So often, photochromic sunglasses are touted as the be-all, end-all, for motorcycle sunglasses and they are for many riders. Many, many customers of ours won't ride without them. Most motorcyclists and those in the general public who wear these type of sunglasses, absolutely love the convenience. Our Original KD's with photochromic lenses and people love them. However, it is very important to gain a clear understand of the benefits and compromises that are made when you choose to wear photochromic, or Day2Nite lenses.
Photochromic, photochromatic, Transitions®, or Day2Nite® lenses are some of the many names for lenses that change with light. Before looking at the more practical use for motorcycle riding, here are a few notes about the history of the lenses. These special lenses were invented by scientists at Corning in 1966. Starting out as glass lenses, they have evolved through the years to include polymers that are safe for motorcycle photochromic sunglasses.
Some of the basic attributes of photochromic lenses effect how these lenses change and under what conditions. The basic premise is that when exposed to Ultraviolet (UV) light from the sun, the lenses will darken and in the absence of UV light exposure (inside a house or building) the lenses will lighten. Most of the time, this happens very well. Bikers and other people who wear photochromic lenses love them and wouldn't do without them. However, there are a few aspects of photochromic lenses that should be taken into consideration.
The first important fact of photochromic lenses is that these lenses typically to do not get as dark as a regular dark sunglass lens. So, if you are used to a super dark lens for bright sunlight in the middle of the day, you may have to decide if Day2Nite lenses are for you. Related to this is the fact that these lenses typically do not fully lighten to the extent of a regular clear lens. Most of the time, the difference is not remarkable so this may not be a factor for you. But if you are sensitive to indoor lighting and need available indoor lighting maximized, then you may need to think about this.
The next feature to consider is the response time for the lenses to change. This is more of an awareness than it is a deal-breaker for people. You will notice when you are moving from the indoors to outside that there is a delay in comfort from the bright sun as the lens slowly (1-2 min) changes to a darker lens. Of course, the reverse is true when you are going inside from bright sunlight to indoors. Just another thing to remember when making your decision.
Another aspect to consider about photochromic lenses is the fact that these lenses have to be exposed to UV light in order to darken. Now that may seem like an obvious, unnecessary statement but when you think of different conditions, it is very important to consider. For example, people will complain, "These photochromic glasses hardly change when I am driving my car!" This is frustrating, to be sure; however, the reason the lenses don't change is that automobile windshield glass and windows are manufactured with UV protection in the glass so very little UV light is actually reaching your lenses in order to change! A similar complaint is often heard from motorcyclists who have a full-face helmet with a clear shield. They reasonably think that they'll just buy a photochromic pair of sunglasses to wear under the clear shield so they can still change. Nope. Rightfully so, regulations to protect consumers in the United States (and other countries) are very specific when it comes to product regulation. Face shields, whether clear, smoke, yellow or almost any other color also have UV protection so the changing lens beneath won't change. This is also true of fit over glasses. Our company, Pacific Coast Sunglasses, Inc., offers fit over padded sunglasses with various lens options, including clear lenses. We quickly tell riders, if they mention that they have Transition® lenses, that their lenses won't change under the UV protected clear lens so they can avoid disappointment.
Is it extremely hot where you live? If so, photochromic lenses may not be for you. The reality is, these lenses change much better in a cool and/or temperate climate. We discuss this with our customers to help them make the best decision regarding these sunglasses and goggles. The change happens on a molecular level and the science tells us that the carbon molecules simply don't change well when they are hot. So, that is just one more important consideration.
The last, unavoidable point for most of us to consider is price. This feature still tends to be more expensive than a regular smoke sunglass or clear lens sunglass. Many people who wear this type of lens, whether it be a motorcyclist or not, don't mind paying a little more for the tremendous convenience of wearing one sunglass instead of carrying that extra pair of clear glasses.
It is our hope that we can provide people with enough information to make an informed decision. That well-worn quote, "Life is a trade-off" certain applies to photochromic lenses. Most of the time, the convenience of having just one sunglass (with a photochromic lens) wins. Enjoy the ride.