Some well-meaning manufacturers of spectacle lenses and spectacle lens coatings have introduced lenses that are highly reflective of blue and/or violet wavelengths. They figured that if you reflect blue/violet away from the eyes, that would be protective. While that is true, it is also true that any surface that heavily reflects this HEV (High Energy Visible light) in one direction, also reflects it in the other direction. This means that any HEV coming from behind the wearer is reflected back into the eyes from the front lens surface. Not only that, it is CONCENTRATED on the eye because the front surface is almost always concave toward the eye, like a reflecting telescope!
These lens companies, Hoya, Crizal (Essilor), Zeiss and VSP all have been made aware of this problem, but continue to market these products as Recharge, Prevencia, DuraVision and TechShield. These products are all safe in a completely dark room or outdoors at night. Under all other conditions, they reflect more HEV into the eyes than is reflected by ANY OTHER LENS DESIGN. They uniformly believe that back side illumination is minimal, and does not present a problem. They are flat wrong. It is the very reason that my first patient who tried a Recharge lens could not wear them due to the distracting and DANGEROUS blue reflections he was seeing. Hoya experts claimed that less than 1% of backside lighting can impinge on the lenses. Simple geometry shows that depending on lens size, this can be anywhere from 20% to 30% or more.
To add insult to injury, the lenses mentioned above are hideous. They reflect so strongly that they look terrible and may even pose a threat to others looking at them because of the strong HEV and because of the UV (Ultra Violet radiation) they reflect towards the observer. I call this "second hand blue". Here is an unretouched iPhone picture of someone wearing her Prevencia lenses, facing a large plate glass window in my office:
And here she is 10 seconds later, facing the same window wearing the first Noviolenses ever produced.
Rachel Maddow, Betty Liu, Ashleigh Banfield, Anderson Cooper, Tom Brokaw are you guys impressed or what?