The world can be a dangerous place, especially if viewed through the naked eye. Ocular hazards resulting from both natural and artificial light are everywhere.

The threat posed by exposure to ultraviolet light is well known to eyecare professionals, and a growing number of consumers are becoming aware of it as well, thanks to advertising by sunglass companies and a new public awareness campaign that’s being undertaken by the Vision Council. The campaign’s message to consumers is simple and direct: Protect your eyes with sun lenses wear lenses that block UV rays up to 400 nanometers, or else you risk retinal damage and other serious eye injuries when you’re outdoors.

Now a new ocular threat has emerged in the form of High Energy Visible (HEV) light. HEV is prevalent not just outdoors, but indoors as well. The indoor threat is posed largely by digital devices such as computer screens, tablets, smartphones and televisions, particularly the new flat screen models with OLED screens.

As with UV radiation, the damaging effects of HEV are cumulative over the course of a lifetime. Therefore, older people are more likely to show its effects. As Mark Mattison-Shupnick, ABOM, and John Lahr, OD pointed out in a recent article in 20/20 Magazine about the impact of UV and HEV on the aging eye, “Newer research about the effects of HEV, in particular the wavelengths centered around 430 nm (±20 nm) also show that…blue light plays a role in the incidence and severity of AMD (age-related macular degeneration). In both cases, free radical damage to the cells of the retina by UV and HEV is suggested.

“While the aging retina is more susceptible to this damage, the yellowing of the lens and the absorption of some of the blue might help reduce blue light exposure. However, oxidative damage of the retina continues to occur with aging and its own protective mechanisms become less effective with age. Fluorescent phototoxic chromophores accumulate in the retina; blue light reacts with them, stops the regenerative process and kills the cells that nourish the cones. The result is a graying, then total loss of central vision.”

Patients who undergo cataract surgery are at particular risk from exposure to HEV light. “A 65 year-old human lens essentially blocks 100 percent of harmful blue light due to the yellowness of the lens and any cataract formation. Once you remove the cataract you lose the protection in the group of patients that need it most,” observed Greg Naes, CEO of Eye Solutions, which developed the blue light filtering technology called BluTech that is used in lenses made by VSP Optics Group and Signet Armorlite. “With BluTech we have taken that natural ocular lens pigment and put it into an eyeglass lens to protect not only those that have had cataract surgery but also excellent protection for children as retinal damage from blue light is a result of cumulative lifetime exposure.”

Mattison-Shupnick and Lahr recommend that patients wear lenses that attenuate 100 percent of UV and HEV radiation, indoors and outdoors. They advise that modern lenses should attenuate UV and HEV using all the properties of the lens, i.e., coatings on the front, lens material, polarizing films, photochromics and the coating applied to the back.

In recent months, 10 different optical companies have developed lens products designed specifically to protect the eye from HEV and UV: BluTech lenses by Signet Armorlite, Coppertone Polarized Lenses by Vision-Ease Lens, Crizal Prevencia No-Glare lenses by Essilor, Happy Lens by Spy Optics, Hoya Recharge by Hoya Vision Care, Nikon SeeCoat Blue anti-reflective coating, iBlu Coat by PFO Global, Retinal Bliss Tech DES coating by Quantum Innovations, Unity with BluTech lenses by VSP Optics Group and UVARity by Laramy-K Optical.

This new generation of lenses takes a sophisticated approach to filtering blue light, using specially designed transmission curves to block out short wave, or “bad blue light” and let in some long wave, or “good blue light.” (To learn more about the differences between “bad” and “good” blue light, read the accompanying article by Cheryl Murphy, OD.)

“The more we are learning about certain wavelengths in the blue violet light spectrum and the impact of those wavelengths on the retina, specifically the retinal pigment epithelium (RPE), the more we believe that selective blue light filtering should be standard on all ophthalmic lenses,” said Larry Rodriguez, chief operating officer at High Performance Optics, a technology company that has signed an exclusive global licensing agreement with Essilor that grants Essilor exclusive rights on HPO patents and technology for blue light attenuating lenses.

Rodriguez believes this technology should be utilized by everyone, starting with children, since RPE damage can be cumulative and begin to affect unprotected eyes at a young age. HPO uses what it calls “Selective Blue Light filtering technology” which blocks only harmful HEV light (400-460 nm) while allowing in blue light which can be beneficial to the body (465-500 nm).

The flurry of activity surrounding blue light filtering lenses represents a significant trend that eyecare professionals may want to take note of. It presents them with an opportunity to provide the highest level of care by protecting patients from a potential ocular hazard. And, as is often the case, what’s good for the patient is good for the practice too, since blue light filtering lenses are a premium product that can be priced accordingly. ■