Airline Pilot Lens and Frame Study

Airline Pilot Lens and Frame Study

March 05, 2026


INTRODUCTION 

The sunglass industry has done little over the last 30 years to improve the performance of sunglasses for airline pilots. Polarized lenses, the last big innovation in lens design, are no longer recommended for pilots. While effectively blocking light reflected from horizontal surfaces, polarization can reduce or eliminate the visibility of instruments that incorporate anti-glare filters, and can reduce visibility through windscreens that use enhanced striations in laminated materials.

Yet lens technology now exists to not only protect pilots against harmful ultraviolet rays, but also against the long term harmful effect of rays in the visible high-energy (HEV) portion of the light spectrum. We also know how to reduce the amount of infrared radiation (IR) that can bring heat to a pilot’s eyes, and thereby create a more relaxing visual experience. As well, we know from work done by industrial lighting engineers the importance of allowing sufficient light into one's eyes to stimulate scotopic vision, vital to peripheral vision and sharp focus; and sufficient light to stimulate photopic vision, vital again to sharp focus and to the seeing of color. Scotopic and photopic vision are explained in the section where ‘rods’ and ‘cones’ are discussed.

Many companies, having long marketed their sunglasses to pilots, have not updated their lens technology to incorporate these new capabilities.

In this article, Method Seven discusses key considerations behind the best possible use of eyeglass technology for airline pilots. We then report on the related test results for sunglasses specifically marketed to pilots.

HOW VISION WORKS AND HOW PILOTS ARE AFFECTED

The Nature of Light 

Sunlight is broadband. It consists of energy across a wide spectrum of wavelengths. Ultraviolet light, which humans cannot see, has a relatively short wavelength of between 100 and 380 nanometers. Most humans can see light within the range of 400 and 700 nanometers. Humans cannot see near infrared light, which is light above 750 nanometers, but they do feel the heat that near infrared carries.

Ultraviolet Light

There are three categories of ultraviolet light. UVC, light between 100 and 290 nanometers, carries the highest energy. It cannot penetrate deeply into our bodies but can break molecular bonds in human tissues. UVC is extremely dangerous to your exterior body surfaces. UVB, light between 290 and 315 nanometers, carries less energy, but penetrates deeper into human tissue and is still damaging. UVA, light between 315 and 380 nanometers, is not immediately damaging to human tissues, but does penetrate the eye, and over time can cause discoloration to the cornea and lens in the eye.

Fortunately, the ozone layer is present over most of the earth’s surface, and it prevents UVC from entering our atmosphere. About 0.3% of light that reaches the earth's surface is UVB and 5.7% is UVA. There is a 15% increase in UV radiation for every 3,000 feet of altitude above sea level. This means the amount of UVA light increases by about 4 times at 30,000 feet than at sea level. So 5.7% UVA radiation at sea level becomes approximately 23% of all light at 30,000 feet above sea level. Most aircraft windscreens effectively filter out UVB light, but not always 100% of UVA.

Pilots are aware that they can accumulate tens of thousands of hours flying in a potent ultraviolet environment, and they are rightfully concerned about the long-term effects to the health of their eyes.

Visible Light

About 52 percent of light energy that makes it to the earth’s surface is visible light. All the colors of the rainbow, and everything that humans can see, are visible in a range of light roughly between 400 – 700 nm.

The three primary colors - blue, green, and red, have centers of distribution around 475, 530, and 660 nm respectively. Every color that we see comes from some combination of these primary colors.

By filtering out colors like yellow, cyan, and orange, in between the primary colors, we can allow the primary colors to stand out more. Such ‘notch’ filters provide contrast to enable color-blind people to better recognize primary colors. Notch filters also enhance contrast for pilots looking into cloud formations and when reading their instruments.

High-energy light (HEV)

In the last few years, greater attention has been paid to high-energy visible light, sometimes called near ultraviolet light, between 380 and 400 nanometers. It is now recognized that even though this light is at a lower energy level than UVA, it can still cause long-term damage to lenses and corneas in our eyes. Research also indicates that HEV light can blur distant vision because this shorter wavelength scatters as it reflects off of particulates in the air.

