Polycarbonate has long been a preferred lens choice for outdoor wear due to its superior impact resistance. But the poor tintability of the hard coating required on this soft lens material has limited its use for sunglass or fashion tints. Consequently, polycarbonate has developed a reputation for difficult tinting. New equipment and compact office units have greatly simplified the tinting process and provided the opportunity for a lucrative profit center – if only there was a polycarbonate lens that tinted easily, as well!

The leading polycarbonate lens (top left) after 30 minutes in the tint bath using a BPI system. The RESOLUTION® lens (top right) after 20 minutes in the tint bath, having achieved an 85% tint density.

RESOLUTION®, promises to end this elusive quest. Not only does the lens tint to the darkest sunglass shades, but it also tints very quickly. In addition to its impressive tinting abilities, the lens also provides the optics of a 1.60 high index plastic product. No small feat considering that polycarbonate has had a reputation for poor optics and is widely known to have patient adaptability issues.

To evaluate how well the lens performed, compared to its leading competitor, two dozen lenses from each company were tested. The testing was done in a controlled environment utilizing a BPI non-stirring system, Model 9799. The tints were mixed to the manufacturer’s recommendations – 10 parts water to 1 part tint concentrate. To prevent any mineral contamination from the local water supply, distilled water was used for the mixer. The temperature range was 205°-210°F. The lenses were prepared by rinsing each lens with distilled water and wiping the lenses dry. The tint mix was stirred at regular intervals. Each lens was placed in the tint mixture for 10 minutes. A dozen lenses each were tinted in gray and brown tints.

Once all the lenses were tinted, each was evaluated for tint density and consistency. The RESOLUTION® lenses tinted to an 80% gray and 80% brown, consistently. The leading competing polycarbonate lenses tinted to a minimal 10% gray and brown density. (See photos bottom left.) Consistent results were observed in all two dozen of the tinted lenses. No streaking was observed in either group. A separate test was conducted for a 20-minute tinting period. The RESOLUTION® lens tinted to a tint density of 85% – five percent darker than the 80% tint achieved in 10 minutes. The leading polycarbonate lens achieved no increase in density after 20 minutes, nor after an additional 10 minutes in the tint mixture – the total elapsed time was 30 minutes. Additional testing was done using neutralizers to lighten up tinted lenses. RESOLUTION® lenses were easily lightened and yielded even and consistent results.

Lens gray tint density results after 10 minutes using a BPI process. RESOLUTION® lenses achieved an 80% density. The leading polycarbonate lenses achieved a 10% density.

New RESOLUTION® lenses have finally removed the limitations on tinting polycarbonate lenses and offer additional profit potential. Optima’s new product offers eyecare professionals a new option for a highly impact resistant lens with superior tinting abilities and remarkable optics.