Fish & Fly - 04/03 - Fishing glasses

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The Eyes Have It - Glasses For Fishing

Our April 2003 contribution from Terry Lawton

Fly fishermen wear polarised sunglasses for two main reasons, eye protection and to make it easier to see fish underwater. Fishing glasses are available in a wide range of styles and lens tints. Terry Lawton has a look at what is available and offers some guidance when buying polarised glasses.

Fly fishermen wear polarised sunglasses for two main reasons, eye protection and to make it easier to see fish underwater. Eye protection takes two forms: physical protection from getting a hook in your eye and reducing glare from the water which in the tropics can be very damaging to your eyes. Ordinary glasses and basic (non-polarised) sunglasses will prevent a wayward fly hitting you in the eye but neither will help protect your eyes from glare nor help you see fish in the water. Lenses must be polarised.

Polarised lenses work by blocking light that is reflected horizontally by river, lake or sea. Light waves travel in a random pattern through the air and vibrate in all directions. But light reflected by water starts to align, or polarise, horizontally and in high concentrations which causes glare and discomfort to your eyes when the concentration is very high. Polarised glasses have a special filter sandwiched between two pieces of glass or applied to plastic lenses. This filter blocks polarised light and allows only vertical ambient light to reach your eyes.

You can tell if lenses are polarised by holding them in front of you and looking at something shiny. If, as you turn the lenses, the shine disappears or is reduced, then the lenses are polarised. If nothing happens, they are not. You can perform a similar test to check the optical quality of the lenses. Hold a pair of glasses at arm’s length and look through them with one eyed closed at a vertical line. Now move the glasses from side to side. If the vertical line bends or wiggles, then the optical quality of the lenses is not the best and could cause the wearer eye strain.

Lenses can be either glass or polycarbonate. Glass provides the highest optical quality, better polarisation, photochromic capability and best scratch resistance. Polarised glass lenses are hand made and the polarising filter is thicker than that used with plastic lenses. The result is better quality glasses and a higher price. Glasses with polycarbonate or plastic lenses are light, durable and cheaper to make than glass. Some are said to be scratch resistant but if abused they will scratch, as will glass.

Lenses should provide 100 per cent UV protection but I noticed when researching this article that not all catalogues provide this information. If in doubt, do check before buying. Good glasses should also protect against infra red and top quality polarised lenses will provide up to 99 per cent protection against reflected light.

Photochromic lenses are made with an outer layer of halide crystals which absorb some UV light. This light heats the crystals which sets them in motion which, in turn, has the effect of darkening the lens. The more light the darker the lenses turn.

A hydrophobic finish is often applied to lenses to reduce fogging and encourage rainwater to run off.

What tint do I choose?

In many respects choosing the right tint for the type of fishing you will be doing is crucial. Amber and vermilion tints block blue light at the upper end of the visible range, just short of ultra violet. When you reduce the amount of blue light – which has the highest frequency and shortest wavelength - entering your eyes, you can focus with greater comfort on the light rays that are left. You are eliminating something called blue blur. This is why these tints and all other tints, except grey, offer better definition but more or less colour distortion.

Grey: transmits all colours evenly so there will be no colour distortion. This is the only tint that does not affect colours. Good for sunny and bright days including offshore fishing. Allows excellent vision in deep water.

Tan: Provides more contrast and is a good general-purpose tint although they are at their best on cloudy or overcast days.

Dark brown: This colour is a good choice for people with sensitive eyes and good for high contrast conditions such as white sandy flats.

Yellow: Yellow lenses enhance the available light and so are good at dusk and anytime the light is very low such as in the middle of the night north of the Arctic Circle.

Copper or vermilion: A high contrast tint which absorbs blue light which in turn enhances contrast making it good for sight fishing. Also recommended for saltwater flats fishing. A very good all-round tint.

My experience of different tints is confined to grey and tan/light brown. I tried a pair of yellow lenses in bright sunlight and they were useless so could not recommend them for all-round use. I used grey lenses for a number of years and was happy with them until trying tan and found that they did offer much better definition. I think that my next pair will be copper or vermilion lenses.

Comfort

For a long time I have used what I would describe as flat glasses. But I read an article in a sailing magazine that pointed out that the human head is not flat but curved. So it would seem sensible to choose sunglasses that are also curved as these will fit your face better and, critically, reduce unwanted light getting in from the sides. Beware of glasses with too much curvature as the optical quality could suffer.

For fishing use, practicality and comfort are more important than style. Lighter glasses will be more comfortable to wear for a long time than heavier ones. And the frames should be as unobtrusive as possible with the minimum of blind spots. Depending on the material from which the frames are made, some (plastic frames with no memory) can be bent, with a little gentle heat, to give a better fit. This is true for metal frames but not nylon which has memory.

If you want to stick with flat glasses you might consider a pair with wide side frames or side shields, to reduce the amount of unwanted light that gets in between your face and the glasses.

Although frames with side arms which hook round your ears will hold your glasses securely, they are not so practical when you want to slip them off, to change a fly for example.

Cost

Good glasses can cost a lot of money. Particularly high fashion models. Do you need to spend a lot on fishing glasses? With one exception, the answer is no. The exception? When you plan to fish tropical flats for bonefish and tarpon etc where the glare can be crippling and can damage sensitive eyes.

Glass lenses are more expensive than polycarbonate, extra coatings add to the cost as does photochromic ability.

Do look after good glasses, particularly prescription lenses and expensive photochromic glasses. Clean them with care and keep them in a case when not in use. Choose a comfortable pair with the right lens tint and they should last you for many years.