Eye diseases and symptoms affect a large percentage of Canadian senior citizens. With eye problems and vision loss come other problems: diminished independence, a poorer quality of life, a lesser ability to contribute meaningfully to society. While eye conditions such as cataracts can be reversed with surgery, others like glaucoma or macular degeneration are progressive diseases with no cures.
Until recently, the best a patient suffering with one of the latter conditions could hope for would be to delay the onset of the advanced stage of the disease. However, current studies into the causes of macular degeneration have yielded information about a substance in the eye known as the macular pigment. Taking care to maintain the density of this protective substance may be the key to slowing the progress of the disease – and perhaps even reversing its effects.
Macular Degeneration and the Macular Pigment
The macula is an area of the eye in the centre of the retina. Inside the centre of the macula, in front of the fovea, is a substance known as the macular pigment. Little was known about the macular pigment until recent years, when two parallel discoveries were made:
Patients with macular degeneration were discovered to have significant thinning or depletion of the macular pigment and
Patients with robust quantities of macular pigment were very unlikely to either have or develop macular degeneration.
These two findings led researchers to look carefully at the macular pigment to ascertain whether it plays a crucial role in the development of macular degeneration.
It's believed that the macular pigment performs two protective tasks:
It protects the eye by filtering UV rays (particularly blue light) and preventing these rays from damaging the delicate photoreceptor cells of the fovea.
It protects the eye by neutralizing dangerous free radical molecules, which are created by body processes such as oxygen metabolism, or by environmental factors such as pollution.
The macular pigment, when dense, is able to protect the eye from both of these harmful effects. However, when antioxidant levels in the blood drop too low, or when the effects of a lifetime of exposure to blue light start taking a toll, the pigment begins to thin.
Protecting the Macular Pigment
The macular pigment is made up of three plant-based substances known as carotenoids. They are: lutein, zeaxanthin, and meso-zeaxanthin. Lutein and zeaxanthin are available through diet, and several supplements designed to promote eye health contain them. However, the third component, meso-zeaxanthin, cannot be obtained from food. This third carotenoid has only recently been identified, but researchers speculate that it is more powerful than the other two, filtering more UV rays, and better able to combat free radicals.
Amazingly, it has been found that taking nutritional supplements containing these three carotenoids can actually help to restore density to the macular pigment. If this happens before too much damage has been done to the retinal tissue, some of the effects of macular degeneration can be reversed. Patients who took a supplement containing all three of the carotenoids for six months displayed a 40% gain in pigment density, and reported improvements in visual acuity.
These findings are promising developments on the road to beating macular degeneration and preventing vision loss.