Book Review

Fixing My Gaze: A Scientist's Journey into Seeing in Three Dimensions

N Engl J Med 2009; 361:100-101July 2, 2009

Article

Fixing My Gaze: A Scientist's Journey into Seeing in Three Dimensions
By Susan R. Barry. 249 pp., illustrated. New York, Basic Books, 2009. $26. ISBN: 978-0-465-00913-8

Seeing the three-dimensional world with two-dimensional retinas presents the brain with two problems. To locate an object in space requires depth perception, which can be acquired from one eye alone through size, perspective, and motion parallax. Stereopsis is an entirely different quality that gives the world dimensionality; it requires binocular vision. Strabismus is the main reason for disrupted stereopsis, although binocular vision fails to develop in a few ostensibly normal persons. This book is about what people with disrupted stereopsis are missing and how the condition can be remedied even late in life.

Susan Barry crafts a story from her personal experience with strabismus, and she uses the advantage of her background as a neuroscientist to weave well-referenced explanations of binocular vision, amblyopia, optical illusions, visual styles, the history of stereoscopic vision and the Victorian stereoscope craze, and David Hubel and Torsten Wiesel's discovery of the specificity of occipital neurons.

Until special exercises allowed her to fuse images and see stereoscopically, Barry was a denizen of a world like that created by Edwin Abbott in his 1884 satirical novella, Flatland: A Romance of Many Dimensions — she could not even conceptualize binocular vision. One axis of her book is a graceful and grateful appreciation of a newly acquired “ability to see the volume of space between objects and to see each object as occupying its own space” — revelations that allowed her to live “among” and “in” the things of this world and gave her first moments of snow falling, trees branching, and a faucet arcing out of the sink. Even her adult sentiment did not prevent her response from being natural and childlike, perhaps similar to our response to a first peek at the leaping vitality of figures in a View-Master (a successor to the handheld stereograph viewer popularized in the 19th century by Oliver Wendell Holmes).

Capitalizing probably more on latent neuronal connections than on the creation of new ones, Barry benefited from orthoptics — a hidden corner of restorative medicine. With contrived ocular exercises, specially trained and imaginative optometrists treat patients whose eyes are cosmetically aligned but imperfectly foveated. The simplicity of the exercises and of the apparatus (such as beads on a string, papers taped to walls, and strips of film) is bracing for a profession enamored with technology.

The book's main contribution, however, is exposing the wrong-headed dogma that acuity and binocular vision can be restored only during a critical developmental period. Surgical correction of strabismus is dominated by this notion, first posited by Claud Worth in his landmark 1903 book, Squint: Its Causes, Pathology, and Treatment, and set at a hard stop at 2 years of age by his student Francis Chavasse. The experiments of Hubel and Wiesel are often cited as confirming the lost malleability of the adult brain, but Barry points out that they did no such thing because there was no attempt at restoration of fusion. Her experiences and those she recounts from others belie the “nothing else can be done” message that ophthalmologists gave to her and to her mother throughout her childhood. Several visual scientists have now demonstrated the reversibility of infantile loss of vision and stereopsis, but blindness to these findings and underappreciation of the solutions offered by orthoptics still persist.

We do not understand the biologic changes that correspond to neurological improvement, any more than we can put ourselves in Barry's position simply by covering one eye. The annoyingly overused term “plasticity” gets in the way of this and similar expositions of the brain. In the meantime, we might heed Barry by rediscovering the visual pleasures of sculpture, architecture, and the Grand Canyon.

Allan H. Ropper, M.D.
Brigham and Women's Hospital, Boston, MA 02115