The eyes of the presidents.
D005139:Eyeglasses / Q000266:history*; D005197:Famous Persons; D049671:History, 18th Century; D049672:History, 19th Century; D049673:History, 20th Century; D006801:Humans; D008297:Male; D011057:Politics; D012030:Refractive Errors / Q000534:rehabilitation; D013285:Strabismus / Q000534:rehabilitation; D014481:United States