Infrared light

About 40% of the light that makes it to the surface of the earth is infrared light with a wavelength greater than 700 nm. IR light cannot be seen, but is felt as heat. Crystalline glass is normally more effective than plastic lenses in blocking infrared light, but there are film coatings and rare earth elements that can help block this heat. When infrared light is blocked there is a palpable sense of coolness and relaxation 

Rods and Cones and Scotopic, Photopic, and Mesopic Vision Rods and Cones
 

Two classifications of photo receptors, embedded in the retina of the eye, detect visible light. About 7 million of these receptors are called cones and about 120 million are called rods.

The cones are tightly concentrated in a small spot (the ‘fovea’) on the retina, behind the lens, in the ‘line of sight’. Cones allow us to recognize colors and to focus on fine features during normal daylight conditions. Our focus is normally confined within 10 degrees of our line of sight. Cones are dispersed sparingly around the rest of the retina, enabling peripheral vision during daylight conditions. We can only detect shapes and movement in our peripheral vision, which normally extends to about 135 degrees around our line of sight.

Rods are considerably more sensitive to light than cones, and during normal daylight conditions they are saturated and non-functional. Rods, however, function well even under dark lighting conditions when cones are rendered useless.

There are no rods in the fovea, which is why pilots cannot focus straight ahead when flying at night. Instead, rods are distributed fairly densely outside the fovea, and diminishing in density outwards towards the periphery of the retina. Rods provide peripheral vision under dark lighting conditions.

During early sunrises, late sunsets, under cloudy conditions, and when using dark sunglasses, rods and cones function at the same time to contribute to our vision.

Scotopic, Photopic, and Mesopic Vision

Our cones do the heavy lifting under normal daylight, responding to the entire visible light spectrum. This is called ‘photopic’ vision. Our rods do the heavy lifting under darker lighting conditions by responding to the higher energy light in the blue part of the light spectrum. This is called ‘scotopic’ vision.

During the transition between daylight and nighttime conditions, rods and cones work together to enable what is called ‘mesopic’ vision. Pilots encounter such conditions flying during early sunrise, late sunset, during overcast conditions, and when wearing sunglasses that significantly diminish the available light. Under such conditions, cones provide focus and colors within our line of sight, and the rods provide most of our peripheral vision.

Why should pilots care?

Under mesopic conditions, a pilot’s peripheral vision can be compromised if eyeglasses diminish the natural proportion of higher energy light (the scotopic to photopic ratio) In nature, this S:P ratio is close to 1. during sunrises and sunsets. Most ‘blue blocker’ lenses (the ones that provide a warm color) bring this ratio well below 1.0. This is why many pilots remove their sunglasses when landing under marginal lighting conditions, to preserve peripheral vision needed to gauge off the runway.

All Method Seven SKY lenses maintain a S:P ratio of greater than 1.0, and may normally be worn from early sunrise to late sunset. This is especially true for the SKY 30 lens.

Visual Light Transmission (VLT)

The percentage of available visible light that a sunglass allows to enter one's eyes is called the visible light transmission (VLT).

It is vital that a pilot use the appropriate VLT for their specific flight situation. When a pilot squints because there’s too much light, the pilot's vision is impaired. Insufficient light can also debilitate a pilot’s vision.

In general, pilots need a lower VLT when flying into the sun and a higher VLT when flying during early morning, early evening, during overcast conditions, or when flying away from the sun. Age and personal physiology also have a dramatic effect on the amount of light a pilot needs to be able to see properly. A typical 40 year old requires 40% more light to see properly than a typical 20-year old, and a 60 year old requires 100% more light than a 20 year old.

There is no one best VLT for pilots. Rather, pilots need different darknesses of sunglasses based on their route, the time of day they are flying, weather conditions, and their own physiology. A pilot might need more than one pair of sunglasses, depending on the conditions of flight.

Contrast

Our ability to recognize features in clouds or differences between certain shades of green or brown comes from our ability to distinguish the differences between colors. People with color blindness cannot recognize the contrast between certain colors.

Historically, lens manufacturers have tinted their lenses amber, yellow, or brown to reduce some of the bluer light. These tints can enable a pilot to better distinguish features in clouds and can provide a warmer sense of color. Such tints, however, also reduce the scotopic to photopic ratio, and thereby can degrade a pilot’s ability to focus and reduce their peripheral vision.

