A study from the early '90's had put that number at more than nine percent.
The reason for the apparent decline is still not clear. Scientists say it may reflect changes over time in smoking behavior, diet, the use of antioxidant vitamins and zinc and other factors associated with Age-Related Macular Degeneration (AMD).
Macular degeneration involves damage to the center of the retina, which makes it difficult to see fine details.
The information comes from the "Archives of Ophthalmology."