The Eye: A Natural History [Hardcover]

There are a good many creatures in Nature with multiple eyes. Few of them, however, are blessed with eyes perceiving the world of air and water at the same time. Known as the "four-eyed fish", they actually bear but two, but each eye has two pupils, allowing them to see flying insects or passing minnows. Anableps is but one of the wonders Simon Ings describes in his engrossing account of the eye. Declaring the eye as part of "The Commonwealth of the Senses", Ings goes on to explain how light enters our lives and how we perceive it. Refuting his own title, he examines the many forms of eyes and their various abilities to cope with light - from wasps to cuttlefish. In this compelling narrative, enriched by many excellent illustrations, the author brings together legend, history and a host of personalities who've been involved in vision and light research.

After a jarring opening - describing his daughter's cyclopean phase in her embryonic development - the author explains how he came to write the book. Although books on vision and light abound, nobody has drawn together all the elements to explain all the elements involved. Knowledge of the eye was scanty for many centuries. The retina, key to all ocular mechanisms, was only coarsely discernible. How the eye dealt with light was the subject of much conjecture. One long-standing myth was the notion that the eye actually emitted light to illuminate the object being viewed. This idea died hard. It took an entirely new view of how Nature operated to begin serious investigation of the mechanisms of the eye. That "new view" was, of course, Charles Darwin's idea of natural selection.

Ings reminds us that Darwin's awareness of the human eye's complexity gave him a "cold shudder". How could something so intricate have ever evolved? Ings gathering of information would have warmed the naturalist immensely. Ings notes how early life did rather well without vision for two billion years. Quietly drifting in food-rich seas, ancient micro-organisms, and even some larger forms, found no need for detecting changes in light. Once one of those creatures absorbed one of the opsin chemicals, however, the world changed. A form of protein, opsins change shape when struck by light. Once called "visual purple", rhodopsin is a component of all animal eyes. As the aeons progressed, the eye formed to process the light rhodopsin detected. From a detection "plate", eyes evolved shapes to improve acuity. Nervous systems evolved to guide reaction to light's stimulations. In sum, all vision systems are present to detect motion.

Following the long progress of investigations into light and vision, Ings explains how various eye forms in animals work and how they likely evolved. The nervous systems branched off in several ways, with each creature's brain processing light signals in its own manner. The brain is tightly linked to what the eye presents, and wide differences in behaviour are the result. The famous case of laboratory frogs starving because they were fed dead insects instead of flying ones is a significant example. They needed to detect motion before sending their tongues flitting out to catch a meal. Many predators, such as the family cat, have their vision tied firmly to the horizon to detect prey. Prey species, in turn, also sweep the horizon for approaching threats. The difference is that cats are binocular to gauge distance, while the victim only wants to know if movement means danger.

As the story develops, the author describes the long years of research into understanding light and colour. Humans, who are often described as "lacking" in vision, are actually among the more talented and versatile "lookers". Our eyes can detect colours many other creatures fail to see. We also have eyes that "saccade", moving jerkily in a constant effort to accumulate information. We are among the few creatures with that ability. Otherwise, we would be moving our heads to take in surroundings. Even birds, which can move their eyes, prefer to move their heads or bodies to view the world. Adding all these elements together, Ings even stretches his narrative to a consideration of where vision, at least that of humans, might go in future years.

Ings' thorough examination of the eye in its many variations and the related topics concerning light and vision is comprehensive and graciously presented. Neither an academic treatise nor a lightweight "pop" science treatment, the author has combined a wealth of research effort with delightful prose skills. Highly recommended for anyone interested in what eyes are, how they work and how we learned of their mysteries. [stephen a. haines - Ottawa, Canada]

I sympathise with Ings. He must have spent months, maybe years, doing a huge literature review on the subjects of eyes, vision and optics then one day he has to sit down and squeeze all this information into a single book that needs to be both accessible and entertaining to people who probably have no previous knowledge of these subjects. Bill Bryson must have been faced with a similar, and certainly bigger, problem when he wrote 'A Short History of Nearly Everything'.

The difference between Ings and Bryson though is that Bryson really has the knack of getting straight to the interesting bits of whatever he is writing about. His enthusiasm and enjoyment fairly jump out of every page. With Ings on the other hand, you often get the sense of the weight of the task he gave himself coming through in his writing. Unsurprisingly, if it was a chore to write it becomes a chore to read.

Another thing that annoyed me about this book was Ings rather pompous use of language. What was his editor thinking letting him use words like 'Palimpsest', 'Gimcrack' and 'Furbelows'? This isn't an academic text book, I'm reading this for pleasure remember; I don't want to have to reach for the dictionary every fifth page.

It's beginning to sound like I hated this book, but I didn't. The fact that I read it in its entirety says a lot, as I am not averse to putting a book to one side if I find it is not an enjoyable read. I actually wish I could have given it 3.5 stars - four is over rating it and 3 does it an injustice. Even after taking into account the gripes I have already mentioned I would still be surprised if this wasn't the best non academic book available on what is a fascinating subject.