by Jonathan Spencer
In the annals of advertising history, Packards ask the man who owns one campaign is remembered as one of the first slogans to elevate brand recognition to a phrase. These days branding seems to count for all in the sales of everything from womens clothing to beer. And yes, sunglasses, too.
In the first part of this article on sunglasses for pilots-see the April, 2003 issue of Aviation Consumer-we set out the basic requirements for a good pair of shades for use in the cockpit. In this second part of our buyer guide on sunglasses for pilots, well examine some specific brands.
The list of sunglass brands and styles pitched specifically to pilots is long. In fact, there are so many brands and types that were providing only a broad survey of some of the more popular offerings. Applying the standards we reported on in the April issue of Aviation Consumer, we did some informal testing of specific brands, including some basic lab work to see how the lenses measured up.
These are the models we examined: Serengeti Drivers, Serengeti Drivers Gradient, Serengeti 555nm, Ray-Ban G15, Randolph AGX, Randolph Grey-3, Randolph Tan-3, Randolph Clip-Ons, Prescription CR-39 lenses tinted Solar Brown (newly tinted).
What to Look For
Reprising the basic standards covered in the previous article, bear in mind that sunglasses are worn primarily to protect the eyes. That means UV coating and shatter-resistant lenses material rank near the top of our list of things to have.
The UV coating should meet ANSI Z80.3-2001, at a minimum. This requires at least 95 percent blocking of UVB and at least 60 percent blocking of UVA. UVB is of the most concern because its implicated in the formation of cataracts, macular degeneration and other eye maladies.
As for shatterproof materials, polycarbonate is the strongest material available and is thus highly recommended. However, CR-39 plastic lenses are more common and have the advantage of readily accepting tints that can be darkened or lightened as needed. Glass is the last choice; its heavy, has limited tint range and is fragile, although it has excellent optics.
After these two primary considerations, the buyer checklist diverges into the subjective and the personal preference, to include tint, density, lens size and style, frames and whether you want a fixed tint or photochromics that lighten and darken according to ambient light.
Tint is somewhat subject to the whims of fashion. But for aviation use, the experts seem to lean toward green and gray lenses as the best choice. This tint preserves color balance and may provide better performance in hazy conditions. Green tints have improved to the point that they now block as much blue light as the previously favored brown tints do. (NASA research indicates that blue blocking lenses improve a pilots ability to see distant traffic.)
Density-the relative darkness of the lens-is a personal preference and we recommend the simple method of walking outside on a sunny day to see how the lenses look. Also, remember that too dark is bad; you wont be able to read charts and cockpit displays. And speaking of reading displays, avoid polarized lenses. They will make some cockpit displays invisible.
All Serengeti lenses are photochromic and all are glass. Eight years ago, Serengeti was owned by Corning and enjoyed a special advantage over other manufacturers of glass photochromic lenses because the glass Corning used was superior to anything they sold to others.
Today, Serengeti is owned by Bushnell. Although it still uses a proprietary Corning glass, Corning now distributes competitive photochromic glass to other lens makers.
Serengetis proprietary formula adds a filtering effect that hasnt been imitated by any other manufacturer, however. These filters, embedded in the glass itself, account for the shade of brown found only in Serengeti Drivers lenses.
Serengeti has recently responded to the markets desire for green lenses with their 555nm model. This is a green lens, which also uses a variation on the Serengeti filter. Serengeti claims that all their lenses are drop-ball tested for impact resistance and although the company is known for quality sunglasses, weve also heard complaints about poor customer service. Its not yet clear whether the change in ownership has improved this.
Ray-Ban-Ray-Bans were the original aviator sunglasses, developed by Bausch & Lomb. Since 1999, theyve been owned by Luxottica, an Italian company that has branched into international optics. Other Luxottica brands include LensCrafters and SunglassHut as well as Armani, Yves Saint Laurent, Ferragamo, and Chanel.
Ray-Bans are available in green, gray and brown, as well as a variety of the fashion colors. The original G-15 lens is now known as the G-15XLT, but it has roughly the same characteristics as the original Ray-Ban lenses. In the Aviator model, the lenses are all glass, although many of the other models have CR-39 and polycarbonate lenses.
Ray-Ban lenses are made by the same lens company that makes Serengeti lenses but of course they cant use Serengetis proprietary formula. Since Ray-Ban has little technical information available, its difficult to tell but they appear to have their own filters for at least some of the lenses.
When Ray-Ban was owned by B&L, they were known for the best customer service in the industry. Its not yet clear whether that is still true with the new ownership but we havent heard any complaints.
Randolph-Randolph has supplied the U.S. military (as well as other countrys militaries) with sunglasses for years. They also sell the same sunglasses to the public. Since they meet military specs, all Randolph lenses have a density of about 15 percent light-transmittance.
