing and vision are key to accurate situational awareness and mission success, allowing for coordination within a service member's unit and other units and forces, she said.
"Service members must be able to recognize, identify and locate threats," she said.
"In situational awareness, we rely on our hearing and vision to help us locate the sound source, identify a weapon or vehicle by sight or sound, and understand whether the sound is moving toward us or away from us."
And the more we can use both vision and hearing, the more accurate we can be at those tasks, she said.
Barker calls this combination a "360-degree threat detection system" that can provide service members the "ability to acquire threats detected," as well as "the opportunity to identify, engage and, when necessary, destroy the threats."
Likewise, military operations rely on communication and observation technologies that can enhance service members' sight and hearing, thereby extending their awareness and allowing them to take precautionary measures and enable overall mission success.
Army Capt. Theresa Galan, chief of the Landstuhl Regional Medical Center Hearing Conservation Clinic in Germany, provides training to soldiers from the 173rd IBCT on hearing loss prevention and hearing protection fitting in Vicenza, Italy (Photo by: Army Staff Sgt. Jacob Sawyer, 173rd Airborne Brigade).
As such, it is paramount to maintain optimal vision and hearing as part of service members' readiness.
"Vision readiness is an integral element of force health protection and operational readiness," said Pattison. "Assessing vision and optical readiness as part of the Periodic Health Assessment ensures that warfighters are ready to deploy in a moment's notice."
Likewise with hearing.
"Monitoring hearing addresses the initial ability to hear, but if an individual suffers temporary hearing loss during a mission, it can degrade the capability of that unit," said Boudin-George.
"Units are only as strong as the weakest link," said Theresa Schulz, a retired Air Force lieutenant colonel with a doctorate in hearing science who serves as chief of HCE's prevention and surveillance branch. "For mission success, all members of a unit need their senses."
The Department of Defense agrees. Joint Publication 4-02 Joint Health Services includes vision readiness and hearing conservation as critical functions of the force health protection initiative that the DOD strives to ensure as one of its most critical priorities.
This is a priority because the decreased ability to see, hear, and communicate properly could result in warfighters' decreased survivability and lethality, according to Boudin-George.
Additionally, said Pattison, "when you consider the increasing use of technology in the battlefield, ensuring that a warfighter's vision and hearing are optimized are becoming more critical in completion of the mission."
When one of the senses is damaged, the body relies on the others to compensate for what's missing, but it's not optimal.
"The systems cannot do that perfectly," said Boudin-George. "Studies done by the Army Public Health Center have shown that when hearing is impaired, even more advanced and experienced ground troops are less effective – their survivability does not necessarily decrease, but their lethality decreases markedly."
To avoid this, protecting service members' eyes and ears is key.
"Hearing and vision protection from approved DOD sources are absolutely essential for every service member," said Barker. "This is true when in the field, in garrison, or even home if potentially hazardous activities are undertaken."
For Pattison, the most important thing for service members to understand is that it's not sufficient to "just get by" when considering their vision or hearing.
"It is important that they get routine eye care periodically from an eye care professional and not just their annual vision screening," he said. "To operate in today's military environment, it is important that they see the best that they can see."
For hearing, said Boudin-George, "wearing properly fit hearing protection that is appropriate for the noise levels you are exposed to is key," said Boudin-George. "Hearing protection worn incorrectly is not effective."