Signal Detection Theory (SDT) is very important field–arguably one of the most important contributions of modern psychology. Simplistically, it looks at how signals are detected amidst noise, and the factors that effect this process.
This is at work when the TSA is screening your luggage, it dictates where street signs are placed, and it informs factories when developing quality control screening programs.
Today, an SDT article went viral. It examines how glasses affect our ability to recognize an otherwise identical face. The short answer is glasses have a small but significant effect on familiar faces, and large significant effect on unfamiliar faces. Unless you were buddies with Clark Kent, he very well might fool you!