Wednesday, May 30, 2012

High Rx, High Wrap, Highly Awesome.

If you have a high power spectacle Rx, or you make eyewear, you are certainly familiar with the difficulties of fitting a thick lens into highly wrapped performance sunglasses. I remember years ago from my retail optical experience the days of mangling and twisting frames and forcing never-going-to-fit lenses into them. The results were always terrible, but in those opticals we neither knew the alternatives nor had access to them.

There are lots of amazing technologies out there to get the previously-impossible done, and done right. This is what happened when I decided to put a -5.00 into a high wrap sun frame. To tackle this job I tried out the well-reputed ICE-TECH lab out of Florida.

This is the frame I decided to put a -5.00 sun lens into
Anyone can make a highly curved lens that can match the curve of a wrapped sun frame. However, bad things happen when you do. First, the lenses become exponentially thicker at the edges. Second, many machines that cut lenses into the shape of the frame (edgers) can only make one type of bevel--flat--which will not securely hold the lens into the angled bevel of the frame. Third, dramatically deviating the curvature of the lens from the corrected curve theory standard (which for a high minus Rx is pretty close to flat) will introduce huge peripheral distortions, obliterating most of the visual benefits of the eyewear. Lame solutions for a professional trying to provide quality vision.

Ice-Tech's specialty is in using their own proprietary digital manufacturing process to generate unique custom curvature lenses that 1) dramatically thin edges on otherwise thick lenses, and 2) alter the optics of the lenses to compensate for the dramatic curvature and preserve excellent vision. And of course both Ice-Tech and I have advanced edgers that will also easily cut the angled bevels necessary to fit the lenses perfectly into any frame. I knew all this could be done, I just hadn't tried it. And the key factor in the entire equation was how well would the customer see out of the finished product?

You can see the unique uneven curve on the lens, designed to thin it out.

Even more dramatic looking through the lens. The center portion offers clear digital optics throughout what will be almost the entire finished lens area, and then the curves dramatically change to keep the lens thin. That's my edger I'm going to cut the lens on.
After edging. That is a -5.00 6 base lens! If you don't know what that means, trust me, it's thin.

Fit right into the frame perfectly, and looks practically plano (non-prescription).

Even more dramatic from the back. No protruding thickness at all.

Observing through the lens you can see the minor concentrated filed of distortion at the far edges of the lens. The digital technology allows us to basically redistribute all the distorted optics one gets from such a high curve and push it far out to the periphery of the lens where it has little impact and is minimally distracting.

Here the result of the custom thinning curve is most apparent, but that area of the lens is going to sit far to the side of the wearer's eyes, well out of the way of the functional areas of vision.
Final verdict, they absolutely looked awesome. Without looking close they were almost indistinguishable from non-prescription sunglasses. Final edge thickness was 4mm. Out of curiosity I calculated what a lens of the same material and curve would be without the custom digital aspherization: 9mm! That would have looked like crap and had far less visually usable area in the lens. I'm pretty impressed.

Best part of all, my customer's vision was excellent. I pointed out the edge customizations and explained the benefits of widened are of view, and as he looked around he said he could barely notice the edge distortions and they didn't bother him at all.

Ice-Tech are my new go-to guys for such craziness.

Ice-Tech on Facebook.

Tuesday, May 29, 2012

Transitions Vantage: the New Polarized Photochromic Lens

Transitions® Vantage™ is a new product that offers what no other photochomic lens on the market does: a full-time wear lens that is clear indoors, and both dark and polarized outdoors. Other products exist that provide dark outdoor tint (Transitions XTRActive), or variable darkness polarized sunglasses (Transitions Performance Sunwear). The key bonus is in variable polarization that allows the lens to go from nearly clear and unpolarized indoors (excellent for all indoor and nighttime vision) to dark and polarized outdoors (best performance for outdoor vision). This is the first photochromic lens to maximize performance in all lighting conditions.

Where Transitions® Vantage™ is different is that the amount of polarization varies with the amount of light in the environment. All other polarized lenses have fixed polarization, meaning there is a minimum clarity they can achieve and that clarity is unsuitable for indoor or nighttime, and thus full time, wear. There is a myth out there that one can have clear polarized lenses, but that's physically impossible. If one uses the common metaphor and imagines polarizing filters as window blinds, the more the slats are closed the more effective the polarization, but also the darker the lens. Turn the slats to allow through more light and the polarizing effect is reduced. To allow full light through mean there is zero polarization. The fixed polarization of traditional polarized lenses is light fixed angle of window blind slats; no matter the amount of light hitting the lens, it will always polarize the same amount. The Vantage does change polarization, so as the light increases so does the polarization, like turning the slats on your window blinds when it gets bright and turning them back when it gets dark.

For consumers, why wouldn't you want it? It falls in the same niche as the XTRActive, meaning extra dark. This is great for many people, the only caveat being that it doesn't get 100% clear indoors; there is always a slight tint to them. They are not dark enough that the wearer will notice any affect on vision, and they are certainly clear enough for safe and perfect night vision. However, when one checks oneself out in the mirror there is a light but noticeable gray tint to the lenses. They also take longer to darken and especially return to light than the traditional Transitions, sometimes 5-10 minutes compared to the traditional lens' 1-2 minutes.

That's already the issue with XTRActive, and honestly straight-up 100% of my customers who I have put into the XTRActive have been happy with them, and most adore the extra darkness. I told every one if they don't like the extra dark lens, I will happily make them new lenses in the regular Transitions free of charge. Zero XTRActive customers have come back to take me up on that offer.

The only other reason is price. Like the premium polarized photochomic lenses that came before (e.g. Drivewear, which are 100% sunwear only, not for indoors like Vantage is), they add the premium of both photochromic and polarization.

The real benefit of the Vantage™ lens is simply in performance. Everyone wants clear vision indoors and at night and sharp darkened glare-reduced vision outdoors during the day. The fact is traditional photochromic lenses never gave us what we wanted. Indoor vision was good, but outdoor vision was always a meager substitute for real, dark, polarized sunglasses. We simply made do, like that friend we all have that buys those fantastic $8 clip-ons from Walmart. Was everything darker than without? Yes. Was the vision good? No. If you just squint all the time you'll get the same brightness reduction as those clip-ons, and that's free! If you are willing to settle for less and suffer inconveniences one can certainly get by with the old solutions, but if you just want it right then Vantage lenses are a great new option.

Transitions® Vantage™ are not the end-all-be-all one pair of everything lenses. There is no such thing as a single pair solution for all optical needs (soon as I find it, I'll let you know). They are not sunglasses. Prescription sunglasses are larger, with a fuller field of vision, wrap around the curvature of the face for maximal sun, wind, debris, and UV protection, ideally are flexible impact-resistance material and offer venting ports to retard steamed lenses when perspiring. Prescription sunglasses are still important for everyone, but Vantage lenses just upped the quality of photochromics.