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.”