Today’s modern aircraft contain glass cockpit instruments where flight data and navigation information are displayed on LCD (Liquid Crystal Display) screens in front of the pilot. These LCD panels have replaced earlier “steam gauge” instruments found in older aircraft, and present new challenges for a pilot’s most important sensory asset – your eyes. Adding to this issue is the fact that aircraft today operate at much higher altitudes than before, and with the thinning of the ozone layer the dangers of ultra-violet radiation from the sun to your eyes has become much more important. The Effects of Eye Strain A Pilot’s Eyes Eye strain has become a more important issue because of the way the muscles of your eyes are required to change your eye’s lens shape in order to focus on these LCD screens. The result is the lens of your eye becomes less pliable over time. As a consequence your eyes have more difficulty in focusing on items nearer to your eye (like the LCD screens in your aircraft instrument panel). When you look at an LCD screen for an extended period the ciliary muscles of your eye are forced to constantly adjust to keep the items on the screen in focus. Think of it this way: if you hold something in your hand at a fixed distance for an extended period of time your muscles will become fatigued; similarly, if your eye focuses on an LCD screen for long periods of time your eye will receive more blood flow (turn red), dry out from not blinking (requiring more tears) and become unable to rapidly change your focus to outside objects. How Dark Is Dark Enough For Sunglass Lenses For Pilots? All too often sunglasses are chosen simply by looking at the lenses and purchasing the pair with the darkest lenses; however, you can’t tell the blocking characteristics of a pair of sunglasses by simply looking at the color (or darkness) of the lenses! In order to make sure the sunglass lenses will block a sufficient amount of ultra violet radiation and blue light they must be specially manufactured with the correct lens materials, tints and blocking layer. A further consideration is whether or not the sunglasses provide for easy night vision adaptation as your flight progresses from daylight to night time. You should be most concerned about the safety of your eyes, and should focus your purchasing decision upon selecting the right lens features instead of the look of the sunglass frame or lens color. Things Pilots Should Look For In A Pair Of Aviator Sunglasses Because your vision is unique to you be sure that you get a good eye exam at least once per year in order to determine your eyes light sensitivity, how your eye handles ambient lighting and be sure to mention the type of flying conditions your eyes are exposed to. As you fly your eyes will need to handle increased exposure to ultra violet radiation, blue light, high contrast in the visual field, increased glare and the need to avoid eye fatigue.Remember, visual acuity (your ability to see things clearly) will vary with the amount of light available and the sensitivity of your eyes to how bright the light available is. The older you get the less light your eyes will let through, therefore an important consideration in your choice of sunglasses is the amount of light transmittance (the amount of light allowed to pass through the lens) to your eyes becomes more important. Important Features For Pilots To Consider In Aviator Sunglasses Darkness: When considering the darkness of the sunglass lens you should ignore the color (tint) and concentrate on the amount of light reduction provided by the lens. The amount of light reduction is calculated as a percentage and as a pilot you should look for aviator sunglasses that provide 98-100% blockage of ultraviolet rays and blue light. Conventional sunglasses darkness can vary from a #1 lens which blocks around 20% of the uv rays and light to a #4 lens which may block as much as 95% of uv rays and light. This is why it is important for pilots like yourself to choose aviator sunglasses which are made especially for pilots like Randolph Engineering Aviator Sunglasses. Glare: Glare is caused by indirect light striking the eye and most people generally think that polarized lenses are best for preventing or reducing glare. But for pilots like yourselves this doesn’t work as polarized lenses will distort the information being presented on an LCD screen because of the way that information is transmitted to the screen. This means that you should choose non-polarized aviator sunglasses with a lens style that covers the maximum area around your eye socket. Tint: All sunglass lenses are tinted and come basically in 6 styles: AGX, or a slight green tinted lenses; Grey lenses; Tan lenses; Mirrored lenses; Gradient lenses; Photochromatic lenses. AGX and Grey lenses will distort color by the least amount, and provide the greatest visual acuity for your eyes. Tan lenses are excellent in hazy light or fog conditions, and as a pilot you should consider carrying an extra pair of tan lens sunglasses with you at all times. Mirrored lenses are a poor choice for pilots as they contain minute particles of metal in them which can lead to blind spots in the lens, and they are easily scratched as well. Gradient lenses (like the Serengeti Aviator Sunglasses with driver gradient lenses) will have the upper part of the lens darker than the bottom part. These lenses may prove better for you when you are flying in extremely bright light conditions looking outside and then glancing down at your flight instruments. Photochromatic lenses darken with direct exposure to uv light rays; however, because aircraft windscreens are designed to block most uv light the lenses will not properly darken inside the cockpit, making these an unacceptable choice for you. In fact the military prohibits pilots from wearing photochromatic lenses while flying. Recommended Aviator Sunglasses For Pilots While there are a number of manufacturers who sell aviator sunglasses my experience has demonstrated that one company stands head and shoulders above all of the rest. Randolph Engineering has provided the highest quality USA made aviator sunglasses available on the market today and delivers on their promise that their aviator sunglasses are serious equipment for serious pilots. Read what Randolph Engineering has to say about their product: “All Randolph Engineering products have been meticulously handcrafted for over 35 years. Utilizing only the finest materials, our craftsmen and women create some of the world’s best eyewear. Over the years, Randolph Engineering has retained an integrated manufacturing approach with the end benefit being a level of American made quality, craftsmanship, and comfort unequaled in the industry. We do not compromise quality even when selecting something as trivial as a lens screw. Our 18% nickel silver frames provide unequaled strength and solder joint integrity. All finishes are topped off with a corrosion resistant clear coat that further protects the frame. Our nose pads are made of soft silicone so that the frames won’t slip, even during heavy perspiration. While fashion may fade in and out of the marketplace, the quality found in Randolph Engineering products will never go out of style. We feel so strongly about the quality of our products that we will repair or replace any broken solder joint for the lifetime of the frame (assuming normal use). That is one of the many reasons we call ourselves “serious equipment”.” A Few Comments From Randolph Engineering Customers “I couldn’t believe how my eyes felt instantly cooler when I slipped these sunglasses on.” ‘‘I found myself spotting other aircraft and aerial hazards quicker than I ever thought possible.” “A relative sat on my 20 year old Randolph Aviators destroying the frame. When I returned them to Randolph for repair they sent me a brand new pair – at no charge! This is what I call ‘excellent customer service!’” These are just a few of the many comments we have heard from our customers. You can find these sunglasses in our Pilot Shop. Until next time keep your wings straight and level Hersch! JetAviator7 ps: Don't forget to sign up for our newsletter "All Things Aviation" here!
by John M. White •