The plastic photochromic market is heating up like never before. And hot it is, as more players bring even more spice to the market by entering this already sizzling category.

Photochromics' popularity can partly be attributed to their lightweight properties, as many are a mid- or high-index plastic rather than CR 39. New products are already peppering the landscape, while a few that have seen their day are being laid to rest. And, there are new twists on old concepts as retro becomes cool in a whole different way. In this article, Eyecare Business brings you up to date on what's hot in today's plastic photochromic lenses.

The Newest Species

The latest lenses to burst onto the scene are SunSensors from Corning. More than five years of research and development went into these lenses before they were released on the market, but they're light-years away from Corning's original glass Photogray lenses.

SunSensors are made in a mid-index plastic, with an index of refraction of 1.56. The lens material is a patented plastic that the company says is actually lighter in weight than polycarbonate, high-index, or standard hard resin lenses. Because of this material, the lenses can be finished with a center thickness of 1.5mm.

The new UV light box by Transitions

Like the company's original changeable lenses, SunSensors lenses have photochromic molecules throughout the lens material that cause the lenses to change in 60 seconds. One difference, however, according to Corning, is that the color change is uniform despite the prescription or lens thickness.

The lenses come in gray single vision (SV), FT 28 and 35, 7x28 trifocals and in progressive design, with power ranges from -10.00 to +6.00D. The tint, according to the company, varies from an 86 percent transmittance indoors to 17 percent in its darkest state. Brown SunSensors and an aspheric design will be released this year. The lenses are available through Corning Connections laboratories as well as from Signet Armorlite.

Way Cool

Still in the embryonic stages, the new Transitions Splitz lenses are nothing short of "way cool." Currently being test-marketed in Michigan through the D.O.C. optical chain, these cafe tints will be released later this year.

The Splitz family is described as indoor-outdoor lenses in cafe, or club, colors. Once exposed to light, the lenses change to a completely different color. Teal blue turns to green, yellow becomes orange, and red transforms into purple. These lenses are designed for fun, and will be available in plano and single vision.

For Sunwear Only

Transitions. Transitions also has another product that is being tested through wholesale labs in Florida, Texas, and on the West Coast. Called Sunlenses for now, these plastic photochromics change from a 40 percent green tint indoors to a sunglass-dark G-15 when exposed to light.

The lenses are not suitable for indoor wear; however, the color in the unchanged state is dark enough to wear comfortably behind the windshield of a car. The company has not yet announced a release date.

KBCo. One of the best-kept secrets in the plastic photochromic category is KBCo.'s Transhades lenses. These hard resin polarized photochromic lenses come in gray and brown colors, and range from an A to a C shade when exposed to ultraviolet light. The power range extends from -7.00 to +6.00 D in SV, and plano lenses are available.

Promotional artwork for Rodenstock's ColorMatic Extra Gray photochromic lens

The color change takes place throughout the lens, with UV activators mixed in the monomer. The front surface is hard-coated, and the lenses can be tinted and anti-reflective coated. Transhades are a molded polarized lens rather than laminated, so they can be edged for rimless frames, if desired.

Hoya. Sungray Lenses from Hoya Lens are 1.55 IOR mid-index plastic photochromics that come in SV, FT 28, and progressive lens styles. The UV-activated color-changing molecules are blended throughout the substrate in a body-cast process, as opposed to a coating. The lenses are tintable; and, in their untinted state, they range from an 89 percent to a 23 percent light transmittance.

Rodenstock. Another choice in changeable plastic sunglass lenses is Rodenstock's ColorMatic Extra, which are available in a scratch-resistant mid-index 1.52 IOR plastic. The company's fourth generation of lenses in this category, they feature a photochromic dye that the company reports is uniformly dispersed throughout the lens.

In an unchanged state the lenses have a 15 percent gray tint, and the color ranges to an 80 percent darkness when completely activated.

The company reports that the lenses are tintable and can be AR coated.

The ColorMatic Extra lenses are available in such lens styles as SV, FT 28, and progressive Life.

Corning's new SunSensors lens

All Around the Town

Other plastic photochromics that are suitable for wear indoors and out include the Transitions family of lenses. Covering almost the entire spectrum of lens availability, Transitions come in gray, brown and XTRActive, and in IORs of 1.50 to 1.56 as well as in polycarbonate. Lens styles include SV, FT 28, FT 35, Round 24, FT 7x28 and FT 8x35, and a variety of progressive designs.

The part of the Transitions lenses that changes color is located on the front surface of the lenses, so the lenses always appear uniform in color throughout, regardless of Rx, according to the company. Lenses are scratch-resistant coated and can be AR coated.

And if your practice is one of those that casts your lenses in-house, don't think you're left in the dark when it comes to indoor-outdoor plastic photochromics.

Phases lenses from Optical Dynamics Corp. are a 1.65 IOR equivalent material with scratch-resistant coating. The lenses are gray and range from about an A to a C tint. They also can be tinted and AR coated, and are available in such styles as SV, FT 28 and progressive, with a power range from -6.00 to +4.00 D.

The photochromic properties are within the lens, rather than existing as a coating.

Going, Going...

For a couple of plastic photochromic lenses, the twilight has arrived. Seiko's Changers lenses are being phased out, as are Photoshades cast lenses from Innotech, which is no longer in the lens casting business. Remaining stock can be ordered until it is depleted. Optical Dynamics, maker of the Phases lenses, is the point of contact to order the last of the Photoshades.

While a few of these older designs are being closed out, there is no question that the photochromic category as a whole is getting hotter and hotter. EB