Their Website (www.randolphusa.com) is relatively understated, informative and has technical information for those who want it. Randolph is also one of the few sunglasses makers that offer their lenses as clip-ons, a real plus in our view.
Vuarnet-Vuarnet has fashionable frame designs that are less extreme than some of the others on this list. They have several good lenses for pilots, including the PX2000, a relatively light-brown lens; the PX3000, a dark gray-green lens and the PX5000, a dark brown lens made for bright light conditions. See more specs at www.vuarnet.com.
American Optical-A small manufacturer that offers an aviator model (Original Pilot) that they claim meets military specs. They also emphasize glass lenses but offer polycarbonate and CR-39 as well. See www.aosunglasses.com for straightforward and complete information.
One thing we did in the lab was test for the ability to block UV. Again, this was not a quantitative test but an informal look to see how well the lenses blocked UV light. This was one test that all of the brands we list above passed without any problem. All blocked UV almost completely, suggesting that the stickers claiming ANSI compliance are probably on the mark. We also checked density. Entire treatises have been written on how to accurately measure density so that the measurements of a green lens and a brown lens are comparable. We stayed away from that controversy and simply compared (by eye) the lenses to lab standard. sample
Most of the lenses were close to the 20 percent light transmittance standard we were using. The only notable exceptions were the three Serengeti photochromic lenses in their faded (lightest) state. These were all noticeably lighter than the other lenses.
We tested the Serengeti photochromic lenses under three conditions: faded, in direct sunlight behind a car windshield and in direct sunlight. As noted, in their faded state the Serengetis were lighter than the non-photochromic lenses.
When placed in a car in direct sunlight coming through the windshield for three minutes, they darkened to about the same as the fixed tint lenses. And when placed in direct sunlight for three minutes, they darkened to a point where they were noticeably darker than the non-photochromic lenses claiming 20 percent transmittance.
In our view, this is a good thing. In the past, some users have complained that photochromics either dont get dark enough or they dont darken fast enough. Our test samples darkened to a point that they were perceptibly darker than a 20 percent fixed tint lens. We also evaluated the tints, again subjectively, but with several observers.
Conclusions: Among the nominally-green lenses, the Randolph Engineering AGX lens and the Ray-Ban G15 lens were both gray-green and identical as near as we could tell by eye.
There are only two or three suppliers of tinted glass for sunglasses, so its possible they use the same supplier, although we couldnt confirm this.
The Serengeti 555nm is nominally green but in fact has a noticeable Serengeti-trademark-brown tinge. Serengeti boasts that their filters enhance the contrast of the image you see through their lenses. Its certainly true that the Serengeti effect is unique, so if thats your preference in a sunglass lens, Serengeti is the only place to get it. Whether theres more contrast as a result is subjective, in our view.
Except for the two Serengeti lenses, the nominally brown lenses were quite different from each other. The Serengeti Drivers and Drivers Gradient lenses have a distinctly red tint. This tint is fairly close to the tint some Air Force research papers 10 years ago said was the most advantageous for spotting targets in haze because of its blue-blocking qualities.
As we reported in the previous article, some research since then has taken issue with those conclusions. But in any case, most sunglasses now block much of the blue band anyway.
The Randolph Engineering Tan-3 lenses are a distinctly yellow shade of brown, while the prescription CR-39 lenses are a red shade of brown, although not as red as the Serengeti lenses.
At one time, Ray-Ban had a brown lens, but weve been told by the Luxottica people who now own Ray-Ban that they have discontinued everything but the gray-green G15 lens in the Ray-Ban Aviator line.
And finally, we had two examples of gray lenses, the Randolph Engineering Grey-3 and the Randolph Clip-Ons. These are, just as advertised, a neutral gray with no noticeable tinges of other colors. If you object to oddball tints-and brown and red will qualify as odd to some-then neutral grays are a good choice, in our view. According to the spectra, they should do a decent job of blocking blue light so there should be little loss of performance.
All tints we compared meet the ANSI standard, so you can be sure you will be able to see all normal traffic signals while driving with any of these sunglasses. As we reported previously, that has proven a problem with some tints.
The issue of material was brought up by a letter-writer responding to our first article (See “Letters”). He was advocating glass as the material of choice. While he has a point, there are arguments on both sides.
Glass is usually cited as having better optical qualities. While this is true, the differences are fairly minute. Glass does have a distinct advantage in maintaining those optical qualities, however, since glass is considerably more scratch-resistant than plastic.
In fact, the best scratch-resistant plastic coatings are only about half as good as glass, and many are considerably worse. Sunglasses often lead a hard life, slipping in and out of a case or a shirt pocket with little thought about scratching. Theres no doubt that glass sunglasses stand up to this better than plastic.
