Why is eye protection afloat so important? What are the dangers and how can you avoid them?
Prolonged exposure to the sun’s harmful rays can have damaging effects on your eyes, and on the water the dangers are heightened as the combination of direct and reflected light is much brighter than on land.. Not only are you likely to be out in direct sunshine for prolonged periods, but the glare off the water, not to mention the deck, sails and other boats, makes your exposure far more intense, just as it is for skiing, for example.
Unfiltered glare, the light reflected off flat surfaces like water, windshields, bright white decks and sails, is so intense that it impairs vision (a clear safety hazard). Glare causes squinting, fatigues the eyes, and can result in visual discomfort and headaches. Glare is present even on hazy days. Most sunglasses reduce light intensity by 80-90 percent with darkening gray, green, amber, or other colored lens.
Andrew Grose, Managing Director of eyewear specialists Bollé, points out that: “Taking your sunglasses off, or leaving them ashore, is rather like going out on the water without sunscreen. A number of eye diseases have been linked to extreme sun exposure, UV rays and harsh glare including cataracts, macular degeneration, keratitis (snow blindness) and pterygium, as well as damage to the sensitive skin around the eyes, which includes wrinkles!”
Colored lenses alone are not enough protection for marine conditions. To filter out intense glare and prevent squinting, sunglasses for boating should be polarized. And they should be coated to block 99-100 percent of the damaging UVA and UVB (ultraviolet) rays that can reduce visual acuity at night, and cause degenerative eye diseases like photokeratitis, snow blindness, cataracts, pterygium, and various forms of eye cancer. Sunglasses should also be shatterproof to protect the eyes from injury in the event of sudden impact.
SUNGLASSES: BUYER’S TOP TIPS
- Look for oversized sunglasses with wide-view wraparound lenses, anti-mist vents and cushioned pads.
- If the glasses are not buoyant, make them so with an adjustable, one-handed floating safety strap.
- On pricier models, look for prescription compatibility.
- A set of interchangeable pursuit-specific, polarised lenses is a top solution.
- The film that blocks UV rays is clear, so don’t equate lens tint with protection. Look instead for sunglasses that advertise UV protection as capable of blocking 99 or 100 per cent of UVB and UVA rays.
- You need to know how they fit properly, so try them before you buy. Take a look outside to see how they handle glare and colour and don’t forget to move your head around to make sure they stay on.
- Although glasses that are polarised also tend to protect from UV, these are in fact two separate issues, so make sure you’re covered on both counts.
- A hydrophobic coating will help keep your glasses clean.
So a pair of marine sunglasses is a vital asset on a boat. Certainly, most non-specialist High Street pairs will filter the worst of the UV rays, but good sailing sunglasses are much more technical than you might think. What about impact-resistance? What about extra eye coverage to help intercept light bouncing upwards off the water or the fibreglass? What about a fit that can resist 40-knot winds and 7G impacts? What about buoyancy if they fall overboard? And what about the performance of the lens itself?
PHYSICAL SUNGLASS CONSTRUCTION
The market is awash with patented materials, designs and systems, but in general terms, a wraparound shape with venting for fog resistance, padding for comfort and strong, lightweight (usually plastic-based) construction for flexible shockproofing is a very sound bet. At the market’s higher echelons, Grilamid (a nylon/plastic blend) is a particular favourite.
SUNGLASS LENS MATERIAL
Acrylic lenses are the cheapest, but they also offer the most distortion and the least durability. Glass lenses are very scratch-resistant and have superior optics, but they are also relatively heavy. In between the two, there are lenses in a variety of proprietary plastics, including polycarbonates and polyurethanes. Polycarbonates are lightweight, inexpensive and durable; and polyurethane adds uprated clarity to those assets at extra cost.
While you’re considering lenses, you should also think about fog, oil and water-repellent coatings. Photocromic technology (which adapts the filter to changing light conditions) can be useful, but as the price increases, the best no-compromise formula is usually a set of interchangeable lenses allied to prescription-compatibility, so you can enjoy a complete solution, whatever conditions you happen to face.
