The introduction reads as follows: “Seeing” involves more than simply looking at an object. Vision is a complex process in which light waves entering the eye are directed toward the retina, where they are transduced into messages the brain can understand. Flaws in the clear outer layer of the eye, the cornea, are primarily to blame for so many people (about a third of the American population) needing glasses or contact lenses (National Eye Institute, n.d.-a). LASIK eye surgery, a popular alternative to corrective lenses, uses a laser to reshape the cornea so that it can focus light properly. The main graphic shows a cross-section illustration of the eye. At the left is an image of a puppy. Lines drawn from the top and bottom of the puppy’s image cross in the center of the eye, and an upside-down image of the puppy shows at the back of the eye. A callout reads, “1. Light waves bouncing off an object enter your eye through the cornea, pupil, and lens.” In the graphic, the white of the eye surrounds the eyeball, with the iris at the front, and a central opening for the pupil. The callout reads, “2. Iris dilates and contracts pupil to control amount of light entering eye.” A translucent covering over the eye is labeled “cornea.” An elongated oval to the right of the pupil is labeled “Lens.” The callout reads, “3. Cornea and lens focus light waves toward the retina, bending the light and projecting an inverted image.” A backwards-C shape lines the back of the eye, labeled “Retina,” extending to a band at the right, labeled “Optic nerve.” Blood vessels are shown over the area where the optic nerve arises, labeled “Optic disc.” A dip in the wall of the retina is labeled “Fovea.” A magnified area of the retina shows a wedge with rows of different-shaped cells. The first row is labeled “Ganglion cells,” and shows long threads with a central bead, with the threads next to the second row of cells, labeled “Bipolar cells.” The bipolar cells are threads with a central bead. The third row of cells are labeled “Photoreceptors,” and show two types of cells. Cells with a thickened end and central bead are labeled “Rods,” and cells with a pointed end and central bead are labeled “Cones.” An arrow labeled “Light” points to the retina side of the wedge, with a callout reading, “4. Light strikes the retina, exciting photoreceptors.” Arrows show the conduction of electricity to the right in the illustration, and then left through the cells and into the optic nerve area. The callout reads, “5. In the retina, rods and cones fire, activating bipolar cells. This excites ganglion cells, which form the optic nerve carrying messages to the brain.”