Anatomy of the Pupillary Light Reflex: A Historical Perspective

One can look at the history of our knowledge regarding the pupillary light reflex as a series of overlapping stories reflecting the human condition. We have abilities to see new avenues and gain new insights that can be extraordinary. We have an even more remarkable ability to ignore the new insights of others if they interfere with our own preconceived notions of how we think things really are. It is the story of several revolutions rather than a slow evolution. These progressions varied over time as new mechanisms for probing the workings of the nervous system were developed. Despite the fact that the pupillary light reflex is fairly simple compared to other aspects of visual processing, with a minimum of way stations and decussations, we are still confused and intrigued by it. We can look forward to many more years of learning how it really works and which of our definite conclusions are wrong.