Age-related macular degeneration, or AMD, is an eye disease that affects central vision. The most common cause of severe vision loss, macular degeneration usually affects people after the age of 60. AMD does not usually lead to blindness but does affect quality of life because it impairs reading, driving and other daily activities that require central vision.
Lens colors, light transmission percentages and blue light absorption are considerations to discuss with an eye care practitioner when choosing darkening lenses for AMD.
Identification
Transition lenses, also called photochromic lenses, change from nearly clear indoors to darker outdoors. This type of lens provides clarity of vision and comfort for someone with macular degeneration.
Most people refer to photochromic lenses as "transition lenses." The company that owns the technology used for the most popular brands of photochromic lenses does have the word "Transitions" in its name, but lenses sold by other manufacturers also use this technology.
Different companies make transition-style lenses in glass, plastic and polycarbonate material, and the lenses come in gray, blue, violet, yellow, brown, green and red.
Advantages
People with AMD should wear lenses that filter ultraviolet A and B rays. The Macular Degeneration Partnership website notes that blue light, the short wavelength of the light spectrum, may cause more damage than previously thought. It recommends sunglasses that protect against both ultraviolet rays and blue light. Photochromic lenses filter blue light and 100 percent of UV light.
Warning
Protecting the eyes from the sun's ultraviolet radiation is a consideration for everyone, not just those diagnosed with macular degeneration. Damage to eyes begins at a young age. Accumulated UVA ray damage is linked to age-related macular degeneration, according to an article in the June 2006 issue of "20/20 Magazine." The article notes that 80 percent of retinal damage occurs before age 18.
Considerations
Most photochromic lenses work because the material in the lens reacts to UV light. Car windshields absorb UV light and prevent the lenses from darkening. A new lens technology, however, does darken the lenses when they're worn inside vehicles. Some lenses also are polarized, which helps reduce glare.
AMD patients have the option of special-order red glass lenses that darken and lighten and reduce glare. Specialty changing lenses are more expensive.
Expert Insight
Macular degeneration reduces the ability to distinguish color and detail and also causes reduced contrast vision. The Dr. Bill Takeshita Foundation website notes that certain lens colors can help a person with AMD distinguish details better. Eye care practitioners are trained to help patients with AMD select the best type of lens color for specific problems related to macular degeneration.
Specific lenses help with contrast vision, which is important for perception or low vision associated with macular degeneration. A yellow or brown tint or contrast filter will help a person with AMD see a curb or step when walking. Gray and green lenses provide comfort from glare and sensitivity to light associated with macular degeneration.