A more modern technique is available that allows those suffering from colorblindness to more easily recognize primary colors and to allow pilots to more easily recognize cloud features and read colored instrument displays. ‘Notch filters’ remove some of the light intensity between the primary colors of red, green, and blue. This technique provides excellent contrast without the need to diminish the scotopic to photopic ratio.

Glare

Polarized lenses are very effective at eliminating the glare off of water, clouds, and plane surfaces. Pilots, however, can no longer use polarized lenses in the cockpit because they may interfere with legibility of modern instrument displays. Fortunately sunglasses mute some of the glare that gets directed through the lens towards the eye.

Glare can also come from light that is reflected off the inside surface of a lens. Such glare can be effectively muted with the use of a quality anti-reflective coating on the inside of a lens.

TEST RESULTS

Lenses Evaluated 

Thirteen non-polarized lenses that are specifically marketed to pilots were selected for testing. Testing was performed at Colt Laboratories in Florida, and at Method Seven Laboratory in California.

These lenses, along with information about overall visual light transmission (VLT), and percent light transmission in each primary color, are listed in Table 1. A lower VLT means less light passes to the pilot’s eyes. Lens that have a more equal intensity in all three primary colors tend to have better color balance. A lens with a higher proportion of red will offer a ‘warmer’ sense of color. A lens with a higher proportion of blue will offer a ‘cooler’ sense of color. The warmer lenses provide a sense of contrast when looking into clouds, but a warmer lens also diminishes peripheral vision. This will be explained further in the section on scotopic and photopic vision.

Discussion of Results

The Bigatmo Amber Polymer, Haze Buster lenses, Method Seven Sky 30 Glass, and Serengeti Amber Glass, allow in a greater percentage of ambient light. These lenses might be preferred when flying away from the sun, during dusk and dawn, or by older pilots.

The American Optical Grey Glass, Method Seven Sky 9 Glass, Oakley Amber Polymer, and Vedalo Argent 02 Polymer might better serve pilots who don’t need as much light, or who are flying sunward.

The American Optical grey glass, Bigatmo grey glass, and all Method Seven Sky lenses provide the best color balance and are better suited to preserve a pilot’s peripheral vision.

Ultraviolet Radiation and High Energy Visible Light

Test Results

Results of UVA and High Energy Visible Light (HEV) testing are shown in Table 2.

Testing not only determined if lenses meet ANSI Z80.3 requirements for filtering UVA light, it also measured the exact percentage of UVA light. Further, light was measured in the most damaging part of the HEV spectrum, light between 380 and 400 nm. These data provide pilots with useful 

information relating to how well a lens might protect their eyes from the long term damage of UVA and HEV light.

Discussion of Results

All of the lenses passed the UVA test requirements prescribed in ANSI Z80.3, and are at least as good as, or better, at protecting a pilot’s eyes from long-term damage as any lens on the market.

The Haze Buster’s Elite Glass and Serengeti Amber Glass let in some UVA light. The rest of the lenses are truly best in class.

Scotopic Vs. Photopic Test Results

The ratios of light that stimulate scotopic and photopic vision are tabulated in table 3. Lenses that create lower ratios can degrade a pilot’s peripheral vision under marginal light conditions.

Discussion of Results

Each of the Method Seven lenses, along with the American Optical Grey Glass and Bigatmo Grey Polymer, provide pilots with more optimal scotopic to photopic ratios than the other lenses. This means these lenses are less likely to diminish a pilot’s range of peripheral vision. 

Infrared Radiation

Test Results 

Light in the range of 750 to 1400 nm is called near infrared radiation. This extended part of the light spectrum is not normally measured so we used the spectrometer test readings at 780 nanometers. This specific reading serves as a first order estimation to the amount of infrared light that can pass through to pilot’s eyes.

Discussion of Results

The three Method Seven lenses are best in class in filtering out infrared light. The American Optical Grey Glass, and the Randolph Amber Glass do a good job. These lenses offer pilots a noticeably cooler and more relaxing experience. Pilots using a Bigatmo, Vedalo, Ray Ban, or Serengeti lens will feel the heat of the sun on their eyes. 

Contrast

Test Results 

Each lens was evaluated to determine whether they used amber or brownish tints or whether they used notch filters to provide better contrast. Results are shown in the table 5.

