Neochromes photochromic lenses darken quickly and fade back fast, thanks to their unique high-performance dyes. As well as blocking 100% of UVA and UVB rays, they offer high protection against blue light, especially outdoors. Engineered to provide consistent performance across a range of materials and temperatures.

Features 

The features of Neochromes lenses can be easily demonstrated by eye care professionals.

What do they look like indoors?
Crystal clear

How quickly do they darken?
In just seconds.

How long do they take to fade back indoors?
At standard room temperature, less than 3 minutes.”

THE KEY /

Photochromic molecules have, under normal conditions, a folded shape that renders them transparent. When absorbing ultraviolet light, their shape changes, the molecular structure opens and absorbs visible light. The two forms of the photochromic molecule – open and closed – exist in balance, with a bond that’s continuously broken and rebuilt.

The photochromic molecule constantly switches between its transparent and dark states. If the lens is exposed to significant levels of UV light, most of the molecules will be in the open state, darkening the lenses. In the absence of UV light, the molecules remain closed, resulting in clear lenses.

NEOCHROMES /
BEHAVIOR

NEOCHROMES LENSES’ CUTTING-EDGE TECHNOLOGY ENSURES MAXIMUM PERFORMANCE IN ANY LIGHT CONDITION.


Before UV light exposure, the lens is in its most transparent state.

When the lens is first exposed to UV light, the photochromic molecules begin to change from clear to dark.

Lenses are at peak activation. Light transmission, activated color, and color uniformity can be assessed at this state.

Fast fade-back is critical. It begins when UV light no longer falls on the lens. The shorter the fade-back, the more comfortable and functional the lens is to the wearer.
 

TEMPERATURE AND ITS EFFECT ON PHOTOCHROMIC TECHNOLOGY

 

Any photochromic lens is affected by temperature. In cold temperatures, photochromic lenses darken more and take longer to fade back. In warmer temperatures, the lenses don’t darken as much and fade back more quickly. This characteristic is a function of the state of balance in the photochromic system.
The performance of Neochromes lenses also adjusts to the ambient temperature, with faster fade-back times in warm conditions.

FUNCTIONALITY /
HOW TO ANALYZE IT

KINETICS CHARTS SHOW FOUR PHASES OF PHOTOCHROMIC LENS ACTIVATION

 

1. The clear stage
2. The darkening stage
3. The dark stage
4. The fade-back stage

The percentage transmission (or transmittance) is on the vertical axis. On the horizontal one, we move over time from the initial transparent state to UV exposure, subsequent darkening and finally, the removal of UV light and the return of the lens to the transparent state.

As seen in the kinetic graph, at room temperature and outdoors, Neochromes lenses have a clear appearance with 85% light transmission, similar to clear high-index lenses. Light transmission is significantly increased with the application of high-quality, low-reflectance anti-reflective coating.

In a photochromic lens, darkening is always much faster than lightening. The darkening speed is the time required for the lens to pass from the transparent state to its mid-transmittance point.

The fade-back speed considers the time required for the lens to pass from the activated state to the mid-transmittance point.