Silver Book Fact
The data from the NEI-sponsored Age-Related Eye Disease Study (AREDS) found that persons with vision worse than 20/40 OU (oculur unitas, meaning “in both eyes) were more likely to be cognitively impaired than those with a visual acuity of 20/40 OU or better.
Clemons T, Rankin M, McBee W. Cognitive Impairment in the Age-Related Eye Disease Study: AREDS report no. 16. Archives of Ophthalmology. 2006; 124(4): 537-43. http://archopht.ama-assn.org/cgi/content/abstract/124/4/537