Discussion of Results

Those lenses featuring amber or brown tints provide pilots a sense of contrast when looking into clouds and into overcast weather. However, these same tints can degrade a pilot’s ability to focus and diminish their peripheral vision, as evidenced by low scotopic to photopic vision ratios.

Notch filters, as used in the Bigatmo Grey lens and the Method Seven lenses, provide superb contrast without adversely affecting the scotopic to photopic ratio. These lenses provide excellent contrast while at the same time optimizing peripheral vision. 

Haze 

Test Results 

Haze testing offers a measure of visual clarity of a lens. It is a measurement of the percentage of a collimated light that gets scattered as it passes through a lens. This scattering of light might be caused by imperfections in the surface of the lens, imperfections within the lens, or by cloudy coatings or dyes.

Test results are shown in Table 6.

Discussion of Results

The ANSI-Z87.1 standards allow up to 3.0% haze in eyeglass lenses. A haze reading of less than 0.40% is an indication of a superior clear lens. The two lenses not in the best in class category are the Haze Busters Polycarbonate and the Randolph Amber. 

Glare

Test Results 

The percentage of light that can be reflected off of the inner concave surface of each lens and back into a pilot’s eyes was measured and tabulated in Table 7. The lower the percent of reflected light the more effective the elimination of such glare.

Discussion of Results

The Bigatmo Grey polymer and amber polymer, as well as the Method Seven Sky 9, Sky 15, and Sky 30, are best in class in reducing the unwanted reflection of light off the inside lens surface.

CONCLUSIONS REGARDING LENS EVALUATIONS

Long Term Eye Health 

Pilots are concerned with the long-term effect on their eyes from a career of flying in a rich ultraviolet environment. The test attributes which most directly correlate to long-term eye health are UVA and HEV. All lenses meet the AS/NZS 1067:2003 standards for reduction of ultraviolet light. However, test results in Table 2 show that some lenses do a better job of filtering UVA and HEV.

The following lenses offer superior protection from long term exposure to UVA and HEV light:

    • • Bigatmo Grey Polymer
    • • Oakley Amber Polymer
    • • Method Seven Sky 9
    • • Method Seven Sky 15
    • • Method Seven Sky 30
    • • Haze Busters Polymer 

 

Discussion of Summary Table

One size doesn’t fit all regarding overall VLT. Pilots flying into the sun would normally prefer a lower VLT. Pilots flying away from the sun, who want protection against UVA, or who wish to easily read their instrument panels throughout the day, would prefer a higher VLT. As shown in Table 1, lenses with the same VLT may render colors differently. Colors will appear more natural when the intensity of the primary colors - blue, green, and red, are matched.

Lenses that filter out too much blue light may appear warm in color, but these lenses remove too much of the light our eyes need for peripheral vision. Sunglasses that have a S:P ratio lower than 1.0 can diminish a pilot’s peripheral vision because they fail to allow sufficient shorter wavelength light to stimulate the rods in the eye.

Historically, lens manufacturers have removed blue light as a way to provide contrast for pilots looking into cloud formations. Unfortunately these ‘blue’ blocker lenses adversely affect peripheral vision. A more modern approach is to achieve contrast by using notch filters. Notch filters remove a portion of the light between the primary colors. This technique provides superb color contrast looking into cloud formations and when reading instruments, without adversely affecting peripheral vision.

Haze is a general measure of the imperfections or lack of clarity in a lens. Superb lenses have a haze less than 0,4%.

Unfortunately pilots cannot use polarized lenses to filter out glare. The next best thing that can be done is to remove the glare that reflects off the inner lens surface. Those lenses that allow less than 2% of light to reflect off the inner surface provide very good attenuation of glare.

Comfort

The attributes that directly correlate with the comfort of wearing a lens are infrared and reflection. The Method Seven lenses provide a more relaxing experience because of the superior filtering of infrared light. They are also best in class in reducing reflection off the inner lens surface.

    • • Method Seven Sky 9
    • • Method Seven Sky 15
    • • Method Seven Sky 30

 

While the Bigatmo lenses do an excellent job of reducing reflection off the inner lens surface, they allow in a great deal of infrared light, which is experienced as heat. 

 

Respectfully submitted by Method Seven Labs

Written by Jamie Mitchell

Tags: pilot

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