By Lynda Clancy
Blue light surrounds us. It brings light to the world with its high energy, transmit to our retinas and is fundamental to vision. It s present in daylight conditions, and even more present in our lives with the added presence of artificial sources — electronic devices and LED lights. Some blue light can be beneficial, but some can be harmful to the eyes. Lenses that absorb harmful blue light or block it can prevent retinal damage.
The sun emits UVA and UVB rays. UVA rays may hurt central vision by damaging the macula, or a part of the retina at the back of the eye. UVB rays typically affect the front part of the eye or the lens and cornea. The following are some common eye conditions that can be linked to exposure to UV rays.
Photokeratitis is the equivalent to a sunburn of the eye. Photokeratitis may occur after spending long hours at the beach or skiing without proper eye protection. UVB rays can burn the cornea, potentially causing pain and temporary vision loss.
Macular degeneration is a deterioration of the part of the retina that is responsible for sharp, central vision. In addition to UV rays, chronic exposure to shorter-wavelength visible blue and violet light can be harmful to the retina. The sun and many artificial light sources, such as LEDs and smartphones, emit blue light.
Pterygium is a growth that forms on the outer portion of the eye, or the cornea and conjunctiva. Prolonged UV exposure can contribute to this condition. Pterygium may extend over the cornea and reduce vision, requiring surgical removal.
Cataracts. UV exposure also can contribute to the formation of cataracts, a clouding of the eye's natural lens, the part of the eye that focuses the light people see.
Sun protection
Sunglasses should completely cover the eyes, including the skin on the eyelids and under the eye, to provide adequate protection for the eyes. Wraparound frames will offer additional protection to those who spend a lot of time outdoors in bright sunlight. The AOA says sunglasses should also do the following.
· Block out 99 to 100 percent of both UVA and UVB radiation.
· Screen out between 75 and 90 percent of visible light.
· Have lenses that are perfectly matched in color and free of distortion and imperfection.
· Have lenses that are gray for proper color recognition.
Antireflective lenses on eyeglasses or filters for screens also can help absorb some of the blue light and limit how much reaches the retina and accesses the central nerve of the eye. This may alleviate digital eye strain as well.
Opticians keep up with the industry trends, and Mid-Coast Optical, in Rockland, offers protection with Color Enhancing Progressive lenses, which provide high absorption of HEV, absorption of harsh yellow to separate green and red, and full ultraviolet protection.