Glass also has an advantage in the tint department. Tinted plastic lenses fade over time, usually several years. Regardless of the original color, when they fade, they turn a muddy red. Glass usually doesnt fade, or at least fades over a much longer period.
Tinted CR-39 plastic lenses can be bleached and re-tinted for a modest price; $16 at one lab we checked with. Polycarbonate lenses cannot be re-tinted. Polycarbonate sunglasses lenses are partially pre-tinted when manufactured, with the final tint added by a local lab.
Randolph Engineering says their polycarbonate lenses are tinted to the final tint when manufactured to make the tint last longer. All of Randolphs clip-ons are polycarbonate, an excellent material choice, in our view, especially for a clip-on.
As noted, glass has one major weakness: safety. Glass breaks under impact. CR-39 plastic is much harder to break and polycarbonate plastic is effectively unbreakable. The glass used in sunglasses is chemically tempered so it doesnt break into shards. But it does break into small pieces that can injure an eye. The risk is small except for situations where you might want your eyes to work, say after a nasty forced landing.
Whether its more important to have clearer sunglasses with better scratch-resistance for years of normal flying or safer sunglasses for that one-chance-in-whatever of an accident, is a personal decision. Obviously, many pilots have opted for glass lenses. Most eyewear professionals seem to lean the other way.
The head of a testing laboratory we spoke to said that what he saw in his lab convinced him to wear only polycarbonate lenses. Our consulting optometrist said that many opticians and optometrists advise against glass lenses because of liability concerns, particularly since car airbags now present a significant risk to your eyeglasses and, therefore, your eyes. (See http://resq.dcom.net/newspub/story.cfm?ID=196 for an interesting analysis of airbag hazards.)
We put the glass hazard question to the president of Randolph Engineering, citing the overwhelming use of glass in sunglasses aimed at the pilot market, including Randolphs product line.
His reasons were the same-optical quality and abrasion resistance. However, he admitted that the military requires polycarbonate lenses for certain operations and Randolph supplies sunglasses in both materials. The polycarbonate models are also available for sale to the public, although Randolph doesnt advertise them.
Curiously, if you want non-prescription sunglasses for flying, its easier to get glass lenses. But if you want prescription sunglasses, its easier to buy plastic (CR-39 or polycarbonate) lenses. If youre intent on getting one of the name-brand glass models with a prescription lens, some manufacturers will grind lenses to your prescription. But it may be expensive with a long delivery delay. And if you really want a pair of non-prescription plastic sunglasses made to your specification, you can always have your neighborhood optometrist or optician make them for you (ask for plano lenses).
If you want polychromic lenses, your choices are more limited. In glass, your choices are Serengeti or a lens prepared by an optometrist made of PhotoGray or PhotoBrown glass.
The PhotoGray/PhotoBrown lenses fade to very light (10-15 percent light transmittance) and darken to different amounts depending on the model you select. But some darken as much as regular sunglasses. In their faded state, theyre good for indoor use but are probably not clear enough for night driving.
In plastic, you can get lenses made (prescription or not) with photochromic plastic. The most popular system is Transitions and the material is a variation on CR-39 called CR-307.
The advertising says theyre clear in dim light and as dark as regular sunglasses in direct sunlight. But in our view, Transitions seem to be taking some license with the definition of clear.
The spectra for Transitions lenses shows a faded level of about 20 percent light transmittance. That may be good enough for indoor use but it certainly wouldnt be clear enough for night driving.
And the manufacturer advises that when driving on a bright day or in very warm weather you might want to wear your prescription sunglasses for greater comfort. In other words, they dont get dark enough inside a car or in very warm weather.
Different frames work for different heads. Our Serengeti 555nm lenses came in large frames and therefore fit me better than my wife. The Drivers Gradient lenses, on the other hand, are in the Tanaga Titanium frame, which are smaller and fit my wife better than me. The number of frames available is much greater than the number of lenses, so pick the lens first, then pick a frame that works for you.
Some of the Randolph frames (the Aviator, for example) come with straight temples, meaning the temple doesnt loop back around your ear. The Randolph Concorde frames are almost identical to the Serengeti 212 frames, which are a traditional aviator style. If youre into retro, get the Randolph Intruder frame and you can look just like General MacArthur.
The Randolph Clip-Ons are a great idea, but be sure to choose one that fits before you buy. The pair they sent us was too small for our standard prescription glasses. However, their website shows Clip-Ons in six different sizes, all gray tint.
In the end, we thought Randolph products represented the best choice/value combination in a market glutted with choices. We like the companys no-nonsense approach to sunglasses and the military experience bodes well, in our estimation.
Jonathan Spencer is a Cardinal owner and writer. He lives in Newton, Massachusetts. He can be reached at email@example.com. Dr. Ernest Loewenstein, (www.eyesdoc.com) served as a consultant for this article.