 |
As I navigated my way through this book, which is slated to hit bookshelves this October, I got the impression that Ings couldn't decide how best to organize his task. Do you start with why we have eyes? How they work? The physics of light? The concept of seeing and awareness? It's often a tough slog, with Ings careening from concept to concept, and discipline to discipline.
The first chapter is a microcosm of the rest of the book, moving quickly between the physics of light, retinal physiology, invertebrate vision and historical figures. Throw in a little (ok a lot) of evolution and you have the basic structure of the text. He begins by explaining how eyes developed to detect movement and the functional perception of this visual stimulus, addressing both the physiologic and the psychological. It is this dichotomy of goals that makes the book both entertaining and difficult.
The next chapter is a travelogue through the history of discovering the chemistry of vision. Normally this would be the most tedious of subjects but approached with Ings's blend of literary flourish and scientific rigor, it is enlightening and entertaining. Ings then quickly switches gears in the next few chapters to address why we have eyes, or rather how complex eyes developed. Seems Charles Darwin initially felt that the human eye was too complex to have properly supported his theory of evolution. Ings shows us how Darwin came to change his mind. "Just as there is a minimum size for a true, image forming eye, there is a minimum level of complexity," Ings writes. "Vision requires a nervous system sufficiently complex to harness the dance of light within the eye." It's a long, seemingly impossible evolutionary path connecting trilobites to humans, with strange detours into the compound eye of the insect world.
The second half of the book takes the reader from how light forms images in the eye, to how these images are translated by the brain to become vision. Ings attempts to bring together many concepts of what constitutes vision and the brain's perception of what we see. It's a lot to take in, and here Ings's flow of historical vignettes gets difficult to follow, as they veer off into frequent tangents. There are some very strange and pointless dead ends, such as the sad story of Charles II of England, whose connection to vision, sight or optics I fail to see.
Fortunately there are also several very enlightening pages on how the ancients attempted to explain vision as rays emanating from the eyes searching the world, then later on as particles radiating from each object and collected by the eye. We now understand that those particles are reflected and projected light, but this concept was slow to gain acceptance.
Ings is a well regarded London-based science writer. It took me a while to get comfortable with the obvious cultural context, different cadence and vocabulary. I attribute the sometimes convoluted sentence structure, and his penchant for historical dramatization, to personal style. His command of the science in this book is impressive although not perfect, with some factual errors and misunderstandings. Equally impressive, even intimidating, is his grasp of the literary arts and his ability to cite extensively from many sources unfamiliar to this liberal arts college-educated American.
I was disappointed by the illustrations that accompany Ings writing. One could fill volumes with wonderful photographs and intriguing diagrams on the subject of vision. The illustrations that are included seem amateurish and insufficient.
As an ophthalmologist, after reading this book, I felt educated in the history of those who brought my field to its present state, humbled by what I didn't know, and exhausted by the bumpy ride.
A Natural History of Seeing. Simon Ings. W.W. Norton & Company, New York, 2008. 336 pp. ISBN: 978-0-393-06719-4. $27.95.
Mark Blecher is in private group practice in ophthalmology in Philadelphia. He is also co-director of the cataract department at the Wills Eye Hospital and senior medical editor at Review of Ophthalmology.
