Polarized or photochromic lenses? How to choose for sport

Sport rarely happens in steady light, and two lens technologies exist to deal with that. They are called polarized and photochromic, and they are often sold as if they were the same thing. They are not. One removes a particular kind of light. The other adjusts to how much light there is. Here is what each one does, where each one falls short, and how to choose between them.

What a polarized lens does

Light that bounces off a flat surface tends to be polarized horizontally, and that reflected light is the harshest part of glare. Wet tarmac sends it back at you. So do water, the bonnet of a car and a field of old snow. A polarized lens carries a filter that blocks much of it. The scene stops shimmering, colours look deeper, and you squint less.
Two limits are worth knowing. The Glaucoma Research Foundation is clear that polarization has nothing to do with UV protection, so the lens needs a UV rating of its own. And a polarized lens does not adapt. It is as dark in the shade as it is in the sun.

There are side effects too. Some screens, such as a bike computer, a watch or a phone,
can look dim or patchy through a polarized lens. And some golfers find that it flattens the fine contours they are trying to read, which is why you will hear them argue about it.

Altera’s answer is ZeroReverb Z11, a Metamorph lens with a polarized filter and an additional anti-glare treatment. It is built for water sports, offers 100 percent UV-A and UV-B protection, and is impact resistant.

What a photochromic lens does

A photochromic lens darkens when UV light grows stronger and clears when it fades. The
idea is simple: one lens for a day that keeps changing.
The cost is time. The change is not instant, and as the Glaucoma Research Foundation notes, it can take a few minutes to adjust. That is no problem on a long ride that drifts between shade and sun. It matters when you drop from bright road into a wood at speed.

Photochrom1c Ph5 is the Altera version. It darkens across low, medium and high light, offers UV-A and UV-B protection, and is designed for sports that need to adapt to
changing conditions, indoors and out.

The third thing: contrast

Neither polarized nor photochromic is about contrast, and in many sports contrast is what
you are really missing: the ball against the grass, the root against the trail, the ice against the snow.

Altera’s Kontrast T1000 reduces the amount of blue light reaching the eye. Altera
describes it as improving depth and colour perception and increasing the difference in brightness between objects and their background. Altera designs it for precision sports such as golf, padel and tennis, and it is worth trying when the light is dull and the world looks flat. Individual perception varies, so treat it as something to test, not as a promise.

The 3 lenses side by side

Choosing by what sport you do

• Road and gravel riding. The light shifts all day. Photochromic is the practical choice, and a second, lighter lens in a pocket covers dawn and dusk.
• Open water. Glare is the enemy. Polarized takes the sting out.
• Golf, padel and tennis. Contrast and depth matter more than glare. Start with a contrast lens.
• Downhill skiing. We advise caution with polarized lenses because they can make icy patches harder to read.

Or stop choosing

Altera Stealth starts from a quieter idea. One frame, and lenses you change. The Metamorph lenses are easily removable, so you can move from maximum sun protection to clear vision in low light without changing glasses. There are five lens types, four shapes
(Teelens, Babalens, Mantalens and Metalens) and five colours, on a Grilamid TR90 frame that weighs 17 grams.