When light rays reflect off a surface, the reflected rays concentrate in one plane and are said to be polarized. Reflected glare is an example of polarized light. Even on overcast days, the high–intensity light we call glare can be harsh and overwhelming to your eyes. It blinds you and masks what’s behind it. Squinting blocks out some of the light, but not the glare. Ordinary sunglasses can reduce the total amount of light reaching your eyes but, like squinting, they don’t eliminate the glare. A polarized lens filters out the glare by blocking all polarized light waves except those traveling in a specific orientation.
A polarized lens blocks horizontally polarized light with a polarizing film of molecules running in parallel vertical chains sandwiched between two optical lenses. These vertical chains block horizontal light waves, allowing only vertical light waves to pass through. Vertical light waves, commonly called “ambient light,” are scattered evenly and don’t produce glare. You can tell if a lens is polarized by rotating the glasses (or tilting your head when you are wearing them). You will find that they reduce glare better in some positions than others.
By blocking out only the polarized glare, the intensity of the light reaching your eyes is not reduced, so objects retain their definition and visual detail. This effect, combined with a tinted lens, makes it much easier to see and identify things both on and below the water like fish, buoys, skiers, wind zephyrs and underwater hazards.
Some manufacturers use polarized lenses to reduce glare on LCD instruments, fish-finders, etc. When viewed through sunglasses that are polarized differently than the instrument lens, no light is transmitted and the instrument face appears black. The only solution is to remove the glasses.
Lenses of different densities absorb different amounts of light. The amount of light passing through the lens is called visible light transmission, expressed as a percentage of total available light. For boating, visible light transmission should fall in the 15-30 percent range. On the brightest days, you want the lowest visible light transmission (darkest) lenses. Lenses are available in a bunch of different colors, and lens color is more than a fashion or attitude question. The technology behind the colors:
- Grey: a neutral all-purpose color that reduces glare, provides good contrast and no color distortion. Ideal for use on both water and land, especially for driving.
- Brown/amber: increases contrast in most light conditions. In addition to bright sun, amber offers excellent light management properties on cloudy or rainy days, and filters high-frequency near-UV light. Good for general purpose, high contrast light situations.
- Purple/rose: heightens visual acuity and enhances color (especially with objects against a blue or green background). Delivers brightest field of vision and is applicable for sight fishing, bass fishing, inshore fishing, sport shooting, extreme sports and skiing.
- Yellow: reduces the blue part of the spectrum. Blue light causes a scattering type of glare known as “blue haze.” Best color for snow. Cuts through fog or haze, but has the worst distortion of colors.
- Green: offers enhanced visual acuity for specific light situations such as sight fishing, but is worn by many for everyday use.
Grey lenses have gained popularity with boaters because they are useful in a wider range of conditions. In particular, the lighter tint enables better performance in overcast conditions, reducing eye fatigue and avoiding any colour distortion when clouds are chasing sunshine across the bay. However, the slight reddish tint of amber, which is also described by various sunglass manufacturers as bronze, copper and brown, improves contrast and depth perception. The colours may not be accurate but amber lenses enable you to spot variations in the water that you’d miss with green or grey lenses. Whether you’re looking for fish, big waves, wind patterns or something more serious like a man overboard, you’ll be glad of the extra contrast and clarity.
What your sunglass lenses are made of also requires some thought. Glass is very scratch-resistant and has excellent optics, but these will also be the heaviest. Acrylic lenses are the cheapest, but also offer the most distortion and least durability. In between, companies offers lenses in a variety of “proprietary” plastics, including polycarbonates and polyurethanes. Polycarbonates are lightweight, inexpensive, and durable, though their optics won’t be as good as glass. Polyurethane combines those benefits with excellent clarity, at an increased cost.
Nylon frames are usually best because they are lightweight and flexible. They can bend and return to their original shape instead of breaking when pressure is applied to them.
When testing sunglasses look to see if the sides and nose have the required grip. Look at the frame material at the contact point. Where the frame sits on the temple is where you get the grip. Many manufacturers use special rubber materials that actually increase grip in humid conditions. Look for a frame that has a large contact area on the temple.
A good pair of sunglasses is likely to be on the expensive side, but if you are using them for hours at a time on the water a good pair is what you need. Once you have your sunglasses chosen, you are ready to spend long hours on the water without worrying about sun damage (as long as you have sunscreen on, too!).